| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | August 6, 2010 |
| Latest Amendment Date: | August 6, 2010 |
| Award Number: | 1031271 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Donald L. Rice
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2010 |
| End Date: | August 31, 2013 (Estimated) |
| Total Intended Award Amount: | $837,905.00 |
| Total Awarded Amount to Date: | $837,905.00 |
| Funds Obligated to Date: |
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| 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: |
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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
Two scientists from Woods Hole Oceanographic Institution will determine the role of enzymatic activity in the cycling of trace metals. Specifically the researchers would address the following questions: (1) degradation of sinking particulate organic material in the Tropical North Pacific can be influenced by the ability of microbes to synthesize zinc proteases, which in turn is controlled by the abundance or availability of zinc, and (2) methylation of mercury is controlled, in part, by the activity of cobalt-containing enzymes, and therefore the supply of labile cobalt to the corrinoid-containing enzymes or co-factors responsible for methylation. To attain their goal, they will collect dissolved and particulate samples for trace metals and metalloenzymes from three stations along a biogeochemical gradient in the Tropical North Pacific (along 150°W from 18°N to the equator). Sinking particles from metal clean sediment traps will also be obtained. The samples will also be used to carry out shipboard incubation experiments using amendments of metals, metal-chelators, B12, and proteases to examine the sensitivity and metal limitation of heterotrophic, enzymatic degradation of organic matter within the oceanic "Twilight Zone" (100-500 m). This study will result in a novel metaproteomic/metalloenzyme datasets that should provide insights into the biogeochemical cycling of metals, as well as co-limitation of primary productivity and controls on the export of carbon from the photic zone.
In terms of broader impacts, an online metaproteomic data server would be created so the community can have access to the raw data files generated by this research. It is anticipated that the current public school outreach activities in Cleveland, Ohio in which the proponents are involved will be continued. During this effort, the proponents plan to use grow-out incubation experiments to teach students about the role of nutrients in phytoplankton growth. One graduate student would be supported and trained by this project.
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.
During this project, we have explored the fundamental biochemistry of marine microbial organisms and the way in which those microbial communities can affect the chemistry of the ocean. Specifically, we focused on proteins, a class of compounds that are responsible for catalyzing the fundamental biochemical reactions inside cells. We have, for the first time, generated vertical profiles of the concentrations of a number of important proteins in the ocean and these profiles have revealed previously unseen details regarding how the ocean operates.
Many of the proteins that we are particularly interested in require a metal atom to be part of their structure (metalloproteins or metalloenzymes). Such metalloproteins are often found as part of a reaction sequence involving oxidation/reduction reactions and are therefore fundamental to the generation and transformation of energy. For example, photosynthesis and nitrate reduction, two processes that are important in our study area of the tropical Pacific Ocean, require metals (iron, manganese and copper). In some instances, organisms find it difficult to obtain enough of these metals to satisfy their metabolic needs, resulting in growth or activity limitation. The tropical Pacific is an example of a location where photosynthesis is iron-limited. Our proteomic results were able to detect which regions were limited by nitrogen, iron and phosphorus using biomarkers, which are molecule that are diagnostic of microbial cellular metabolism. Wealso examined the metal requirements of aerobic heterotrophic organisms (ones that degrading existing organic matter for energy), particularly for zinc. This is because several important classes of proteins involved in degradation, notably proteases and phosphatases, require zinc to function properly at the pH of seawater. We observed a stimulatory response of zinc on the activity of phosphatases in sediment trap experiments, which implies there could be zinc limitation of these microbial remineralization processes and has implications for carbon cycling in the oceans.
Finally, we also hypothesized that metal limitation of protein function might affect the behavior of the toxic element mercury in the ocean. We found evidence that the transformation of mercury into the form that bioaccumulates in fish is connected to the activity of group of proteins that are related to vitamin B12, a cobalt containing biomolecule. A connection to proteins that use B12 has been observed in laboratory studies, but this is the first time that field data have suggested a similar connection.
Thus, our research on this project has developed novel biochemical methods to study the oceans and has provided fundamental information on the healthy function of the ocean, as well as processes that could if disturbed, represent a threat to the health of people.
Last Modified: 12/29/2013
Modified by: Carl H Lamborg
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