EDGES of

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EDGES of Long-term Ecological Research in
Antarctica Hugh Ducklow, The Ecosystems Center,
MBL (LTER-PAL) Scott Collins, Univ. New Mexico
(LTER-SEV, ISSE)
Thanks Thanks Bill Fraser Berry
Lyons Doug Martinson Diana Wall Sharon
Stammerjohn John Priscu
Palmer Station marine sea-ice, continental
margin ecosystem,
McMurdo Dry Valleys glacier-stream-lake-soil
ecosystem
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Other LTER people and relevant statements Byron
Adams Berry Lyons Doug Martinson Sharon
Stammerjohn Diana Wall Kevin Arrigo Dont think
of it as LTER think of this research as AISS
Sustained, integrated systems science about
Antarctica
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LTER Edge questions for AISS

• How do polar ecosystems respond to the press and
  pulses of climate change? What are the climate
  thresholds triggering ecosystem regime change?
• What are the biophysical ecological mechanisms
  governing responses?
• How does multiscale climate variability influence
  polar ecosystems?
• How is Antarctica coupled to the global
  socioecological system?

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A vastly changed continent in coming
decades Rapid climate change Receding glaciers
ice shelves Species invasions, extinctions,
range changes Possible violations or abrogation
of Antarctic Treaty (already occurring) Colonizat
ion, exploitation, tourism Research needs for
AISS Continued long-term commitment Continenta
l-scale approach International collaboration
(closer) Human dimensions / social sciences
integration
Future challenges for Long-term Ecological
Research
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Future challenges for Long-term Ecological
Research
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PALMER ANTARCTICA LONG TERM ECOLOGICAL
RESEARCH 1990 2008 Marine ecosystem of the
Western Antarctic Peninsula (WAP)
The WAP is the only location in Antarctica where
the Antarctic Circumpolar Current (ACC) is
directly adjacent to the shelf break. The ACC is
Antarcticas warmest water.
D. Martinson
Doug Martinson, Bill Fraser
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Upwelling environment Webb-Slocum Rutgers Glider
Jan
6-23 07
Latitude
Longitude
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Climate Changesurface air and ocean temperatures
Ocean temperature increases
regime shift?
Doug Martinson, Bill Fraser
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SEA ICE in PAL study region

Perennial Ice
Sharon Stammerjohn
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Changes in seabirds and mammals at Palmer Station
1976 - 2006
Ice-dependent Adélies, Crabeater Weddell
seals. Independent Chinstrap Gentoo
penguins, elephant fur seals
Bill Fraser
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Palmer LTER

• Marine Ecosystem rich in large vertebrate
  predators
• Rapid regional warming
• Decline of sea ice duration extent
• Loss if ice-dependent species
• Invasion of ice-tolerant spp
• Changes at lower trophic levels biogeochemistry
  harder to detect
• Teleconnections and interactions of ENSO SAM
• No terrestrial organic matter subsidies (yet?)

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McMurdo Dry Valleys LTER 1993-2011
Glaciers
Soils
Lakes
Diana Wall
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The Dry Valley Ecosystem Bacteria, algae,
nematodes, tardigrades, protozoans, rotifers
Alan Tunnacliffe
Diana Wall
Randy Miller
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Taylor Valley at Last Glacial Maximum with 340m
H20 asl
John Priscu
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Taylor Valley today
John Priscu
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Water content and Nematode Dynamics
No. organisms/kg soil
0
No. organisms/kg soil
0
Multiple regression analysis showed that 63 of
variation for E. antarcticus could be explained
by soil water and chlorophyll a content (P0.034)
1999
2000
2001
2002
2003
2004
2005
1998
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Dry Valleys

• Cold, dry, water limited soil ecosystem
• Simple ecosystem with few metazoan predators
  sensitive to small environmental changes
• Lake metabolism receives legacy organic matter
  from previous high stands
• Strong biological/ecosystem responses to climate
  trends and climate events
• Climate/ecosystem modulation by SAM

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Southern Annular Mode (SAM or Antarctic
Oscillation) was in a positive phase causing a
strong polar vortex preventing warmer air from
mixing with frigid polar air
2001-02 Switch to negative SAM

• McMurdo LTER started in 1993
• Nature cooling trend paper

LAKE ELEVATION
John Priscu
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Back to Palmer 2001-02 switch to negative SAM
heavy ice, cold temperatures, spring snowstorms
near-total penguin breeding failure
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Ecological dynamics linked by climate
teleconnections

• Dry Valleys decadal cooling trend in response to
  positive SAM
• Palmer decadal warming trend enhanced by
  positive SAM
• Dry Valleys 2001-02 warming, flooding event
• Palmer 2001-02 cooling, snow (flooding) event
• Similar ecosystem responses in both systems at
  upper trophic levels