| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | April 2, 2010 |
| Latest Amendment Date: | June 6, 2011 |
| Award Number: | 0963026 |
| 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, 2013 (Estimated) |
| Total Intended Award Amount: | $307,861.00 |
| Total Awarded Amount to Date: | $354,065.00 |
| Funds Obligated to Date: |
FY 2011 = $46,204.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
266 WOODS HOLE RD WOODS HOLE MA US 02543-1535 (508)289-3542 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
266 WOODS HOLE RD WOODS HOLE MA US 02543-1535 |
| 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: |
01001112DB 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
GEOTRACES is an international program to study the global marine biogeochemical cycles of trace elements and their isotopes (TEIs). Its guiding mission is to "identify processes and quantify fluxes that control the distributions of key trace elements and isotopes [TEIs] in the ocean" (GEOTRACES Science Plan, 2006). Because particles in the ocean serve as important sources and/or sinks for many trace elements and isotopes, particulate TEIs are key parameters for GEOTRACES. Indeed, the composition and distribution of particles in the ocean is crucial to understanding all three themes identified by the Science Plan: 1) Fluxes and processes at ocean interfaces, 2) Internal cycling, and 3) Development of proxies for past change.
In this project, researchers at the Woods Hole Oceanographic Institution will be supported to ensure the collection of high quality trace metal clean size-fractionated particles on the US North Atlantic GEOTRACES Atlantic section and the analysis of key trace elements and major particulate phases. They will analyze size-fractionated particles collected by battery operated in-situ filtration for all key trace elements listed in the Science Plan (Fe, Al, Zn, Mn, Cd, Cu), a suite of other trace elements of interest (e.g. Co, Ti, Ba), and major carrier phases (e.g. CaCO3, biogenic Si, and POC). The operation of battery operated in-situ filtration (McLane pumps) for short-lived radionuclides is already funded for the Atlantic GEOTRACES section. This project will coordinate closely with the short-lived radionuclide group to adapt McLane pumps for simultaneous sampling of size-fractionated particles for trace metal analysis and radionuclide collection.
Broader Impacts: Inasmuch as this will be the first full ocean depth zonal section of size-fractionated particulates, the result should be a novel and comprehensive understanding of the distribution, composition, and dynamics of the particles that control much of the chemical distribution, carbon uptake, and the biological productivity of the ocean. Because of the importance of particles in so many processes affecting the cycling of TEIs, this dataset will be invaluable in conjunction with other parameters measured on the GEOTRACES Atlantic section. Many as yet unposed scientific questions will emerge from this unprecedented dataset, which will be made available through publication and electronically through the BCO-DMO data office at Woods Hole so that it can be mined in the future by anyone in the community exploring questions about particle distribution and composition. A summer undergraduate student will help with some sample analyses, as will a graduate student in the MIT-WHOI Joint Program in Oceanography.
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.
We collected large (>51um) and small (<51um) marine particles from the whole water column (surface to 5500m depth) from 22 stations across the North Atlantic ocean as part of the US GEOTRACES North Atlantic Zonal Transect project. This was a collaborative project between several dozen scientists, each an expert at measuring and interpreting the concentrations of trace elements and isotopes (TEIs), with the goal of understanding how these TEIs are cycled in the ocean. Particles in the ocean are a key mediator of the cycling of TEIs. For example, mineral dust blowing from the Sahara desert over the North Atlantic is deposited into the ocean as micron-sized particles. These particles partially dissolve, supplying essential micronutrients such as iron that help fuel biological production. In all oceans including the North Atlantic, the even more dominant source of particles is from the biological production of phytoplankton in the surface ocean, which produces particulate organic matter, as well as shells made of calcium carbonate or silica. Phytoplankton are also in the micron to tens of micron size range, a size that is small enough that they generally don’t sink on their own. But when phytoplankton die, the relatively small phytoplankton particles are actively (through being eaten and excreted) or passively (through sticking) packaged into large aggregates, generally >51um, which then sink out of the surface ocean. In the process of aggregation, other small particles such as dust are swept into the process, and are also removed. This sinking of large particles is termed the biologial pump, and is one mechanism by which the ocean sucks carbon dioxide from the atmosphere. As large particles sink, they tend to break up as they are decomposed into small particles again, which can be a source or sink of dissolved TEIs deeper in the water column. Our data elucidate this process of particle dynamics, providing a key piece to the puzzle of cycling of TEIs in the ocean.
This is the first ever full ocean depth section of size-fractionated particle composition. This alone would make this project significant, but the even greater impact is in the synergies that have emerged from having dozens of scientists work collaboratively to solve the mysteries of the cycling of key elements in the ocean.
This project has provided many training opportunities for developing the next generation of scientists, as well as for diversifying our scientific workforce. It is a main part of Daniel Ohnemus’ PhD thesis dissertation. It has also provided training opportunities for two female undergraduate students, both of whom were from Historically Black Colleges.
Last Modified: 06/28/2013
Modified by: Phoebe J Lam
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