| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | June 24, 2014 |
| Latest Amendment Date: | June 24, 2014 |
| Award Number: | 1417789 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Marc Stieglitz
mstiegli@nsf.gov (703)292-4354 OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | July 1, 2014 |
| End Date: | June 30, 2017 (Estimated) |
| Total Intended Award Amount: | $290,667.00 |
| Total Awarded Amount to Date: | $290,667.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
51 COLLEGE RD DURHAM NH US 03824-2620 (603)862-2172 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
NH US 03824-3525 |
| 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): | ANS-Arctic Natural Sciences |
| 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): | 47.078 |
ABSTRACT
Methane is a potent greenhouse gas that is present in large amounts in frozen soils and marine sediments in the Arctic. In marine sediments, methane may be present either in permafrost or in gas hydrates. Warming of the Arctic may lead to the release of stored methane, leading to further warming and then to further methane releases in a reinforcing cycle. The East Siberian Sea, in the Arctic Ocean, is a large area with a great deal of undersea permafrost and, likely, stored methane. Recent work has suggested large sources of methane from parts of the East Siberian Sea, but the area needs to be mapped and studied in much greater detail before either the amount of methane stored there or the amount being released can be fully understood. In the summer of 2014, an international program called the Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) will undertake a 90-day expedition to map, and study the carbon cycle in, the East Siberian Sea. The principal investigators of this proposal are leaders in ocean mapping and they have recently pioneered techniques for acoustic imaging of methane plumes released from the seafloor in the Gulf of Mexico. They have been invited by the leaders of the SWERUS-C3 team to participate in one leg of the expedition. They propose to use the multibeam sonar on board the ODEN to locate and characterize gas seeps in the water column and then apply a newly developed wideband transceiver to the split-beam echosounder on board the ODEN to constrain the size and fate of gas bubbles rising to the surface. Together, these acoustic observations will help the SWERUS-C3 team understand the flux of methane from the seafloor into the water column and potentially into the atmosphere. If successful, these techniques will allow the mapping of the gas flux in the Arctic over scales never before possible. This proposal requests support for the participation of the UNH team on this expedition and for post-cruise work-up of the data. The project will support a full time graduate student at UNH. A UNH undergraduate student will participate as well. The SWERUS-C3 program as a whole will support over 15 postdoctoral researchers and graduate students, and has a broad suite of outreach activities planned. The UNH Center for Coastal Ocean Mapping will also incorporate this work into ongoing outreach and education activities.
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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.
The Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) was a major international, multi-disciplinary program aimed at increasing our understanding of the complex interactions among climate, Arctic ice and carbon dioxide in the atmosphere. Our (University of New Hampshire) component of the program was to help in the detailed mapping of the seafloor using a sophisticated seafloor mapping system known as a multibeam echosounder and particularly to evaluate whether multibeam and other echosounders may be able to help us find natural gas seeps coming from the seafloor and quantify that amount of gas (methane) being put into the ocean and atmosphere. Methane is a powerful greenhouse gas that can greatly affect the acidity of the ocean and climate. The amount of methane being put into the ocean and atmosphere by natural gas seeps is currently unknown and we are seeking to develop tools that will allow us to detect natural gas seeps and measure the amount of gas from surface ships.
We were successfully able to map and identify gas seeps on the East Siberian Continental Margin (Figure 1). We have been able to use a specialized echosounder to identify individual gas bubbles from these seeps and measure their size and rise rate (Figure 2). Knowing this, we have been able to remotely measure the “flux” or amount of gas coming from the gas seeps. The approaches we have developed to do this are now being used by both the oil and gas industry to search for resources and by the regulatory agencies to get a better handle on natural background levels as well as leaky oil rigs and pipelines. In the long-run we hope they will contribute to more accurate models of methane into the ocean and atmosphere and it impact on climate and ocean acidification.
Additionally, we had an unexpected, but exciting result. In the very high Arctic where waters from the Atlantic mix with waters from the Arctic our specialized echo-sounders recorded very fine-scale layering that turned out to be the inter-fingering of these two water masses (something called thermohaline stair steps). We were able to match the changes in water properties measured by lowering instruments through the water column with the layers in the echosounder (Fig 3) indicating that we now have the ability to map and trace, over large distances the complex mixing processes in the ocean. With such a capability, we hope to be able to better understand the distribution of heat through the ocean, and associated oceanographic phenomena like upwelling which drives productivity.
Finally, mapping of the seafloor during this cruise revealed two important new insights into the history of ice sheets and sea level in the Arctic. First the discovery of the imprint of ice sheets on the seafloor in the middle of the Arctic at water depths as much as 1000m (3300ft) imply that about 140,000 years ago much of the Arctic may have been covered by a 3300-foot thick ice shelf. This idea had been proposed more than 100 years ago but had been dismissed for lack of evidence. Secondly, we were able to determine through detailed mapping and dating of cores recovered from the seafloor that the Beringia Land Bridge – the land bridge that connected Asia to North America approximately 18,000 years ago during the peak of the last ice age, became flooded later than previously thought (about 11,000 years ago). This new dating of the end of the land bridge has important implications on our understanding global circulation (Pacific water could now flow into the Arctic and vice-versa) as well as on the migration of early people from Asia to North America.
Last Modified: 08/15/2017
Modified by: Larry A Mayer
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