warming of the arctic ocean, marine ecological consequences · 2014-06-29 ·...
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Warming of the Arctic Ocean,
Marine Ecological Consequences
© Gordon Lax
Short version of a presentation at the summer school in Potsdam, 25 th June 2014
eva-maria.noethig@awi.de
Only for working purposes
Do not use overheads without asking respective proper citing of the original source
The Arctic Marine Ecosystem
Introduction
Changes
Consequences
Examples
The Arctic Marine Ecosystem
CAFF. 2010. Arctic Biodiversity Trends: Selected indicators of change
http://www.grida.no/graphicslib/detail/arctic-sea-ice-food-web-schematic-illustration_14df
Who lives in the Arctic Ocean and
needs the sea ice? • 16 species of mammals like polar bear, ringed seals, walruses, whales
like Beluga & narwhale
• 60 species of seabirds like puffins and fulmars
• In sea ice ~ 2100 single cell organisms from viruses to ice algae protozoan and more than 50 species of larger grazers
• In the water column ~ 240 fish species like polar cod
• ~ 1800 phytoplankton species, 50 % diatoms who serve as food for ~ 340 zooplankton species of amphipods and other crustaceans
• On the sea floor in shallow coastal areas 160 seaweeds, ~ 2600 animal species in shallow and ~ 1100 in the deep sea, besides crustaceans many worm species like annelids
http://www.awi.de/fileadmin/user_upload/News/Background/IPCC_AR5_2013/Factsheets/Factsheet_Arktis_final_20140304.pdf
Key species determine flux of organic matter
© Christine Klaas
Nöthig et al. 2009
Ice algae and phytoplankton growth
Taken from Nöthig et al 2009, modified from Tilzer 1992
The Arctic Marine Ecosystem
Introduction
Changes
Consequences
Examples
Changes
6-10°C higher air temperature than global average by 2100 in the Arctic
Drastic reduction in sea ice extent and volume during the last 30 years
Twice as much light income through the ice, at the ice edges
Ice melt and warming produce more stable surface waters thus a
stronger stratification and prevent the surface form mixing with deeper
nutrient rich water
Low nutrient supply to surface layers result in less harvestable
production
Increase in acidity
The Arctic Marine Ecosystem
Introduction
Changes
Consequences
Questions & Examples
Consequences for seasonal aspects
Wassmann, Oceanography 24 2011
Consequences: Effects on trophic levels
Directly and
indirectly effects
Sea birds and marine mamals
Demersal fish and benthal
Pelagic fish and larvae
Zooplankton
Phytoplankton
Consequences for the food web
• Switch in food-web: large, Arctic smaller Atlantic species
• Limitation of food sources for top predators
• Increase in number & diversity of small carnivores, dissipating the energy flow
“Warming in the
Arctic may
result in the
negative effects
of increased
biodiversity” Weslawski et al. (2009)
Predictions in fish populations
Polar cod
(Boreogadus saida)
Model predicted:
Extirpated in parts of
the Arctic Ocean after
30 years of
hypothetical warming.
and retreating sea ice
edge at a rate of 5 km
per year.
http://www.grida.no/graphicslib/detail/simulated-projections-for-polar-cod-distribution-with-global-warming_923b#
Cheung, W.W.L., Lam, V.W.Y. & Pauly, D. (eds.) 2008. Modeling present and climate-shifted distribution of marine fishes
and invertebrates. Fisheries Centre Research Reports 16(3).72 pp.
Consquences from acidification
Citation
AMAP, 2014. Arctic Ocean
Acidification 2013: An Overview.
Arctic Monitoring and Assessment
Programme (AMAP), Oslo, Norway. xi
+ 27 pp.
The Arctic Marine Ecosystem
Introduction
Changes
Consequences
Examples
Instead
Melt ponds Under ice
Melosira arctica
Deep sea sediments
Boetius et al. 2013
ROV- AWI
Massive development of Melosira arctica in 2012
20 cm
Production in the central Arctic Ocean
Long-term obeservations
Beszczynska, et al., 2012
Oceanography in Fram Strait
Beszczynska-Möller, A., Fahrbach, E., Schauer, U., and
Hansen, E.
Variability in Atlantic water temperature and transport at the
entrance to the
Arctic Ocean, 1997–2010. – ICES Journal of Marine
Science, doi:10.1093/icesjms/fss056
Beszczynska-
Möller
Temperature in Fram Strait
(1999-2010)
Warm anomaly
Oceanography in Fram Strait
Beszczynska-Möller, A., Fahrbach, E., Schauer, U., and Hansen, E.
Variability in Atlantic water temperature and transport at the entrance to
the
Arctic Ocean, 1997–2010. – ICES Journal of Marine Science,
doi:10.1093/icesjms/fss056
Sediment trap sampling in AWI ‘HAUSGARTEN‘
(2000-2012)
~79°N 4°E
0
20
40
60
80
100
2007
.1
2008
.1
No
. m
-2d
-1
2009
.1
2010
.1
0
20
40
60
80
100
2004
.1
2005
.1
No
. m
-2d
-1
Lander
2.5 m above bottom
Bauerfeind et al 2014, JMS
Traps
200 - 300m
0
100
200
300
700
800
900
No
. m
-2d
-1
L. retroversa
NO
DA
TA
NO
DA
TA
2000
.1
2001
.1
2002
.1
2003
.1
2007
.1
2005.
1
2006
.1
Pteropods
2008.
1
2009
.1
L. helicina
HAUSGARTEN
Key species: Pteropods in moored sediment traps
Kraft et al. 2011 Mar Biodiv 41:353-364, Kraft et al. 2012 J Mar Sys 95:1-15, Kraft et al. MarEcolProgSer, submitted
HAUSGARTEN
Key species: Themisto spp in moored sediment traps
2012: 14 % contribution of the North Atlantic T. compressa
2000-2011: 15x increase in amphipod occurrences
22
Themisto compressa
North Atlantic invader
Kraft et al. 2013, Mar. Ecol. Prog. Ser.
Themisto compressa a successful invader
Biogeographical shift &
successful reproduction
under Arctic conditions
Klekowski and
Weslawski 1991
HAUSGARTEN
Dalpadado 2002, Dalpadado et al. 2008
Atlantic Reference Centre 2012
After the warm anomaly we observed a shift in
biomass and species
Did we pass a tipping point?
Concluding Remark
“Warming in the Arctic may result in the negative
effects of increased biodiversity” Weslawski et al. (2009)
Yes, there are indications of this, as prove, we need to continue studies at
Fram Strait
Questions
• Will production & carbon flux in the Arctic
change under reduced ice conditions?
• Is the carbon flux affect & the coupling of
pelagic and benthic ecosystems?
• Will organisms be able to adapt to
changing conditions?
• Will new species successfully migrate
and sustain?
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