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European Climate Change Programme Working Group II – Impacts and Adaptation Brussels 12 April 2006 Overview and predictions for the coastal zone and shallow seas Keith Hiscock Stephen Hawkins David Sims Marine Biological Association, Plymouth, UK The presentation will: 1. Describe the environmental factors likely to cause change. 2. Describe human factors likely to worsen climate change effects on biodiversity and ecosystem functioning. 3. List likely effects of climate change on species and habitats. 4. Describe what changes have already happened. 5. Advocate the importance of long-term data. 6. Introduce some ideas on moderating adverse impacts of climate change. What are the major climate change factors likely to cause change in species abundance and distribution? 1. Seawater temperature increase (surface temperatures as much as 2.5°C higher in summer and 2.3°C higher in winter than in 2005 than in 2000 (Viles, 2001. In: Harrison, Berry & Dawson (eds). UKCIP). 2. Air temperature increase (up to 2.1°C higher in 2005 than in 2000 (Austin et al., 2001. In: Harrison, Berry & Dawson (eds). UKCIP) . 3. Slowing of the North Atlantic thermo-haline circulation (the ‘Gulf Stream’). and subsequent cooling of seawater temperatures (Bryden et al. 2005. Nature, 438, 655-657) 4. Sea level rise (up to 80 cm by 2005 compared to 2000 (causing ‘coastal squeeze) (Viles, 2001. In: Harrison, Berry & Dawson (eds). UKCIP). 5. Increased instances and strength of thermal stratification of seawater leading to de-oxygenation events 6. Increased storminess. What are the human factors likely to worsen climate change effects on biodiversity 1. Transportation of non-native species through mariculture, shipping (fouling organisms) and ballast water discharge. May: 1. Displace native species (e.g Crassostrea gigas); 2. Change habitats (e.g. Crepidula fornicata); 3. Be poisonous to native fauna and flora (e.g. Karenia mikimotoi (Gyrodinium aureolum)). 2. Input of contaminants that reduce resistance to change especially through loss of biodiversity. 3. Construction breaching distributional barriers including for nonnative species (new coastal defences and windfarms etc. create ‘stepping stones’). 4. Increased nutrients working with warming to create opportunities for disease and deoxygenation. 5. Physical disturbance (destroying species and biogenic habitats which may not return because of new climatic conditions). Temperature increase Predicted changes in temperatures (From: www.meto.govt.uk/sec5/CR_div/Brochure98/index.html) Mean annual SST (ºC) Sea-surface temperature offshore Plymouth 1905-2004 13.5 13.0 12.5 12.0 11.5 11.0 1905 1925 1945 1965 1985 2005 Year Data source: Met Office Hadley Centre Grid square 50-51ºN, 4-5ºW See also Sheppard, 2004, Mar. Poll. Bull., 49: 12-16 Factors to consider in predicting change in abundance and distribution of species 1. Presence of suitable habitats for range extension. 2. Temperature effects, including: development of eggs or other propagules; ‘triggering’ release of propagules; survival of larval stages of animals; survival of post-settlement of juveniles; survival of adults (heat or cold stress). 3. Effects of non-native species (competition, predation) 4. Hydrographical conditions - direction of currents. 5. Geographic barriers. 6. Water ‘quality’. But, change (range extensions and reductions) may happen in ‘jumps’ For instance, because of: • Natural barriers ‘relaxing’ for a while, allowing spread of species beyond previous limits – and species will persist if conditions are amenable (e.g. Patella rustica in Portugal and Spain where upwelling cold water declined for a few years resulting in northward spread – Fernando Lima and others, in prep.) • Unusual hydrographic conditions that breach geographical barriers (for instance, species may spread through enhanced larval dispersal if ‘jet-stream’ currents occur). See: Rennell J. 1793. Observations of a current that often prevails to the westward of Scilly; endangering the safety of ships that approach the English Channel. A paper presented to the Royal Society in June 1793. • Human activities that introduce species. For instance, the introduction of ormers, Haliotus tuberculata to Cornwall and the Isles of Scilly from the Channel Isles. • Human activities that destroy populations. For instance, destruction of horse mussel beds in the Irish Sea and Strangford Loch by fishing – a northern species that might not return. Climate change beginning to show effects Warm-water assemblages Cold-water assemblages Plankton sampled using Continuous Plankton Recorders Courtesy of The Sir Alister Hardy Foundation for Ocean Science: www.sahfos.ac.uk Sedentary and sessile species showing slower change: The top shell – Gibbula umbilicalis • eastward range extension of ~70km in North Scotland since 1986 (Miezskowska, unpublished) In the UK: southern species – advancers? Laminaria ochroleuca Paracentrotus lividus Eunicella verrucosa Anemonia viridis In the UK: northern species – retreaters? Alaria esculenta Strongylocentrotus droebachiensis Swiftia pallida See Hiscock et al. 2004. Aquatic Conservation 14, 333-362. Bolocera tuediae An example of predicted change: Current distribution Snakelocks anemone, Anemonia viridis Distribution after seawater temperature increase of about 2ºC. Catch (tonnes) Landings of pelagic fish at Plymouth 8000 7000 6000 5000 Herring - Clupea harengus 4000 3000 2000 1000 0 192019301940 1950196019701980 19902000 Year Sutton Harbour, 1925 Data source: UK Government records Catch (tonnes) 6000 Pilchard - Sardina pilchardus 5000 4000 3000 2000 1000 0 19201930 19401950 196019701980 19902000 Year Fish stocks in relation to exploitation and climate: separating the causes of change November 2001 October 1963 Marine Biological Association Standard Hauls (started 1913) -6 1985 2005 -8 Warm -4 0 4 PC1 (Sea Temperature) Increase PCA of MBA standard hauls 8 Cold Species correlated with more fishing 0.4 d Species increasing with warming 1985 2005 Decline PC 2 (More Fishing) 0.2 (No cold water species losses correlated with warming) 0 -0.2 -0.4 -0.4 Increase -0.2 0 PC1 (Warming) 0.2 0.4 Species declining with fishing Decline Genner, Sims, Southward, & Hawkins, 2004, Proc. Roy. Soc., 271, 655-661. Fish community of the English Channel Datasets • Catches during 23 years (1913 - 2002) • 72 species of fish from 707 ‘otter’ trawls Community composition • 24% of variation (PC1) explained by sea surface temperature: strong correlation (r2 = 0.73) with warming • 19% of variation (PC2) explained by fishing Population structure • Size and abundance strongly affected by fishing Genner, Sims, Southward, & Hawkins, 2004, Proc. Roy. Soc., 271, 655-661 Day of peak abundance in year off Plymouth (Day 1 = April 1) Timing of annual migration also affected 300 200 r 2 = 0.51 p < 0.001 100 0 10 10.5 11 11.5 12 12.5 Mean Sea Bottom Temperature ºC (Previous year April to March) Sims, Genner, Southward and Hawkins, Proc. Roy. Soc. L, 2001, 268, 2607-2611. Trophic mismatch in the plankton Courtesy of The Sir Alister Hardy Foundation for Ocean Science: www.sahfos.ac.uk Phytoplankton peaks Season Group Spring Diatoms 0d Summer Diatoms 22 d Dinoflagellates 23 d Copepods 10 d Other zooplankton 10 d Meroplankton 27 d Autumn Diatoms Germination of diatom spores photoperiod dependent Days forward 5d O. Oku Edwards & Richardson (2004) Nature Trophic mismatch: worsening cod collapse? Courtesy of Sir Alister Hardy Foundation for Ocean Science: www.sahfos.ac.uk Increased thermal stratification: isolation of deeper waters, leading to: 1. Trapping of nutrients below the thermocline and consequent loss of shallow water productivity. 2. Isolation of bottom waters in enclosed areas leading to increased instances of de-oxygenation. Bacterial mat in de-oxygenated sediment Human factors: non-native marine species are becoming more prevalent – and their spread is being encouraged by warming • For instance, there are about 60 established non-native species in UK waters – brought in with shellfish, on the hulls of ships and in ballast water. Pacific oyster – ‘escapees’ solitary at present in SW England. But, in Holland, they have overtaken mussel beds (and are not harvestable!) Image: Norbert Dankers Japweed, Sargassum muticum See: www.marlin.ac.uk/marine_aliens Human factors: increased nutrients worsen impacts of warming seas E.g. German Bight in 1980s • Algal blooms. • Oxygen depletion. • Death of flatfish and invertebrates such as brittlestars & clams. Decline of seagrass beds? Agent in sea fan deaths? Human factors: coastal defences: introduce new habitats and bridge natural barriers (‘stepping stone’ effect) Ocean acidification – not climate change but same cause (CO2 Emissions) While climate change has uncertainty, these geochemical changes are highly predictable. Only the time scale, and thus mixing scale length are really under debate. Anthropogenic CO2 predicted to decrease surface ocean pH by 0.77 pH has probably already changed by 0.1 in surface waters due to absorption of anthropogenic CO2 Caldeira & Wickett 2003, Nature: A simulation of changes in ocean pH assuming continued usage of known fossil fuel reserves. Acidification of oceans a significant concern A coccolithophore plankton bloom Coccolithophores - Important role in the global carbon cycle through the transport of calcium carbonate to deeper waters and sediments Recent-past levels carbon dioxide Increased levels carbon dioxide (median scenario) Riebesell et al. "Reduced calcification of marine phytoplankton in response to increased atmospheric CO2", Nature, 407, pg 364-7, 21 September, 2000 The importance of long-term research – MBA & Port Erin 1999 1994 1989 1984 1979 1974 1969 1964 1959 Port Erin Bay annual running mean 1954 1949 1944 1939 1934 1929 1924 1919 1914 1909 Port Erin Bay monthly mean SST 1904 SST (°C) Port Erin Bay Sea Surface Temperature (SST) 20 18 16 14 12 10 8 6 4 2 0 Port Erin Plymouth 1999 1994 1989 1984 1979 1974 1969 1964 1959 1954 1949 1944 1939 1934 Satellite annual running mean 1929 E1 annual running mean Satellite monthly mean SST 1924 E1 monthly mean SST 1919 1914 1909 E1 1904 SST (°C) E1 (50°02'N 4°22'W) Offshore Sea Surface Temperature (SST) 20 18 16 14 12 10 8 6 4 2 0 Southward et al., 2005, Adv. Mar. Biol., 47, 1-105. N.B. Satellite SST data obtained from NOAA Pathfinder AVHRR data for 1° grid square centered on 50°N 4°W Is there a role for marine protected areas? Lundy No-Take Zone (red) Strictly protected marine nature reserves are areas where as many as possible of the pressures that adversely affect marine life are taken off. In such situations, species and biogenic habitats likely to be adversely affected by climate change may survive longer because they are not being adversely affected by controllable factors. Cautions Any true long-term change is likely to be obscured initially by: • short-term changes driven (for instance) by the decadal but irregular cycle of the North Atlantic Oscillation (Hurrell, 1995); • the 11-year cycle of sunspot activity (Southward et al., 1975), and • longer-term fluctuations such as the Russell cycle (Russell, 1973; Flushing and Dickson, 1976; Southward, 1980). Uncertainties abound – not least the possibility that melting polar ice may resulting in ‘switching-off’ or at least slowing of the ‘Atlantic conveyor belt’ which draws warm water northwards along the western seaboard of Europe. Conclusions: expected consequences of climate change: • Southern spp move northwards • Northern spp retreat • Low-lying land reverts to saltmarsh and mudflats • Increased stratification of waters causes isolation of nutrients or planktonic food and de-oxygenation events in some enclosed waters. Conclusions: unexpected consequences of climate change?: • Mismatch of food availability and need for that food • Non-native spp expand abundance & distribution (facilitated by coastal defences and better conditions for what are often warmer waters spp) • Poisonous non-native plankton spp (e.g. Gyrodinium) blooms increase. • Synergistic effects with increase nutrients leading to de-oxy events Moderating the effects of climate change Unavoidable effects: 1. Live with them (e.g. allow flooding of low-lying agricultural land, enjoy species re-distributions) 2. Turn them to the advantage of biodiversity (e.g. through design of coastal defence structures to provide better habitats for species) 3. Adjust eating habits (in the case of commercial species). Avoidable effects 1. Take other pressures off to avoid synergistic effects (e.g. reduce physical damage to habitats, reduce nutrient inputs, stop non-native species being introduced). Further information: Intergovernmental Panel on Climate Change: http://www.ipcc.ch US Environment Protection Agency http://yosemite.epa.gov/oar/globalwarming.nsf/content/ImpactsCoastalZones.html Natural Environment Research Council http://www.nerc.ac.uk/publications/climatechange/ UK Government Department of Environment, Food and Rural Affairs. http://www.defra.gov.uk/environment/climatechange Sir Alister Hardy Foundation for Ocean Science (Continuous Plankton Recorder Survey) http://www.sahfos.ac.uk (Links to ‘Climate Change Encyclopaedia’) The website for the Global Climate Change Student Information Guide. http://www.doc.mmu.ac.uk/aric/gccsg Woods Hole Research Center. The Warming of the Earth. http://www.whrc.org/globalwarming/warmingearth.htm MBA Marine Life Information Network. http://www.marlin.ac.uk/learningzone (link to topic notes) MarClim - Marine Biodiversity and Climate Change http://www.mba.ac.uk/marclim This presentation has benefited from work undertaken in the following EC-funded programmes: MARBENA Thanks to the Sir Alistair Hardy Foundation for Ocean Science for use of slides from various presentations (see: www.sahfos.ac.uk for their Climate Change Encyclopedia) Thanks to Dan Laffoley (English Nature / IUCN) for use of slides from a presentation on Perspectives of Marine Conservation in the UK: Marine Protected Areas and climate change