| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | July 11, 2014 |
| Latest Amendment Date: | July 11, 2014 |
| Award Number: | 1434706 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Henrietta Edmonds
hedmonds@nsf.gov (703)292-7427 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | February 1, 2015 |
| End Date: | January 31, 2017 (Estimated) |
| Total Intended Award Amount: | $91,205.00 |
| Total Awarded Amount to Date: | $91,205.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
411 BH GOETHERT PKWY TULLAHOMA TN US 37388-9700 (931)393-7212 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
TN US 37388-9700 |
| 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): | Chemical Oceanography |
| 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): | 47.050 |
ABSTRACT
In this project, a group of investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will measure concentrations of atmospherically-derived mercury in the Arctic Ocean. In common with other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. Mercury, primarily as methylmercury, is an element that substantially bioaccumulates through aquatic food webs and impacts neurological functions in humans and wildlife, and it is therefore critical to understand the inputs of mercury to the region. Educational activities as part of this study include training and mentoring of undergraduate and graduate students and a postdoctoral researcher. Researchers will also conduct public outreach activities about mercury impacts to local Arctic communities.
In the Arctic Ocean, subsistence local fishermen and several species of Arctic wildlife, such as beluga whales, seals and polar bears, commonly have elevated levels of methylmercury in their system. Atmospheric deposition is the major pathway of mercury input to the marine environment as both wet and dry (aerosol and gaseous ionic mercury) deposition. Therefore, measurements of mercury and a better understanding of its cycling in the Arctic Ocean are critical. This study will provide further understanding of the drivers of mercury speciation in air and surface waters, including snow/ice, melt ponds, and surface seawater and how these concentrations, and other physical and biological factors, impact deposition rates at the air-sea interface. The primary measurements to be made include a baseline of mercury measurements over the open water from the ship, and over sea-ice environments of the Arctic Ocean, which will be compared to simultaneous and historic coastal measurements, as well as model studies. Overall, results will provide the crucial data and information necessary to comprehend the role of human activity and climate change in exacerbating or ameliorating the exposure of humans and wildlife to methylmercury in the Arctic Ocean.
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.
This project was a collaboration among the Universities of Connecticut, Nevada and Tennessee. As part of the GEOTRACES Arctic 2015 cruise on the Coast Guard Icebreaker Healy, we installed and operated a variety of mercury (Hg) sensors to determine the mercury contamination, and bio-chemical cycling, in the air, ice and water. This US Arctic Geotraces cruise took place between August and October 2015. Steve Brooks (PI – University of Tennessee) was on-board for the entire cruise and conducted all measurements. Also, samples were collected by Steve Brooks, or others on our behalf, from surface waters, ice cores, melt ponds and snow. Atmospheric samples of aerosols (Brooks and Landing) and precipitation (Landing) were also collected. The primary measurements made by our group on the cruise included baseline measurements of Hg species in the air, and gaseous elemental Hg (Hg0) in the open water from the ship, and under sea-ice environments of the Arctic Ocean.
Mercury is a major contaminate in the Arctic environment where it bio-accumulates in top predators, causing foraging and reproductive problems. Results from this study confirm the theory that dissolved Hg0 builds up under uniform ice, and that these concentrations are higher than those found in open water. Also, the Hg0 concentrations in the ice-free waters were very low, suggesting the potential for Hg0 deposition to the ocean from the atmosphere. This has rarely been observed, and this finding suggests the air-sea exchange of Hg in the Arctic is unique compared to other ocean basins.
Results were presented at the ASLO 2017 meeting, contributed to a PhD dissertation, and have been incorporated into three journal papers (in manuscript). Students at five Public Schools (3 Elementary and 2 Middle) produced ~250 student-made boats at part of the “Float Your Boat” outreach. We deposited these boats with tracking buoys on the sea ice close to the North Pole. The tracking of these “boats” is available to the public on the internet.
Halogen-mercury chemistry was also investigated during this cruise. However, no significant halogen chemistry was detected during the time period (Aug-Oct) of the cruise. While halogen chemistry plays a substantial role in Arctic Hg cycling during the winter/spring (Feb-June), it was effectively absent during this cruise (Aug-Oct.). Also investigated were the ship-board Hg concentrations compared to our concurrent Hg measurement at the coastal site of Barrow, Alaska. Open (ice free) areas showed similar atmospheric Hg concentrations to Barrow, indicating that this ice-free coastal site (Barrow) was reflective of the regional ice-free marine environment.
Last Modified: 06/21/2017
Modified by: Steven B Brooks
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