Arctic Ocean Biology from the surface to the deep sea Christina Bienhold Helmholtz Max Planck Research Group for Deep Sea Ecology and Technology cbienhol@mpi-bremen.de ACCESS Summerschool, Bremen, Germany 23 September 2013
Outline Introduction Life in the Arctic The Arctic a changing ocean Marine habitats Sea ice Water column Seafloor From the surface to the deep sea Research examples Central Arctic Ocean Expedition IceArc 2012 Long-term observatory HAUSGARTEN 2
Animal life in the Arctic Thick fur with hollow shafts to trap warm air, dark skin, layer of blubber Polar bear http://www.arcodiv.org/mammals/harp.html http://www.stanford.edu/gro up/ccr/ccrblog/2010/03/pol ar_bears_in_sweden.html IceArc team Harp seal Blubber, two sets of blood vessels to prevent heat loss http://en.wikipedia.org/wiki/fil e:blanchon-idlm2006.jpg 3
Animal life in the Arctic Beluga whale Blubber special blood vessel system to prevent heat loss http://i.telegraph.co.uk/ Bowhead whale wwf.panda.org 4
Life in the Arctic Arctic fish (e.g. Polar cod) do not keep their body much warmer than the water. Need to keep ice crystals from forming in their bodies. Solution: Hauke Flores Fragilariopsis sp. Bind to small ice crystals to inhibit growth and recrystallization of ice. Found in fish, but also in ice algae, e.g. Fragilariopsis sp. Mar Fernández Méndez 5
The global conveyer belt Source: AWI 6 http://en.wikipedia.org/wiki/thermohaline_circulation
Arctic Ocean circulation Circulation influenced by both Atlantic and Pacific waters 7 Source: AWI
The Arctic a changing ocean Sea ice extent in September (National Snow and Ice Data Center) 1981 2007 2012 7.3 Mio km 2 4.3 Mio km 2 3.4 Mio km 2 8
The melting Arctic sea ice Average monthly Arctic sea ice extent September 1979-2012 Ice thickness Iceextent(Miokm 2 ) Relative abundance National Snow and Ice data center S. Hendricks, AWI 9
The Arctic a changing ocean To understand what that may mean for Arctic organisms, we will look at the different marine habitats from the: Ice Water column Seafloor 10
Primary Production Photosynthesis Chl a 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Water column Melt Ponds Sea Ice Mar Fernández Méndez 11
Primary Production in the Arctic Seasonality in the sea ice habitat Keck & Wassmann 1993 Sea ice algae and phytoplankton are light-limited: sunlight for primary production only from May to September 12
Sea ice as a microbial habitat C Krembs, J Deming, University of Washington 13
Marine life in the Arctic 14
Sea-ice associated fauna Arctic cod Under-ice habitat as nursery ground Important food source for many Arctic mammals and birds Zooplankton Graze on the under-ice algae Under-ice habitat for protection (Hauke Flores) Clione limacina 15
Arctic seafloor 16
Export flux to the seafloor Sediment traps E Nöthig, C Lalande, AWI 17
Life at the Arctic seafloor 18
Biological Carbon Pump Biological carbon pump Physical carbon pump Chisolm et al., 2000 (Nature) 19
Primary Production Photosynthesis Chl a 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Water column Melt Ponds Sea Ice Mar Fernández Méndez 20
Changes in Arctic Productivity Increase in primary production in 2007: 30% attributed to decreased minimum summer ice extent, 70% to longer growing season Annual primary production (Tg C yr -1 ) Arrigo et al. 2008
Environmental changes in the Arctic Ocean How will changes in sea ice cover affect the carbon cycle in the Arctic? 22
Central Arctic Ocean Expedition IceArc RV Polarstern ARK-XXVII/3 2 August 8 October 2012 Mar Fernández-Méndez, AWI
Central Arctic Ocean 24
S Hendricks, AWI 25
Control of photosynthesis rates 26 M. Nicolaus, AWI
Control of photosynthesis rates Total transmittance Example data from ROV light measurements Nicolaus et al. GRL, 2012 27
Control of photosynthesis rates More light will reach the Arctic Ocean 28 M.Nicolaus & C.Katlein (AWI Sea Ice Physics)
Sampling of algae Water column Sea Ice Melt Ponds 29 Mar Fernández-Méndez, AWI
Sea ice algae Pennate diatoms Melosira arctica 5 cm 5 cm Mar Fernández-Méndez, AWI 30
Seafloor sampling: bacteria, macrofauna, megafauna Agassiz Trawl Photos: IceArc team 31
Sampling seafloor: bacteria, macrofauna, megafauna TV-Multicorer Top photos: IceArc team AWI 32
Export flux to the seafloor AWI ~ 5 cm AWI Kolga hyalina, opportunistic holothurian (sea cucumber) AWI 33AWI
Benthic oxygen consumption C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + heat 34
Benthic oxygen consumption Oxygen is consumed below algae patches. Sediment depth (mm) F Wenzhöfer, J Felden et al., AWI/MARUM 35
Export of algal biomass from the sea ice Boetius et al. 2013 When the ice melts, ice algae rapidly sink to the seafloor to depths of several thousand meters. Deep-sea animals feed on the algae and bacteria metabolize what is left, consuming oxygen in the seabed. Warming and the associated physical changes in the Central Arctic cause reactions in the entire ecosystem down to the deep sea. 36
IceArc Movie Watch it on the AWI youtube channel: http://www.youtube.com/watch?v=0xdp2ftqjde 37
Long-term observations 38
HAUSGARTEN Fram Strait Circulation influenced by both Atlantic and Pacific waters 39 Source: AWI
HAUSGARTEN - Fram Strait T [ C] 4.4 0.0-1.6 Beszczynska-Möller A et al., 402012
HAUSGARTEN Long-term observatory Established in 1999 16 permanent stations 9 stations along depth transect: 1000 m to 5500 m depth 8 stations at 2500 m depth Parameters: Abiotic: temperature, hydrography, ice coverage Biotic: primary productivity, carbon flux, bacterial activity, biodiversity of all size classes Soltwedel, 2005 41
Temperature anomalies at HAUSGARTEN Oceanographic moorings across Fram Strait (Beszczynska-Möller et al., 2012)
Changes in phytoplankton and zooplankton Temporal variability of plankton species in sediment traps between 2000 and 2009 2000/1 2002/3 2004/5 2005/6 2006/7 2008/9 Coccolithophorids Diatoms Tintinnids (Bauerfeind et al., 2009, 2012) proportion of amphipods in sediment traps (%) 90 80 70 60 50 40 30 20 10 0 T. Polar libellula species T. abyssorum Atlantic species 2000/01 04/05 06/07 07/08 08/09 after Kraft et al. 2012
Coupling of ice and organic matter flux The presence of ice influences organic matter flux. POC flux (mg C m -2 d -1 ) Ice concentration (%) 2002 2003 2004 2005 2006 2007 2008 Lalande et al., 2013 POC = Particulate organic carbon 44
Litter in the Arctic Abundance of litter Types of litter 45
Litter in the Arctic 46 Bergmann & Klages 2012 Marine Pollution Bulletin 64
To think about... Future of the Arctic Ocean Ecosystem? How can we improve predictions? Increasing or decreasing primary productivity? Increasing or decreasing stratification? Increasing or decreasing nutrient availability? Increasing or decreasing research effort? Sustainable and responsible use of Arctic resources? M. Schiller; AWI Sea ice observatory 47
Thank you for your attention S. Hendricks, AWI Captain and Crew RV Polarstern RV Maria S. Merian 48