Antarctic Food Web
Krill in Antarctic Food Webs
Phytoplankton
Krill Swarms
Phytoplankton
Antarctic Circumpolar Current (ACC)
The WAP is the
location where
the ACC is
closest to the
continent
Using the WAP as zone to study how rapid
warming can alter food webs
50-year changes in winter air temperature
3.7
Seawater heat content
3.6
3.5
9
-2
2
Qslope
(x10 (x10
J m9 J) m-2)
content
Heat
3.8
9 10
joules
per m
°
C
3.4
3.3
3.2
1992
1994
1996
1998
2000
YEAR
2002
2004
Martinson et al. 2008
Fastest winter warming location on Earth
Increase of 6°C in the past 50 years
Increase in ocean heat content
2006
Questions?
Recent rapid warming at WAP
reverberates through the food web
• Declines in phytoplankton and shift
to small cell size that krill can not
feed on (but salps can)
100 μm
• Declines in nutritious Antarctic krill;
increase in much less nutritious
gelatinous salps
• Declines in krill and ice-dependent
Adélie penguins, but increases in
subpolar (warmer adapted) species,
Gentoo and Chinstraps, that can dive
deep and eat deep-water fish
10 μm
Recent rapid warming at WAP
reverberates through the food web
• Declines in phytoplankton and shift
to small cell size that krill can not
feed on (but salps can)
100 μm
• Declines in nutritious Antarctic krill;
increase in much less nutritious
gelatinous salps
• Declines in krill and ice-dependent
Adélie penguins, but increases in
subpolar (warmer adapted) species,
Gentoo and Chinstraps, that can dive
deep and eat deep-water fish
10 μm
Recent rapid warming at WAP
reverberates through the food web
• Declines in phytoplankton and shift
to small cell size that krill can not
feed on (but salps can)
100 μm
• Declines in nutritious Antarctic krill;
increase in much less nutritious
gelatinous salps
• Declines in krill- and ice-dependent
Adélie penguins, but increases in
subpolar (warmer adapted) species,
Gentoo and Chinstraps, that can dive
deep and eat deep-water fish
10 μm
Recent changes in Adélie Penguins
Line 600 (north)
• Decrease in Adélie penguins, increases in subpolar species
(Gentoos, Chinstraps)
Questions?