| NSF Org: |
DEB Division Of Environmental Biology |
| Recipient: |
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| Initial Amendment Date: | January 19, 2012 |
| Latest Amendment Date: | January 19, 2012 |
| Award Number: | 1145313 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Henry L. Gholz
DEB Division Of Environmental Biology BIO Directorate for Biological Sciences |
| Start Date: | March 1, 2012 |
| End Date: | February 28, 2015 (Estimated) |
| Total Intended Award Amount: | $133,983.00 |
| Total Awarded Amount to Date: | $133,983.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
150 MUNSON ST NEW HAVEN CT US 06511-3572 (203)785-4689 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
CT US 06520-8047 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ECOSYSTEM STUDIES |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.074 |
ABSTRACT
Glaciers and ice sheets represent the second largest reservoir of water and cover 10% of the earth. They also constitute an important, but poorly understood ecosystem. Improving knowledge of glacier biogeochemistry is particularly important as they are among the environments most sensitive to climate warming. Most notably, glacier melting is accelerating due to rising temperatures, changing precipitation patterns and the deposition of black carbon, which darkens glacier surfaces enhancing their absorption of light and heat. Glacier ecosystems were recently identified as a significant source of ancient, yet highly bioavailable dissolved organic carbon to downstream aquatic ecosystems. This finding runs counter to logical perceptions of age-reactivity relationships, in which the least reactive material withstands degradation the longest and is therefore the oldest. The remnants of ancient peatlands and forests since overrun by glaciers have been invoked as a source of this ancient, labile organic carbon. Preliminary results upon which this study is based, challenge the peatland/forest source hypothesis, indicating instead that glacier organic carbon is predominantly from aerosol deposition and enters glaciers in a pre-aged form. This study will determine the contribution to the glacial organic carbon pool made by fossil fuel derived aerosols, verify whether this organic carbon is indeed ancient and labile, and quantify the extent to which it is being exported to downstream ecosystems.
Today, around 60% of organic aerosols are derived from anthropogenic activities, indicating that organic deposition has also increased dramatically since the industrial revolution. Therefore, if the organics found on, within and being exported from Gulf of Alaska glaciers are from aerosols, the glacier ecosystem structure we observe today is fed by the waste products of industrial activity occurring thousands of miles away. If this is the case, then the organic carbon which is exported to ecosystems downstream of glaciers would also be of anthropogenic origin, suggesting these receiving ecosystems are also transformed relative to their pre-industrial status. As deposition of combustion products is a global phenomenon, all ecosystems may be receiving this ancient, labile carbon subsidy. In warmer ecosystems, the labile carbon windfall is presumably rapidly processed and its signal is lost. In frigid glacier environments, these inputs stand out, making glaciers sentinel ecosystems for the detection and study of anthropogenic deposition. Although the study focuses upon glaciers along the Gulf of Alaska, findings will be relevant to any ecosystem receiving depositional inputs. The project provides a highly interdisciplinary and collaborative research environment from which the undergraduates from under-represented groups in science, a masters student, and a postdoctoral researcher will all benefit. The collaboration extends beyond the funded US scientists to include German colleagues supported by the Max Planck Institute's Marine Geochemistry Group. This international component expands the possibilities for knowledge transfer and provides the US-based researchers access to unique, state-of-the-art analytical facilities. Results will be disseminated to the public through the U.S. Forest Service Mendenhall Glacier Visitor Center in Juneau, providing an opportunity for public outreach on the effects of climate change on glaciers.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Project Outcomes Report for the General Public
Project Title: Collaborative Research: Is the export of ancient, labile carbon from glacial ecosystems driven by the deposition of fossil fuel combustion byproducts?
A team of US scientists studied the carbon cycle of glaciers in Alaska. Our research was assisted by colleagues in Germany and expanded to include glaciers on the Tibetan Plateau through collaborators in China. Together we discovered that apparently pristine, remote glacier ecosystems in Alaska and Tibet are polluted by industrial processes occurring miles away. Winds carry carbon from sites of fossil fuel burning all around the world. This windblown manmade carbon settles on glaciers, changing the glacier environment. The export of carbon from glaciers reaches socio-economically important downstream freshwater and coastal ecosystems that support recreation, fisheries, and supply freshwater.
Glaciers and ice sheets are an understudied component of the global environment. Glacier ecosystems contain the second largest reservoir of water and cover 10% of the earth. Improving knowledge of glacier ecosystems is important as they are among the environments most sensitive to global warming and industrial forcing. Glacier melt is accelerating due to rising temperatures, changing rain and snowfall patterns, and the windblown transport of soot. Soot darkens glacier surfaces and absorbs the sun’s heat, speeding the glaciers melt.
The natural carbon cycle of the planet has shaped global climate for millennia. Glaciers are an important part of this natural system. Today, human activity is so widespread that it is changing natural systems. This is obvious when we compare a wild forest to a parking lot. It is also apparent at the global scale, as burning of fossil fuel has increased carbon dioxide levels in the atmosphere and is driving climate change. However, when we see mountain glaciers, they appear pristine and natural.
In our earlier work we studied the carbon of glaciers, thinking of them as pristine systems. This work showed that streams draining from the base of glaciers carried ancient, yet highly bioavailable dissolved organic carbon. This was puzzling for a couple of reasons. First, we normally find that old carbon cycles slowly. Yet in glacier waters we found 3000 year old carbon that was consumed by bacteria in a matter of weeks. How could carbon that was so quick to be degraded by bacteria last so long in the natural environment?
Initially, viewing glaciers as pristine systems, we proposed that carbon in streams draining glaciers came from ancient soils and forests buried beneath the glacier. However, for the current research project we went to the top of glaciers to collect snow, ice and water. What we found surprised us. The carbon on top of the glacier had the same chemical fingerprint and was as old as the carbon coming from underneath the glacier. The carbon in snow was also ancient. This told us the carbon was entering the glacier in a pre-aged form.
Other research has shown that the burning of biomass and fossil fuels creates soot and other carbon forms. A fraction of this “black carbon” gets blown around the world, high up in the atmosphere. Snow and rain clean the atmosphere. The black carbon stripped from the air by snow and rain then falls to earth. This is the carbon our data suggests is the main source of carbon to glaciers. As deposition of combustion products is a global phenomenon, all ecosystems may be receiving this manmade carbon subsidy. In vibrant ecosystems, the carbon windfall is presumably rapidly processed and its signal is lost. In frigid glacier environments, these industrial inputs stand out, making glaciers sentinel ecosystems for the detection and study of perturbation to global ecosystems through increasing atmospheric inputs of manmade carbon. Thus, alt...
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