Download Predicting algal bloom dynamics in a changing climate

Predicting algal bloom dynamics in a changing climate
Predicting algal bloom dynamics
in a changing climate
R.J. Sorichetti, S. Sharma, A.M. Paterson, J.A. Rusak, H. Yao
York University and Ontario Ministry of the Environment and Climate Change
[email protected]
R.J. Sorichetti, S. Sharma,
A.M. Paterson, J.A. Rusak, H. Yao
York University and Ontario Ministry of the Environment and Climate Change
[email protected]
Benthic Algae
Attached
Pelagic Phytoplankton
Free-Floating
Chrysophytes
fmp.conncoll.edu
Cyanobacteria
Diatoms
www.micromagus.net
Chlorophytes
www.rolfsbild.se
microbewiki.kenyon.edu
protist.i.hosei.ac.jp
Cryptophytes
Dinoflagellates
tolweb.org
www.biologycorner.com
Euglena
www.lakesuperiorstreams.org
www.studyblue.com
Aquatic Ecosystem
Trophic Food Web
www.alchemistclub.wikispaces.com
Increased occurrence of algal blooms
• Previous: large basins, eutrophic systems (Downing et al., 2001)
• Recent: small basins, oligotrophic systems (Carey et al., 2008)
• Increased occurrence over last decade in:
o Laurentian Great Lakes Basin (Brittain et al., 2000; Molot
et al., 2010; Watson et al., 2004; Winter et al., 2011)
o Globally (Berger et al., 2008; Figueredo et al., 2007)
No longer strictly associated with eutrophication
Gordon Campbell, Dean Lake
Concerned citizen, Twin Lakes
Ecosystem health implications
• Bloom forming
o Cyanotoxins, noxious (T&O) compounds
• Microcystin (MC), anatoxin, saxitoxin, nodularin, 2-MIB, geosmin
• Laurentian Great Lakes Basin
o Microcystis spp.  MC (Hotto et al., 2007)
Gordon Campbell, Dean Lake
Chemical determinants of algae
• Phosphorus  Schindler, Downing
• Nitrogen  Paerl, Bergström, Herrero
• N:P  Smith, Havens
• Iron (Fe)  Trick, Molot, Wilhelm
o Photosynthesis, Chl-α synthesis, N-fixation
o Organic ligands (catecholate and hydroxamate)
Climate is changing
Increasing blooms in Ontario
No. algal bloom reports
50
other
golden-brown algae
green algae
40
blue-green algae
30
20
10
0
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
(Winter et al., 2011; Updated by OMOECC Algae Laboratory, Toronto, Canada)
Blooms increases in all parts of the Province
(Winter et al., 2011; Updated by OMOECC Algae Laboratory, Toronto, Canada)
Blooms occurring later in the year
December
320
300
280
260
240
220
2012
2010
2008
2006
2004
2002
2000
1998
1996
200
1994
Last day of the year
blooms reported
340
(Winter et al., 2011; Updated by OMOECC Algae Laboratory, Toronto, Canada)
Active community involvement
10
Revisit climate – algal dynamics relationship
Common questions asked in 20th and 21st century:
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Where do we see blooms and why?
Can we identify lakes with highest bloom risk?
Which algal groups bloom where?
Why do algae produce bioactive compounds?
What are the human and ecosystem health implications?
Can blooming lakes be remediated or recovered?
Will answers to these questions support new effective legislation?
Framing a context for algal blooms in lakes
• Linkages between algal blooms and climate change
• Lake physical and chemical attributes – not one size fits all!
Climate
Need for a lake typology
Physical basis for investigation
Physical Structure
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Chemical Structure
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Nutrients
Oxygen
Trophic status
Temperature
Thermocline
Wind patterns
Mixing regime
Biological Structure
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Algae
Fish
Microbial loop
A lake typology from first principles
Phytoplankton Group
Vertical Distribution
Common Bloom Season
Diatoms
Epilimnion – Metalimnion (cool, dense)
Spring and fall mixis
Chrysophytes
Epilimnion – Metalimnion (some motile)
End of spring, early
summer
Cyanobacteria
Epilimnion – Metalimnion (some motile)
End of summer
Greens
Epilimnion (some motile)
Early summer
Browns
Epilimnion – Metalimnion (some motile)
End of spring, early
summer
Lake Type
Greatest Response to Climate Change
Response Season(s)
Deep Stratified
Later fall mixis, higher internal loading
Fall
Shallow Non-Stratified
Increased lake water temperatures
Summer
High DOC
Reduced/warmer epilimnion, cooler at depths
Summer
Low DOC
Increased lake water temperatures and stability
Summer and Fall
How will lake typology help identify the lakes most at-risk from the
effects of climate change on algal dynamics?
York University and OMOECC partnership
Dr. Sapna Sharma Dr. Andrew Paterson
York U
OMOECC
Dr. Jim Rusak
OMOECC
Dr. Huaxia Yao
OMOECC
Thomas Van Zuiden
York U
Research Questions:
1. What are the linkages between algal blooms and climate change?
2. Which lakes are at highest risk for algal blooms under climate change
scenarios?
Modeling algal dynamics in a changing climate
• LTER site data across Ontario (ELA, Algoma, Muskoka, Algonquin)
• Lake physical parameters, water chemistry, biology (algal group
biomass), meteorological and climate data
• Identify lake characteristics at highest risk of algal blooms
• Predict future algal dynamics in lakes in 2050 and 2070 under 126
scenarios of climate change:
Present
2050
2070
(Van Zuiden et al., 2016)
DESC inland waters monitoring program
9 lakes
(monthly to bi-weekly)
1981-present
25 streams
(weekly; 14 gauged)
4 climate stations
(automatic, real-time)
2 lake buoys
(automatic, real-time)
climate station
lake buoy
Algal trends in Dorset A lakes
Year
2012
2009
2006
2003
2000
1997
1994
1991
1988
1985
1982
2.5
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
1979
1981-2013 = No change
1981-1999 = Increasing biomass
2000-2013 = Decreasing biomass
Relative Biomass (z-scores)
Plastic Lake Dinoflagellate Biomass
Group-level changes in relative biomass
1981-1999
2000-2013
Increasing chrysophytes
Decreasing diatoms
Decreasing chrysophytes
Increasing diatoms
Warmer and longer Ontario summers in 2070
20
Mean summer temp increase
Later ice-on
Earlier ice-off
Earlier stratification onset
Later fall mixis
15
Temperature (C)
25
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1950−2000 temp
RCP 2.6
RCP 4.5
RCP 6.0
RCP 8.5
Climate Change Scenar io
(S. Sharma Unpubl. Data, 2016)
(Crossman et al., 2016)
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Climate change has affected thermal properties of Dorset lakes
Lake warming driven by increased autumn air temperature
Decreasing mixing depths (climate-driven increases in lake DOC)
Delayed autumn mixing
Synchronous changes among lakes points to regional driver (climate?)
How has changing lake physics influenced algal dynamics?
Summary
• Climate and algal dynamics are changing
• Climate  lake physical structure (temperature/mixing)  lake
chemistry and biology
• Must first understand how climate affects lake physics and in turn,
biology (algal dynamics)
• Understanding effects of climate change = national water strategy
Thank you!