Transcript Presentation 9 Mb - The Marine Life Information Network

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