NSF Org: |
OCE Division Of Ocean Sciences |
Recipient: |
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Initial Amendment Date: | September 22, 2010 |
Latest Amendment Date: | April 18, 2013 |
Award Number: | 1046017 |
Award Instrument: | Continuing Grant |
Program Manager: |
David Garrison
OCE Division Of Ocean Sciences GEO Directorate For Geosciences |
Start Date: | October 1, 2010 |
End Date: | September 30, 2017 (Estimated) |
Total Intended Award Amount: | $2,395,087.00 |
Total Awarded Amount to Date: | $2,419,273.00 |
Funds Obligated to Date: |
FY 2011 = $1,861,935.00 FY 2013 = $16,686.00 |
History of Investigator: |
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Recipient Sponsored Research Office: |
4333 BROOKLYN AVE NE SEATTLE WA US 98195-1016 (206)543-4043 |
Sponsor Congressional District: |
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Primary Place of Performance: |
4333 BROOKLYN AVE NE SEATTLE WA US 98195-1016 |
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): |
BIOLOGICAL OCEANOGRAPHY, Dimensions of Biodiversity |
Primary Program Source: |
01001112DB NSF RESEARCH & RELATED ACTIVIT 01001314DB 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
Intellectual Merit. Microorganisms sustain the biogeochemical cycling of nitrogen, one of the most important nutrient cycles on earth. A key step in this cycle, the oxidation of ammonia to nitrite by autotrophic microorganisms, was for a century thought mediated by a few restricted bacterial genera. Significant ammonia oxidation, perhaps most, is now attributed to a previously enigmatic group of Archaea - the ammonia-oxidizing archaea (AOA) - of high abundance in both marine and terrestrial environments. The investigators prior physiological and environmental analyses, the foundation for this proposal, have shown that AOA are active within the marine photic zone and that their competitive fitness in the marine environment is at least in part attributable to an extremely high affinity for ammonia - growing at near maximum growth rates at concentrations of ammonia that would not sustain known bacterial ammonia oxidizers and an unusual copper-based respiratory system that may render them more competitive in iron limited environments. The compelling inference from these prior analyses is that AOA alter and possibly control the forms of fixed nitrogen available to other microbial assemblages within the photic zone by converting ammonia, a nearly universally available form of nitrogen, into nitrite, a form only available to nitrite oxidizing bacteria and some phytoplankton. If correct, this has a significant impact on biodiversity.
The PIs will use the most recent technological advances in protein and high throughput sequencing to evaluate the significance of nitrification in shaping biodiversity (genomic and metagenomics), activity (transcriptome, proteome and stable isotope probing), and in controlling availability of an important trace element (copper). In turn, by resolving the environmental and biotic variables that influence the diversity, distribution and activity of AOA, they will advance general understanding of their taxonomy. More directly, functional knowledge of the contribution of AOA to regenerated nitrate will improve estimates of new ocean production ("biological pump") based on nitrate assimilation, which in the past has mostly neglected the importance of nitrification as a major source of nitrate. Together these studies will transform understanding of the marine nitrogen cycle, estimates of new production, and will ultimately provide a better understanding of the impact of human activity on this critical nutrient cycle.
Broader impacts. The nitrogen cycle has been profoundly affected by anthropogenic inputs of reactive nitrogen into terrestrial, marine, and atmospheric systems - having, or predicted to have, major impacts on marine biological production, increased N20 emissions, nitrogen pollution, and eutrophication. Likewise, there is a poor understanding of the relationship between nitrogen cycling and productivity in marine ecosystems. Marine systems are increasingly affected by ocean acidification and by atmospheric inputs of reactive nitrogen. Since both changes greatly alter nitrogen available to microorganisms, the characterization of the response of these environmentally relevant AOA is of tremendous relevance to understanding the affect of acidification and anthropogenic nitrogen inputs on major ocean processes. The work will also provide an excellent interdisciplinary research opportunity for high school teachers and students. Outreach will enhance understanding among students and teachers of the role of microorganisms in global elemental cycles such as the N cycle. The research will also enhance collaboration among members of the Nitrification Research Coordination Network funded by NSF.
Integration. The proposed project encompasses and integrates the three dimensions (functional genetic, and taxonomic) of biodiversity. First, the project is framed by function: microbial control of one of the most important nutrient cycles on earth, the nitrogen-cycle. Second, it is motivated by recent genetic analyses that associate activities of a novel clade of Archaea (provisionally assigned to a new kingdom within the Archaea, the Thaumarchaeota) with control of ammonia oxidation in the ocean. Third, it is built upon a compelling synthesis of physiological and environmental data that lead to its central hypothesis, that by altering and possibly controlling the form of nitrogen, the AOA also alter biodiversity and ecological function in one of the most productive environments on earth. It identifies a specific taxonomic imperative. The tremendous genetic diversity among the globally abundant AOA, catalogued almost exclusively by gene sequencing surveys and therefore lacking formal description, makes it essential to resolve membership into ecologically relevant groups or clades as a prelude to developing a formal taxonomy. The investigators have assembled a group of collaborators with specific expertise in each of dimension and uniquely qualified to address the research objectives outlined in an integrative way.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
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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 research used culture-based studies of model marine microorganisms to guide environmental analyses of the significance of ammonia-oxidizing microorganisms in shaping the activity and structure of plankton in the upper ocean. By using the most recent technological advances in molecular characterization and analytical chemistry this research established that the greater part of nitrification (the microbiological conversion of ammonia to nitrate) in the North Pacific and coastal areas is controlled primarily by the ammonia-oxidizing archaea (AOA), and served to identify specific biotic and abiotic factors controlled by, and controlling, the activities of the AOA. By better quantifying the contribution of AOA to regenerated nitrate in the upper water column it should now be possible to improve estimates of new ocean production (“biological pump”), an estimate that has been based on nitrate assimilation and the assumption that there is very little endogenous production of nitrate in regions of active photosynthetic production. These analyses have also provided new information about environmental and biological controls of the production of nitrous oxide and methane in the upper ocean, both potent greenhouse gases, and forced a reevaluation of the use of AOA lipids preserved in marine sediments to inform historical excursions in ocean surface water temperature associated with past climates. Together the results of this work have significantly advanced understanding of environmental variables influencing the coupling of marine nitrogen and carbon cycles, and offer new insights into microbial processes relevant to past and future climates. These studies should ultimately provide a better understanding of the impact of human activity on critical marine nutrient cycles.
Last Modified: 02/15/2018
Modified by: David A Stahl
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