Transcript SO GLOBEC Program

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 1999-2000
• Field studies finished in 2007/08
• SO GLOBEC program is now in synthesis and
integration phase
UK
Germany
Korea
US, Germany
Australia
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
(Beardsley et al., 20)04
Stratification, retention and
frontal exchanges
Sea ice modifies all of these
Ice shelf effects on circulation
(Klinck et al., 2004)
Snow petrel and
Adélie Penguin
distribution in
relation to water
masses
(Chapman et al., 2004)
Extensive observations
of predator abundance
and distribution
Humpback Whale
Locations
Habitat use, predator and
prey interactions
Food web interactions
Biological Hot Spots
(Thiele et al., 2004)
Biological Hot Spots
(Costa et al., 2007)
Not all parts of the shelf are biologically similar
MB : Marguerite Bay
MT : Marguerite Trough
AI : Alexander Island
CS : Crystal Sound
Drake
Passage
LF : Laubeuf Fjord
Predator Hot Spots
MT
CS
LF
MB
Bellingshausen
Sea
AI
Role of circulation and biology in producing hot spot regions?
Circumpolar distribution of Antarctic krill
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)
(Lawson et al., 2004)
Zooplankton Population Variability
Shifts in Abundance and Distribution
Reconsider Krill Dominated Food Web
(Ashjian et al.,
2004)
Alternative Food Web Pathways
High krill
Low
krill
Alternative pathways buffer change - reflect/support long-term change?
Need better quantification of alternative pathways
Three-dimensional rendering of Crabeater seal
Movements obtained from satellite tags
Studies of habitat use,
behavior, predatorprey 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