| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | August 24, 2012 |
| Latest Amendment Date: | March 19, 2014 |
| Award Number: | 1237108 |
| 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: | September 1, 2012 |
| End Date: | April 30, 2018 (Estimated) |
| Total Intended Award Amount: | $135,035.00 |
| Total Awarded Amount to Date: | $141,165.00 |
| Funds Obligated to Date: |
FY 2014 = $6,130.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
6530 KISSENA BLVD FLUSHING NY US 11367-1575 (718)997-5400 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
NY US 11367-1597 |
| 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, International Research Collab |
| Primary Program Source: |
01001415DB NSF RESEARCH & RELATED ACTIVIT |
| 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 2013, a multi-institutional team of U.S. marine chemists and geochemists will launch a major expedition to the Pacific Ocean to map and study the distribution of trace elements and isotopes as part of the International GEOTRACES Program. Because of their proven value as natural tracers of both sedimentation dynamics and hydrodynamics in the sea, radioactive daughter isotopes in the natural U-Th radionuclide series will be of immense value to all GEOTRACES researchers. In particular the naturally-occurring Pb210/Po210 radioisotope pair would be useful for quantifying rates of particulate scavenging of other trace elements and isotopes of interest in the U.S.GEOTRACES Pacific campaign. This is because these two isotopes are themselves particle-reactive and radioactive, thus providing a natural clock for tracking the vertical transport of other particle-reactive substances.
In this project, researchers at Wayne State University and CUNY Queens College will sample and analyze several hundred dissolved and particulate (large and small) samples for 210Po and 210Pb along the U.S.GEOTRACES Eastern South Pacific section. About two thirds of the samples will be focused at six so-called "super stations" (sites chosen for intensive study), half above the main thermocline and the other half down across the benthic nepheloid layer (the zone of suspended material extending several meters above the seafloor). The depths will be chosen according to regional atmospheric input, ecosystems, and coordinated with sampling by other researchers onboard. The other third will be taken within the hydrothermal plume in the vicinity of the East Pacific Rise. The data will be synthesized according to interface scavenging models by particle types (e.g. fine/colloidal, lithogenic and biogenic). As such, the proposed work will be closely coordinated with that of other U.S.GEOTRACES PIs funded to study other particle-reactive or dissolved trace elements and radionuclide isotopes during the campaign.
BROADER IMPACTS: The broader impacts are closely linked to those of the GEOTRACES Program as a whole: to enhance (1) research infrastructure by providing a broad array of 210Po and 210Pb data useful for biogeochemical scavenging models, (2) education by mentoring graduate and undergraduate students, teaching by example from proposed research, (3) participation of under-represented students interested in careers in the geosciences, (4) research training of graduates in marine radiochemistry, and 5) public dissemination of results through publications, presentations, and on a dedicated public website at Wayne State University.
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.
This project funded the collection, processing, and analyses of hundreds of samples of 210Po and 210Pb activity in both the dissolved and particulate phase along the two transects: EPZT in the Eastern Pacific between Peru and Tahiti, and GEOVIDE in the North Atlantic and Arctic beteen Portugal and Newfoundland, Canada. Along both transects, samples were collected at specific stations and the activity of the radionuclides was measured on both particle (small and large) and in the water column. This data could tell us about the partitioning of the natural radionuclides in these various oceanic environments. This radionuclide pair is interesting for two reasons: first, the fact that the grandparent (210Pb) is much longer lived than the grand-daughter (210Po), means we can use the deviations from secular (radioactive) equilibrium of this pair to determine the export of particles from the surface ocean. Second, 210Po is the only natural radionuclide that bioaccumulates and so it can trace the behavior of organic material through the ocean, and the known half-life means we can understand the timing of partioning, uptake, export, and dissolution/remineralization. In fact, we connected the activity of the radionuclide to the respiration rate of the water column using the oxygen utiiization rate, so we could consider how quickly or slowly organic matter was being respired by bacteria in the top 200m or so of the surface ocean.
The transects were chosen due to their diverse conditions, from shallow coastal settings, to areas with upwelling, areas over ocean spreading centers, the deep, open ocean, and the shallow seas and basins of the Arctic. Understanding the cycling of 210Po and 210Pb in these areas can provide insight into the behavior of other particle-reactive elements, but also the fate of organic matter in the ocean. And together, the isotopes can tell us about the magnitude and efficiency of the sequestration of arbon from the atmopshere via the biological pump. As climate change due to increasing carbon in the atmopshere is one of the biggest threats facing the planet, this research aims to understand some of the temporal and spatial variability in the surface ocean's ability to take carbon dioxide from the atmosphere and shuttle it to depth where it is stored for hundreds to thousands of years.
This project was crucial in training a future oceanographer, and the results and insights from this project were described in undergraduate and graduate classes at Queens College, in the City University of New York. Queens College is the most diverse college in the country and the School of Earth and Environmental Sciences serves a unique population of urban and often under-priveleged students. In addition, most fo the students at Queens College are first generation Americans, and getting them interested and involved in understanding the environment around them (and specifically the ocean) is one of the major impacts of this project.
We feel that we have managed to meet both the Intellectual Merit and Broader Impacts goals set forth in our proposal and will continue to share the knowledge gained through this project through presentations at conferences, peer-reviewed journal articles, and coursework and public lectures at Queens College.
Last Modified: 07/02/2018
Modified by: Gillian Stewart
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