Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan...
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Transcript of Negative feedback in the cold: ice retreat produces carbon sinks in Antarctica Marshall Callahan...
![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.](https://reader036.fdocuments.us/reader036/viewer/2022062720/56649ef65503460f94c0a359/html5/thumbnails/1.jpg)
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
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Overview• Purpose of Research• Importance of Research• Background Information• Data/Methods• Results• Conclusions• My Opinion• Questions
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Purpose• Find out if loss of sea ice is counteracted by
increase in marine ecosystems for global warming
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Why is this Important?• Could Provide a new variable to take into account
when estimating future global CO2 levels
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Antarctica
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Antarctica
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Sea Ice• Can reflect around 70% of incoming Shortwave
radiation (Acts as a negative feedback)
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Melting Sea Ice• The melting of sea ice acts as a positive feedback
for global warming• Less Sea Ice = Less reflected short wave radiation
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Marine Ecosystems• All based off of phytoplankton or zooplankton =>
other animals (nekton and benthic)
Benthic Nekton
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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
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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
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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
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Data/Methods• Used Sea WiFS (satellite) measurements to
determine plankton amounts• Red = Higher concentration
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Data/Methods• Measurements of plankton at depths deeper than
satellites can view over a year
Peak Season
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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)
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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
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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
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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.
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Results• Unable to determine how much carbon comes
from deep ocean currents or from the atmosphere
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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)
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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
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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
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Qué?