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Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A. J. Cook, A. H. Fleming and A. Clarke

Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

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Page 1: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica

Marshall CallahanAtmospheric Science

By: L. S. Peck, D. K. A. Barnes, A. J. Cook, A. H. Fleming and A. Clarke

Page 2: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Overview• Purpose of Research• Importance of Research• Background Information• Data/Methods• Results• Conclusions• My Opinion• Questions

Page 3: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Purpose• Find out if loss of sea ice is counteracted by

increase in marine ecosystems for global warming

Page 4: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Why is this Important?• Could Provide a new variable to take into account

when estimating future global CO2 levels

Page 5: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Antarctica

Page 6: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Antarctica

Page 7: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Sea Ice• Can reflect around 70% of incoming Shortwave

radiation (Acts as a negative feedback)

Page 8: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Melting Sea Ice• The melting of sea ice acts as a positive feedback

for global warming• Less Sea Ice = Less reflected short wave radiation

Page 9: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Marine Ecosystems• All based off of phytoplankton or zooplankton =>

other animals (nekton and benthic)

Benthic Nekton

Page 10: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Marine Ecosystems• Act as a carbon sink producing a negative

feedback• An increase in amount of biomass can take more

carbon out of the atmosphere

Page 11: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Unanswered Questions

• Timescale of moving carbon from atmosphere to new marine ecosystems around Antarctica

• Effect on total carbon cycle

• Uncertainty due to other factorso Nutrient release from sea-iceo Role of Antarctica Circumpolar Current

Page 12: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Data/Methods• Use of Satellite images, preexisting charts, and

averaging for the retreating of sea ice estimation

1950 Ice Front

2008 Ice Front

200m Isobath

Page 13: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Data/Methods• Used Sea WiFS (satellite) measurements to

determine plankton amounts• Red = Higher concentration

Page 14: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Data/Methods• Measurements of plankton at depths deeper than

satellites can view over a year

Peak Season

Page 15: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Results• More area opened to phytoplankton

productivity due to increase in open ocean

• Around 23,900 km² of near shore area (200m or less) uncovered since 1950’s along Antarctica Peninsula

• From the 1980’s18,800 km² now has phytoplankton productivity that did not before

(About the size of Rhode Island, Connecticut, and Delaware or New Jersey)

Page 16: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

ResultsEstimates of Carbon held in each type of biomass in the Ecosystem around Antarctica Peninsula (Total > 4.1 x 10⁵ tonnes)

• Use other studies estimates then scale to area of lost sea ice (176 gCm⁻² and 109 gCm⁻²)• 1 tonne = 1000 kg

Page 17: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Results• Once the Carbon has entered the marine

ecosystem it becomes very unlikely that it will be reintroduced into the atmosphere

• Noted the benthic productivity can vary greatly, however the chances for it to happen around Antarctica are slim

Page 18: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Results• These new marine ecosystems act as a one-time

carbon sink that has a limit, not as a continuing feedback

• Once limit has been reached no more carbon can be added.

Page 19: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Results• Unable to determine how much carbon comes

from deep ocean currents or from the atmosphere

Page 20: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Conclusions• Melting of sea ice around Antarctica Peninsula

allows for the development of new marine ecosystems

• These new ecosystems act as a limited carbon sink that can hold from 3.85 x 10⁵ to 2.36 x 106 tonnes

• What seems like a influential carbon sink is actually smallo Total sink from Antarctica peninsula would only be around 11% of the

carbon sink created by the expanding boreal forests (~8.4 x 106 tonnes)

Page 21: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Conclusions• Some species have experienced faster growth

rates due to increase of carbon in environment• Hard to predict flow of carbon and timescale of

flow• Glaciers/Ice shelves around the Antarctica

Peninsula occupy < 1% of the total area of glaciers/Ice shelves of Antarctica

• Unpredictability of future events

Page 22: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

My Opinion• Interesting predictions on new carbon

sinks/negative feedback• Actually compare affect between sea albedo

to carbon sink on climate• Carbon Cycle• Apply to other areas (ex: Antarctica, other

near shore sea ice)• Boils down to time and money

o Paying for research vessels to test o Time to study relationships

Page 23: Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan Atmospheric Science By: L. S. Peck, D. K. A. Barnes, A

Qué?