| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
|
| Initial Amendment Date: | March 25, 2010 |
| Latest Amendment Date: | June 7, 2011 |
| Award Number: | 0961653 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Donald L. Rice
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | April 1, 2010 |
| End Date: | March 31, 2014 (Estimated) |
| Total Intended Award Amount: | $140,201.00 |
| Total Awarded Amount to Date: | $151,294.00 |
| Funds Obligated to Date: |
FY 2011 = $11,093.00 |
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
550 S COLLEGE AVE NEWARK DE US 19713-1324 (302)831-2136 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
550 S COLLEGE AVE NEWARK DE US 19713-1324 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Chemical Oceanography |
| Primary Program Source: |
01001112DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Trace elements and isotopes (TEIs) in the natural U-Th radionuclide series are central to the goals of the U.S. GEOTRACES during its funded North Atlantic phase over the next three years. The radionuclide 210Po-210Pb pair is designated as one of the priority TEIs by the U.S. GEOTRACES Zonal North Atlantic Survey Section Implementation Plan. The pair has seen application since GEOSECS for quantifying particulate scavenging and carbon flux within the ocean, but processes are still poorly understood at oceanic interfaces. The atmospheric source and half lives of the two isotopes (138 d and 22.3 y) present time frames uniquely suited to trace interface (air-water, bio-water, and sediment-water) processes in the North Atlantic sections.
Under this award, researchers at the University of Delaware, Wayne State University, and Queens College will participate in the U.S.GEOTRACES North Atlantic campaign to study the relationships between these two radioisotopes and the other trace elements and isotopic tracers that will be surveyed. Their work will center around a set of hypotheses. At the air-sea interface, they hypothesize that as the primary input of 210Pb into the surface ocean, levels will be source dependent on the continental input mixtures, in the western temperate and easterly sub-tropical sections. At the biotic-water interface, they hypothesize that different biogenic particle types encountered in the upper waters will affect the fractionation and remineralization depths of 210Po and 210Pb. At the particle-water interface, they hypothesize that interfaces between intermediate lithogenic nepheloid layers (INL) or hydrothermal plumes will be zones of enhanced 210Po and 210Pb scavenging from the surrounding waters.
To test these hypotheses, they will sample and analyze several hundred dissolved and particulate (large and small) samples for 210Po and 210Pb along the GEOTRACES North Atlantic section. About two thirds of the samples will be focused at the six designated "super stations", half above the main thermocline and the other half down across the BNL. The depths will be chosen according to regional atmospheric input, ecosystems, and coordinated TEI sampling. The other third will be detailed across INL detached plumes from coastal waters, across the BNL, and within hydrothermal plumes. 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 GEOTRACES PIs already funded to for other particle-reactive (e.g. Th, Pa) or dissolved (e.g. Ra) radionuclide isotopes in the Atlantic Survey Section of GEOTRACES.
Broader Impacts: The broader impacts are closely linked to 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 undergraduates, teaching by example from proposed research, (3) participation of under-represented students careers in the geosciences, (4) research training of graduates in marine radiochemistry, and 5) broad dissemination of results through publications, presentations, and on dedicated public UD websites (www.ocean.udel.edu) and at GEOTRACES (www.geotraces.org).
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 (NSF 0961653; 2009-14)
Intellectual Merit
This project is a collaborative between University of Delaware (Church), Queens College SUNY (Stewart) and Wayne State University (Baskaran). The subject is on the distribution and exchange of the 210-Po/210-Pb nuclide pair across major oceanic interfaces on a basin wide scale. Studies of this complexity and magnitude have not been done for decades and never in this detail. The goal is to provide accurate and quantitative tracers for a host of surrogate trace element isotopes. The findings reveal significant details related to carbon and particle transfer from the surface to the deep sea within the North Atlantic Ocean basins, and across key interfaces near the coast, the bottom layers and a hydrothermal plume. As such, polonium proves to be an intimately timed tracer for biogenic material, and by proxy that of oceanic carbon uptake, flux and benthic regeneration. This is a major component of the global carbon budget and thus climatically important carbon dioxide.
Broader Impacts
Support has been provided for research with the participation of undergraduate and graduate students on subjects central to the proposed research. Specifically, two postdoctoral fellows, three graduate and two undergraduate students have been trained in the processing and analysis of the natural 210-Po/210-Pb pair. They have been educated in model application to oceanic and estuarine carbon dynamics and processing of trace elements by isotopic proxy. One was a Latino student who was awarded a National Science Foundation-Bridge to the Doctorate Research Fellowship for granting of a Masters degree. Key aspects of the research have been used for student presentations to professional meetings, and in courses by the principle investigator on oceanography, isotopic geochemistry and environmental chemistry.
Last Modified: 06/18/2014
Modified by: Thomas M Church
Please report errors in award information by writing to: awardsearch@nsf.gov.
