Southern Ocean GLOBEC Program Eileen E. Hofmann Third GLOBEC PRSW Boulder, February 2009

SO GLOBEC Program Understand physical and biological factors that contribute to enhanced growth, reproduction, recruitment, and survivorship of krill - include predators and competitors Overwintering strategies and role of sea ice and circulation are primary focus

SO GLOBEC Program SO GLOBEC is part of International GLOBEC and US SO GLOBEC is a contribution to the international effort Field studies began in Field studies finished in 2007/08 SO GLOBEC program is now in synthesis and integration phase

UK Australia US, Germany Germany Korea SO GLOBEC Field Study Sites

Target Species Approach

Two special issues of Deep-Sea Research II devoted to SO GLOBEC results Third volume is in progress and should be done by end of 2009 Synthesis approach

Research Highlights Understanding of circulation Connections of circulation to top predator distributions Connection of SO GLOBEC region to larger system Innovative use of seal-derived hydrographic data

Stratification, retention and frontal exchanges Sea ice modifies all of these Ice shelf effects on circulation (Klinck et al., 2004) (Beardsley et al., 20)04

(Thiele et al., 2004) Humpback Whale Locations Extensive observations of predator abundance and distribution Habitat use, predator and prey interactions Food web interactions Biological Hot Spots Snow petrel and Adélie Penguin distribution in relation to water masses (Chapman et al., 2004)

Not all parts of the shelf are biologically similar Biological Hot Spots (Costa et al., 2007)

Bellingshausen Sea Drake Passage MB MB : Marguerite Bay MT : Marguerite Trough AI : Alexander Island CS : Crystal Sound LF : Laubeuf Fjord MT AI CS LF Predator Hot Spots Role of circulation and biology in producing hot spot regions?

Atkinson et al (2004) Circumpolar distribution of Antarctic krill

(Lawson et al., 2004) (Ashjian et al., 2004) Zooplankton Population Variability Shifts in Abundance and Distribution Reconsider Krill Dominated Food Web

Alternative pathways buffer change - reflect/support long-term change? Need better quantification of alternative pathways Alternative Food Web Pathways High krillLow krill

Three-dimensional rendering of Crabeater seal Movements obtained from satellite tags Studies of habitat use, behavior, predator- prey interactions Studies of animal physiology and biology

Summary Large scale connectivity in zooplankton populations - combination of local retention and import from other regions Considerable interannual variability in zooplankton composition and relative abundance Variability related to chlorophyll values Bottom up control? Implications for food web structure?

Summary Technology that has been advanced through SO GLOBEC Seal-derived hydrographic measurements are important data Large-scale applications for understanding circulation and ice shelf dynamics Important data for evaluation of numerical circulation models Important for understanding habitat use

Concluding Remarks SO GLOBEC provides comprehensive biological and physical data sets from several sites in the Antarctic Provide the basis for investigating physical controls of Antarctic marine food web, alternative food web structures, e2e food webs structures, and climate variability Poised for comparative studies with GLOBEC and related programs outside of the Antarctic