Southern Ocean GLOBEC Program
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Southern Ocean GLOBEC Program
Eileen E. HofmannThird 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 1999-2000 • Field studies finished in 2007/08• SO GLOBEC program is now in synthesis
and integration phase
UK
AustraliaUS, Germany
Germany
Korea
SO GLOBEC Field Study Sites
Target Species
Approach
Two special issues of Deep-Sea Research IIdevoted 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 theseIce shelf effects on circulation (Klinck et al.,
2004)
(Beardsley et al., 20)04
(Thiele et al., 2004)
Humpback WhaleLocations
Extensive observationsof predator abundanceand distribution
Habitat use, predator andprey interactions
Food web interactions
Biological Hot Spots
Snow petrel andAdélie Penguindistribution in relation to watermasses
(Chapman et al., 2004)
Not all parts of the shelf are biologically similar
Biological Hot SpotsBiological 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?
No. krill /m2
0
< 2
2-4
4-8
8-16
16-32
32-64
64-128
128-256
>256
no data
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 krill Low krill
Three-dimensional rendering of Crabeater sealMovements obtained from satellite tags
Studies of habitat use, behavior, predator- prey interactions
Studies ofanimalphysiologyand 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
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