Ice matters. Arctic and Antarctic under-ice communities linking sea ice with the pelagic food web

Transcription

1 Ice matters Arctic and Antarctic under-ice communities linking sea ice with the pelagic food web Hauke Flores, J. A. van Franeker, C. David, B. Lange, V. Siegel, E. A. Pakhomov, U. Bathmann...

2 Hauke Flores Studies UHH Fisheries observer Federal Research Centre for Fisheries (HH) PhD Univ. of Groningen IMARES (NL) Junior Scientist IMARES Current project: Iceflux Ice-ecosystem carbon flux in polar oceans Since Jan 2012 Group leader HGF Young Investigators Group AWI & UHH

3 Outline 1. Introduction 2. The sea ice food web link a) Lessons from the Antarctic ice underside b) The Iceflux approach c) First insights from a field study in the Arctic 3. Conclusions

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5 Antarctic krill Fish feed akerbiomarine.com Euphausia superba Functional food whoi.edu Cosmetics

6 Antarctic krill Bioluminiscent Size up to 6 cm Age up to 6 yrs Swimming speed up to 0.65 m s -1 Euphausia superba Total biomass ~ 380 Mio t (NE Atlantic herring SSB: ~ 6 Mio t) Huge swarms (up to 10s of km) Key prey item of Antarctic birds and mammals whoi.edu

7 Krill decline in past decades Atkinson et al (2008) Mar Ecol Proj Ser 362: 1-23 Atkinson et al (2004) Nature 432:

8 Flores et al. 2012

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10 Sea ice habitats Emperor Penguins Air Snow Flying birds Penguins (Antarctic) Seals Stephos longipes Slush Brine Copepods Amphipods Ciliates Turbellarians Copepods Nematodes Rotifers 1 mm J. Michels Krill larvae Water column Ice-water interface Krill (larvae) Amphipods Copepods Zooplankton Squid Fish Whales

11 Arctic Ocean Southern Ocean Ice algae High life stock in a low productive ocean?

12 Annual water column primary production (g C m -2 y -1 ) Arctic Ocean Southern Ocean 57 %?* Max. sea ice extent %?** Arrigo et al. (2008) Geophys Res Lt Arrigo et al. (2008) J Geophys Res *Gosselin (1997) Deep-Sea Res II ** Arrigo & Thomas (2004) Ant Sci, McMinn et al. (2010) Mar Biol Proportional contribution of ice algal primary production

13 Euphausia superba Boreogadus saida Sea ice-associated fauna Antarctic Arctic Gammarus wilkitzkii J.A. van Franeker Arcodiv.org Apherusa glacialis Eusirus laticarpus Eusirus microps Onissimus glacialis Arcodiv.org

14 Surface & Under-Ice Trawl SUIT B. Lange

15 Macrozooplankton sampled under Antarctic sea ice Lazarev Sea RV Polarstern

16 Antarctic krill under sea ice Summer: Krill signific. more abundant under ice than in ow Under ice per-area abundances consistantly higher than m abundances from pelagic nets Winter Maximum seasonal abundances under winter sea ice Local per-area abundances far exceeded m abundances Flores et al. (2012) PLoS ONE

17 Ice algae J.A. van Franeker Calanus glacialis Carbon flux through sea ice food web Antarctic krill Humpback whale

18 Ice algae J.A. van Franeker Calanus glacialis Carbon flux through sea ice food web Antarctic krill Humpback whale

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20 Iceflux approach

21 Iceflux approach

22 Ice algae J.A. van Franeker Calanus glacialis Carbon flux through sea ice food web P a s s i v e Microbial loop T r o p h i c Antarctic krill Humpback whale

23 Lectures & Seminars Introduction to Biological Oceanography (Msc, IHF) MSc, BSc projects Research projects ANDEEP-SYSTCO II (DFG) KuramBio (BMBF) Brandt et al. (2011) Deep-Sea Res II

24 Collaboration AG Brandt Taxonomy Biodiversity studies Cryo-benthic coupling Museum samples Education Other possible collaborations Trophic studies (FA, SI) Habitat modeling Zooplankton ecology

25 ARK XXVII/3 IceARC

26 Multi-disciplinary surveys

27 Ice station

28 Flügelschnecke Clione limacina Flohkrebs Gammarus wilkitzkii Rippenqualle Beroe sp. Polardorsch Polardorsche

29 Polar cod

30 Community composition Carmen David

31 Linking data Benjamin Lange

32 Linking data Arctic Ocean 2012 Under-ice fauna Under-ice fauna Clione limacina Carmen David

33 Linking data Arctic Ocean 2012 Under-ice fauna Under-ice fauna Lazarev Sea 2007/08 Clione limacina Under-ice fauna Carmen David

34 Biomass comparison Hauke Flores Carmen David

35 Conclusions The Antarctic under-ice habitat hosts an abundant and diverse community Antarctic krill is particularly associated with sea ice nearly year-round In the Arctic Ocean, a similarly diverse under-ice community exists throughout the low productive central basins Arctic cod and Antarctic krill may play similar key roles in transferring carbon from sea ice into the pelagic food web In both Polar Regions, sea ice-associated key species are threatened by rapidly changing habitats, with possible ramifications for ecosystem structure

36 Thank you. SUIT on-deck crew, Polarstern ARK XXVII/3