Looking Back in Time Through Marine Looking Back in Time Through Marine Ecosystem Space: A Predator’s Ecosystem Space: A Predator’s

Perspective on Climate and Change in the Perspective on Climate and Change in the Western Antarctic PeninsulaWestern Antarctic Peninsula

William R. FraserWilliam R. Fraser

Polar Oceans Research GroupPolar Oceans Research GroupSheridan, MontanaSheridan, Montana

Outline Outline

• PAL Space/Time Regional PAL Space/Time Regional Setting Setting

• Climate Change OverviewClimate Change Overview• Geology and Adélie Geology and Adélie

Penguin Population Penguin Population DistributionsDistributions

• Climate Change Effects Climate Change Effects and Ecosystem Responseand Ecosystem Response

• Conclusions and Future Conclusions and Future DirectionsDirections

The Western Antarctic Peninsula (WAP)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 Antarctica’s

warmest water.

Ross Sea gyre

Weddell gyre

D. Martinson

PAL Spatial Operational Area and Data Time PAL Spatial Operational Area and Data Time SeriesSeries

WAP = 220,000 kmWAP = 220,000 km22

Anvers IslAnvers Isl.Palmer StationPalmer Station

LTER Grid = 120,000 kmLTER Grid = 120,000 km22

LTER Research 1991-2007LTER Research 1991-2007

Top Predator Studies 1974-Top Predator Studies 1974-20072007

E. Erdman, SO-GLOBEC databaseE. Erdman, SO-GLOBEC database

Sampling capitalizes on a nested grid approach by Sampling capitalizes on a nested grid approach by using research platforms that annually operate using research platforms that annually operate over large and small scales during the October-over large and small scales during the October-March periodMarch period

Climate Change…surface air and ocean Climate Change…surface air and ocean temperatures temperatures

Meredith & King, 2005Meredith & King, 2005

Martinson et al., In PressMartinson et al., In Press

Coldest Water in January Water Coldest Water in January Water ColumnColumn

D. Martinson. D. Martinson.

0.107˚ C/year Significant at 0.05~5.4x global average

British Antarctic SurveyBritish Antarctic Survey

Climate Change…sea and glacial ice Climate Change…sea and glacial ice

83% of glaciers are in retreat

Major loss of perennial sea ice cover

Duration of the sea ice season has decreased by 85 days during the last 25 years

Cook et al. 2005Cook et al. 2005

Sea Ice Cover S. S. StammerjohnStammerjohn

PerennialIce

S. S. StammerjohnStammerjohn

Breeding Distribution of Adélie Penguin Breeding Distribution of Adélie Penguin Populations in the Western Antarctic Peninsula Populations in the Western Antarctic Peninsula RegionRegion

Photo by H. Geisz, PAL LTER

Fraser & Trivelpiece 1996Fraser & Trivelpiece 1996

Hypothesis: Hypothesis:

The breeding distribution The breeding distribution of Adélie penguins is of Adélie penguins is limited to regions where limited to regions where prey availability is prey availability is predictable over predictable over ecological time scales ecological time scales (decades to centuries)(decades to centuries)Rationale? Rationale?

Adélie penguins are Adélie penguins are flightless and incapable of flightless and incapable of foraging at night, which foraging at night, which greatly limits the range greatly limits the range over which they can over which they can search for prey in summer search for prey in summer when feeding chickswhen feeding chicks

Hypothesis Testing: Technological AdvancesHypothesis Testing: Technological Advances

Mapping the ocean’s floorMapping the ocean’s floor

Miniaturizing satellite-Miniaturizing satellite-linked instruments to linked instruments to track Adélie penguins at track Adélie penguins at seasea

Hypothesis Testing: Geology and BathymetryHypothesis Testing: Geology and Bathymetry

The Palmer Deep off The Palmer Deep off Anvers IslandAnvers Island

ANVERS ANVERS IsIs

E. Domack

Hypothesis Testing: Bathymetry and Adélie Hypothesis Testing: Bathymetry and Adélie Penguin Foraging EcologyPenguin Foraging Ecology

Anvers IslandAnvers Island

E. Domack

Anvers IsAnvers Is

Bathymetry and Adélie Bathymetry and Adélie Penguin Foraging Ecology: Penguin Foraging Ecology: Causal Factors and Larger Causal Factors and Larger ScalesScales

Primary ProductionPrimary Production

Contour of Contour of regions of regions of low pCOlow pCO22

(highlighte(highlighted in red), d in red), based on based on

WAP WAP January January cruises cruises 1993-1993-

1996. D. 1996. D. Karl, Karl,

unpublisheunpublishe

dd Adelaide IsAdelaide Is

Anvers IsAnvers Is

Bathymetry and Adélie Bathymetry and Adélie Penguin Foraging Ecology: Penguin Foraging Ecology: Causal Factors and Larger Causal Factors and Larger ScalesScales

Regions of Polynya Regions of Polynya FormationFormation

WINTER 2001 and 2002WINTER 2001 and 2002..

Anvers IsAnvers Is

Bathymetry and Adélie Bathymetry and Adélie Penguin Foraging Ecology: Penguin Foraging Ecology: Causal Factors and Larger Causal Factors and Larger ScalesScales

Importance to Other Importance to Other Predators (Crabeater Seals)Predators (Crabeater Seals)

Climate Change Effects and Ecosystem ResponseClimate Change Effects and Ecosystem Response

0.107˚ C/year Significant at 0.05~5.4x global average

PerennialIce

One of the mechanisms by which One of the mechanisms by which climate change induces change in climate change induces change in ecosystem structure is by disrupting ecosystem structure is by disrupting the evolved life history strategies of the evolved life history strategies of component species. component species. Rhodes & Odum 1996Rhodes & Odum 1996

New Paradigm…Climate MigrationNew Paradigm…Climate Migration

Key Physical Variables are

Changing Along a North to South

Gradient

Sub-Antarctic Life History Groups are

Replacing Antarctic Life

History GroupsWAP

Ecosystem Structure is Changing in

Fundamental and Possibly

Unprecedented Ways

Key Implication:

Ecological changes are due to region specific changes in sea ice as a temperature isotherm migrates north to south

Sea ice data Sea ice data courtesy of courtesy of E. Chapman E. Chapman

How is Climate Migration Operating?

Net Average Effects?...Annual Winter Sea Ice no Net Average Effects?...Annual Winter Sea Ice no Longer Covers Approximately 50% of the WAP Longer Covers Approximately 50% of the WAP

m

m

m

Adelaide Isl.Adelaide Isl.

Renaud Isl.Renaud Isl.

Anvers Isl. Anvers Isl. Palmer Sta.Palmer Sta.

WAP Ecosystem Structure is Changing in

Fundamental and Possibly Unprecedented

Ways

Sub-Antarctic Life History Groups are

Replacing Antarctic Life

History Groups

North to South Changes in Primary Production North to South Changes in Primary Production (climatology, 1995-2004) Relative to Penguin (climatology, 1995-2004) Relative to Penguin PopulationsPopulations

M. Vern

et

ADELAIDE IS

ANVERS ISANVERS IS

Statistically significant north to south differences in recruitment frequency and population size structure

North to South Changes in Antarctic Krill North to South Changes in Antarctic Krill ((Euphausia superba)Euphausia superba) Populations Populations

Atkinson et al. 2004Atkinson et al. 2004

A two-fold A two-fold decrease/decade in krill decrease/decade in krill densitydensity

North to South Changes in Antarctic silverfish North to South Changes in Antarctic silverfish ((Pleuragramma antarctica) Pleuragramma antarctica) PopulationsPopulations

ANVERS IS

98%

1%

1%

Krill

Fish

Other

54%

45%

1%ADELAIDE IS

North to South Changes in Populations of the North to South Changes in Populations of the Lanternfish (Lanternfish (Electrona antarcticaElectrona antarctica))

ADELAIDE IS

Silverfish

ANVERS IS

Lanternfish

North to South Changes in Stable Isotope Signatures North to South Changes in Stable Isotope Signatures (krill dominated diets at Palmer vs silverfish (krill dominated diets at Palmer vs silverfish

dominated diets at Avian Isdominated diets at Avian Is

PALMER STA

AVIAN IS

North to South Penguin North to South Penguin population changespopulation changes

Habitat optimum hypothesis: Too much ice is as detrimental to Adélie penguins as too little ice.Fraser & Trivelpiece 1996, AGU

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2,000

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AdelieGentooChinstrap

On Anvers Island chinstrap and gentoo penguins, two sub-Antarctic species, are replacing Adélie penguins

Conclusions and Future DirectionsConclusions and Future Directions

• Climate migration is having an Climate migration is having an impact on a range of impact on a range of ecosystem properties, from key ecosystem properties, from key physical variables to food web physical variables to food web structurestructure

• Trends indicate that the ice-Trends indicate that the ice-dependent life history group dependent life history group that once populated the that once populated the northern sectors of the WAP are northern sectors of the WAP are being replaced by an ice-being replaced by an ice-intolerant life history group intolerant life history group over ecological time scales.over ecological time scales.

• Glacially incised, cross shelf Glacially incised, cross shelf canyons are focal points of canyons are focal points of physical and biological physical and biological processes affecting WAP processes affecting WAP ecosystemsecosystems

• Future directions…Future directions…

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Future Future DirectionsDirections

Looking back in time throughLooking back in time throughmarine ecosystem space…marine ecosystem space…

… … by emphasizing changes inby emphasizing changes insampling strategies that willsampling strategies that will““capture” climate migrationcapture” climate migrationand provide a more and provide a more mechanistic understanding ofmechanistic understanding ofmarine ecosystem responsemarine ecosystem response