Download 4th European Large Lakes Symposium

4th European Large Lakes Symposium
Ecosystem Services and Management
in a Changing World
August 24-28, 2015, Joensuu, Finland
Programme
Hall C2, Carelia building, University of Eastern Finland, Joensuu Campus, Yliopistokatu 4,
Joensuu
SUNDAY, AUGUST 23
19:00 – 21:00 Get-together party, Joensuu Arts Museum (Kirkkokatu 23)
MONDAY, AUGUST 24
8:00 – 9:30
Registration
9:30 – 9:40
Vice-Dean of the Faculty of Science and Forestry, Prof. Elina Oksanen:
Symposium opening
Session: Climate change induced physical and biological responses in large lakes
Chair: Orlane Anneville
9:40 – 10:30
Keynote Dr. Dietmar Straile: The response of large and deep lakes to
climate change (p. 10)
10:30 – 11:00 Coffee break
11:00 – 11:20 Jonna Kuha: Abiotic and biotic response of boreal lakes to episodic weather
events (p. 22)
11:20 – 11:40 Fabien Cremona: Modelling phytoplankton and periphyton primary
production in hemiboreal lakes (p. 15)
11:40 – 12:00 John Lenters: Long-term trends in global lake surface temperature: A
century of measurements from in situ and remotely sensed data (p. 23)
12:00 – 13:00 Lunch
Chair: Lauri Arvola
13:00 – 13:20 Petri Kiuru: A process-based model for simulation of lake oxygen and
dissolved inorganic carbon (p. 22)
13:20 – 13:40 Külli Kangur: Changes in water temperature and chemistry preceding the
massive kill of bottom-dwelling fish: an analysis of high–frequency buoy
data of shallow Lake Võrtsjärv (Estonia) (p. 20)
1 13:40 – 14:00 Sten-Åke Wängberg: Lake Vänern - physical and biological features and
effects from climate change (p. 35)
14:00 – 14:20 Arkady Terzhevik: Russian-Swiss cooperative study of under-ice
convection in Lake Onego: Preliminary results (p. 32)
14:20 – 14:40 Yang Yang: The effects of physical factors on spring phytoplankton in a
temperate lake (Lake Erken, Sweden) (p. 37)
14:40 – 15:10 Coffee break
15:10 – 15:30 Nikolai Filatov: Lakes of Russia: Diagenesis and prediction of state of
ecosystem under climate change and anthropogenic impacts (p. 17)
Session: Long-term changes in nutrient and organic matter loading and trophic status of
large lakes
Chair: Arkady Terzhevik
15:30 – 15:50 Orlane Anneville: Fish communities in the Anthropocene: detecting drivers
of changes in two peri-alpine lakes (L. Geneva and L. Annecy) (p. 13)
15:50 – 16:10 Marko Järvinen: Brownification of large lakes in Finland - implications to
ecological status (p. 19)
16:10 – 16:30 Karl-Otto Rothhaupt: Impacts of oligotrophication on seasonality and depth
distribution of chlorophyll in a deep large lake – Lake Constance (p. 27)
16:30 – 16:50 Natalia Belkina: The chemical composition of sediments as indicator of
changes in the ecosystem of Lake Onega under the influence of
anthropogenic factors (p. 14)
TUESDAY, AUGUST 25
Session: Ecosystem services of large lakes – more than fishing and recreation
Chair: Anne-Mari Ventelä
8:30 – 9:20
Keynote Dr. Laurence Carvalho: Putting Ecology into Ecosystem Services:
the Challenges ahead for Lakes Research (p. 9)
9:20 – 9:40
Peeter Nõges: Carbon sequestration by an alkaline lake (p. 25)
9:40 – 10:00
Sami Taipale: High nutritional quality phytoplankton fuels food webs of
large boreal lakes (p. 32)
10:00 – 10:20 Sirje Vilbaste: Ecosystem services (ES) of Võrtsjärv (VJ) under multiple
stress (p. 35)
10:20 – 10:50 Coffee break
2 Session: Long-term changes in nutrient and organic matter loading and trophic status of
large lakes
Chair: Tiina Nõges
10:50 – 11:10 Kari-Matti Vuori: Lake ecosystem changes in Finland as reflected by
human experience and limnological evidence (p. 36)
11:10 – 11:30 Lauri Arvola: CDOM of large Finnish lakes relative to their landscape
position (p. 13)
11:30 – 11:50 Teija Kirkkala: Challenges of nutrient load reduction in the catchment of
Lake Pyhäjärvi (SW Finland) in fluctuating climate (p. 21)
11:50 – 12:10 Kristjan Piirimäe: Climate scenarios to phosphorus load to a large boreal
lowland lake - case study in Lake Peipsi drainage basin (p. 26)
12:10 – 13:10 Lunch
Session: Biotic interactions and biodiversity in large lakes
Chair: Nico Salmaso
13:10 – 14:00 Keynote Dr. Priit Zingel: Microbial loop in large lakes (p. 11)
14:00 – 14:20 Jouko Sarvala: Planktivorous fish regulate crustacean zooplankton
dynamics in a large, shallow lake (p. 30)
14:20 - 14:40
Elizabeth Yohannes: Isotopic puzzle of Lake Constance: Is particulate
organic material genuine indicator of food web base? (p. 37)
14:40 – 15:10 Coffee break
Chair: Elizabeth Yohannes
15:10 – 15:30 Katrit Karus: Effects of macrophytes, fish and metazooplankton on a
microbial food web (p. 21)
15:30 – 15:50 Kimmo Tolonen: Decomposing variation in the species composition of
specialists and generalists between local environmental variables and spatial
processes in a large lake system (p. 33)
15:50 – 16:10 Alexander Rusanov: Beta diversity patterns of phytoplankton, periphytic
diatom and macrophyte communities in a large lake (Lake Ladoga,
Northwestern Russia) (p. 27)
16:10 – 16:30 Helen Agasild: Small cladoceran Chydorus sphaericus forms an important
link in food web of eutrophic lake (p. 12)
16:30 – 16:50 Anastasiya Sidorova: Distribution and population characteristics of
Baikalian invader Gmelinoides fasciatus (Crustacea: Amphipoda) in lake
Onego (p. 30)
16:50 – 18:00 Poster session
3 WEDNESDAY, AUGUST 26
Session: Occurrence and impacts of toxic cyanobacteria on the food webs of large lakes
Chair: Lauri Arvola
8:30 – 9:20
Keynote Prof. Hans. W. Paerl: Controlling a global proliferation of toxic
cyanobacterial blooms in large lakes: The case for dual nutrient (N & P)
input reduction strategies (p. 10)
9:20 – 9:40
Camilla Capelli: Dolichospermum lemmermannii (Cyanobacteria) in
European waters: distribution patterns and toxic potential (p. 15)
9:40 – 10:00
Nico Salmaso: Unravelling anatoxin-a in the large lakes south of the Alps:
Occurrence and toxic potential of Tychonema (Cyanobacteria) (p. 29)
10:00 – 10:20 Ekaterina Voyakina: Cyanobacterial blooms in Lake Ladoga around
Valaam islands (p. 36)
10:20 – 10:50 Coffee break
10:50 – 11:10 Valerii Tonkopii: Danger of anatoxin-a(s) and organophosphorus pesicides
for aquatic ecosystem health (p. 33)
Session: Sustainability of ecosystem services and good ecological status in large lakes challenges for management
Chair: Dietmar Straile
11:10 – 11:30 Juha Niemistö: Hypolimnetic aeration intensifies phosphorus recycling and
increases organic material sedimentation in a stratifying lake: Effects through
increased temperature and turbulence (p. 25)
11:30 – 11:50 Jukka Ruuhijärvi: Responses of fish and zooplankton to the pumping of
epilimnetic water into hypolimnion in Lake Vesijärvi (p. 28)
11:50 – 12:10 Noora Mustamäki: Structural changes in three coastal fish assemblages in
the northern Baltic Sea archipelago (p. 24)
12:10 – 12:30 Behnam Zamani: Simulation of the movement of a turbid density current
during a flood event in a large reservoir with complex morphology (Maroon
reservoir, southwest Iran) (p. 38)
12:30 – 13:30 Lunch
14:00 – 17.00 Mid-Excursion (Lake Pyhäselkä onboard M/S Vinkeri II), Passanger harbor,
Rantakatu 2
4 THURSDAY, AUGUST 27
Session: New tools for monitoring and assessment of ecological status in large lakes
Chair: Kari-Matti Vuori
8:30 – 9:20
Keynote Dr. Seppo Hellstén: Recent trends and future perspectives in
ecological status monitoring of Finnish lakes (p. 9)
9:20 – 9:40
Daud Hassan: International Legal Regimes for Fisheries Management: An
Evaluation (p. 18)
9:40 – 10:00
Alfred Sandström: Assessing the potential of remote sensing derived
variables to explain spatial variation in fish distribution and assemblage
composition in large lakes (p. 29)
10:00 – 10:20 Lea Tuvikene: Using a single metric for a water quality element may cause
unfair judgement of the ecological status of a lake (p. 34)
10:20 –10:50
Coffee break
Chair: Helen Agasild
10:50 – 11:10 Dina Dudakova: A new method of combined aerial videofilming (using
unmanned aerial vehicle - UAV) and underwater research in the studies of
biogeocenosis of littoral zone of Lake Ladoga (p. 16)
11:10 – 11:30 Tapio Sutela: A littoral fish index responds to eutrophication in boreal lakes
(p. 31)
11:30 – 11:50 Árpád Ferincz: Risk assessment of non-native fishes in the catchment of a
Central-European large, shallow lake (Lake Balaton Hungary) using the
FISK system (p. 16)
11:50 – 12:10 Nataliya Kalinkina: Lake Onego biomonitoring: estimates of spatialtemporal heterogeneity and scales of biological processes (p. 20)
12:10 – 13:10 Lunch
Session: Fish and fisheries management in large lakes
Chair: Jouko Sarvala
13:10 – 14:00 Keynote Dr. Anne-Mari Ventelä: Fisheries and climate change (p. 11)
14:00 – 14:20 Tiina Nõges: Cascading fisheries impact on the ecosystem of a large and
shallow eutrophic lake (p. 25)
14:20 – 14:40 Roland Rösch: Drastic changes in the fish community of Lake Constance
Upper lake with re-oligotrophication (p. 26)
14:40 – 15:10 Coffee break
15:10 –15:30
Anssi Vainikka: Size limit -based management of pikeperch (Sander
lucioperca) in Finnish lakes with respect to life-history variation (p. 34)
5 15:30 – 15:50 Ain Järvalt: Fishery regulation has effect on the ecological status of lakes
(p. 19)
15:50 – 16:10 Jimmiel Mandima: Potential application of Limnothrissa miodon
(Boulenger, 1906) daily ration and population food consumption estimates to
predict the potential standing biomass in Lake Kariba, Zambia/Zimbabwe (p.
23)
16:10 – 17:30 Poster session
19:00 – 22:00 Conference dinner at Teatteriravintola, Rantakatu 20
FRIDAY, AUGUST 28
Session: Fish and fisheries management in large lakes
Chair: Martti Rask
9:00 – 9:20
Aurora Hatanpää: Radio telemetry surveillance of landlocked salmon
(Salmo salar m. sebago) in the River Ala-Koitajoki (p. 18)
9:20 – 9:40
Thomas E. Axenrot: Consequences of variable seasonal habitat volume for
vendace population size and stock assessment (p. 14)
9:40 – 10:00
Timo J. Marjomäki: Potential for the ecologically sustainable yield (ESY)
of vendace from Finnish large lakes (p. 24)
10:00 – 10:20 Ádám Staszny: Scale shape based identification of fish species inhabiting
the largest shallow lake of Central Europe (p. 31)
10:20 – 10:50 Coffee break
10:50 – 11:10 Hiroshi Suito: Heterogeneous wind field and lake circulation – atmospheric
and aquatic modelling results (p. 51)
11:10 – 11:30 Kai Ginter: Linkages between fish-zooplankton interactions and changed
fish assemblage in large shallow Lake Peipsi (Estonia/Russia) (p. 17)
Session: Emerging contaminants
Chair: Paula Kankaala
11:30 – 11:50 Timo Huttula: Modelling the transport and fate of contaminants in the
aquatic environment (p. 18)
11:50 – 12:10 Jarkko Akkanen: Anthropogenic particles as emerging contaminants in
freshwater environments are a challenge for aquatic ecotoxicology and risk
assessment (p. 12)
12:10 – 12:30 Closing the symposium
12:30 - 13:30
Lunch 6 LIST OF POSTERS
1.
Abel Sebastian, Nybom Inna, Mäenpää Kimmo, Hale Sarah, Cornelissen Gerard,
Akkanen Jarkko: Activated carbon in sediment remediation – adverse effects vs.
remediation potential (p. 39)
2.
Äijälä Cecilia, Leppäranta Matti, Arvola Lauri: Colour of Finnish inland waters in 1913
and 2014 (p. 39)
3.
Aleshina Dina, Kurashov, Evgeny: Modern state of zooplankton in tributaries of Lake
Ladoga (p. 40)
4.
Axenrot Thomas E, Guillard Jean, Riha Milan: Applying and evaluating the European
Standard Water quality – Guidance on the estimation of fish abundance with mobile
hydroacoustic methods – experiences from three countries (p. 40)
5.
Belicheva Lidia, Lukina Julia: Histopathological alterations in feral fish of Lake Onego a baseline study for environmental monitoring purposes (p. 41)
6.
Belkina Natalia, Kulik Natalia, Lozovik Petr, Efremenko Natalia: Trace elements in Lake
Onega (p. 41)
7.
Eronen Risto, Vainikka Anssi, Huuskonen Hannu, Kiljunen Mikko, Syväranta Jari,
Kortet Raine: Diet of pikeperch (Sander lucioperca) in Lake Höytiäinen: stomach
contents vs. stable isotope analysis (p. 42) - CANCELLED
8.
Fukushima Takehiko, Matsushita Bunkei, Oyama Youichi, Yoshimura Kazuya, Terrel
Meylin, Kawamura Shimako, Takegahara Akito, Yang Wei: Semi-analytical prediction
of Secchi depth using remote-sensing reflectance for lakes with a wide range of turbidity
(p. 42)
9.
Haberman Juta, Blank Kätlin, Laugaste Reet, Loigu Enn: The health of Lake Peipsi
(Estonia/Russia): improvement stabilization or deterioration? (p. 43)
10. Haldna Marina, Möls Tõnu, Tammeorg Olga: Methods for testing the relationships
between water and weather variables of the large shallow Lake Peipsi (p. 43)
11. Hiltunen Minna, Taipale Sami, Strandberg Ursula, Kahilainen Kimmo, Kankaala Paula:
Fatty acid composition of Eudiaptomus spp. in boreal and subarctic lakes (p. 44)
12. Juvelius Juha, Auvinen Heikki, Marjomäki Timo, Peltonen Heikki, Degtev Andrei,
Bergstrand Eva, Enderlein Olof: Fish density and fish length distribution in varying light
conditions with single and split beam echo-sounding and trawling (p. 44)
13. Kangasniemi Ville, Mustonen Joni, Forsman Tero, Ikonen Ari T. K.: Element transfer to
and distribution in signal crayfish (Pacifastacus leniusculus) in Lake Säkylän Pyhäjärvi
SW Finland (p. 45)
14. Karjalainen Juha, Jokinen Linda, Keskinen Tapio, Knott Emily, Marjomäki Timo: The
role of parental effect and relatedness on early development of coregonids in short and
long winter (p. 45)
15. Kolari Irma, Eskelinen Päivi, Salmi Pekka, Mellanoura Junani, Hirvonen Esa: Water
owners´ attitudes towards ringed seal conservation in Lake Saimaa (p. 46)
16. Kuivalainen Jarmo: Autonomous measurement platform for monitoring lakes – LILA
project (p. 46)
7 17. Lenters John, Blanken Peter, Spence Christopher, Gronewold Andrew, Kerkez Branko,
Froelich Norma, Austin Jay, Xue Pengfei: The Great Lakes Evaporation Network
(GLEN): Building an integrated observing system for large-lake flux measurements (p.
47)
18. Marenkov Oleg: The use of artificial spawning grounds for fish spawning in lake
ecosystems (p. 47)
19. Mukhin Ivan, Dudakova Dina, Dudakov Mikhail: Integrated approach to the study of
submerged surfaces community (p. 48)
20. Pellikka Katja, Räsänen Marjut: Changes in phytoplankton and water carbon
concentration in the southern part of Lake Päijänne Southern Finland (p. 48)
21. Salmaso Nico, Milan Manuela, Bigler Christian, Szeroczynska Krystyna, Tolotti
Monica: Effects of climate change and nutrients on the secular evolution of the
planktonic community in Lake Garda (northern Italy): a multi-proxy approach (p. 49)
22. Seppänen Eila, Forsman Leena: Outliers form the majority of recreational fishers in the
living area of the Saimaa ringed seal: Do the fishing regimes differ between outliers and
locals? (p. 49)
23. Silander Jari, Kanninen Antti, Kahiluoto Joonas, Kaukonen Lari, Latva Mira, Sojakka
Pekka, Savolainen Miia, Göransson Johanna, Koivuniemi Jenni, Vartiainen Minna:
Developing mobile services for in-situ monitoring, data storing and sharing
(HALIproject) (p. 50)
24. Soulignac Frédéric, Danis Pierre-Alain, Bouffard Damien, Chanudet Vincent, Dambrine
Etienne, Guénand Yann, Guillermin Baptiste, Harmel Tristan, Kiefer Isabel, Trevisan
Dominique, Uittenbogaard Rob, Anneville Orlane: Impacts of neglecting spatial
heterogeneity in the water quality assessment of large lakes: evaluation on remote
sensing and 3D-model data (p. 50)
25. Stepanova Anastasija, Voyakina Katerina: Effects of hydro-meteorological parameters
on plankton community of the Valaam Archipelago coastal zone (Lake Ladoga) (p. 51)
26. Suito Hiroshi, Doi Shota, Morifuji Shin-ya, Ropponen Janne, Huttula Timo: Heterogenic
wind field and lake circulation – atmospheric and aquatic modelling results (p. 51)
27. Susloparova O.N., Leonov A.G.,.Zuyev Yu.A, Ogorodnikova V.A., Tereshenkova T.V.:
Spatial distribution and long-term dynamics of the basic biota communities in the
southern part of Ladoga lake (p. 52)
28. Tamm Marju, Freiberg René, Tõnno Ilmar, Kangro Kersti, Nõges Peeter, Nõges Tiina:
Phytoplankton pigments – a powerful tool for quantitative analysis of phytoplankton in
lakes (p. 52)
29. Zamani Behnam, Koch Manfred: The role of bottom outlet in minimizing future
ecological problems in a proposed dam reservoir using three-dimensional modeling
(Abolabbas Dam) (p. 53)
30. Zhang Min, Straile Dietmar, Chen Feizhou, Cai Yongjiu, Yu Jinlei, Wenxia Wang, Kong
Fanxiang: The shift and driving factors of phytoplankton composition and richness along
productivity gradients (p. 53)
31. Zuyev Yury, Zuyeva Nadejda, Lapenkov Artem: Rocky littoral zone macrozoobenthos of
Krestovyi bay (Lake Ladoga) (p. 54)
8 KEYNOTE PRESENTATIONS
Putting Ecology into Ecosystem Services: the Challenges ahead for Lakes Research
Laurence Carvalho
Centre for Ecology & Hydrology, Wallingford, UK
The sight of an algal bloom on a lake is an indicator of trouble. Trouble for anglers, swimmers, water supply
and public health. An algal bloom is also an indicator of change. Changing community structure and
functioning impacts the regulatory services that lakes provide in purifying our water or trapping carbon.
Understanding the relationship between the biophysical structure of our lakes and the delivery of ecosystem
services is fundamental to any notion of sustainability.
Large lakes are not only exposed to multiple stressors but they are often iconic features in landscapes as well
as often being flagship biosphere reserves for the conservation of freshwater species and habitats. To manage
multiple stressors and multiple benefits raises a number of challenges. How do we incorporate ecological
understanding into models of ecosystem services? Can we accurately represent all the values that lakes
provide? How do we manage large lakes to minimise conflicts and maximise benefits whilst sustaining
environmental quality?
The talk will highlight some difficulties and solutions for addressing these challenges. It will focus on
fisheries, recreation and nature conservation, but highlight the need to develop a more holistic perspective, in
particular recognising regulatory services that provide benefits beyond the immediate water environment.
Demonstrating the linkage between freshwater biodiversity and service provision will require substantial
investigation involving detailed case studies, landscape experiments and modelling. The potential
application of functional trait-based approaches and new monitoring datasets from earth observation and
citizen science will be highlighted to address some of these challenges.
Recent trends and future perspectives in ecological status monitoring of Finnish lakes
Seppo Hellsten
Freshwater Centre, Finnish Environment Institute (SYKE), Oulu, Finland
Ecological status classification has been one of the major tasks among European scientists based on the
recent implementation of EU Water framework directive (WFD). In water body rich countries like Finland
the demands of monitoring are impossible to fill due to limited and even diminishing resources of water
authorities, and therefore new ways of monitoring must be applied in forthcoming years. In general there are
three kinds of development strategies to improve the monitoring; streamlining, technical innovations and
crowdsourcing. In “streamlining” we improve existing methodologies and assessment procedures by
developing methods, increasing standardization, enhancing databases and shortening the route of data. Using
smart ways of grouping of water bodies to larger units and reducing the frequency of sampling can be
included to “streamlining”. “Technical innovations” mean that cost can be reduced by using remote sensing
or modelling approach and in some selected parameters collected by automates. Increased accuracy of
satellite images and the use of unmanned aerial vehicles (UAV) have significantly improved possibilities of
remote sensing including also public GIS-databases. “Crowdsourcing” is a magic word meaning that official
monitoring could be partly replaced or taken by public observations. In real life this means that followed
parameters should be easy to monitor and interesting for citizen. Despite of all innovations and giant steps
forward we should keep in mind that long term monitoring by using traditional hydrological, water quality
9
and biological parameters gives a solid background for the evaluation of global or other unpredicted changes
in the future.
Controlling a global proliferation of toxic cyanobacterial blooms in large lakes: The case for dual
nutrient (N & P) input reduction strategies
Hans W. Paerl1, Wayne S. Gardner2, Mark J. McCarthy2, Hai Xu3, Guangwei Zhu3, Boqiang Qin3, Timothy
G. Otten4, Nathan S. Hall1, Karen L. Rossignol1 & Steven W. Wilhelm5
1
Institute of Marine Sciences, The University of North Carolina at Chapel Hill, Morehead City, NC, 28557
USA; 2 Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373 USA; 3 State
Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography & Limnology, Chinese
Academy of Sciences, Nanjing 210008, PR China; 4Department of Microbiology, Oregon State University,
Corvallis, OR 97331 USA; 5Department of Microbiology, The University of Tennessee, Knoxville, TN
37996-0845 USA
Like many smaller lakes and reservoirs, large lake ecosystems are experiencing a global proliferation of
harmful cyanobacterial blooms (CyanoHABs). Controlling this troublesome symptom of eutrophication has
historically focused on reducing phosphorus (P) inputs. This is based on the assumption that nitrogen (N)
fixation will supply ecosystem N needs. Much has changed in terms of human nutrient inputs to and climatic
alterations of bloom-sensitive waters since this paradigm was introduced. Recent studies indicate that
cyanobacteria flourish in response to combined N and P loading, or even N enrichment, and this is
exacerbated by climatic changes, including warming, more extreme storms and droughts. The toxic
CyanoHAB genus Microcystis often dominates under these conditions. This genus cannot fix atmospheric
N2, and thus requires combined N sources to support growth. Despite decades of P loading controls in the
Great Lakes basin and elsewhere, Microcystis blooms are proliferating worldwide, threatening drinking
water supplies, fishing, tourism and overall sustainability of impacted systems. Burgeoning usage of N
fertilizers, urban and agricultural N wastes, and atmospheric N deposition have increased bioavailable N in
receiving waters. N occurs in gaseous forms, unlike P, and is “lost” to the atmosphere via denitrification and
other N sinks, perpetuating N-limitation. In-system N2 fixation does not appear to compensate for N loss, so
external N input is a key driver of eutrophication and CyanoHABs. We suggest that the “P-only”
management paradigm should be amended to incorporate controls on external N inputs.
The response of large and deep lakes to climate change
Dietmar Straile
Limnological Institute, Department of Biology, University of Konstanz, Konstanz, Germany
Lakes around the world have been shown to be sensitive to climate variability and warming. The
consequences of climate forcing for the thermal characteristics, chemistry and biology of lakes have been
analysed based on paleolimnological remains, long-term data and model simulations. This contribution will
review this work with a special emphasis on large and deep lakes. One focus will be to analyse and discuss to
which extent the specific characteristics of large and deep lakes (e.g., the slow thermal response of a large
volume of water; a maximum depth preventing algal bloom development during the mixing period) might
result in specific ecosystem responses to climate variability and warming.
10
Fisheries and climate change
Anne-Mari Ventelä
Aquatic environment, Pyhäjärvi Institute, Kauttua, Finland
It is expected that the pressure on the lakes and their ecological state will increase in the future due to both an
increasing world population demanding a higher food production and to climate change. Such changes will
further challenge the ecosystem services such as fisheries, not least because nutrient loading and climatewarming effects act in synergy. Thus, adaptation and management actions are often needed. Predicting future
climate change is, however, difficult due to the high uncertainty regarding the large-scale dynamics,
mechanisms and timing of the changes. Moreover, it is expected that the frequency and magnitude of
extreme weather events will increase, which will further challenge the function and quality of lake
ecosystems. However, many climate induced changes have already been observed, I here review European
studies, which show that the response of fish to the warming has been surprisingly strong and fast in recent
decades, making them ideal sentinels for detecting and documenting climate-induced modifications of
freshwater ecosystems. The case study of Pyhäjärvi (SW Finland) shows that the local lake fishery has
already been forced to adapt to climate change. The economic and ecological consequences of climate
change have been estimated and results show that the outcome is not necessarily negative for the economy of
the local fishery or even the water quality of the lake if the adaptation is successful. However, monitoring
and detailed analyses of the long-term dynamics of lake ecosystems, key factors and interactions are needed
to allow implementation of the climate change adaptation tools.
Microbial loop in large lakes
Priit Zingel, Helen Agasild, Arvo Tuvikene, Lea Tuvikene, Katrit Karus, Tõnu Feldmann, Peeter Nõges &
Tiina Nõges
Estonian University of Life Sciences, Centre for Limnology, Tartumaa, Estonia
The concept of microbial loop is nothing new – it has been around for many decades. Still, considering all
the data available on lake ecosystems there are relatively few papers that focus on the microbial loop. One
reason for that is the lack of experts that study protozoans – the central link in the microbial loop. This is
especially true concerning ciliates – these tiny organisms have received disproportionately little attention. In
this presentation I will briefly introduce the available data on the microbial loop in large lakes. Then I will
focus on our own recent studies to demonstrate the importance of planktonic ciliates in lake food webs.
During last 10 years we have carried out several studies in Estonian large lakes – we have implemented
several feeding experiments, mesocosm experiments and nutritional analysis of fish larvae to clarify the
aspects of microbial loop functioning. Labelling experiments with natural planktonic ciliates have revealed
that microciliates are important food for crustacean zooplankters but their predation impact is relatively low.
Enclosure experiments with removal and addition of crustaceans demonstrated the indirect effect of smallsized crustacean population on ciliate community structure, which is mainly controlled by the interactions
within the ciliate assemblage. Larval fish studies study showed that without ciliates their daily food
requirement would not be met, and that most fish species require ciliates as their initial food. We also
investigated the influence of macrophyte thickets to the feeding of planktivorous fish larvae and showed that
in the macrovegetation even more ciliates are consumed.
11
ORAL PRESENTATIONS
Small cladoceran Chydorus sphaericus forms an important link in food web of eutrophic lake
Helen Agasild, Priit Zingel, Ilmar Tõnno, Jaana Salujõe & Tiina Nõges
Estonian University of Life Sciences, Tartumaa, Estonia
Chydorus sphaericus is a characteristic zooplankton species in eutrophic lakes, co-occurring often with
cyanobacterial blooms. It does equally well in open water and in lake littoral zone. C. sphaericus is known to
be tolerant of a wide range of conditions found in lakes, which together its generalist nature of feeding,
account for its success in nutrient rich lakes. Although it often dominates numerically among zooplankton,
only little attention has been paid on its interactions to plankton communities and fish. To reveal the role of
C. sphaericus in shallow eutrophic lake we gathered information from long-term monitoring of zooplankton
and from previous zooplankton feeding studies in Lake Võrtsjärv (Estonia). Applying various methods
(grazing on fluorescent microparticles, natural ciliate labelling, zooplankton gut pigment analyses, fish gut
content analyses) has revealed that C. sphaericus can be the major grazer on bacteria, micro-ciliates and
small algae, including colonial cyanobacteria, and is also comprising food to juvenile fish. Consuming the
productions of various trophic levels and being one of the major feeding objects of young of the year fish, C.
sphaericus forms an important link transferring carbon from lower to higher levels in food web of eutrophic
lake.
Anthropogenic particles as emerging contaminants in freshwater environments are a challenge for
aquatic ecotoxicology and risk assessment
Jarkko Akkanen, Greta Waissi-Leinonen & Kukka Pakarinen
Department of Biology, University of Eastern Finland, Joensuu, Finland
The term “emerging” has been used to describe chemical contaminants that are new to the environment or
that we have recently found out that they are present in the environment. In the past years, there has been two
big newcomers in the ecotoxicological research. First one was engineered nanomaterials (ENMs) whose
production and applications have increased exponentially during the past ten-fifteen years. Another topic that
is just starting to bloom is the environmental effect of micro- and nanosized plastic debris (MPs). These two
emerging contaminants share similar features, but also differ in some. For example the environmental
research on MPs have increased only recently, yet the debris has been there already for longer time. On the
other there is yet quite little studies showing the presence of ENMs in the environment. As similarity we can
mention that both materials potentially have two ways to induce adverse effect in the aquatic environment.
The effects can be direct, where the particulate material itself causes harmful effects and/or indirect, where
the effects are caused by toxic chemicals carried by the particulate material into the organisms. There are
also analytical questions to be solved in the future, since the detection of both particulates in environmental
samples can be challenging. Not to mention that studies on MPs in the freshwater environments are really
scarce. This presentation will describe above mentioned and further challenges for assessing ecological risks
of the various particulates.
12
Fish communities in the Anthropocene: detecting drivers of changes in two peri-alpine lakes (L.
Geneva and L. Annecy)
Orlane Anneville1, Camille Vogel1, Jérémy Lobry2 & Jean Guillard1
1
UMR CARRTEL, INRA, Thonon les Bains, France; 2IRSTEA, Bordeaux, France
Human activity is a main driver of changes and has impacted the dynamics of many populations and
ecosystems. Some lakes are highly anthropized ecosystems whose properties and dynamics are strongly
influenced by human pressure. Changes in climate, in combination with local management policies, have
caused drastic modifications in the physical and chemical properties of many lakes worldwide. These
changes may directly or indirectly, e.g. via plankton communities, impact the abundance of fish populations.
In the context of global changes and fish exploitation, it is essential to identify the main stressors impacting
fish populations to prevent stock collapses and promote sustainable fisheries. Using fish catches, we
analysed and compared long-term changes of fish communities in two peri-alpine lakes (L. Geneva and L.
Annecy). Both lakes are located in the same regional area but, they are undergoing distinct phosphorus
management policies leading to quite different trophic evolutions. Results indicated that decrease in
phosphorus concentrations has been the main driver of structural changes in the fish community.
Generalized linear mixed models were implemented using CPUE data to explain interannual changes in the
abundance of 3 key fish species (Coregonus lavaretus, Perca fluviatilis and Esox lucius) sampled in Lake
Geneva. We showed that phosphorus local management has played a major role in determining the
abundance of these species but rising in water temperature appeared as an additional driver that cannot be
excluded. Our results suggest that understanding the interactions between global and local forcing has
become a major challenge for developing sustainable fishery policies.
CDOM of large Finnish lakes relative to their landscape position
Lauri Arvola1, Cecilia Äijälä2 & Matti Leppäranta2
1
Lammi Biological Station, University of Helsinki, Lammi, Finland; 2Department of Physics, University of
Helsinki, Finland
In the global perspective coloured dissolved organic matter (CDOM) concentrations are high in Finnish
lakes. In this study we present results from 87 lakes with a surface area >10 km2 relative to their landscape
position. The CDOM measurements have been carried out in 1913 and 2014 with spectrophotometers. The
earlier data set was measured by Rolf Witting, and in summer 2014 we re-sampled his sites and collected the
landscape information from the data archives of the Finnish Environment Institute. Our results show that
landscape position explains >50% of the variability in the CDOM concentrations among the lakes. The key
landscape position factors influencing the CDOM concentrations were lake percentage in the uppermost
catchment area and lake position relative to the sea level which was strongly correlated with the peat-land
coverage of the catchment area. High lake percentage indicated low CDOM concentration while high peatland coverage showed the opposite action. The results suggest that besides hydrological conditions landscape
position of the water bodies and their catchment areas should be considered when CDOM properties of
inland waters are evaluated and modelled.
Witting, R. 1914. Redogörelse afgifven af arbetsutskottet för undersökning af de finska insjöarnas vatten och
plankton. I. Optisk och kemisk undersökning af vattenprofven från sommaren 1913. Fennia 35(7).
13
Consequences of variable seasonal habitat volume for vendace population size and stock assessment
Thomas Axenrot
Department of Aquatic Resources, Swedish University of Agricultural Sciences, Drottningholm, Sweden
Vendace (Coregonus albula (L.)) is a cold water species, and as such yearling-and-older fish are generally
found below the metalimnion during periods of thermal stratification. These periods usually last for 3-4
months in areas where vendace is distributed. In lakes with heterogeneous distribution of depths that can
hold volumes of cold water during the stratified period, the habitat volume for vendace vary drastically over
the year. This can have both aggravating and facilitating implications for stock assessment. The habitat
volume often shows some variation between years as a result of climatic differences when the annual
thermocline is established. Thus, a variable habitat volume with food and oxygen depletion in the
hypolimnion through the period of stratification could act as a population size regulating factor. Future
climate changes may result in changed habitat volume for cold water species like vendace. Based on
hydroacoustic data, trawling results and temperature profiles, we attempt to predict population consequences
of changes in habitat volume. We also discuss if seasonal aggregations of fish demand for special
intervention with regard to fisheries management and protection.
The chemical composition of sediments as indicator of changes in the ecosystem of Lake Onega under
the influence of anthropogenic factors
Natalia Belkina
Karelian Research Centre RAS, Institute of Northern Water Problems, Petrozavodsk, Russia
The study is based on comparative analysis of original chemistry data of Lake Onega sediments for the
period of 1964-2013. The authors come to the conclusion that the natural heterogeneity of the ecosystem of
Lake Onega has increased due to the uneven territorial distribution of human activity on the coast. On the
example of the bays, exposed to intensive anthropogenic influence, it is shown that any changes in the
quantitative and qualitative composition of anthropogenic discharges are bound to affect the chemical
composition of sediments. The main trend marked within last fifty years was the gradual expansion of the
polluted bottom area of these bays. The impact of contaminated sediments on the content of nutrients, gas
and ion composition of the lake waters are shown based on the study of the chemical composition of
sediments, pore and near bottom waters. The distribution of phosphorus in the sediments of Onega Lake and
internal nutrient load were assessed. It is shown that the dynamics of change corresponds to the nature of
changes in the external phosphorus load and eutrophication processes of the lake. At present, there is a
process of stabilization of the ecosystem of Lake Onega after a period of intense anthropogenic
eutrophication in the early nineties. The study has been financially supported by the Russian Science
Foundation (#14-17-00766).
14
Dolichospermum lemmermannii (Cyanobacteria) in European waters: distribution patterns and toxic
potential
Camilla Capelli1, Andreas Ballot2, Leonardo Cerasino1 & Nico Salmaso1
1
Research and Innovation Centre, Fondazione E. Mach, S. Michele all’Adige, Trento, Italy; 2Norwegian
Institute for Water Research (NIVA), Oslo, Norway
Populations of Dolichospermum lemmermannii (Nostocales) have been widely identified in Central and
Northern Europe. In Southern Europe, extended surface blooms of this species were recorded for the first
time in Lake Garda in 1990/91. Since then, blooms of D. lemmermannii were documented in lakes Iseo
(1990s), Maggiore (2005), and Como (2006). Recent studies have shown that populations collected in
different water bodies are characterised by high variability to temperature adaptation. Actually, although this
species is typical of cold environments, specific strains of D. lemmermannii show high temperature optima
(i.e. between 19°C and 26°C). Further, in the large lakes south of the Alps, populations of Dolichospermum
have the ability to form huge water blooms in summer stratified conditions and during calm weather. These
results could suggest the existence of different ecotypes adapted to different European climatic regions. In
this work, we report the preliminary results of a wide research carried out on populations isolated from
different European waterbodies. The analyses are based on taxonomical, genetic and metabolomic
determinations carried out on isolated strain cultures. A phylogenetic study on 16s rRNA and housekeeping
genes (e.g. rpoB,) was integrated by the assessment of potential toxicity, evaluating the presence of
cyanotoxins (i.e. Microcystins, Anatoxins, Saxitoxins) encoding genes. Further studies will allow gaining
insight about the phylogeography of this fast spreading species at a continental level, along climatic
gradients.
Modelling phytoplankton and periphyton primary production in hemiboreal lakes
Fabien Cremona1, Alo Laas1, Lauri Arvola2, Don Pierson3, Peeter Nõges1 & Tiina Nõges1
1
Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartumaa, Estonia;
University of Helsinki, Helsinki, Finland; 3Uppsala University, Uppsala, Sweden
2
The distribution of whole-lake primary production between planktonic and benthic habitat, also called
autotrophic structure, carries critical information about lake food web layout and organic matter fluxes.
Although planktonic primary production has been intensively studied since the onset of limnology, the
paucity of estimates for benthic production is still blatant, meaning that autotrophic structure of lakes
remains poorly known to date. In this study we have modelled both planktonic and benthic production and
autotrophic structure of thirteen hemiboreal lakes from Estonia, Finland and Sweden including large lakes
Peipsi, Võrtsjärv and Vanajanselkä. We employed an empirical model based on a limited set of variables
easily available from basic limnological databases, with a high precision in time (10 min) and depth (every
10 cm). Our results showed that although the studied lakes ranged from periphyton- to phytoplanktondominated, phytoplankton represented on average 85% of their primary production. Shallow and/or clear
lakes with low chlorophyll a (chla) were generally more favourable to benthic production than deep and/or
turbid lakes. An increase of chla and turbidity in hemiboreal lakes caused by climate warming is expected to
skew the pelagic to benthic production ratio even more towards dominance of phytoplankton, with dramatic
consequences on lake carbon fluxes.
15
A new method of combined aerial videofilming (using unmanned aerial vehicle - UAV) and
underwater research in the studies of biogeocenosis of littoral zone of Lake Ladoga
Dina Dudakova1, Mikhail Dudakov1 & Ivan Mukhin2
1
Institute of Limnology, RAS, Saint-Petersburg, Russia; 2Vologda State University, Vologda, Russia
The method of the study of aquatic ecosystems, which covers a multi-scale objects varying from small
structural subdivisions of individual biotopes of the lake to large scale geographical structural units (inlets,
bays, islands) is considered. An unmanned aerial vehicle (UAV), which produces video of the studied coastal
water area have been used. Scuba diver underwater work on selected model polygon of size 100x100 meters
gave the possibility to explore the biotopes and distribution of benthic communities. By the proposed method
it was investigated seven polygons. Aerial photographs allowed assessing differences in the spatial
complexity of the ecosystems on different polygons, the presence of clear subzonation in littoral zone of the
Northern part of the Lake Ladoga. The spatial complexity of the environment strongly affects the distribution
of periphyton and benthos. Polygons located on undisturbed areas had a similar structure within their types
of the littoral zone. Using of aerial photographs allows detecting type and accessing the significance of
anthropogenic disturbances such as navigating channel as a result of dredging, the remains of the mining of
building stone in the coastal zone, coastal waste drop offs of furniture industry, algal blooms with visible
color change of the water surface in places exposed by domestic waste water. Also for these evaluations the
algorithm of photos geographical binding to maps of program “Google Earth pro” was made. Thus, the
proposed method can be a powerful tool for monitoring and assessing the ecological status of coastal areas of
large lakes.
Risk assessment of non-native fishes in the catchment of a Central-European large, shallow lake (Lake
Balaton Hungary) using the FISK system
Árpád Ferincz1, Ádám Staszny1, Péter Takács2, Gábor Paulovits2 & Béla Urbányi1
1
Department of Aquaculture, Szent István University, Gödöllo, Hungary; 2Balaton Limnological Institute,
Hungarian Academy of Sciences, Tihany, Hungary
The negative effect of non-native, invasive species on their recipient ecosystem is a widely discussed,
commonly recognized fact nowadays. The size of this effect is largely asymmetric, either between the
species, or the habitats being invaded, and the possibility of further introductions is still high, therefore
appropriate risk analysis required. Ecological Risk Assessment of non-indigenous species was performed
using the Fish Invasiveness Scoring Kit (FISK). This study was the first application of this tool in a relatively
small, and isolated catchment area. The threshold between “medium” and “high” risk was determined to be
13.625, which is slightly higher than that determined for the neighboring Balkan-peninsula (i.e. 9), but much
lower than the original threshold for the United Kingdom (i.e. 19) and that determined for a FISK application
in southern Japan (i.e. 19.8) or in southern Finland (i.e. 22.5). After the calibration of the method to the local
conditions, fourteen of the 27 assessed species were highlighted as of ‘high risk’ or invasive species, of
which Carassius gibelio was considered to be the most dangerous, characterized by the highest score.
16
Lakes of Russia: Diagenesis and prediction of state of ecosystem under climate change and
antropogenic impacts
Nikolai Filatov1, G.Panin2, N.Diansky3, R. Ibraev3, L. Nazariova1, S. Golosov 1 & T.Viriuchalkina2
1
Northern water problems institute Karelian Research center RAS, Petrozavodsk, 2Water Problems Institute
RAS, Moscow, 3Institute of Numerical mathematic RAS, Moscow
Russia has more than 2.7 million lakes, among them such as large lakes Baikal, Ladoga and Onego, Caspian
Sea-Lake. Among priorities there is a revealing of principal causes of fluctuations of level of reservoirs,
observed in tool measurements (19-21 centuries), and to develop the estimated forecast of its change for the
next decades. It will use as the modern data of supervision reanalysis NCEP, ERA-Intrim, CORE, and results
of modeling on reproduction of a modern climate and oceanic circulation. Results of numerical experiments
on reproduction of circulation of the World ocean, and the modern 3-D mathematical models for great lakes
(Ladoga and Onego, 2010). As the basic indicators of the climatic changes influencing change of level of
reservoirs will be used for this purpose, indexes of NAO, АМО, ATHC will be used. It will be investigate
elements of water balance and water level of largest lakes of Europe and Caspian Sea, the Ladoga and Onego
lakes. It will be provide a full-scale study to forecast changes of lake’s ecosystems by 10-50 years.
Acknowledgements. This work is based on the results of Grant RSF No. 14-17-00740.
Linkages between fish-zooplankton interactions and changed fish assemblage in large shallow Lake
Peipsi (Estonia/Russia)
Kai Ginter, Kätlin Blank, Ellen-Juta Haberman, Andu Kangur & Külli Kangur
Centre for Limnology, Estonian University of Life Sciences, Rannu, Estonia
Over the six-year period (2007–2012) the diet of juvenile fish was analysed and the abundance dynamic of
zooplanktivorous fish and zooplankton since the end of 1980´s were examined to assess the linkages between
fish and zooplankton in large shallow eutrophic Lake Peipsi. According to the test trawl samples, major
shifts in the fish assemblages have been detected: the abundance of planktivorous lake (dwarf) smelt
Osmerus eperlanus m. spirinchus and vendace Coregonus albula have declined to a historically low level,
whereas the share of pikeperch Sander lucioperca, Eurasian perch Perca fluviatilis and ruffe
Gymnocephalus cernuus have risen. The stomach content analyses revealed, that the target species in
zooplankton community have changed. Smelt predated mostly on Daphnia spp., vendace on Mesocyclops
leuckarti. In recent years, the pressure has shifted to Leptodora kindti and Bythotrephes longimanus,
consumed by pikeperch and perch fries, and to Bosmina spp, chosen by ruffe and common bream Abramis
brama fries. In result, large cladocerans like L. kindti and B. longimanus were almost completely absent in
zooplankton samples and Bosmina spp. biomass has decreased. Additionally, cladocerans mean weight was
negatively correlated to the abundance of juvenile fish, the relationship was especially strong in the years
with large fish cohorts. Despite the decline of adult zooplanktivores, there have been a significant increase in
the abundance of juvenile fish in the lake. Species-specific diet of zooplanktivorous fish, shifts in dominant
zooplanktivores and appearance of extra-large cohorts may be the reason behind the peculiar fluctuations in
zooplankton abundance in Lake Peipsi.
17
International Legal Regimes for Fisheries Resources Management: An Evaluation
Daud Hassan
School of Law, University of Western Sydney, Penrith, Australia
The aim of this paper is to critically evaluate the applications and shortcoming of the current regimes for
fisheries resources management in a sustainable manner. In this context United National Convention on the
Law of the Sea, the 1995 Fish Sticks Agreement and other international law and policies relating to fisheries
management will be analysed. Various obstacles and challenges that the current fisheries resources
management could pose to the effective conservation and management due to climate change will be
highlighted in the paper. Applications of management principles, vulnerability, adaptive capacity and
mitigation measures of the current regimes will be considered in this respect. Exploring the reasons for
weaknesses in current arrangements the paper will suggest an effective and rational cooperative regime for
the conservation and management regimes for sustainable fisheries resources management.
Radio telemetry surveillance of landlocked salmon (Salmo salar m. sebago) in the River Ala-Koitajoki
Aurora Hatanpää1, Hannu Huuskonen1, Raine Kortet1 & Jorma Piironen2
1
Department of Biology, University of Eastern Finland, Joensuu, Finland; 2Natural Resources Institute
Finland, Joensuu, Finland
Landlocked salmon populations were last known to spawn in Finland in the 1970s. Due to construction of
hydroelectric power plants the populations ceased to be able to migrate back to their spawning grounds.
Since then, the Lake Saimaa landlocked salmon population has been dependent on fish farming in Finland.
To enhance natural reproduction, the first parental fish of landlocked salmon were released in autumn 2013
into their former spawning river, the River Ala-Koitajoki. The fish originated either from Paltamo fisheries
research station (n=24) or from the River Pielisjoki (n=9). The farmed fish were either standard reared
(n=12) or enriched reared (n=12). The fish from the River Pielisjoki were originally stocked under Kuurna
hydroelectric dam as smolts and were now returning to spawn. All fish were released into two different sites
in the River Ala-Koitajoki and they were tagged with ATS radio telemetry tags for follow-up of their
spawning behaviour. The salmon were monitored from the beginning of October until the end of November.
Monitoring was done with handheld antennas and field logging stations. After the spawning season their
redds were localized by snorkeling. Based on our preliminary results it seems that the migration pattern in
the river is dependent on the release site as well as the origin and rearing background of the fish. The
telemetry recording will be repeated in two additional autumns.
Modelling the transport and fate of contaminants in the aquatic environment
Timo Huttula1, Janne Juntunen1 & Katri Rankinen2
1
Finnish Environment Institute, Jyväskylä, Finland; 2Finnish Environment Institute, Helsinki, Finland
Despite the highly developed waste water treatment and the process of drinking water production, several
factors may threaten water safety. Harmful contaminants such as microbes and chemicals of diverse sources
are not always sufficiently removed or disinfected and they may be transported from water resources to
consumer waters. The same water resource is often a recipient of municipal and industrial waste waters, as
well as nutrients released from agriculture and settlement in the catchment area. The phenomenon being
18
multidimensional, there is a need for holistic, system-wide approach to water safety. We present modelling
approach and results from the 4-year Conpat research project funded by the Academy of Finland. The basic
challenge in our modelling work is how certain harmful contaminants in recipient waters of sewage
treatment plant are transported downstream and finally to a consumer's tap? We apply mathematical models
(3D COHERENS lake model and SOBEK river model) in order to simulate the transport of microbes and
chemicals originating from purification plants in Pyhäjärvi (Viinikanlahti and Rahola) and in the study area
to the drinking water production site in Virttaankangas Esker, in which the groundwater models MODFLOW
and MT3DMS are used for contaminant fate computation by Turku Region Water Ltd. A new version of
catchment model INCA is formulated by University of Reading and other international collaborations to
simulate the functions of pathogens in the catchment.
Fishery regulation has effect on the ecological status of lakes
Ain Järvalt & Lea Tuvikene
Centre for Limnology, Estonian University of Life Sciences, Tartu, Estonia
Though the ecological status of Lake Võrtsjärv (270 km2, mean depth 2.8 m) can be estimated to be only
moderate, several status indicators have been showing promising trends during the last decade. The positive
tendencies occur independently of the water level which is generally the leading factor influencing biota in
this lake. Moderate status is determined mainly by low water transparency, high pH and chlorophyll a
concentration, and by dominance of Myriophyllum spicatum L. among submerged macrophytes. The long
decreasing trend in P concentrations in water has lowered also the sediment P content resulting in less P
released through sediment resuspension. The decreasing trend of biochemical oxygen demand and
chlorophyll a, and increasing number of phytoplankton species are the most prominent positive trends. Fish
composition of Võrtsjärv was successfully and for many years improved via rearrangements of fishery: since
1970s there are used only passive fishing gears – fyke nets and gill nets. Bycatch of fyke nets was 100-250
tons per year of non-valuable fish (mostly small bream, white bream, roach) which was used as food for
domestic animals, and this arrangement functioned as biomanipulation. Since 2010 there is no market for
small fish anymore and professional fishermen release most of bycatch back into the lake. Mean value of
CPUE gained from experimental trawling applied yearly since 1978 was 250 kg per trawl hour in 2011 and
increased two-fold by 2014 (475 kg). This way, the abovementioned positive indications for status
improvement of Võrtsjärv may discontinue or revert.
Brownification of large lakes in Finland - implications to ecological status
Marko Järvinen
Freshwater Centre, Finnish Environment Institute (SYKE), Jyväskylä, Finland
Lakes are experiencing simultaneous impacts from multiple stressors. Recent results (Arvola et al. 2010)
have shown a reduction in total phosphorus and total-nitrogen in many large (>100 km2) lakes in Finland
during the last decades. At the same time reports on increased water colour, i.e. brownification, has been
reported from lakes in Northern Europe. In this study, water colour, total carbon (TOC), and ecological
status from 20 large lakes from southern to northern Finland, earlier studied by Arvola et al. (2010), are
analyzed to detect long-term trends and regional differences. The data sets represent summer period (JuneAugust) from the late 1970s to the present. In this study the focus is on three questions: 1) Are there any
systematic long-term increase in water colour in the large Finnish lakes?, 2) Are there regional differences in
19
changes in water colour in different parts of Finland, and 3) Are the changes in water colour reflected to
ecological status of lakes during the last 30 years?
Lake Onego biomonitoring: estimates of spatial-temporal heterogeneity and scales of biological
processes
Nataliya Kalinkina, Tamara Polyakova, Mariya Syarki, Elena Tekanova & Tatyana Chekryzheva
Northern Water Problems Institute, Petrozavodsk, Russia
Lake Onego still retains the natural state in the main area that determines the uniqueness of this lake.
However, the changes of some parts of the lake occur due to human impacts and climate change, which
requires biomonitoring. The modern biomonitoring includes the following requirements: to investigate the
dynamic of ecosystems; to take into account the spatial and temporal scales of biological processes and their
regional particularities. The state of biota is determined by various factors of different scales, such as
geological factors, climate change, long-term human impacts, annual cycles, and stochastic factors. The
analysis of these factors was the basis of scientific recommendation for the biomonitoring of Lake Onego.
The high heterogeneity of the benthic communities habitat was revealed which related to the ancient and
recent tectonics and influence of anthropogenic factors. It was shown that annual cyclical patterns of
plankton were one of the bases for monitoring of Lake Onego as large water body. The phenology
investigation of plankton communities allows to study the impact of climate change and to assess the
sustainability of the ecosystem as a whole. The transformation of aquatic communities in the conditions of
long-term anthropogenic influence (wastewater of pulp-and-paper industry) was analyzed. The
recommendations were proposed and the biotic indices system was developed to assess the current state of
Lake Onego ecosystem.
Changes in water temperature and chemistry preceding the massive kill of bottom-dwelling fish: an
analysis of high–frequency buoy data of shallow Lake Võrtsjärv (Estonia)
Külli Kangur, Kai Ginter, Peeter Kangur, Andu Kangur, Peeter Nõges & Alo Laas
Centre for Limnology, Estonian University of Life Sciences, Rannu, Estonia
Massive fish kills are wide-spread but information on exact causal mechanism is lacking. In large shallow
Lake Võrtsjärv, an unexpected fish kill occurred since the middle of June 2013. At the time of the fish kill,
an investigation of species composition, number and sizes of dead fish along the lake shore was carried out.
To find out possible causes of the fish kill, we analysed the dynamics of key physical and chemical
parameters of lake water (including diurnal fluctuations of water temperature (WT), pH, dissolved oxygen
(DO), ammonium ion concentrations (NH4-N), and the development of water stratification) during the
growing season of 2013 using high-frequency water quality monitoring buoy and monthly manual
monitoring data. Water data since 2010 when there was no fish kill, were used as a reference. The results
suggest that the fish kill was induced by a combination of successive and co-occurring extreme water
parameters such as high WT (up to 24.5 oC), pH (up to 9.2), and NH4-N (up to 0.13 mg N L-1), short-term
stratification and low DO concentration in the bottom water (0.49 mg L-1, saturation 5.4%) induced by quick
warming up of this shallow lake after a long ice-covered period and leading to a likely ammonia poisoning
and hypoxia. The main target species was the bottom–dwelling ruffe (Gymnocephalus cernuus) indicating
that the summer kill started at the bottom of the lake. The event highlights the significance of short-term
disturbances on fish populations, which can be detected only using high–frequency monitoring data.
20
Effects of macrophytes, fish and metazooplankton on a microbial food web
Katrit Karus, Priit Zingel, Helen Agasild, Tõnu Feldmann & Tiina Nõges
Centre for Limnology, Estonian University of Life Sciences, Rannu, Estonia
The influence of macrophytes, planktivorous fish and metazooplankton on different trophic levels of aquatic
food webs, especially on microbial loop, is only poorly studied. Our studies focused on the following aspects
– how macrophytes as habitats and planktivorous fish as predators shape the microbial communities in
eutrophic lakes. The results of the studies appeared that macrophyte distribution and changes in their
community influence strongly the distribution, diversity and abundance of different ciliate groups. Also
planktivorous fish feeding had remarkable effects on the zooplankton community structure – in the presence
of fish, small-sized metazooplankton dominated, while in the absence of fish large forms prevailed. Despite
the predation pressure of planktivorous fish on metazooplankton was high, it did not cascade down to the
microbial loop communities as we expected. Our study demonstrated that we must also know the species
composition of different planktonic groups not only their abundance and biomass – are predaceous species
present or have some species developed defensive responses against predation? Only by knowing the species
composition of all the planktonic organisms can we predict changes in food web dynamics. In addition to
that fish not only consumed large-sized metazoans, which are generally considered as the principal food
source for fish, but also fed small-sized protozooplankters, which importance in fish feeding is strongly
underestimated. Our study showed that without consumption of protozoans the daily food requirement for
larval fish would not be met as in eutrophic lakes zooplankton community is often dominated by small-sized
protozoans and the share of metazoans is minute.
Challenges of nutrient load reduction in the catchment of Lake Pyhäjärvi (SW Finland) in fluctuating
climate
Teija Kirkkala
Pyhäjärvi Institute, Kauttua, Finland
Eutrophication caused by anthropogenic nutrient pollution has become one of the most severe threats to
water bodies. Agricultural non-point sources have been increasingly identified as the largest source of
nutrient loading. Lake Pyhäjärvi is a good example of a large and shallow lake that suffers from
eutrophication and is subject to measures to improve this undesired state under changing conditions. Climate
change is one of the most important challenges faced by Lake Pyhäjärvi and other water bodies. Seasonal
suspended solid, phosphorus and nutrient load of inflowing rivers were calculated on the basis of long term
hydrological and water quality data. Our results show that climatic variation affects the amounts of runoff
and nutrient loading and their timing during the year. The findings from the study area concerning warm
winters and their influences on nutrient loading are in accordance with the IPCC scenarios of future climate
change. Therefore new, effective methods for the reduction of nutrient loading and the treatment of runoff
waters from agriculture, such as sand filters, were tested in Pyhäjärvi catchment in field conditions. The
results confirm that the filter technique is an applicable method for nutrient reduction, but further
development is needed. The ability of sand filters to absorb nutrients can be improved with nutrient binding
compounds, such as lime. The filters can be used as an additional nutrient reduction measure, but primarily
the nutrient release from land area should be prevented by improving soil condition and using sustainable
agricultural practices.
21
A process-based model for simulation of lake oxygen and dissolved inorganic carbon
Petri Kiuru1, Anne Ojala2 & Timo Huttula1
1
Finnish Environment Institute, Jyväskylä, Finland; 2University of Helsinki, Lahti, Finland
Freshwater lakes are important in carbon cycling especially in the boreal zone, ventilating carbon originally
fixed by the surrounding terrestrial system. Advances in high-frequency measurement of surface water
concentration and air-water flux of carbon dioxide (CO2) form the basis for model development and enable
reliable model validation. We present a one-dimensional process-based model for simulating the vertical
distribution of dissolved oxygen (DO) and dissolved inorganic carbon (DIC) in boreal lakes. The model is an
extension of a lake model MyLake which simulates lake thermodynamics and phosphorus–phytoplankton
dynamics. The model includes oxygen production by photosynthesis and surface reaeration as well as
oxygen consumption by respiration and biochemical and sediment oxygen demand. The production of CO2 is
coupled to consumption of oxygen. We calibrated and validated the model with measurement data from Lake
Valkea-Kotinen, a steeply stratified, humic lake (years 2002–2005). We found that the lake is a demanding
target for modelling due to its tendency to incomplete spring mixing. Nevertheless, the model reproduces
measured CO2 distributions reasonably well at different depths, Nash-Sutcliffe efficiencies being 0.46–0.79
in the calibration period and 0.25–0.38 in the validation period. The model is quite capable of describing
seasonal DO and DIC conditions even though biochemical and sedimentary oxygen demand as well as
phytoplankton dynamics are implemented in a rather simplified manner. The model can be efficiently
utilized to predict the effects of climate change on carbon cycling in boreal lakes.
Abiotic and biotic response of boreal lakes to episodic weather events
Jonna Kuha1, Lauri Arvola2, Paul Hanson3, Jussi Huotari2, Timo Huttula4, Janne Juntunen4, Marko Järvinen4,
Kari Kallio5, Mirva Ketola6, Kirsi Kuoppamäki6, Ahti Lepistö5, Annalea Lohila7, Riku Paavola8, Jussi
Vuorenmaa5, Luke Winslow9 & Juha Karjalainen1
1
Department of Biological and Environmental Science, University of Jyväskylä, Finland; 2Lammi Biological
Station, Finland; 3University of Wisconsin, Madison, USA; 4Finnish Environment Institute, Jyväskylä,
Finland; 5Finnish Environment Institute, Helsinki, Finland; 6University of Helsinki, Lahti, Finland; 7Finnish
Meteorological Institute, Finland; 8Oulanka Reseach Station, Finland; 9U.S. Geological Survey, Middleton,
Wisconsin, USA
Impacts of weather induced episodic mixing events on lake ecosystems are often unpredictable. They are
typically followed by a rapid abiotic response, including changes in water temperature and stratification, and
poorly understood effects on the lake’s biology. In this study we used high-frequency automated water
quality monitoring station data from eight boreal lakes to examine how the frequency and magnitude of
episodic weather related events (increased wind speed and changes in air temperature) influenced the thermal
structure, dissolved oxygen (DO), chlorophyll a (Chl-a) and gross primary production (GPP) in lakes with
varying size during the stratified period. To assess ecosystem resilience to disturbance, the return period of
the observed disruptions were also examined. Wind speed had an effect on both abiotic and biotic variables
of the lakes with low water column stability. Lakes with high stability had little response in the hypolimnetic
DO but mixing of the epilimnion had an effect on lake primary production (Chl-a and GPP). The events had
three different effects on Chl-a. In an oligotrophic dimictic Konnevesi mixing had a long lasting effect on the
seasonal Chl-a. In two eutrophic lakes, Vesijärvi and Vanajanselkä, mixing decreased surface water Chl-a,
then increased post-event in Vanajanselkä while in Vesijårvi Chl-a remained at the pre-event level. Although
the weather events that caused the severe changes in the water column were infrequent, knowing the severity
of the events would allow the prediction on how future changes may influence the boreal lakes.
22
Long-term trends in global lake surface temperature: A century of measurements from in situ and
remotely sensed data
John Lenters1, Jordan Read2, Sapna Sharma3, Catherine O'Reilly4, Stephanie Hampton5, Derek Gray6, Peter
McIntyre7, Simon Hook8, Philipp Schneider9, Noemi Barabas10, Dendy Lofton11 & GLTC Contributors
1
Water Resources, LimnoTech, Ann Arbor, USA; 2USGS, Madison, USA; 3York University, Toronto,
Canada; 4Illinois State University, Normal, USA; 5Washington State University, Pullman, USA; 6California
University of Pennsylvania, California, USA; 7University of Wisconsin-Madison, Madison, USA; 8California
Institute of Technology, NASA JPL, Pasadena, USA; 9Norwegian Institute for Air Research, Kjeller,
Norway; 10LimnoTech, Ann Arbor, USA; 11LimnoTech, Oakdale, USA
Recent studies have shown significant warming of inland water bodies throughout the world. To better
understand the patterns, mechanisms, and ecological implications of global lake warming, an initiative
known as the “Global Lake Temperature Collaboration” (GLTC) was started in 2010, with the objective of
compiling and analyzing lake temperature data from numerous satellite and in situ records dating back at
least 20-30 years. The GLTC project has now assembled data from over 250 lakes, with some in situ records
dating back more than 100 years. Here, we present an analysis of the long-term warming trends, interdecadal
variability, and a direct comparison between in situ and remotely sensed summer lake surface temperatures
from 1895-2009. The results show consistent trends of increasing summer-mean lake surface temperature
across most but not all sites. Lakes with especially long records show accelerated warming in the most recent
two to three decades, with almost half of the lakes warming at rates in excess of 0.5 °C per decade during the
period 1985-2009, and a few even exceeding 1.0 °C per decade.
Potential application of Limnothrissa miodon (Boulenger, 1906) daily ration and population food
consumption estimates to predict the potential standing biomass in Lake Kariba, Zambia/Zimbabwe
Jimmiel Mandima
Department of Biology, University of Eastern Finland, Kuopio, Finland
In Lake Kariba, the pelagial is dominated by the Lake Tanganyika clupeid, Limnothrissa miodon, which is
mainly zooplanktivorous. The population dynamics of this freshwater sardine shows a lot of seasonal
fluctuations that are directly related to physical processes that influence the trophic status of the lake. Diel
feeding periodicity and mean stomach fullness of L. miodon were used to estimate the daily ration and
population food consumption rates in Lake Kariba. The daily ration (Rd) was estimated from mean stomach
contents and evacuation rates using the modified Bajkov (1935) formula. Data on stomach contents present
at different time intervals over continuous feeding cycles under experimental conditions were analysed using
the MAXIMS Model. The results showed a daily ration of 8.8-9.9% of fresh body weight per day. The
estimated population food consumption rate points to very efficient grazing. It is concluded that if this
grazing rate is used as a guideline, it should be possible to estimate the potential standing biomass of L.
miodon that the lake can sustain under a known zooplankton standing biomass regime. Considering that Lake
Kariba is an artificial reservoir, the daily and seasonal variability of input parameters is likely to be very
high. It is recommended that a more intensive study that accommodates spatial and temporal dynamics and
climate change influences be conducted in order to come up with a realistic food consumption estimate for
the L. miodon population in Lake Kariba that informs a predictive model for standing biomass of this
freshwater fishery.
23
Potential for the ecologically sustainable yield (ESY) of vendace from Finnish large lakes
Timo Marjomäki1, Tapio Keskinen2 & Juha Karjalainen1
1
Department of Biological and Environmental Science, University of Jyväskylä, Finland; 2Natural Resource
Institute Finland, Jyväskylä, Finland
Vendace (Coregonus albula) is the main target for commercial fishing in ca. 70 large Finnish lakes and
notorious for its strong and unpredictable stock fluctuations. The new Fishing Act stipulates that fisheries
must be managed ecologically, economically and socially sustainably and that the intensity of fishing must
be adjusted based on the best available knowledge. To this end we combined the available information on the
biological variables affecting vendace production and firstly, roughly approximated the potential average
ESY for the study lakes with most detailed data available and secondly, expanded the results to approximate
the potential total yield for the Finnish commercial inland vendace fisheries. We assessed the effect of the
uncertainty and natural variability of the key variables on the accuracy and precision of the ESY estimate.
The majority of the high uncertainty in these estimates stems from our limited knowledge on the probability
and duration of the long term recession periods, i.e. several subsequent very sparse year classes, typical of
vendace. Therefore, commercial vendace fisheries should be managed according to the principles of adaptive
management: Fishing itself together with complementary monitoring methods must produce continuous
information flow for stock assessment. The fishing mortality, technically the number of commercial fishing
units allowed in certain lake and year, must be adjustable according to the stock status without too much
delay. The possibility of the commercial fishing units to switch between different lakes would promote the
demanded flexibility.
Structural changes in three coastal fish assemblages in the northern Baltic Sea archipelago
Noora Mustamäki & Johanna Mattila
Environmental and Marine Biology, Åbo Akademi University, Finland
Globally, evidence for structural changes in coastal marine ecosystems is increasing. Coastal areas are
ecologically and socio-economically important, and under multiple anthropogenic stressors. In this study,
changes in the structure of fish assemblages were observed during a ten-year study period (1999–2009) in
three coastal areas in the northern Baltic Sea. The assemblages differed from each other in terms of species
abundances, but a similar shift towards higher proportions of cyprinid fish and lower proportions of
pikeperch (Sander lucioperca) was observed in all study areas. The resulting proportional increase of the
small-bodied lower trophic level cyprinids was also reflected as declining mean length and mean trophic
level of fish in all three assemblages. The results indicate that in the studied systems similar structural
changes occurred simultaneously within a relatively short period of time. Variation in the fish species
abundances was related to environmental factors and catches of commercial fisheries. The results suggest
that the observed changes were caused by regional patterns of eutrophication in combination with fishing
pressure.
24
Hypolimnetic aeration intensifies phosphorus recycling and increases organic material sedimentation
in a stratifying lake: Effects through increased temperature and turbulence
Juha Niemistö, Petrina Köngäs, Laura Härkönen & Jukka Horppila
1
Department of Environmental Sciences, University of Helsinki
The effect of hypolimnetic aeration on the sedimentation of inorganic and organic material as well as
phosphorus was examined in a spatially comprehensive investigation in a dimictic northern temperate lake in
southern Finland. Two years of aeration strongly increased the gross sedimentation of dry matter (44 %) and
phosphorus (70 %). Although the organic content of the settling material decreased, the total amount of
organic matter reaching the lake bottom increased by 31 %. This was due to an aeration-induced increase in
the hypolimnetic water temperature and turbulence, which not only increased the mineralization of organic
matter but also phosphorus recycling, and consequently the production of excess organic material.
Carbon sequestration by an alkaline lake
Peeter Nõges1, Sirje Vilbaste1, Tõnu Martma2, Eva-Ingrid Rõõm2 & Tiina Nõges1
Estonian University of Life Sciences, Tartu, Estonia, 2Institute of Geology at TUT, Tallinn, Estonia,
For a long time, lakes were considered unimportant in the global carbon (C) cycle because of their small total
area compared to the ocean. Over two last decades, a number of studies have highlighted the important role
of lakes in both sequestering atmospheric C and modifying the C flux from the catchment by degassing CO2
and methane and settling calcite and organic matter to the sediment. Based on a full C mass balance, high
frequency measurements of lake metabolism and stable isotope analysis of the in-and outflowing waters of a
large shallow lake in Estonia, we attempt to show that alkaline lakes in carbonate catchments, although
processing large amounts of carbon, mostly just re-precipitate fossil carbon derived from carbonate rocks in
the catchment and rapidly degass CO2 that was bound during the weathering process compromising in this
way the value of carbonate weathering as a temporary sink for atmospheric CO2. Even the C bound in
organic matter by phytoplankton and macrophytes and accumulating in the sediments in this type of lakes
originates largely from the catchment and not from a new uptake from the atmosphere.
Cascading fisheries impact on the ecosystem of a large and shallow eutrophic lake
Tiina Nõges, Ain Järvalt, Alo Laas & Peeter Nõges
Estonian University of Life Sciences, Tartu, Estonia
In large lakes fish yield and composition can be considered as one of the most important “ecosystem
services” that also has a cascading impact on other ecosystem services as e.g. water quality, plankton
composition and water blooms. Moreover, the commercial fishery can be an important anthropogenic
stressor controlling ecosystem status and its services in large lakes. The impact of commercial fisheries on
the status of lakes has been poorly studied and in most cases fish as a biological quality element is omitted in
water bodies with commercial fisheries. Large and shallow eutrophic Lake Võrtsjärv in Estonia has intensive
commercial fisheries with well documented catches for all commercial fish species. The lake is unregulated
and has a peculiar hydrology. Fluctuating water level is a powerful factor affecting the functioning of the
ecosystem through sediment resuspension, internal loading of nutrients, altered underwater light conditions
and modified spawning conditions for fish. In present study we analyze available long-term (<40-year) data
25
series on biota, fish (catch per unit effort and commercial catches), hydrochemistry, hydrology, and
meteorological parameters to find out the effect of fisheries on fish community structure and its cascading
effects on other ecosystem components. We demonstrate for the first time that pikeperch can be important in
controlling phytoplankton biomass. Based on short-term high frequency studies we could reveal connections
between high temperature, intensive primary production and fish-kill events.
Climate scenarios to phosphorus load to a large boreal lowland lake - case study in Lake Peipsi
drainage basin
Kristjan Piirimäe
Institute of Environmental Engineering, Tallinn University of Technology, Tallinn, Estonia
The aim was to determine climate change impact to the ecological quality of lakes. In this purpose, I studied
the effect of future potential increase of water runoff to the load of P in lake Peipsi, a large boreal lowland
lake. The drainage basin of Peipsi, 44 725 km2, is shared mostly by two countries: Estonia and the Russian
Federation. PolFlow model, based on raster GIS, was applied, calculating a five-year average load and
concentration of P in each km of stream segments. The input data involved point and diffuse emissions and
retention in streams. The calculation of diffuse emissions used parameters based on landcover and soil
texture. Slope erosion was calculated for steep and cultivated slopes. Two scenarios were considered:
‘actual’ scenario, representing P load nowadays, and ‘wet’ scenario, representing a ‘high change’ climate
situation in 2040 - 2069. As P load changes proportionally with water runoff, it will increase, in case of
‘damp’ scenario, by 16%. In the Estonian rivers the increase will be more than 20% while in Russian rivers
less than 15%. Such difference comes mostly from the fact that Russian rivers receive more load from point
sources while diffuse load plays less important role there. Erosion process, according to the model, removes
significant amount of P from cultivated soils but waterbodies receive only a small fraction of that. Thus,
erosion formed only ca 1% of the total P load. Although erosion might increase by 25 – 40%, it will not
necessarily rise total P load.
Drastic changes in the fish community of Lake Constance Upper lake with re-oligotrophication
Roland Rösch
Fisheries Research Station Baden-Württemberg, LAZBW, Langenargen, Germany
Lake Constance Upper Lake has undergone re-oligotrophication in recent years. With actually 6 µg P L-1 Pconcentration is now back at the level before eutrophication. A statistics of the professional fisheries yield
exists since 1910. Actually about 120 professional fishermen and > 10.000 anglers are active on the lake.
Whitefish (Coregonus lavaretus) and perch (Perca fluviatilis) are the economically most important species.
A routine monitoring is done on both species. Age at catch of whitefish increased from 2 years during the
eutrophic phase to 3-5 years now. Fishing depth, shown as mean depth of pelagic gill nets, decreased. During
the eutrophic phase perch were found in the pelagic zone of the lake. Its main prey was zooplankton. Now
perch are piscivorous again from a size of 12 cm on and and stay nearshore throughout the year.
Since middle of the 1990’s professional fisheries yield decreased drastically, and in 2014 only 434 t of fish
were caught, with 69 % whitefish and 12 % perch. This is a yield as low as before eutrophication. For
comparison, only 10 years earlier (2004) 1049 t of fish (77% whitefish and 15 % perch) had been caught.
This decrease caused an economically very serious situation for the professional fishermen. It is assumed,
26
that fisheries yield will remain at this low level. In the presentation long-term trends will be shown more in
detail.
Impacts of oligotrophication on seasonality and depth distribution of chlorophyll in a deep large lake –
Lake Constance.
Karl-Otto Rothhaupt & Dietmar Straile
Limnological Institute, University of Konstanz, Konstanz, Germany
Upper Lake Constance (A 473 km2; Zmax 254 m) is a warm-monomictic peri-alpine lake, bordering Germany,
Switzerland and Austria. In the second half of the 20th century, Lake Constance became eutrophicated due to
wastewater disposal in the whole catchment area. Owing to successful restoration measures, total phosphorus
concentrations during spring overturn dropped from a peak level of 87 µg/L in 1979 to actual values of ca. 6
µg/L. Long-term data from 1980 to 2013 with a high temporal (weekly sampling during the vegetation
period) and spatial resolution (ca. 20 measurements per depth profile) allow for the analysis of seasonal and
vertical patterns of chlorophyll concentrations and their responses to re-oligotrophication. During the shift of
Lake Constance from eutrophic back to oligotrophic, the chlorophyll dynamics mirrored the dichotomy in
the typical seasonal patterns that, according to the PEG model, occur in stratifying lakes with and without
elevated levels of summer algal biomass. In eutrophic times, Lake Constance displayed the typical biphasic
chlorophyll pattern of an early spring algal bloom and high summer algal crops that are separated by a
clearwater phase in late spring. With decreasing trophic state, the biphasic chlorophyll pattern was gradually
lost. First, the summer algal biomass decreased, and subsequently chlorophyll during spring. With a lower
spring bloom the clearwater phase became less pronounced. These changes were accompanied by altered
chlorophyll depth distributions, i.e., with oligotrophication light penetration was improved and the deepened
euphotic zone allowed for the vertical extension of the algal growth zone.
Beta diversity patterns of phytoplankton, periphytic diatom and macrophyte communities in a large
lake (Lake Ladoga, Northwestern Russia)
Alexander Rusanov1, Elena Protopopova1 & Eva Acs2
1
Institute of Limnology RAS, St. Petersburg, Russia; 2Danube Research Institute MTA, Budapest, Hungary
Beta diversity - spatial turnover of community composition - is simultaneously regulated by different
extrinsic and intrinsic factors. Extrinsic factors include environmental heterogeneity and spatial processes,
while intrinsic factors include species characteristics related to dispersal ability. Body size belongs to species
traits with detected effect on beta diversity. Since organisms with smaller body size are less dispersallimited, and a high rate of dispersal reduces compositional differences among sites, it should negatively
affect species turnover rate. In this study, beta diversity of phytoplankton, periphytic diatoms and
macrophytes and their controlling factors were investigated in littoral zone of Lake Ladoga. We compared
beta diversity patterns across these communities to test whether spatial species turnover is linked to dispersal
ability. Data were analysed by using a distance-based approach and variation partitioning based on canonical
correspondence analysis. We found faster turnover of compositional similarity with spatial distance for
macrophytes than for phytoplankton and periphytic diatoms. At the same time, comparison of two groups of
periphytic diatoms with different mode of attachment - firmly and loosely attached taxa - revealed that the
former group had significantly higher rate of spatial turnover than the latter. According to variation
partitioning, both environmental heterogeneity and spatial gradient were important drivers for the turnover of
27
macrophytes and periphytic diatoms while turnover of phytoplankton was controlled solely by environmental
variation. Our results indicate that the importance of environmental and spatial effects on beta diversity
patterns may be predicted using species traits (body size, mode of attachment) related to dispersal ability.
Seasonal effects on fish distributions: effects from biotic and abiotic factors
Atle Rustadbakken & Thrond Haugen
Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas,
Norway
Understanding processes that affect fish distribution in time and space is of profound importance in fisheries
and ecological research. Fish species differ in preferences and tolerance towards temperature and
eutrophication, and in behavioural responses towards predator- and prey densities. Spatiotemporal variations
in environmental attributes affects the spatiotemporal distribution patterns of fish species. Hydroacoustics
surveys data are attained by continuous sampling along transects. As a consequence, the data are
spatiotemporarilly autocorrelated. The autocorrelation structure holds important biological information
pertinent to understanding the spatial distribution structure. By including the autocorrelation structure in
statistical models inferences about degree of evenness or patchiness in the distribution of fish can be
quantified. By including such as day of year, time of day, water quality, temperature and zooplankton
availability as explanatory variables driving mechanisms behind observed distributions may be better
understood and quantified. We explore seasonal effects on fish and zooplankton distributions in Lake
Maridalsvann. The lake serves as drinking water reservoir for the large city Oslo, and is strictly protected
against anthropogenic interventions. The lake constitutes a rare opportunity for studying fish distribution
dynamics in a lake under insignificant anthropogenic influence. During June-October 2013, monthly day and
night high-resolution hydroacoustics surveys were undertaken. In addition, stratified gillnet surveys were
performed along with quantitative zooplankton sampling and water quality profiling. The influence of
temperature, oxygen, turbidity and zooplankton on seasonal spatiotemporal autocorrelation structure in the
individual-based echosounding data is quantified. Comparisons among candidate model structures along
with their ecological inferences is presented.
Responses of fish and zooplankton to the pumping of epilimnetic water into hypolimnion in Lake
Vesijärvi
Jukka Ruuhijärvi1, Tommi Malinen2, Kirsi Kuoppamäki3, Pasi Ala-Opas1 & Mika Vinni1
1
Natural Resources Institute Finland, Lammi, Finland; 2University of Helsinki, Helsinki, Finland; 3University
of Helsinki, Lahti, Finland
In order to prevent anoxia and the release of phosphorus from sediment, epilimnetic water has been
mechanically pumped to hypolimnion of the Enonselkä Basin of Lake Vesijärvi since 2010. During summer,
this has increased hypolimnetic temperature, which might be harmful to fish and zooplankton species
dependent on cool water habitat. Enonselkä Basin has been rehabilitated through food web management for
almost 30 years. Pumping may induce unwanted consequences, such as the increase of cyprinid fish
populations. Fish stocks were monitored before (2009) and during (2011-2014) pumping. Zooplankton was
studied in 2009, 2011 and 2013. Fish were studied with hydroacoustics (abundance and biomass) and
experimental fishing using multimesh gillnets and pelagic trawl (community). Zooplankton was sampled
fortnightly in May-October. The population of smelt, the most important pelagic planktivore, collapsed in
28
2010. The vacant niche of smelt was partially occupied by young perch in 2011, but cladocerans,
nevertheless, reached high biomasses. The smelt stock gradually recovered in 2012-14, while cyprinids did
not increase in the pelagial. Percids dominance over cyprinids persisted in the entire basin, both in pelagial
and littoral. The biomasses of cladocerans and predatory zooplankton increased over the course of the three
study years and also the body size of cladoceran grazers increased. The age structure of smelt population
turned into the prevalence of young-of-the-year fish. The changes in pelagic fish and zooplankton
communities seem to be largely driven by the fluctuation of smelt population, which is strongly impacted by
variations in summertime temperatures. Pumping appears to enhance these changes.
Unravelling anatoxin-a in the large lakes south of the Alps: Occurrence and toxic potential of
Tychonema (Cyanobacteria)
Nico Salmaso, Camilla Capelli, Adriano Boscaini & Leonardo Cerasino
DASB-LEF, Fondazione Mach - Ist. Agrario S.Michele all'Adige, S. Michele all'Adige, Italy
The investigations carried out in the largest lakes south of the Alps (Garda, Iseo, Como and Maggiore) have
demonstrated, besides the widespread occurrence of microcystins (MCs), the presence of significant
concentrations of anatoxin-a (ATX). Genetic analyses and metabolomic profiling of strains isolated from
Lake Garda allowed excluding both Dolichospermum lemmermannii and Planktothrix rubescens among the
potential producers of ATX. P. rubescens is the dominant cyanobacterium in the deep subalpine lakes. From
the other side, extended surface blooms of D. lemmermannii were recorded for the first time in Lake Garda
in 1990/91, and successively in the other deep southern subalpine lakes. The problem arising from the
production of ATX without the apparent identification of a toxin producer was elucidated in Lake Garda in
the spring 2014. During the isolation of cyanobacteria filaments, several strains of Tychonema bourrellyi
(Oscillatoriales) were identified and cultivated. Successive analyses demonstrated that this species was able
to produce consistent amounts of ATX. This was confirmed also by the amplification of genes involved in
the biosynthesis of ATX and by the discovery of ATX producing populations of T. bourrellyi and T. bornetii
in Norwegian waterbodies. Preliminary analyses, still in progress, are demonstrating that similar populations
of Tychonema able to synthetize ATX are present also in the other largest lakes south of the Alps. In this
contribution we will evaluate i) the taxonomic attribution of several Oscillatoriales strains in the subalpine
lake district by phylogenetic analyses, and ii) the toxic potential of populations by metabolomic profiling and
genetic analyses.
Assessing the potential of remote sensing derived variables to explain spatial variation in fish
distribution and assemblage composition in large lakes
Alfred Sandström1, Petra Philipson2, Anders Asp1, Anders Kinnerbäck1 & Thomas Axenrot1
1
Aquatic Resources, Freshwater Research, Drottningholm, Sweden; 2Brockmann Geomatics AB, Kista,
Sweden
A number of ecological indicators can be measured with remote sensing techniques with a higher temporal
and spatial resolution than with traditional water monitoring methods. We have tried to test if this auxiliary
information can be used to: i) explain patterns in fish distribution and assemblage composition, ii) optimize
the design of fish monitoring programs and iii) assess ecological status in large water bodies. We have used
images from the MERIS satellite (active from 2002-2012) which was developed specifically for water color
measurements. MERIS derived layers describing chlorophyll a (chl a), total suspended matter (TSM) and
29
colored dissolved organic matter (CDOM) was overlaid on all available fish monitoring data from the four
largest Swedish lakes (L. Vänern, L. Vättern, L. Mälaren and L. Hjälmaren). We assessed the influence of
remote sensing derived parameters in the three main habitats in large lakes: the pelagic, the offshore benthic
and the inshore benthic. Our results demonstrated that chl a as well as CDOM together with depth at the
sampling site explained a significant part of the variation in the distribution of individual species as well as
assemblages. These predictors were particularly important in the pelagic but also in inshore areas. Remote
sensing was considered as a useful tool for modelling fish distributions and to describe pressure variables
such as eutrophication. Additionally, it can be useful when ensuring that existing fish species and
assemblages are representatively collected with the desired habitat coverage in monitoring programs.
Planktivorous fish regulate crustacean zooplankton dynamics in a large, shallow lake
Jouko Sarvala1, Harri Helminen2, Marjo Tarvainen3 & Anne-Mari Ventelä3
1
Department of Biology, University of Turku, Finland; 2Centre for Economic Development, Transport and
the Environment Southwest Finland, Turku, Finland; 3Pyhäjärvi Institute, Kauttua, Finland
Relationships between crustacean zooplankton and planktivorous fish were assessed from a 26-year time
series from the mesotrophic Lake Säkylän Pyhäjärvi in SW Finland (area 155 km2, mean depth 5.4 m). The
size of one-summer-old vendace (Coregonus albula), the most important planktivorous fish in the lake, was
used to indicate the predation pressure by planktivorous fish. The numbers and biomass of the larger
herbivorous zooplankton, such as Eudiaptomus graciloides, Daphnia galeata and Limnosida frontosa
declined in years of high planktivory, while smaller species, such as Mesocyclops leuckarti, Thermocyclops
oithonoides, Ceriodaphnia spp., Bosmina spp. and Chydorus sphaericus, remained unaffected. Although
relatively large, the very thin and transparent Daphnia cristata and D. longiremis also maintained stable
populations. Early spring species Cyclops kolensis was to some extent affected by predation during the
previous summer. Under heavy predation, the cladoceran length distributions also shifted towards smaller
sizes. Zooplankton/phytoplankton ratio was inversely related to planktivory, indicating cascading water
quality effects of fish predation.
Distribution and population characteristics of Baikalian invader Gmelinoides fasciatus (Crustacea:
Amphipoda) in lake Onego
Anastasiya Sidorova
Institute of Northern Water Problems, KarRC, RAS, Petrozavodsk, Russia
There are pressing needs to investigate biological invaders in aquatic ecosystems in the face of long-term
changes and anthropogenic influences on these systems. Gmelinoides fasciatus (Stebbing), an amphipod
native to the Baikal region, was discovered in south-west part of Lake Onego in 2001 (Berezina, Panov,
2003). As a part of the present study spatial distribution of this recent exotic amphipod in littoral zone of the
east part of the lake was revealed. Population characteristics and reproduction of this alien species in the
Petrozavodsk and Povenets bays was investigated. According to the study results, the average density of G.
fasciatus ranged from 786 to 3454 ind. m-2, biomass from 1.1 to 7.7 g m-2. The seasonal dynamics of G.
fasciatus abundance was characterized by two peaks (in July and August). The sexual structure of the
population is stable, the sex ratio registered in G. fasciatus rarely deviate from a 1:1 ratio during the
vegetative season. Female fecundity varied from 4 to 26 eggs per female, the average variation of fertility
was 9-10 eggs per female. It can be concluded that the Baikalian amphipod G. fasciatus successfully
30
established in the new conditions on the northern border area of the European part of Russia and has a oneyear life cycle with the generations of the previous and current years. The study has been financially
supported by the Russian Science Foundation (No 14-17-00766).
Scale shape based identification of fish species inhabiting the largest shallow lake of Central Europe
Ádám Staszny1, Árpád Ferincz1, Gábor Paulovits2 & Béla Urbányi1
1
Department of Aquaculture, Institute of Aquaculture and Environmental Safety, Gödöllo, Hungary; 2Balaton
Limnological Institute (MTA ÖK), Tihany, Hungary
The suitability of fish scale shape for discriminating species or populations were proved in several studies.
The background (genetics, environmental factors) of these fine-scale differences have also been studied.
However, the relation of scale shape to taxonomical status have not been studied yet, therefore scales of ten
common fish species (roach Rutilus rutilus, chub Squalius cephalus, gibel carp Carassius gibelio, razor fish
Pelecus cultratus, bleak Alburnus alburnus, carp Cyprinus carpio, topmouth gudgeon Pseudorasbora parva,
perch Perca fluviatilis, pikeperch Sander lucioperca, rudd Scardinius erythrophthalmus), caught in the same
catchment (Balaton-catchment, Hungary) were analyzed, using landmark-based geometric morphometry to
clarify this issue. Morphometric results (CVA scores) were analyzed using UPGMA clustering. Results
showed relations between the taxonomic status and scale shape, therefore this method could be an useful and
cheap tool for the rough classification unidentified scale samples, e.g. : in case of archaeological finds, or
nutritional assessments of predators.
A littoral fish index responds to eutrophication in boreal lakes
Tapio Sutela1, Teppo Vehanen1 & Martti Rask2
1
Natural resources and Bioproduction, Natural Resources Institute Finland, Helsinki, Finland; 2Natural
Resources and Bioproduction, Natural Resources Institute Finland, Jyväskylä, Finland
In large lakes, the first signs of eutrophication may be found earlier in littoral than in pelagic zone. Littoral
fish assemblages were sampled by electrofishing in the Kitka lake group (lakes Ala-Kitka, Yli-Kitka and
Posionjärvi) in northeastern Finland at 70 nearshore sites. Water quality was also monitored, and results
indicated total phosphorus ranging from 5 to 75 µg/l across the sampling sites. Fish assemblages were
usually dominated by littoral fish species, especially European minnow (Phoxinus phoxinus) and alpine
bullhead (Cottus poecilopus). Young individuals of other fish species, such as ruffe (Gymnocephalus
cernuus), burbot (Lota lota) and perch (Perca fluviatilis) were also recorded frequently. A littoral fish index
(LiFI) was developed to respond the degree of eutrophy. Of the candidate metrics, finally three were chosen
for the index: (1) Proportion of minnow and alpine bullhead individuals in the electrofishing catch, (2)
Density of perch and (3) Average weight of all fish individuals in the catch. Values of these metrics were
adjusted to range from 0 to 1, and the LiFI index value was calculated as an average of these three metrics.
Index value responded to the extent of eutrophy; total phosphorus explained 55.3 % of the variation in LiFi
index values. Finally, the index values from the Kitka lakes were classified from Bad to High in assessing
the ecological status of the littoral sites around the studied lakes. A test of the index with data from other
Finnish lakes suggested that the index is feasible to use in a broad context.
31
High nutritional quality phytoplankton fuels food webs of large boreal lakes
Sami Taipale1, Kristiina Vuorio2, Ursula Strandberg1, Marko Järvinen3 & Paula Kankaala1
1
Department of Biology, University of Eastern Finland, Joensuu, Finland; 2Department of Biological and
Environmental Science, University of Jyväskylä, Finland; 3Freshwater Centre, Finnish Environmental
Institute, Jyväskylä, Finland
In ecological studies phytoplankton is often seen as a solid group being a homogenous food source for
primary consumers. However, the abundance of biomolecules (e.g. fatty acids and sterols) essential for
consumers’ growth and reproduction can vary greatly among different phytoplankton taxa. We studied the
availability of polyunsaturated fatty acids and phytosterols to boreal lake food webs by culturing altogether
37 strains of 10 freshwater phytoplankton classes, typical in these lakes, and analyzed their fatty acid and
sterol profiles. In addition, we analyzed the phytoplankton community composition of lakes in Finland.
Biochemical analyses showed that Cryptophyceae and Bacillariophyceae are rich in EPA and dinoflagellates
are rich in DHA, whereas Chlorophyceae or Cyanophyceae did not contain any EPA or DHA. Additionally
Cryptophyceae and Bacillariophyceae have Δ5-sterols as their primarily sterols, whereas Δ7-sterols are
major sterols among Chlorophyceae. The large dataset for the lakes showed that phosphorus and water color
had a strong impact on phytoplankton community composition. High nutritional quality taxa
(Bacillariophyceae, Cryptophyceae) seem to predominate in phytoplankton community of certain large
boreal lakes and, thus, fuelling pelagic food webs.
Russian-Swiss cooperative study of under-ice convection in Lake Onego: Preliminary results
Arkady Terzhevik1, Roman Zdorovennov1, Damien Bouffard2 & Galina Zdorovennova1
Northern Water Problems Institute, Petrozavodsk, Russia; 2Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne, Switzerland
In March 2015, the Russian-Swiss multi-disciplinary project “Lake Ladoga: Life under ice” has been started.
One of the project objectives was a field study of the under-ice convection driven by solar radiation with a
main goal to better understand physics of the phenomenon and its effect on the development of algae in the
great lakes during early spring. The following measurements were performed during 14-25 March: vertical
profiling of temperature, conductivity, dissolved oxygen, chlorophyll a for four different algae groups (one
hour apart each), and photosynthetically active radiation within the water column (one min apart). Besides,
the thermistor chain was deployed to evaluate temporal dynamics of the water temperature at smaller time
scales (down to one min). Measurements of solar radiation above and beneath the ice, registration of wind
speed/direction, air temperature and humidity, determination of ice and snow thickness during the period of
observations were also performed. First results of data analysis are demonstrated. Among others, the effect
of changing weather conditions on the course of convection is considered.
32
Decomposing variation in the species composition of specialists and generalists between local
environmental variables and spatial processes in a large lake system
Kimmo Tolonen1, Annika Vilmi1, Tapio Sutela2 & Jani Heino1
1
Natural Environment Centre/Biodiversity, Finnish Environment Institute, Oulu, Finland; 2Natural Resources
Institute Finland, Oulu, Finland
Modern views on metacommunities recognize that structuring of local communities is the interplay between
local environmental (species sorting) and regional (dispersal) processes. Theory assumes that species with
broad environmental tolerances, i.e. habitat generalists, are more dependent on the spatial processes than
environmental conditions. On the other, habitat specialists with narrow environmental tolerances should
show stronger dependence on local environmental conditions than regional processes. To test these
hypotheses, we sampled littoral macroinvertebrates from 70 stony shore sites distributed evenly along the
entire perimeter of a large (305 km2) lake system. Invertebrates were classified into specialists, intermediate
and generalist species based on the OMI-analysis (Outlying Mean Index), Levins niche breadth and
literature-based classification of habitat specialization. We decomposed variation in community composition
of species from different classes into that explained by abiotic (water chemistry, wind fetch, bottom slope
and substrate composition) and biotic (periphyton biomass and fish abundance) and spatial (PCNM, principal
coordinates of neighbour matrices) variables. Depending on the species group classification, 4-25 % of the
variation in community structure were explained by environmental and spatial variables (adjusted R2). In
general, our analyses indicated that community structuring in all species classifications were more strongly
dependent on species sorting than dispersal processes. However, the importance of environmental processes
was higher for specialist and intermediate species than for generalists. Although spatial variables accounted
for only small pure fractions (0-5 %) of the variation in community composition, the relative importance of
spatial variables was higher for intermediate and generalist species groups than for specialists.
Danger of anatoxin-a(S) and organophosphorus pesticides for aquatic ecosystem health
Valerii Tonkopii
Institute of Limnology Russian Academy of Science, St.Petersburg, Russia
Anatoxin-a(s) are mainly produced by cyanobacteria Anabaena flos-aque and A. lemmermannii. Anatoxina(s) is the only known natural organophosphorus compound with inhibition of cholinesterase (ChE). The
toxicity of anatoxin-a(s) and different organophosphorus pesticides in the experiments on Daphnia magna
and albino mice was investigated. Anatoxin-a(s) was produced by Anabaena flos-aquae clone NRC 525-17
and was purified from lyophilized cells. Besides, in experiments in vitro we investigated the antiChE activity
of compounds using the mice brain and Daphnias homogenates as source of enzyme - cholinesterase. The
results of experiments demonstrate that some organophosphorus pesticides with a very small toxicity on
mice differ extraordinary toxicity for Daphnia. The most toxic for Daphnia magna from all investigated
compounds was anatoxin-a(s).
33
Using a single metric for a water quality element may cause unfair judgement of the ecological status
of a lake
Lea Tuvikene & Tõnu Feldmann
Centre for Limnology, Estonian University of Life Sciences, Tartumaa, Estonia
Macrophytes as long-lived organisms have a great potential for development of stabile indicators to assess
ecological status of water bodies. We analyse macrophyte data from the large shallow eutrophic Lake
Võrtsjärv (Estonia) monitored during the last decade against long-term trends revealed in hydrochemical
variables to clarify the sensitivity of macrophyte parameters and their appliccability as status indicators for
the lake with a large natural variability. Dominance of single indicator species of submerged macrophytes is
currently used as the only macrophyte metric to estimate the ecological status of Võrtsjärv. This rigid
criterion stably overshadows the clear positive trends of several other quality indicators when the “one out all out” principle is applied. Myriophyllum spicatum L. covering approximately 20% of the lake area has
been the dominant submerged macrophyte species in Võrtsjärv at least since the 1990s. As invasive species it
has been set to indicate moderate ecological status of the lake. The species has shown a clear and stable
distribution pattern in Võrtsjärv over the last ten years. This way, not higher than moderate status estimate of
the lake will be always “guaranteed” unless the macrophyte metrics for water quality assessment will be
changed for this lake type. We analyse the macrophyte data to find out whether any of the macrophyte
metrics reflects the positive tendencies found in the ecological status of Võrtsjärv. The aim is to find
additional, more sensitive macrophyte metrics to improve the methodology for status assessment for this
lake.
Size limit -based management of pikeperch (Sander lucioperca) in Finnish lakes with respect to lifehistory variation
Anssi Vainikka1, Hannu Huuskonen1, Risto Eronen1, Pekka Hyvärinen2, Mikko Olin3 & Jukka Ruuhijärvi4
1
Department of Biology, University of Eastern Finland, Joensuu, Finland; 2Kainuu Fisheries Research
Station, Natural Resource Institute Finland, Paltamo, Finland; 3Department of Environmental Sciences,
University of Helsinki, Helsinki, Finland; 4Natural resources and bioproduction, Natural Resource Institute
Finland, Helsinki, Finland
Finnish pikeperch (Sander lucioperca) fisheries are managed using minimum size limits (MSLs) rather than
regulation of total fishing effort or catch. While high MSLs can secure natural recruitment, too high MSLs
may decrease biomass yields. Optimal MSL for pikeperch has been under intensive public discussion with
very few scientific evaluations of the presented alternatives. We examine potential fisheries yields from five
Finnish pikeperch stocks (Lake Höytiäinen, Lake Pielinen, Lake Oulujärvi, Lake Pääjärvi and Lake
Vesijärvi) under varying MSLs using an age-, size-, and maturity-structured evolutionary population model
which is carefully parameterized for the stocks in focus and captures both environmental stochasticity and
density-dependence in growth and reproduction. The model shows that the MSL of 45 cm is a relatively
good compromise for most stocks, while it does not prevent growth overfishing at high harvesting intensities.
Increased MSL would greatly increase pikeperch predation on prey fish stocks and as such help to cope with
eutrophication. Optimal management that also takes into account evolutionary considerations would require
regulation of the total fishing mortality. Further results of this ongoing work will be presented and discussed.
34
Lake Vänern - physical and biological features and effects from climate change
Sten-Åke Wängberg1, Lars Arneborg2 & Göran Broström2
1
Department of Biological and Environmental Sciences, University of Gothenburgh, Sweden; 2Department
of Earth Science, University of Gothenburgh, Sweden
Lake Vänern is a large lake in central Sweden. Its area is over 5000 km2 and the watershed covers 10% of
Sweden, and some part of Norway. The hydrography of the lake is, to a large extent, depending of the
geological features with a division in two parts by a ridge with a maximum depth of <20 meter. Both major
parts have depths around 100 meter, counter clock circulations, and develops thermal bars. Its location and
size gives the lake a maritime character with unique fauna and flora elements. The lake is commercially used
both for transport and for fishing. The lake is also important for recreation both for tourists and for those
living in the area. The ecosystems in the lake have, historically, been exposed for a large numbers of
stressors. Some have decreased (eutrophication, toxics) while new will or might come connected climate
change, water regulation regimes and invasive species. Intensive fishing (commercial and recreational) has
for centuries been an important factor. Climate change, will 1) increased inflow with more humic water, that
change the transport pattern and reduces light penetration and photosynthesis depths 2) reduces ice cover
time and strength which changes hydrographic conditions and erosion on beaches. 3) higher water
temperature that changing phenology, hydrography, chemistry and species completion patterns. This
presentation will give an overview of the basic physical and biological features of the lake and how they are
affected by climate change.
Ecosystem services (ES) of Võrtsjärv (VJ) under multiple stress
Sirje Vilbaste & Kristel Kalpus
Centre for Limnology, Estonian University of Life Sciences, Tartu, Estonia
The ecosystem of the large, shallow, eutrophic, unregulated VJ is significantly influenced by the fluctuation
of water level and by eutrophication. Annually, VJ is covered by ice on an average of 131 days. The studied
ES were (1) provisional: fish catches (eel, pike-perch, pike, bream, burbot, perch, total) and the annual sales
revenue of reed manufacture; (2) regulating: self-purification of VJ (retention of DIC, DOC, TN, TP, DSi);
(3) cultural: number of visitors of the Lake Museum and the annual sales revenue of the two large guest
houses. In PCA the first two principle components explained 41.03 % and 27.81 % of the changes in VJ,
respectively. The catch of eel and the total fish catch were positively correlated with eutrophication indices
and negatively with Secchi depth. PCA showed negative relationship between catch of pike and Q into the
lake. The catch of perch was higher in the years when Q from the lake was larger. Reed manufacture was
more successful in the years of deeper water. The lake retained more DIC, DOC, and TN in the years when
O2 was higher. The retention of DSi was negatively correlated with Secchi depth. According to PCA, the
retention of TP increased with the prolonged ice cover period and with higher TP. Correlation analysis
revealed that in the years of lower trophy there were more visitors of the Lake Museum. The provisional and
regulating ES were more closely related to the state and pressure of the lake compared to the cultural ES.
35
Cyanobacterial blooms in Lake Ladoga around Valaam islands
Ekaterina Voyakina
Department of Natural Chemical and Ecological, Saint-Petersburg Scientific Research Center of Ecological
Safety, Saint-Petersburg, Russia
Eutrophication of water bodies leads to active vegetation of cyanobacteria and water blooms. Harmful algal
blooms occur worldwide, including in water bodies in northwestern Russia. The aim was to analyze the
dynamics of structural and functional parameters of phytoplankton, especially cyanobacteria in various sites
of a coastal zone of Lake Ladoga around Valaam archipelago and to find environmental factors defining it.
Valaam islands are located in the northern part of Lake Ladoga. The phytoplankton samples were collected
from 12 - 18 stations around the archipelago during July-August of 2008 - 2014. The total number of taxa
identified in the studied material was 181. The discovered species consisted of nine taxonomic groups of
algae. Large numbers of species of green algae (30 %), cyanobacteria (19%) and diatoms (18%) are typical
for most lakes of northwestern Russia. Usuallly Aphanizomenon flos-aquae (L.) Ralfs ex Born. et. Flah.
Limnothrix planctonica (Wolosz) Meffert, Snowella lacustris (Chod.) Kom. et Hind were dominated on
these stations. It was shown that the abundance and biomass of phytoplankton varied significant. Density of
phytoplankton varied from 0,1 till 56,1 mln cell/L, biomass - from 0,1 till 29,5 mg/L. The highest biomass
was noted in the closed and shallow bay. The average concentration of chlorophyll a was 4,5 mkg/L in study
region. The study area of structural and functional parameters of phytoplankton related to mesotrophic water
bodies.
Lake ecosystem changes in Finland as reflected by human experience and limnological evidence
Kari-Matti Vuori
Laboratory Centre, Finnish Environment Institute, Jyväskylä, Finland
Finland is marketed as a land of a thousand clean lakes. Recently Country Brand Delegation stated that “lake
rescuing” turned Finland from the land of thousands of dirty lakes into the land of drinkable lakes. Indeed,
past gross pollution problems no longer exist in many lakes due to efficient waste water management.
However, substantial ecosystem recovery stories apply to relatively few lakes. Ecological status
classification concerns mainly lakes over 1000 ha (total number 2555 lakes). We have, however 55098 over
1 ha lakes mostly lacking data for status assessment. In public hearings on River Basin Management local
people criticize official status assessments and worry about ecosystem changes also in smaller lakes. I used
questionnaires and interviews to gather knowledge of lake-residents on potential ecosystem changes.
Questionnaire yielded 223 answers containing information from 100 lakes. Ten lakes with adequate
monitoring and paleolimnological data were selected for interviews and comparison to limnological
evidence. Most answers (over 70%) reported moderate or substantial changes in transparency, colour,
clogging of nets, littoral vegetation and bottom quality mainly since 1950’s. Exceptions were few lakes
previously heavily polluted by waste waters. Four lake groups were distinguished: Country Brand Lakes,
Small Totally Altered Lakes, Brownificated Forest Lakes and Agricultural Lakes. Human observations were
in line with limnological evidence. Results indicate that Finland is full of totally altered small lakes and that
ecosystem services of large oligohumic lakes are threatened more by brownification than eutrophication.
36
The effects of physical factors on spring phytoplankton in a temperate lake (Lake Erken, Sweden)
Yang Yang & Kurt Pettersson
Limnology, Erken Laboratory, Uppsala University, Norrtälje, Sweden
Phytoplankton seasonal succession is linked with variations of a series of environmental factors, especially
climate-induced physical variables. Spring phytoplankton goes through winter and initiates the annual
dynamics. It inherits from the earlier memory and affects the following succession. This study compares the
phytoplankton dynamics in three types of years in a dimictic Lake Erken, Sweden, especially the spring
development and aims to investigate how the development of phytoplankton varies along the winter severity
gradient and to what extent winter status shapes the dynamics. Results suggest that warm winter temperature
advances the spring diatom bloom with short ice cover duration and earlier ice-off timing. Spring diatom
bloom is added to the initial overwintering community instead of replacement and start from almost zero.
But cold and long winter could undermine this pile-up effect, because diatom would sink into the sediment
instead of the hypolimnion, which requires complete mixing in the spring. Spring bloom is caused by group
A in cold years, group B in normal years and group P in warm years. After warm winters, community
diversity was less variant. Taxonomic distinctness was introduced to compare the functional diversity in the
spring, which suggested that community after normal winters were more diverse. Winter harshness
influences the vernal community composition, warming winter shifts spring community less diverse, and this
explains the inter-annual variation of phytoplankton dynamics under different weather conditions.
Isotopic puzzle of Lake Constance: Is particulate organic material genuine indicator of food web base?
Elizabeth Yohannes & Karl-Otto Rothhaupt
University of Konstanz, Limnological Institute, Konstanz, Germany
Single or dual stable-isotope analysis (δ13C or δ15N) of primary producers and consumers is a useful tool for
distinguishing among potential dietary sources and depicting food web arrangements. The method is based
on a known or predictable change in isotopic composition between trophic levels and has been widely used
in a range of ecosystems. Formulated isotope enrichment pattern, typically known as discrimination or
fractionation pattern, generally assumes that heavy isotopes are enriched at each trophic level in a known
manner (e.g., δ15N+3.4‰) and can thus be used to assess the trophic level of an organism. Often the isotopic
assessment of predator and grazer zooplankton ‘‘food web base’’ is based on isotopic values of mostly
particulate matter obtained from filtered water. In a year round sampling campaign, we assessed the simple
‘linearity’ of the food chain from micro phytoplankton prey to the micro- and macro-zooplankton consumer
and to the zooplanktivorous fish using samples from two different depths (0-20m and 30-60). Results were
compared to stable isotope values of filter feeding mussels. Our results showed a triple isotopic ‘mis-match’
(δ13C, δ15N and δ34S) between microplankton prey and zooplankton predator. The pelagic food webs in the
upper and lower depths of Lake Constance provide a model instance as how stable isotopic analyses may not
always be clear-cut and precise. We pose the question: “Is particulate organic material a genuine indicator of
food web base?” and discuss the challenge and importance of finding an appropriate baseline indicator for
ecosystems.
37
Simulation of the movement of a turbid density current during a flood event in a large reservoir with
complex morphology (Maroon reservoir, southwest Iran)
Behnam Zamani1, Manfred Koch1 & Ben Hodges2
1
Department of Geohydraulics and Engineering Hydrology, University of Kassel, Kassel, Germany;
Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin,
USA
2
Turbidity currents move through the thalweg and seriously impact the whole lake ecosystem in the reservoirs
with narrow-deep morphology. Controlling and minimizing the effects of increasing turbidity on the light
penetration and aquatic ecosystem is of great importance in reservoir management. In this study a 3D
hydrodynamic model coupled with a particle dynamics model has been used to simulate the effect of
propagation of a turbid density current due to a large flood event in 2011 (peak flow of 2000 m3s-1) in a very
large reservoir in southwest Iran, Maroon reservoir, which has a deep-narrow morphology. This reservoir is a
combination of two main basins that are connected by a very narrow canyon, which makes the numerical
discretization, under consideration of various other accuracy and stability criteria in the code, a rather
difficult task. The inflow with multiple suspended sediment sizes (SS), determined by means of a grain- size
analysis of the river suspended sediments. The model was validated by using in-situ data sampled during the
flood event by Doppler current sensors (for current speed) and optical back scatter sensors (for turbidity
measurements) in 6 measurement stations within the reservoir. Both of the coupled models showed a good
agreement with the in-situ sampled data. Despite of the complex morphology, the model performance in
simulating the propagation of the flood density current in the reservoir, as well as stratification and mixing
processes which are of critical importance for a better understanding of the limnology and ecosystembiology of this large deep reservoir.
38
POSTER PRENTATIONS
Activated carbon in sediment remediation – adverse effects vs. remediation potential
Sebastian Abel1, Inna Nybom1, Kimmo Mäenpää1, Sarah Hale2, Gerard Cornelissen2 & Jarkko Akkanen1
1
Department of Biology, University of Eastern Finland, Joensuu, Finland; 2Norwegian Geotechnical
Institute, Oslo, Norway
The in-situ treatment of contaminated aquatic sediments with activated carbon (AC) has been shown to be
highly efficient in reducing mobility and bioavailability of persistent organic pollutants. However, it has also
been found that the sorbent material itself might have toxic effects on benthic organisms. The goal of this
study was the comparison of the remediation potential and the adverse effects of different AC application
methods and sorbent mixtures. All tests were carried out in bioassays using Lumbriculus variegatus as test
organism and natural, PCB contaminated sediments from lake Kernaalanjärvi, Finland. The activated carbon
was applied in pure form and mixed with kaolinite clay. This was done using two different methods: mixing
of the sorbent into the sediment and the application in form of a thin layer cap on top of the sediment. Each
form of treatment was carried out with two sorbent material doses. The results showed that PCB
bioaccumulation was significantly reduced in all treatments. However, it was also found that the test
organism shows a greatly reduced growth rate or even a loss of biomass when activated carbon is applied in
any form. The strongest impact was observed when high concentrations of pure activated carbon were
applied as a thin layer cap (significant mortality occurred). The addition of clay to the sorbent mixture was
able to prevent these most severe effects, while it does not lower the sorbent’s contaminant binding potential.
Colour of Finnish inland waters in 1913 and 2014
Cecilia Äijälä1, Matti Leppäranta1 & Lauri Arvola2
1
Department of Physics, University of Helsinki, Helsinki, Finland; 2Lammi Biological Station, University of
Helsinki, Lammi, Finland
The colour of inland waters is classified according to the degree of brown, determined by the absorption of
short wavelengths of filtered water samples. An exceptional data set was published by Rolf Witting, who
measured the water colour at 212 sites in Finland using a spectrometer in the years 1913-1914. It is one of
the earliest publications on the topic worldwide. The data consists of 7-channel absorption spectra between
467 and 709 nm. The measurements and the documentation was carefully done. We repeated the
measurements in the summer of 2014 for 153 sites. Our measurements consists of high resolution spectra
between 200 and 750 nm produced by a spectrophotometer. The colour values of filtered water are
proportional to the CDOM (coloured dissolved organic matter) content. The results showed no large-scale
change in the summer colour values in the 101-year period: the absorption coefficients at the wavelength (λ)
467 nm were 0.019 ± 0.010 cm–1 and 0.017 ± 0.012 cm–1 in 1913 and 2014, respectively. The shape of the
CDOM absorption spectrum was unchanged with absorption proportional to exp(–Sλ), λ is wavelength. The
estimates for the shape factor were S ⁼ 0.0109 ± 0.0015 nm–1 in 1913 and S ⁼ 0.0106 ± 0.0025 nm–1 in 2014.
The catchment properties, primarily the lake and peat-land coverage, explained approximately 50% of the
variation of the optical properties in the present data. The results do not support the common hypothesis that
the colour of inland waters would be increasing.
39
Modern state of zooplankton in tributaries of Lake Ladoga
Dina Aleshina & Evgeny Kurashov
Laboratory of Hydrobiology, Institute of limnology RAS, St.Petersburg, Russia
Zooplankton was studied in 2011 - 2014 in the lower reaches of the 20 tributaries of Lake Ladoga to discover
its composition and quantitative development, to assess the possible influence of abiotic conditions in the
rivers and the characteristics of their catchment areas as well as to evaluate the water quality in the rivers on
a basis of zooplankton indices. A total of 184 taxa were identified: 81 species of Rotifera (44%), Cladocera 77 (42%), Copepoda - 26 (14%), including 5 representatives of Calanoida (3%) and 21 species of
Cyclopoida (11 %). Basically zooplankton in the rivers were formed by representatives of lacustrine and
coastal-macrophytes complexes of zooplankton organisms. The highest values of species richness were
observed in the major tributaries of Lake Ladoga (Svir, Vuoksa, Volkhov). The greatest similarity in
structure and quantitative development was characteristic for major tributaries and for geographically close
rivers. Representatives of Copepoda and Rotifera were dominants in the spring, Cladocera prevailed in the
summer, and Cladocera and Copepoda – in the autumn. In general, low values of the number (up to 9600
ind./m3) and biomass (up to 194,5 mg/m3) of zooplankton were typical for investigated tributaries. The
saprobity indeces varied from 0.57 to 1.92 and characterized the waters from "very clean" to "moderately
polluted". In different seasons (spring, summer, autumn) different effects of the physical-geographical
characteristics of the rivers as well as physical-chemical parameters on the formation of the composition and
quantitative development of zooplankton in the tributaries of Lake Ladoga was observed.
Applying and evaluating the European Standard Water quality – Guidance on the estimation of fish
abundance with mobile hydroacoustic methods – experiences from three countries
Thomas Axenrot1, Jean Guillard2 & Milan Riha3
1
Department of Aquatic Resources, Swedish University of Agricultural Sciences, Drottningholm, Sweden;
INRA - Université Savoie Mont Blanc, Thonon-les-Bains, France; 3 Biology Centre AS CR v.v.i., Ceske
Budejovice, Czech Republic
2
Hydroacoustics is an internationally approved method to study fish for abundance estimates and behaviour,
and to increase our understanding of aquatic ecosystems. In Europe and North-America the need to compare
results between years, lakes and countries has been recognized and as a consequence of this acoustic
methods are being standardized. To study how the European Standard (CEN) Water Quality – Guidance on
the Estimation of Fish Abundance with Mobile Hydroacoustic Methods was perceived by different users, a
joint evaluation has been performed by three European countries when implementing the new standard in
2014. For some paragraphs the participants´ actions were different from what is enjoined by the standard,
and in some cases methods differed among the participants. The general explanations for most of these cases
were that stable performance by equipment and long experience from discrete surveys reduce the need of
controlling actions. We suggest that the result of this study is considered at the revision scheduled for 2017.
40
Histopathological alterations in feral fish of Lake Onego - a baseline study for environmental
monitoring purposes
Lidia Belicheva & Julia Lukina
Hydrobiology laboratory, Institute of Northern Water Problems, KarRC, RAS, Petrozavodsk, Russia
The use of histopathology in various fish species as a biomarker in monitoring programmes to assess the
biological effect of anthropogenic load, environmental quality or occurrence of adverse ecological
consequences is well established. Although Lake Onego ecosystem state has repeatedly been estimated using
different groups of organisms, information on histopathological alterations in fish inhabited this water body
is scarce. In order to obtain an overview and assess the specificity and prevalence of histopathological
changes in Onego Lake fish, gills, liver and kidney of two native species (perch and roach) were
histologically analyzed. Fish were collected in August 2013 and 2014 from several sites which considered as
undisturbed locations and distributed over different parts of the Lake. As a result a variety of the lesions,
which can be classified into 5 groups (circulatory disturbances, progressive, regressive and inflammatory
alterations and neoplastic changes) were found. A high prevalence of non-specific and early toxicopathic
non-neoplastic lesions was recorded. In contrast, pre-neoplastic and neoplastic lesions were observed only in
rare occasions. Several cases of unspecified parasite invasions were also diagnosed. Studied fish displayed a
range of pathologies similar to those seen in species from water bodies with high anthropogenic load such as
Vygozero reservoir and urban tributaries of Lake Onego. Thus, a comparison with this data on other fish
species revealed that the observed alterations may indicate effects of environmental stressors. The study has
been financially supported by the Russian Science Foundation (No 14-17-00766).
Trace elements in Lake Onega
Natalia Belkina, Natalia Kulik, Petr Lozovik & Natalia Efremenko
Karelian Research Centre RAS, Institute of Northern Water Problems, Petrozavodsk, Russia
We have investigated the content of biogenic microelements (Fe, Mn, Zn, Cu, Co, Ni, Pb, Cd) in water
Onega Lake and its tributaries, and their distribution in the surface layer of sediments. A metal concentration
(total content) in rivers varies considerably, increasing their content characteristic of the rivers of southeastern and southern coasts. Dissolved forms of metals prevail in winter, during the period of open water
increases the proportion of suspended forms. Trace elements in the waters of lake unevenly distributed.
Maximum concentrations of metals are typical for areas subject to anthropogenic influence, minimum - for
the central areas of the lake. The determining factor in maintaining a stable concentration of the investigated
elements in the water is the process of sedimentation of insoluble forms of the elements. The distribution of
trace elements in sediments of Lake Onega observed a close relationship with the granule size and the depth
of the lake. High concentrations of iron and manganese in the sediments reflect the peculiarities of the local
geochemical province. Clarke values observed excess Ni, Cu, Cd, Zn in areas subjected to anthropogenic
influence. Highs content of Zn, Cu, Co, Ni, Pb, Cd in the surface layers of sediments of the deep lake
indicate an increase in the rate of their income from the fine fraction of particulate matter in the last hundred
years, which may be a consequence of how human activities and climate change. The study has been
financially supported by the Russian Science Foundation (#14-17-00766)
41
Diet of pikeperch (Sander lucioperca) in Lake Höytiäinen: stomach contents vs. stable isotope analysis.
Risto Eronen1, Anssi Vainikka1, Hannu Huuskonen1, Mikko Kiljunen2, Jari Syväranta3 & Raine Kortet1
1
Department of Biology, University of Eastern Finland, Joensuu, Finland; 2Department of Biology,
University of Jyväskylä, Jyväskylä, Finland; 3Department of Biosciences, University of Aarhus, Aarhus,
Denmark
Overall, the diet of pikeperch (Sander lucioperca) is relatively well known, consisting mostly of perch
(Perca fluviatilis) and smelt (Osmerus eperlanus), but also of vendace (Coregonus albula), roach (Rutilus
rutilus) and ruffe (Gymnocephalus cernuus). The diet is traditionally assessed from stomach content samples,
but stable isotope analysis (SIA) offers another possibility. One of the advantages of SIA is the ability to
determine the diet from a longer time period, whereas the stomach content can only reveal the very latest
prey. We examined the diet of pikeperch of varying size in a North-Karelian Lake Höytiäinen in order to
estimate the impact of pikeperch stock on prey fish populations. We used both of the methods to get the best
possible picture of the diet and to compare them. According to the SIA, the diet possibly consists mostly of
vendace and perch but we likely underestimated the importance of smelt due to unrepresentative prey
samples. Roach was not among the prey according to the SIA, but they were found in the stomachs. Perch
was another common prey in the stomach samples, but no vendace or smelt were found in them. The
different results between the methods pinpoints the importance of using both SIA and stomach content
analysis when assessing fish diets. We will further analyse the prey consumption with respect to pikeperch
size and season, and finally use the data to model the impact of pikeperch stock on the prey fishes and as
such on the whole food web.
Semi-analytical prediction of Secchi depth using remote-sensing reflectance for lakes with a wide
range of turbidity
Takehiko Fukushima1, Bunkei Matsushita2, Youichi Oyama3, Kazuya Yoshimura4, Meylin Terrel2, Shimako
Kawamura2, Akito Takegahara2 & Wei Yang5
1
Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan; 2University of
Tsukuba, Tsukuba, Japan; 3Kushiro Board of Education, Kushiro, Japan; 4Japan Atomic Energy Agency,
Tokyo, Japan; 5Japan Agency for Marine-Earth Science & Technology, Yokohama, Japan
It is crucial to monitor the light environment in large lakes using satellite remote sensing data. A lot of
studies have proposed the prediction schemes of transparency information, but most of them were sitespecific. In the present study, we applied semi-analytical retrieval procedures of inherent optical properties
(IOP) from in-situ measured remote-sensing reflectance and then predicted Secchi depth (SD) using the
contrast transmittance theory. Two types of water regions, i.e. clear waterbodies or turbid ones, were first
classified based on spectral characteristics and a selection from two retrieval procedures for clear and turbid
water regions was made. In addition, the relationship between SD and sum of attenuation coefficients (beam
and diffuse attenuation coefficients), which arises in contrast transmittance theory, was determined by
analyzing the data from the previous research. The predicted SD values were compared with the observed
ones in ten lakes (Lakes Biwa, Kasumigaura, Shirakaba, Suwa, Ikeda, Unagi, Akan, Motosu, Saiko, and
Shoji) with a wide variety of turbidity (SD from 0.4 m to 17 m). A fairly good agreement between them was
obtained indicating the usefulness of this prediction scheme. We then discussed on the classification
procedure, the coefficient in the contrast transmittance theory, and the occasionally happened discrepancies
in addition to the future directions of this approach.
42
The health of Lake Peipsi (Estonia/Russia): improvement, stabilization or deterioration?
Juta Haberman1, Kätlin Blank1, Reet Laugaste1 & Enn Loigu2
1
Centre for Limnology, Estonian University of Life Sciences, Tartumaa, Estonia; 2Tallinn University of
Technology, Tallinn, Estonia
Lake Peipsi sensu lato consists of eutrophic Lake Peipsi sensu stricto, and hypertrophic Lake Pihkva. The
aim of this study was to find out if the health of L. Peipsi s.s. and L. Pihkva had improved, stabilized or
deteriorated during the ten-year period of 2003-2012. For this purpose, the data on loadings, in-lake nutrient
concentrations, water transparency, water level, chlorophyll a concentration, as well as phyto- and
zooplankton were compared for two five-year periods (2003-2007 and 2008-2012). Comparison
demonstrated a decline in the total phosphorus (TP) loading from the rivers on the Estonian (270 to 219 t/y)
and Russian (489 to 397 t/y) side and also in the mean TP concentration in L.Peipsi s.s. (50 to 46 μg/l) and
L.Pihkva (165 to 124 μg/l). Phytoplankton biomass (10.0 to 6.3 mg/l in L. Peipsi s.s., 32.1 to 15.5 mg/l in L.
Pihkva) and cyanobacterial biomass (5.7 to 4.0 mg/l in L. Peipsi s.s., 22.9 to 9.2 mg/l in L. Pihkva). The
responses of zooplankton were contradictory. Changes in the amount of indicatory species and mean
zooplankter weight demonstrated a continuous eutrophication, while changes in the amounts of rotifers and
Daphnia species indicated a subtle shift towards recovery. As zooplankton is affected also by several other
important drivers, the expected signs of improvement in the lake may be delayed. Different natural
conditions (morphology, catchment area, relative depth) and pollution loads into two lake parts resulted in
apparently different resistance in their ecosystems and response to human activity.
Methods for testing the relationships between water and weather variables of the large shallow Lake
Peipsi
Marina Haldna, Tõnu Möls & Olga Tammeorg
Estonian University of Life Sciences, Tartu, Estonia
Understanding of the relationships among great number different biotic and abiotic variables is of crucial
importance for solving issues in ecology including hydrobiology. It is often unclear if studied variables
influence each other directly, depend on the same third factors or have the same oscillation coincidentally.
Different questions about water ecosystems meet concrete statistical hypothesis and modeling methods. Our
study propose appropriated statistical methods for answering the questions like: (a) how do water color,
transparency and nutrients depend on climate and weather conditions; (b) how are plankton biomasses
connected with factors mentioned above; (c) how to separate and estimate the short-term and long-term
(climatic) changes in water condition. For the analysis, we used data of the growing season for large shallow
Lake Peipsi (3555 km2) in 1997-2014. To eliminate the effect of background factors (season, year,
geographical coordinates of the sampling point, water temperature, water level etc.) on studied
hydrobiological parameters, we used residuals obtained with the help of the SAS Thin Plate Spline model.
Our study demonstrates that statistical approach presented here opens more convenient ways for explaining
complicated dependence structure between water and weather variables. Modeling supports the improvement
the results of water quality monitoring.
43
Fatty acid composition of Eudiaptomus spp. in boreal and subarctic lakes
Minna Hiltunen1, Sami Taipale2, Ursula Strandberg1, Kimmo Kahilainen3 & Paula Kankaala1
1
Department of Biology, University of Eastern Finland, Joensuu, Finland; 2Lammi Biological Station,
University of Helsinki, Lammi, Finland; 3Kilpisjärvi Biological Station, University of Helsinki, Kilpisjärvi,
Finland
The fatty acid (FA) composition of consumers is known to have taxon-specific characteristics but is also
influenced by their diet and physiological status. We studied whether differences in lake properties (location,
morphometry, water chemistry and temperature) are manifested in the FA composition of the common
freshwater calanoid copepod Eudiaptomus spp. The proportions of saturated and polyunsaturated FA in
Eudiaptomus, sampled from 25 lakes in boreal and subarctic regions, showed large variation (ca. 20 - 60%
and 30 -70%, respectively), while the proportion of monounsaturated FA varied less (5% - 15%). The FA
composition of Eudiaptomus differed significantly between subarctic and boreal lakes. Eudiaptomus had
higher proportions of docosahexaenoic acid (DHA) and lower proportions of linoleic acid (LIN), α-linolenic
acid (ALA) and eicosapentaenoic acid (EPA) in subarctic than in boreal lakes. In the boreal lakes, the FA
composition of Eudiaptomus was related to water chemistry, with total nitrogen concentration (totN)
explaining 20% of the variation. Interestingly, the ω3:ω6 ratio in Eudiaptomus increased with increasing
totN in the large and clearwater lakes but not in the small and humic ones. In particular, the proportion of
EPA in Eudiaptomus was strongly connected to totN in large and clearwater lakes. This presumably
indicates the importance of diatoms in the phytoplankton community and hence, in the diet of Eudiaptomus
in these lakes. Copepods, including Eudiaptomus, are important prey for planktivorous fish. EPA and DHA
are vital for fish nutrition and the observed among lake differences in their proportions may influence fish
growth and reproduction.
Fish density and fish length distribution in varying light conditions with single and split beam echosounding and trawling
Juha Jurvelius1, Heikki Auvinen2, Timo Marjomäki3, Heikki Peltonen4, Andrei Degtev5, Eva Bergstrand6 &
Olof Enderlein6
1
Natural Resources Institute Finland, Enonkoski, Finland; 2LuBi, Natural Resources Institute Finland, Turku,
Finland; 3Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland;
4
Finnish Environmental Institute, Helsinki, Finland, 5Petrozavodsk State University, Petrozavodsk, Russia;
6
Institute of Freshwater Research, Stockholm, Sweden
To study the consistency of historic hydro-acoustic results, fish density (fish ha-1) and fish length (TS, dB)
estimates of three single and two split beam echo-sounders were compared in varying light conditions.
Acoustic estimates were compared with trawling. Studied fish were vendace, Coregonus albula (L.), and
smelt, Osmerus eperlanus (L.). In dusk and darkness, the catch-ability in trawling indicated the dispersing of
fish schools. Also density estimates from hydro-acoustics and trawling, and the TS-distribution between the
single and split beam echo-sounders were more consistent than in daylight. At daylight, the 70 kHz single
beam sounder produced fish densities that were ca. 10 % higher than those produced by the 38 kHz split
beam sounder. At night, the 120 kHz split beam transducer and the 70 kHz single beam transducer gave on
average equal fish density estimates. In darkness, single and split beam echo-soundings form a comparable
time-series from the 1980s to the 2010s.
44
Element transfer to, and distribution in, signal crayfish (Pacifastacus leniusculus) in Lake Säkylän
Pyhäjärvi, SW Finland
Ville Kangasniemi1, Joni Mustonen1, Tero Forsman2 & Ari T. K. Ikonen1
1
Environmental Research and Assessment EnviroCase, Ltd., Pori, Finland; 2 Pyhäjärvi Institute, Eura,
Finland
Lake Säkylän Pyhäjärvi has been a subject of scientific research for long due to its ecological, recreational
and commercial importance. Signal crayfish was introduced to the lake in the 1980s and over the years it has
become a common species and a valuable catch for the local fishermen. Olkiluoto Island, about 50
kilometres north-west to Lake Säkylän Pyhäjärvi, has been selected as a repository site for nuclear waste.
Due to the post-glacial land uplift, the present sea areas around Olkiluoto Island will change into terrestrial
and limnic ecosystems (including lakes, lacking from the site at present). Lake Säkylän Pyhäjärvi has been
used as one of the analogues for the future lakes of the Olkiluoto site. To contribute to input data of the
radionuclide transport modelling and the dose assessments for both the people and the biota, crayfish were
caught and water samples were taken from Lake Säkylän Pyhäjärvi in the autumn of 2011. Weights and
dimensions of the crayfish individuals were measured and the element composition of the crayfish samples
and the lake water were analysed. This contribution will present element distribution in the signal crayfish
body and concentration ratios of elements from water to crayfish in this large lake and thus provide new
information for water conservation and radioecology.
The role of parental effect and relatedness on early development of coregonids in short and long
winter
Juha Karjalainen1, Linda Jokinen1, Tapio Keskinen2, Emily Knott1 & Timo Marjomäki1
1
Dept Biological and Environmental Science, University of Jyväskylä, Finland; 2Natural Resources Institute
Finland, Jyväskylä, Finland
We studied experimentally parental effect of vendace (Coregonus albula (L.)) and whitefish (C. lavaretus
L.) on egg survival, embryonic growth, hatching time and hatching size under different climate change
conditions using two different experimental designs: pair spawning (monogamy) and communal spawning
(polyandry). In pair spawning, eggs of individual females were fertilized by sperm of individual males
separately, and in communal spawning, eggs of each individual female were fertilized by a mixture of sperm
of three males. Moreover, the relatedness of the parent pairs of vendace was examined genetically to find out
if inbreeding depression could explain the variation in reproductive success between different pairs. The eggs
were incubated under short and long winter conditions. Whitefish had significantly higher fertilization and
embryonic survival rates than did vendace, but the different winter conditions did not affect the early
survival of either species. In the pair spawning experiment, the survival rate of vendace was clearly lower
than it was in the communal spawning experiment. For whitefish, there was no difference in survival rates
between the two designs. Increase in the water temperature was the main factor influencing the hatching
time of larvae, but within the time range set by the temperature, parental origin and especially the female
also had an effect. All the vendace parents that had very low reproductive success also had very high or low
inbreeding coefficients. Therefore, the individuals’ inbreeding coefficients of vendace seem to be related to
its reproductive success.
45
Water owners´ attitudes towards ringed seal conservation in Lake Saimaa
Irma Kolari1, Päivi Eskelinen2, Pekka Salmi3, Juhani Mellanoura3 & Esa Hirvonen1
1
LUBI, Natural Resources Institute Finland (Luke), Enonkoski, Finland; 2Natural Resources Institute Finland
(Luke), Jyväskylä, Finland; 3Natural Resources Institute Finland (Luke), Turku, Finland
By-catch mortality in fishing gears forms a great challenge to Saimaa seal ringed conservation. Water
owners play crucial role in implementation of conservation strategies because they manage fisheries in
private waters. We studied water owners´ attitudes towards ringed seal conservation by three aspects: Is
Saimaa ringed seal an endangered species? Is the population size estimate correct? And is seal population
threatened by fishing? A postal questionnaire was sent to 1 700 water owners, 60 % of them answered.
Attitudes were studied in relation to fishing activity, age, sex, place of residence, participation in activities of
local shareholders´ fishery associations. Most of young and female water owners, as well as those, who lived
outside Saimaa area and those who never participated in water owners´ activities, considered ringed seal as
an endangered species.
Majority of all respondents did not have an opinion of the official seal population estimate. Only those who
were active in local shareholders´ fishery associations did not believe in that population estimate. Greater
part of water owners who themselves fished, used mostly gill nets when fishing, lived in Saimaa area and
were at least sometimes active in water owners in local shareholders´ associations thought that fishing does
not threaten ringed seal. Among other water owners less than one third shared this attitude. Attitudes varied
according to fishing activity and most important gear type used; gill net fishers considered ringed seal less
threatened and fishing less harmful to the seal than those who fished with other gear types.
Autonomous measurement platform for monitoring lakes - LILA project
Jarmo Kuivalainen
University of Oulu / CEMIS-Oulu, Kajaani, Finland
Environmental consciousness and worry at local environment has increased among people. People want
more accurate information about the state of water systems and especially about changes in them. This
growing need can’t be satisfied with traditional water analysis and static measurements thus new kind of
tools for monitoring must be invented. To meet this need we developed autonomous measurement platform
in LILA project. Platform enables comprehensive water systems monitoring. In one measurement the
developed platform can simultaneously monitor water quality with many sensors, take water samples for
laboratory work and map the lake bed with sonar (depth, solidity and flora). The platform navigates using
GPS and so the measurement routes can be repeated accurately. When monitoring is done regularly one
obtains reliable information about the state of the water system and the changes in its condition can be
noticed. Platform has been tested for monitoring Vimpelinlampi in Kainuu region where first results has
been obtained. On the ground of results the developed platform is suitable for monitoring state of the water
systems.
46
The Great Lakes Evaporation Network (GLEN): Building an integrated observing system for largelake flux measurements
John Lenters1, Peter Blanken2, Christopher Spence3, Andrew Gronewold4, Branko Kerkez5, Norma Froelich6,
Jay Austin7 & Pengfei Xue8
1
Water Resources, LimnoTech, Ann Arbor, USA; 2University of Colorado-Boulder, Boulder, USA;
Environment Canada, Saskatchewan, Canada; 4NOAA Great Lakes Environmental Research Laboratory,
Ann Arbor, USA; 5University of Michigan, Ann Arbor, USA; 6Northern Michigan University, Marquette,
USA; 7University of Minnesota-Duluth, Duluth, USA; 8Michigan Technological University, Houghton, USA
3
The North American Great Lakes constitute the largest freshwater surface in the world. Beginning in the late
1990s, the Great Lakes experienced a regime shift toward reduced winter ice cover, warmer summer water
temperatures, and higher summer evaporation rates. This was followed shortly thereafter by a dramatic
decline in water levels due, in part, to a sustained shift toward an earlier evaporation season. On the other
hand, cold, high-ice winters such as 2013-14 have caused occasional deviations from this trend, highlighting
the large interannual variability in the system and the continued need for long-term observations over large
lakes. A growing ensemble of in situ measurements – including offshore eddy flux towers, buoy-based
sensors, and vessel-based platforms – are being deployed on the Great Lakes through an ongoing, bi-national
collaboration to reduce uncertainties in the water balance, provide a more robust basis for short- and longterm projections, and fill a significant gap in over-lake flux measurements and related meteorological data.
Here, we provide an overview of this initiative, known as the Great Lakes Evaporation Network (GLEN).
Although the network was initiated in response to the need for improved estimates of large-lake evaporation,
it is intended to be of utility for a wide range of applied and basic research needs. As such, we provide an
overview of the latest data collection efforts, the current and planned array of instrumentation and platforms,
and the network of heat/moisture/carbon fluxes and meteorological observations that are likely to be of
interest to the large-lakes research community.
The use of artificial spawning grounds for fish spawning in lake ecosystems
Oleg Marenkov
Oles Honchar Dnepropetrovsk National University, Dnepropetrovsk, Ukraine
The ecosystem of the Zaporozhian reservoir reminds the big lake. As a result of the creation of the reservoir
changed the composition of fish fauna, disappeared anadromous and semi-fish species. Number the
rheophilous species of fish that still remained in the top river-bed part of a reservoir was significantly
reduced. The lower part of the reservoir with the typical lake hydrological regime has been actively
assimilated fish limnophilic complex. In many regulated reservoirs natural reproduction of native fish
species is under significant stress factors - violation level regime in the spring, the adverse condition of
spawning grounds, poaching of fish during the spawning season. Rectify the situation with the lack of
spawning is possible by means of the exhibition of artificial spawning grounds. Our research has shown that
the installation of artificial spawning grounds can improve the environment phytophilic spawning fish. So,
from 2010 to 2013 it was established 4000 artificial spawning grounds in the bottom of the Zaporozhian
reservoir, which allowed each year receive an average 56 million of fish fry. To make optimal use of
artificial spawning grounds, we recommend setting the spawning nests in stages, according to heating of the
water and as the approach of fish to spawning grounds. The best time of the installation of spawning grounds
- before spawning, when setting the temperature at 2-30°C below spawning. If the spawning substratum is
filled with spawning of fish roe by 75%, and spawning is still ongoing, it is recommended the installation of
additional spawning grounds.
47
Integrated approach to the study of submerged surfaces community
Ivan Mukhin1, Dina Dudakova2 & Mikhail Dudakov2
1
Zoology and ecology, Vologda State University, Vologda, Russia; 2Institute of limnology RAS, SaintPetersburg, Russia
Fouling community has a high value in the functioning of aquatic ecosystems. However, the community of
microperiphyton inadequately studied. This is related with different methodological approaches to the study
of different organisms. It was founded before that various ecological structure cilioperiphytic
microcommunity on artificial substrates with different spatial structures formed. In order to confirm the
possibility to extrapolate the statement on other taxonomic groups heterogeneous periphyton community was
considered. Morphoecological approach was applied for analyze the community structure. The material was
collected in August 2014 in the north coastal area of Lake Ladoga. Natural and artificial (glass fouling)
substrates were used. The study area has rocky coastline. Unicellular (flagellates, ciliates and amoebae) and
multicellular (hydra, rotifers, nematodes, oligochaetes, insects) organisms formed periphyton communities of
investigated substrate. A bit few numbers of ciliate species were registered in compares with rotifers. In view
of ecology, two components of the surface residents that are attached and mobile forms are separated. It had
been found out that on natural and artificial substrates the community structure had qualitative and
quantitative differences. For example, colonial ciliates were not marked on natural substrates. This complies
with our earlier research data on role structure of space factor in the formation of periphytic community
ecological structure. In addition, differences in communities from front and back side of stone were
considered. The possibility of simultaneous study meio- and microperiphytic through conventional methods
has been demonstrated.
Changes in phytoplankton and water carbon concentration in the southern part of Lake Päijänne,
Southern Finland
Katja Pellikka & Marjut Räsänen
Environment Centre, City of Helsinki, City of Helsinki, Finland
Lake Päijänne is one of the largest lakes in Finland (1081 km2). The mean depth is 16 m and the deepest
point is 95 m, which makes it the deepest lake in Finland. The water quality in Southern Lake Päijänne is
excellent and the ecological status is good. The northern and central parts of the lake have suffered from
organic and harmful substance load caused by paper and pulp industry. At present the load of the paper and
pulp industry is negligible and the diffuse loading is the most serious threat to water quality. About million
Helsinki metropolitan area residents use water from Päijänne as drinking water. Water from the southern
Päijänne to Helsinki flows through a 120 km long tunnel at about three m3 s-1. In general the raw water
quality is good but the concentration of humic substances is increasing. The City of Helsinki has studied the
water quality and phytoplankton composition at Asikkalanselkä in the southern Päijänne since the 1980´s.
The amount of total phytoplankton biomass has been small indicating a quite oligotrophic environment.
However, the abundance of some algae groups has varied annually. In recent years, the amount of humic
sustances has increased, resulting in changes in water colour, chemical oxygen demand and total organic
carbon. Even though the reason for the increase of humic substances is still unclear, the shorter snow period
caused by climate change and diminishing of the sulfur deposition are considered to be the main reasons.
48
Effects of climate change and nutrients on the secular evolution of the planktonic community in Lake
Garda (northern Italy): a multi-proxy approach
Nico Salmaso1, Manuela Milan1, Christian Bigler2, Krystyna Szeroczynska3 & Monica Tolotti1
1
DASB-LEF, Fondazione Mach - Ist. Agrario S.Michele all'Adige, S. Michele all'Adige, Italy; 2Department
of Ecology and Environmental Science, Umeå University, Umeå, Sweden; 3Institute of Geological Sciences,
Polish Academy of Sciences, Warsaw, Poland
Lake Garda, the largest Italian lake (368 km2), is a key resource for drinking water supply and irrigation, for
tourism, and for biodiversity conservation. The evaluation of the lake’s vulnerability to human stressors
within the current climate change emerges as a stringent necessity. Paleoecological methods were used to
understand long-term environmental and ecological changes. Two short sediment cores were collected from
the deepest NW basin (Brenzone, 350 m depth) and in the shallower SW basin (Bardolino, 81 m). According
to radiometric dating, the cores cover ~700 years. Subfossil diatoms were analyzed to reconstruct the lake
total phosphorus and to identify the lake’s reference conditions. Until the 1960s, the two basins were
ultraoligotrophic and inert toward climatic variability. Since the nutrient enrichment in the 1960s, meso- to
eutraphentic planktonic pennate and filamentous centrics increased and partially displaced the formerly
dominant oligotraphentic taxa. Analyses of cladoceran remains supported and supplemented the diatom
results. Since the 1960s, the drastic change in plankton species composition, from oligo- to mesotrophic taxa,
was interpreted as a result of the combined effects of nutrient enrichment and climate change. A peak in
sedimentation rates in the mid-1940s, followed by a clear decrease in mineral content, reflects the beginning
of the hydroelectrical exploitation of the lake catchment. The study confirms the strength of the multi-proxi
paleoecological approach to complement limnological investigations and to understand ecosystem changes at
secular scale.
Outliers form the majority of recreational fishers in the living area of the Saimaa ringed seal: Do the
fishing regimes differ between outliers and locals?
Eila Seppänen & Leena Forsman
Management and Production of Renewable Resources, Natural Resources Institute Finland (Luke),
Enonkoski, Finland
Almost the whole of Lake Saimaa represents the habitat of the Saimaa ringed seal (Pusa hispida saimensis)
that is the most endangered seal in the world. It is a landlocked subspecies of ringed seal (Pusa hispida). The
entire population of the Saimaa ringed seal currently totals 250-360 individuals. The species has been
protected since 1955, and the protective measures consist among all of conservation areas and fishing
restrictions. The most important form of restriction is a refusal for fishing nets from April 15 to the end of
June in about 15% of the lake. Nearly all fishing in the area is recreational fishing, and thus these restrictions
concern a large group of recreational fishers.
The number of recreational fishers from outside the area has considerably increased during recent decades
being nowadays as much as 70% of all the recreational fishers in the area. However, local fishers caught
more than half of the catch in the area. Local households preferred net fishing, angling and ice fishing in
contrast to outsiders, who preferred spinning.
The main reason for the quantity of outsider fishers is probably connected with summer cottages as summer
cottage dwellers represent the majority of outsiders. The capital region and bigger towns near the lake-area
are the most important regions from where recreational fishers come to fish in the area.
49
Developing mobile services for in-situ monitoring, data storing and sharing (HALI-project)
Jari Silander1, Antti Kanninen2, Joonas Kahiluoto1, Lari Kaukonen1, Mira Latva2, Pekka Sojakka2, Miia
Savolainen2, Johanna Göransson1, Jenni Koivuniemi3 & Minna Vartiainen3
1
Finnish Environment Institute, Helsinki, Finland; 2 North Savonia Centre for Economic Development,
Transport and the Environment, Kuopio, Finland; 3Savonia University of Applied Sciences, Kuopio, Finland
The goal of the HALI-project (2014-2015) is to improve the flow of environmental monitoring data. This is
achieved by giving up on paper forms used in field observations: requirements for a common mobile data
collection and open data service are defined and piloted with professional observers and volunteers.
Additionally, water quality monitoring tools suitable for volunteers and professionals are tested. The project
supports the objectives of the Finnish national environmental monitoring strategy implemented by the
development program Monitor2020.
To test professional water quality sensors and data management tools, comparative measurements in the field
and laboratory experiments were performed. During a 2-day field measurement campaign, 19 participants
performed four different measurements with 13 devices and uploaded the data to a database. The participants
tested two different mobile data collection platforms for saving the metadata of the measurements. The
uncertainties of some of the sensors were calculated with the MUkit software. The results indicated that field
meters are suitable for measuring oxygen, conductivity, turbidity, temperature and pH in Finnish surface
waters when the equipment is properly maintained and calibrated.
To evaluate the readiness of volunteers to perform water quality measurements, an internet questionnaire was
send to interest groups related to water management. Results of the survey (n=128) revealed that only a few
individual citizens are willing to pay more than 100 euros for a measurement kit. This limits the possibilities
for extensive citizen participation to simple measurements, like Secchi depth, temperature and use of lowcost test strips.
Impacts of neglecting spatial heterogeneity in the water quality assessment of large lakes: evaluation
on remote sensing and 3D-model data
Frédéric Soulignac1, Pierre-Alain Danis2, Damien Bouffard3, Vincent Chanudet4, Etienne Dambrine5, Yann
Guénand6, Baptiste Guillermin1, Tristan Harmel7, Isabel Kiefer3, Dominique Trevisan1, Rob Uittenbogaard8
& Orlane Anneville8
1
INRA, Thonon-les-Bains, France; 2ONEMA, Aix-en-Provence, France; 3EPFL, Lausanne, Switzerland;
EDF, Chambéry, France; 5Université de Savoie, Chambéry, France; 6SEGULA Technologies, Chambéry,
France; 7LOV, Villefranche-sur-Mer, France; 8Deltares, Delft, The Netherlands
4
In 2000, the European Parliament set out a framework (European Water Framework Directive) for managing
and protecting water bodies in Europe. Classification of water bodies into “ecological quality status” has
been a key issue for implementation of that framework. In France, the assessment of the ecological quality of
lakes is based on four measurements per year vertically integrated over the euphotic zone at the deepest point
of the lake. However, in large lakes, ecological parameters, used for water quality assessment (e.g.
chlorophyll-a concentration and Secchi depth), exhibit strong spatial heterogeneities. Consequently, the
representativeness of those data might be questionable and needs to be verified. We propose to combine
remote sensing data and 3D modelling to evaluate how spatial heterogeneity in chlorophyll-a may impact the
assessment of Lake Geneva ecological status. While remote sensing provides horizontal instantaneous
observation of integrated parameters, 3D modelling provides supplementary information on the vertical
distribution and temporal variability. First, in situ and remote sensing (MERIS) chlorophyll-a data are used
50
to quantify the horizontal heterogeneity of the lake. Then, exploitation of those data to calibrate and validate
the 3D ecological model (Delft3D-WAQ coupled to Delft3D-Flow) should provide important information to
identify enhanced sampling strategies for the water quality monitoring of large lakes such as Lake Geneva.
Effects of hydro-meteorological parameters on plankton community of the Valaam Archipelago
coastal zone (Lake Ladoga)
Anastasija Stepanova1 & Katerina Voyakina2
1
Russian State Hydrometeorological University, Saint-Petersburg, Russia; 2Scientific Research Center of
Ecological Safety, Saint-Petersburg, Russia
We analyzed the results of long-term observations (1997 to 2014) on biodiversity, composition and phytoand zooplankton biomass in the Valaam Archipelago coastal zone. This zone is located in the north deepwater part of Ladoga Lake, and it is a rare example of a variety of diverse near-shore biotopes. Plankton
samples were collected from stations (12 to 17) with different depth and hydrological regime around the
archipelago.
Plankton biomass, species richness, and Shannon index significantly varied between stations and year-onyear. We found a highly significant relationships between plankton biomass, biodiversity, meteorological
factors of a certain year and Ladoga water’ level. Inter-annual diversity in limnological parameters in the
coastal zone of archipelago is determined mostly by temperature. Due to the significant water dynamics
during the establishment of stratification in this part of the coastal zone of Lake Ladoga there is considerable
variability in temperature throughout the water column, associated with the coastal upwellings. It was shown
by data of logger water temperature observations (period: June - October 2013; 2014). Substantial increase in
the water temperature during the temperature stratification does not increase the plankton quantity. Warm-up
reduce the differences between coastal zones: for temperature and hydro-chemical parameters vertical and
horizontal gradients get significantly lower, so the condition in the water becomes more homogeneous.
Therefore the structure of plankton community is becoming less diverse. During 1997 – 2014 we found no
significant changes in phyto- and zooplankton communities. That means the whole coastal zone of Valaam
Island remains in its natural state.
Heterogenic wind field and lake circulation – atmospheric and aquatic modelling results
Hiroshi Suito1, Shota Doi1, Shin-ya Morifuji1, Janne Ropponen2 & Timo Huttula2
1
Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan; 2Finnish
Environment Institute, Jyväskylä, Finland
In this paper, computational simulations for flows in two lakes in Finland are presented. Flow simulation in
lakes is a useful tool for ascertaining the flow behavior, for estimating the amount of
pollution/eutrophication, and for decision making for better planning and control. Flows in lakes are driven
by various forces such as incoming flow, temperature distribution, and wind effects. In shallow ice free lakes
without big inflowing rivers, flows are driven mainly by the wind. Wind blowing near the water surface
gives a certain amount of shear stress to the water surface, which introduces flows of the water. However, the
water flow does not always occur parallel to the wind because of various factors such as the lake shape or
depth distribution. Furthermore, wind fields are not homogeneous because obstacles such as mountains, hills,
buildings, and forests around the targeted lake can affect the airflow above the lake. Therefore, coupled
51
simulations between wind fields in the air and water current fields in the lake are highly recommended. In
these simulations, we consider one-way coupling from air to water, which means that the airflow affects the
water flow, although the water flow does not affect the airflow. This assumption might be appropriate under
these circumstances. Wind filed is computed by using a nesting technique, which can include both large- and
small-scale atmospheric effects.
Spatial distribution and long-term dynamics of the basic biota communities in the southern part of
Lagoda Lake
O.N. Susloparova, A.G. Leonov, Yu.A. Zuyev, V.A. Ogorodnikova & T.V. Tereshenkova
FGBNU "GosNIORKH", St.-Petersburg, Russia
Materials of hydrobiological (summer period) and ichthyological researches executed in 2000-2014 are
presented. Phytoplankton. Average (on areas) biomass varied within 0,143-5,109 g/m3 at domination of
Bacillariophyta. The least values were noted in the central area, maximum - Volkhov Bay. Zooplankton. The
average biomass fluctuated within 0,16-2,45 g/m3 at prevalence Copepoda, Cladocera. The minimum was
marked in the central area, the highest - southern bays. The highest planktonic communities numbers and
biomass have been dated for years with warm summer.
Macrozoobenthos. Average biomass varied within 0,13-25,11 g/m2 at domination Oligochaeta,
Chironomidae larvae, Crustacea, Mollusca. The least values were noted in the Western area, Svirsky Bay,
the greatest - in Volkhov and Petrokrepost Bays. Since 2000 to 2008 the tendency of decreasing in bottom
communities quantity indicators was observed; in 2009 it replaced on the opposite.
Ichthyofauna. In the end of the last century vendace numbers varied within 110-400 million ind. In the XXI
century gradual decrease in vendace numbers and biomass of fish stock is observed. Numbers of smelt fish
stock last fifth anniversary fluctuated within 398-405 million ind., ichthyomass - 3.46-4.10 thousand tons.
The average whitefish fish stock in 1989-2014 was 1902 tons (at maximum 2480 tons in 2008). In the XXI
century pike perch numbers and biomass of fish stock on the average was 1.94 million ind. and 2.87
thousand tons, accordingly. Within the first decade growth of pike perch numbers and biomass of fish stock
was observed, it has stopped to 2010.
Phytoplankton pigments – a powerful tool for quantitative analysis of phytoplankton in lakes
Marju Tamm1, René Freiberg1, Ilmar Tõnno1, Kersti Kangro2, Peeter Nõges1 & Tiina Nõges1
1
Estonian University of Life Sciences, Tartu, Estonia; 2University of Tartu, Tartu, Estonia
Quantification of phytoplankton biomass by taxonomic groups serves as an excellent tool for evaluating
water quality and status of aquatic ecosystems. Standard method for determining taxonomic composition of
algae is inverted microscopy which is time-consuming, subjective and fails to detect picoplankton. The
pigment-based chemotaxonomy is considerable alternative to microscopy in research which requires
processing large amounts of samples. Despite being well acknowledged method in oceanographic studies it
is still moderately used in freshwater ecosystems. The main objectives of our study were (1) to compare the
results of direct microscopy and CHEMTAX in describing phytoplankton community composition and
seasonal dynamics in a large, shallow and eutrophic lake, (2) analyse the effectiveness of CHEMTAX
method in describing phytoplankton community composition in lakes with different optical water properties,
(3) to assess the suitability of available marker pigment:chlorophyll a ratios to determine phytoplankton
52
community composition in variety of lakes. A 5-year (2009-2013) parallel phytoplankton analysis by direct
microscopy and by CHEMTAX was conducted in a large shallow and eutrophic lake using published marker
pigment:chlorophyll a ratios. Despite displaying some differences from microscopy results, the pigmentbased method successfully described the overall pattern of phytoplankton community dynamics during
seasonal cycle in a eutrophic lake. Similar one-time comparison was carried out (October 2014) in five
optically distinct lakes.
Good agreement between the methods was achieved for abundant phytoplankton groups – e.g. cyanobacteria,
chlorophytes and diatoms. The agreement was poorer in case of less abundant phytoplankton groups (e.g.
dinoflagellates, chrysophytes).
The role of bottom outlet in minimizing future ecological problems in a proposed dam reservoir using
three-dimensional modeling (Abolabbas Dam)
Behnam Zamani & Manfred Koch
Department of Geohydraulics and Engineering Hydrology, University of Kassel, Kassel, Germany
Modeling of hydrodynamics and limnological processes before building a dam gives valuable information to
design an appropriate project. In this study a 3D hydrodynamic model (ELCOM) coupled with an aquatic
ecosystem model (CAEDYM) were used to simulate hydrodynamics and dissolved oxygen cycle in
Abolabbas proposed reservoir in the southwest Iran. The results were used to predict the effects of droughts
on the oxygen cycle in the reservoir. A drought analysis, using long term hydrological data, was performed
on the inflow and the contaminants. The effects of four different scenarios, introducing the hydrological
effects of climate change, were simulated in a 12 months period. The results confirmed the effective
performance of the reservoir in normal conditions. However, according to the results, severe droughts have a
potential to impose a deep hypoxia and anoxia in the hypolimnion which can lead to serious ecological
problems in the reservoir. The results showed that, lowering the bottom outlet by 10 meters below the
designed level and hypolimnetic water withdrawal via this outlet draws down the permanent anoxia level by
20 meters. This would considerably increase the reservoir performance during severe droughts by developing
the oxygen distribution below the thermocline in hypolimnion. The sensitivity analysis of some parameters
determining the fate of the nutrients and the oxygen cycle in the model demonstrates that the wind drag
coefficient, the light intensity and the sediment-oxygen exchange exhibit the highest sensitivities, which
means that these parameters should be well known to have model confidence.
The shift and driving factors of phytoplankton composition and richness along productivity gradients
Min Zhang1, Dietmar Straile2, Feizhou Chen1, Yongjiu Cai1, Jinlei Yu1, Wang Wenxia1, 3 & Fanxiang Kong1
1
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology,
CAS, Nanjing, China; 2Limnological Institute, Department of Biology, University of Konstanz, Konstanz,
Germany; 3University of Chinese Academic of Science, Beijing, China
The shape of the productivity–richness relationship (PRR) for phytoplankton has been suggested to be
unimodal, that is, richness peaking at intermediate levels of productivity. However, there has been little
attempt to understand the mechanisms that would lead to such a shape. Here we investigated phytoplankton
data from 71 lakes along the Yangtze River covering an altitude range 0-2700m, and a chlorophyll a range
from 0.65-258.70 µg/L. Within these lakes we observed an unimodal PRR. Temperature (T) and underwater
53
available light (Im) were two primary variables explaining the variations of phytoplankton richness,
independently explaining 33.1% and 14.2% of the variance, respectively. With decreasing altitude, T
increased significantly, which was positively related to richness. However, due to eutrophication, increasing
productivity decreased Im, which had a negative feedback effect on richness. With increasing productivity,
phytoplankton composition tended to become similar. Cyanobacteria, especially Microcystis and Anabaena,
gradually dominated most water bodies. In the low end of the PRR curve (oligotrophic conditions), beta
diversity of the phytoplankton community was higher than in the high end (eutrophic conditions). T was the
primary variable contributing to the composition variation in the low end, with ions concentrations, pH,
zooplankton biomass and nutrients also partially were additionally associated with the composition. In the
high end, Im and ions concentrations were the major variables associated with composition variation. Our
results contribute to an increased understanding of the mechanisms resulting in a hump-shaped PPR within
phytoplankton.
Rocky littoral zone macrozoobenthos of Krestovyi bay (Lake Ladoga)
Zuyev Yury, Zuyeva Nadejda & Lapenkov Artem
Russian State Hydrometeorological University, Saint-Petersburg, Russia
The coastal shallows of Lake Ladoga have characterized by the most abundant benthic community. More
that 85% of the total number of species of macrozoobenthos have been registered. The lake has been
inhabited the valuable commercial species (grayling, ladoga salmon, arctic char and several species of
whitefish). These species feed in coastal shallows of the lake.
Littoral and especially its rocky part are the least-studied biological zones of the lake. Depth research of
rocky shallows with difficult terrain is limited to 1 meter.
A set of techniques were developed for investigation of the rocky littoral benthos. At first a description of the
relief and the type of substrate was conducted along transects. Bottom invertebrates on the every type of
substrates have been collected by usage a hydrobiological frame. Amphipods and other movable species
have skulked in niches near boulders. To collect such a species a special sampler was developed.
Benthic species were presented by 103 taxa. The greatest number of taxa have been observed among insect
larvae (51) and fewer numbers have been presented by oligochaeta (21) and crustaceans (9).
The number and biomass of macrozoobenthos varies widely with an average of 2727 ind./m2 and 6.92 g/m2.
On average the forage base of benthophagous fish on littoral has been characterized as "high".
Three types of benthic communities were identified. These communities are inhabited three types of
substrates such as: sand, large boulders and rocks. These communities statistically significant differ in
species composition, abundance and by a dominant species.
54
LIST OF PARTICIPANTS
Abel Sebastian, University of Eastern Finland, Finland, [email protected]
Agasild Helen, Estonian University of Life Sciences, Estonia, [email protected]
Äijälä Cecilia, University of Helsinki, Finland, [email protected]
Akkanen Jarkko, University of Eastern Finland, Finland, [email protected]
Alenius Beatrice, Lake Vättern Society for Water Conservation, Sweden, [email protected]
Aleshina Dina, Institute of Limnology, Russia, [email protected]
Anneville Orlane, INRA, France, [email protected]
Arvola Lauri, University of Helsinki, Finland, [email protected]
Axenrot Thomas, Swedish University of Agricultural Sciences, Sweden, [email protected]
Belicheva Lidia, Institute of Northern Water Problems, Russia, [email protected]
Belkina Natalia, Institute of Northern Water Problems, Russia, [email protected]
Capelli Camilla, Fondazione E. Mach, Italy, [email protected]
Carvalho Laurence, Centre for Ecology & Hydrology, United Kingdom, [email protected]
Cremona Fabien, Estonian University of Life Sciences, Estonia, [email protected]
Dudakova Dina, Institute of limnology, Russia, [email protected]
Eronen Risto, University of Eastern Finland, Finland, [email protected]
Ferincz Árpád, Szent István University, Hungary, [email protected]
Filatov Nikolai, Russian Academy of Sciences, Russia, [email protected]
Forsman Leena, Natural Resources Institute, Finland, [email protected]
Fukushima Takehiko, University of Tsukuba, Japan, [email protected]
Ginter Kai, Estonian University of Life Sciences, Estonia, [email protected]
Haberman Ellen-Juta, Estonian University of Life Sciences, Estonia, [email protected]
Haldna Marina, Estonian University of Life Sciences, Estonia, [email protected]
Hassan Daud, University of Western Sydney, Australia, [email protected]
Hatanpää Aurora, University of Eastern Finland, Finland, [email protected]
Hellsten Seppo, Finnish Environment Institute (SYKE), Finland, [email protected]
Horppila Jukka, University of Helsinki, Finland, [email protected]
Huttula Timo, Finnish Environment Institute, Finland, [email protected]
Järvalt Ain, Estonian University of Life Sciences, Estonia, [email protected]
Järvinen Marko, Finnish Environment Institute (SYKE), Finland, [email protected]
Kaittola Helena,,City of Imatra, Finland, [email protected]
55
Kalinkina Nataliia, Northern Water Problems Institute, Russia, [email protected]
Kangasniemi Ville, EnviroCase, Ltd., Finland, [email protected]
Kangur Külli, Estonian University of Life Sciences, Estonia, [email protected]
Kankaala Paula, University of Eastern Finland, Finland, [email protected]
Kanninen Antti, Pohjois-Savon ELY-keskus, Finland, [email protected]
Karjalainen Juha, University of Jyväskylä, Finland, [email protected]
Karus Katrit, Estonian University of Life Sciences, Estonia, [email protected]
Keskinen Tapio, Natural Resources Institute Finland, Finland, [email protected]
Kirkkala Teija, Pyhäjärvi Institute, Finland, [email protected]
Kiuru Petri, Finnish Environment Institute, Finland, [email protected]
Kolari Irma, Natural Resources Institute Finland (Luke), Finland, [email protected]
Kortet Raine, University of Eastern Finland, Finland, [email protected]
Kuha Jonna, University of Jyväskylä, Finland, [email protected]
Kuivalainen Jarmo, University of Oulu, Finland, [email protected]
Kukkonen Minna, Savo-Karjalan Ympäristötutkimus Oy, Finland, [email protected]
Lenters John, LimnoTech, USA, [email protected]
Lindell Måns, Lake Vattern Society for Water Conservation, Sweden, [email protected]
Lyytikäinen Merja, University of Eastern Finland, Finland, [email protected]
Mandima Jimmiel, University of Eastern Finland, Finland, [email protected]
Marenkov Oleg, Oles Honchar Dnipropetrovsk National University, Ukraine, [email protected]
Marjomäki Timo J., University of Jyväskylä, Finland, [email protected]
Mukhin Ivan, Vologda State University, Russia, [email protected]
Mustamäki Noora, Åbo Akademi University, Finland, [email protected]
Niemistö Juha, University of Helsinki, Finland, [email protected]
Nishiura Yasumasa, Tohoku University, Japan, [email protected]
Nõges Peeter, Estonian University of Life Sciences, Estonia, [email protected]
Nõges Tiina, Estonian University of Life Sciences, Estonia, [email protected]
Paerl Hans W., University of North Carolina at Chapel Hill, USA, [email protected]
Pellikka Katja, City of Helsinki, Finland, [email protected]
Piirimäe Kristjan, Tallinn University of Technology, Estonia, [email protected]
Rask Martti, Natural Resources Institute Finland, Finland, [email protected]
Rothhaupt Karl-Otto, University of Konstanz, Germany, [email protected]
Rusanov Alexander, Institute of Limnology RAS, Russia, [email protected]
56
Rustadbakken Atle, Norwegian University of Life Sciences, Norway, [email protected]
Ruuhijärvi Jukka, Natural Resources Institute Finland, Finland, [email protected]
Räsänen Marjut, City of Helsinki, Finland, [email protected]
Rösch Roland, LAZBW, Germany, [email protected]
Salmaso Nico, Fondazione Mach - Ist. Agrario S.Michele all'Adige, Italy, [email protected]
Sandström Alfred, Freshwater Research, Sweden, [email protected]
Sarvala Jouko, University of Turku, Finland, [email protected]
Savolainen Miia, Pohjois-Karjalan ELY-keskus, Finland, [email protected]
Seppänen Eila, Natural Resources Institute Finland (Luke), Finland, [email protected]
Sharov Andrey, St-Petersburg Scientific Research Center for Ecological Safety, Russia, [email protected]
Sidorova Anastasiya, Institute of Northern Water Problems, Russia, [email protected]
Soulignac Frédéric, INRA, France, [email protected]
Staszny Ádám, Szent István University, Hungary, [email protected]
Stepanova Anastasija, Russian State Hydrometeorological University, Russia, [email protected]
Straile Dietmar, University of Konstanz, Germany, [email protected]
Suito Hiroshi, Okayama University, Japan, [email protected]
Sutela Tapio, Natural Resources Institute Finland, Finland, [email protected]
Taipale Sami, University of Eastern Finland, Finland, [email protected]
Tamm Marju, Estonian University of Life Sciences, Estonia, [email protected]
Terzhevik Arkady, Northern Water Problems Institute, Russia, [email protected]
Toivanen Tuula, University of Eastern Finland, Finland, [email protected]
Tolonen Kimmo, Finnish Environment Institute, Finland, [email protected]
Tonkopii Valerii, Institute of Limnology, Russia, [email protected]
Tuvikene Lea, Estonian University of Life Sciences, Estonia, [email protected]
Vainikka Anssi, University of Eastern Finland, Finland, [email protected]
Wängberg Sten-Åke, University of Gothenburg, Sweden, [email protected]
Ventelä Anne-Mari, Pyhäjärvi Institute, Finland, [email protected]
Vilbaste Sirje, Estonian University of Life Sciences, Estonia, [email protected]
Viljanen Markku, University of Eastern Finland, Finland, [email protected]
Voyakina Ekaterina, St-Petersburg Scientific Research Center of Ecological Safety, Russia,
[email protected]
Vuori Kari-Matti, Finnish Environment Institute, Finland, [email protected]
Vuorio Kristiina, University of Jyväskylä, Finland, [email protected]
57
Yang Yang, Erken Laboratory, Uppsala University, Sweden, [email protected]
Yohannes Elizabeth, University of Konstanz, Germany, [email protected]
Zamani Behnam, University of Kassel, Germany, [email protected]
Zhang Min, Nanjing Institute of Geography and Limnology, China, [email protected]
Zingel Priit, Estonian University of Life Sciences, Estonia, [email protected]
Zuyev Yury, GosNIORKh, Russia, [email protected]
58
ORGANIZING COMMITTEE OF THE 4TH ELLS
Paula Kankaala (chair, University of Eastern Finland, Joensuu Campus, Finland)
Orlane Anneville (French National Institute for Agricultural Research, France)
Lauri Arvola (University of Helsinki, Finland)
Heikki Hämäläinen (University of Jyväskylä, Finland)
Marko Järvinen (Finnish Environment Institute, Finland)
Tiina Nõges (Estonian University of Life Sciences, Estonia)
Kurt Pettersson (Uppsala University, Sweden)
Martti Rask (Game and Fisheries Research Institute, Finland)
Nico Salmaso (Fondazione Mach-Instituto Agrario di S. Michele all'Adige, Italy)
Dietmar Straile (University of Konstanz, Germany)
Arkady Terzhevik (Northern Water Problems Institute, Russia)
Anne-Mari Ventelä (Pyhäjärvi Institute, Finland)
Tuula Toivanen (secretary, University of Eastern Finland, Joensuu Campus, Finland)
Merja Lyytikäinen (web master, University of Eastern Finland, Joensuu Campus, Finland)
SPONSORS OF THE 4TH ELLS
University of Eastern Finland
Maj and Tor Nessling Foundation
Federation of Finnish Learned Societies
Joensuun yliopiston tukisäätiö
City of Joensuu
4th ELLS 2015, Joensuu, Finland
Time
8:00:00
8:30:00
8:40:00
8:50:00
9:00:00
9:10:00
9:20:00
9:30:00
9:40:00
9:50:00
10:00:00
10:10:00
10:20:00
10:30:00
10:40:00
10:50:00
11:00:00
11:10:00
11:20:00
11:30:00
11:40:00
11:50:00
12:00:00
12:10:00
12:20:00
12:30:00
12:40:00
12:50:00
13:00:00
13:10:00
13:20:00
13:30:00
13:40:00
13:50:00
14:00:00
14:10:00
14:20:00
14:30:00
14:40:00
14:50:00
15:00:00
15:10:00
15:20:00
15:30:00
15:40:00
15:50:00
16:00:00
16:10:00
16:20:00
16:30:00
16:40:00
16:50:00
17:00:00
17:10:00
17:20:00
17:30:00
18:00:00
19:00:00
Mon 24 Aug
Registration
Tue 25 Aug
Wed 26 Aug
Thu 27 Aug
Fri 28 Aug
Carvalho (Keynote) Paerl (Keynote) Hellsten (Keynote)
Hatanpää
Opening Straile (Keynote)
Nõges P
Capelli
Hassan
Axenrot
Taipale
Salmaso
Sandström
Marjomäki
Vilbaste
Voyakina
Tuvikene
Staszny
Coffee break
Coffee break
Coffee break
Coffee break
Vuori
Tonkopii
Dudakova
Suito
Arvola
Niemistö
Sutela
Ginter
Kirkkala
Ruuhijärvi
Ferincz
Huttula
Piirimäe
Mustamäki
Kalinkina
Akkanen
Coffee break
Kuha
Cremona
Lenters
Closing
Zamani
Lunch
Lunch
Lunch
Lunch
Lunch
Kiuru
Kangur
Zingel (Keynote)
Ventelä (Keynote)
Terzhevik
Sarvala
Nõges T
Yang
Yohannes
Rösch
Climate change induced physical and
biological responses in large lakes
Coffee break
Coffee break
Coffee break
Long-term changes in nutrient and organic
matter loading and trophic status of large
lakes
Filatov
Karus
Anneville
Tolonen
Järvinen
Rusanov
Wängberg
Rothhaupt
Agasild
Belkina
Sidorova
Mid‐excursion Lake Pyhäselkä
Vainikka
Järvalt
Mandima
Sessions:
Ecosystem services of large lakes – more
than fishing and recreation
Biotic interactions and biodiversity in large
lakes
Occurrence and impacts of toxic
cyanobacteria on the food webs of large
lakes
Poster session
Sustainability of ecosystem services and
good ecological status in large lakes challenges for management
New tools for monitoring and assessment of
ecological status in large lakes
Poster session
Fish stock assessments and fisheries
management in large lakes
Conference dinner
Emerging contaminants