| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
|
| Initial Amendment Date: | August 20, 2020 |
| Latest Amendment Date: | December 14, 2021 |
| Award Number: | 2041539 |
| 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, 2020 |
| End Date: | August 31, 2022 (Estimated) |
| Total Intended Award Amount: | $185,920.00 |
| Total Awarded Amount to Date: | $217,813.00 |
| Funds Obligated to Date: |
FY 2022 = $31,893.00 |
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
3100 MARINE ST Boulder CO US 80309-0001 (303)492-6221 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
3100 Marine Street, Room 481 Boulder CO US 80301-1058 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Chemical Oceanography |
| Primary Program Source: |
01002021DB 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
Nitrogen is a limiting nutrient for life in many marine environments. Its availability shapes the structure and productivity of marine ecosystems. To better understand the cycling of nitrogen, scientists need tools to track the processes that affect nitrogen in nature. Past research into the nitrogen and oxygen stable isotopes of nitrate has enabled pivotal insights into the global nitrogen cycle. At the same time, it has highlighted many unresolved complexities in the cycling of nitrogen. Unfortunately, classical isotope measurements are limited in capturing the processes that transform nitrogen in nature. This is because the resulting isotope signatures are always a combination of at least three factors. First, the isotopic composition of the source compound. Second, the mechanism of the process. And third, the completeness of the transformation. In this EArly-concept Grant for Exploratory Research (EAGER) project, the investigators thus propose to explore a new analytical approach. The goal of the proposed research is to measure the doubly-substituted or ?clumped? isotopologs of nitrate for the first time. Clumped nitrate isotopes have the potential to record specific nitrogen transformations. The proposed work could unlock these clumped nitrate isotope signatures as a new tool to study nitrogen in the oceans. In addition to the technology itself, this project will develop open-source software tools for the analysis of isotopolog data to support future work on similar analytes of interest. The proposed project will also create an opportunity for community college students to visit participating laboratories at CU Boulder. In collaboration with the five community colleges of the Denver Metro STEM Alliance for Minority Participation, interested students will meet current CU Boulder students, learn about ongoing undergraduate research, summer research opportunities and 4-year college transfer pathways. The participating community colleges educate a large number of students from underrepresented backgrounds. Creating pathways for these students to continue on to a 4-year degree and a successful career in STEM research and industry fields is a critical piece of the puzzle for increasing diversity in STEM disciplines nationwide.
Specifically, the investigators propose to develop a new technological approach to studying the isotopes of marine nitrate by electrospray ionization (ESI)-Orbitrap mass spectrometry. This approach provides a path to quantifying up to 3 new isotopic dimensions of nitrate. These doubly substituted, ?clumped? nitrate isotopologs (15N18O, 18O18O, 17O18O) have never before been analytically accessible and could fundamentally transform our understanding of how individual nitrogen cycling pathways interact to shape ocean ecosystems and the global nitrogen cycle. Because they are intramolecular isotopic dimensions, the relative abundances of these clumped nitrate species directly reflect kinetic and equilibrium isotope effects of the processes that form and destroy them. The objectives of this project are thus to 1) establish an ESI-Orbitrap methodology for the reproducible quantification of all singly and the three major doubly substituted isotopologs of nitrate; 2) develop and demonstrate scalable and easily transferable protocols for the extraction and preparation of nitrate from marine samples for ESI-Orbitrap analysis; 3) initiate a pilot study of the clumped nitrate space in marine samples. Beyond its immediate impact on research in chemical oceanography, this project will introduce the geochemistry community to a new generation of intact molecule isotope-ratio mass spectrometry that can be adapted to other oxyanions and metabolites widely studied in marine systems (e.g., sulfate, amino acids, lipids). Developing nitrate as a model for ESI-Orbitrap isotope analytics also will benefit other fields of science including agricultural research, terrestrial ecosystems science, and atmospheric chemistry.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
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.
Stable isotope patterns allow unique insights into natural processes because they can be used to relate mechanisms that take place at the atomic level to effects on much larger scales. All existing approaches to measure stable isotopes, however, have severely limited capabilities to measure isotopic variants of metabolites, drugs, oxyanions, and other compounds that are soluble in water. Our results demonstrate that a radically different approach, based on electrospray ionization Orbitrap mass spectrometry, is capable of measuring isotope signatures of intact water-soluble compounds directly, comprehensively and with high accuracy. Specifically, we used the nitrate oxyanion (NO3-) as a model for developing this new technology.
Nitrate is the predominant form of bioavailable nitrogen in the ocean, and observations of its isotopes allows a means of understanding the nitrogen cycle in important details, including processes such as nitrogen fixation, nitrate assimilation, and denitrification. Human activities have profoundly altered global and local nitrogen biogeochemistry in ecosystems through fertilizer use and fossil fuel burning. A better understanding of the fate of anthropogenic nitrogen in modern environments through novel isotope fingerprinting approaches could be useful to better mitigate the dramatic long-term impact of anthropogenic nitrogen on the loss of biodiversity.
For this reason we have developed methods to measure for the first time information encoded in the rare forms of nitrate molecules that contain more than one isotopic substitution ("clumped isotopes"). Together with theoretical predictions, newly developed software and laboratory protocols, this project has established a framework to test hypotheses and ask more nuanced mechanistic questions about nitrogen cycling in natural and human-impacted ecosystems. The resulting tools have been made available to several laboratories already and will open new areas of investigation into biogeochemistry. We expect that despite short-term technical delays, the progress made with support of the EAGER grant will in the longer term benefit every field that uses stable isotope analysis, including research on climate, the environment and health.
Last Modified: 12/01/2022
Modified by: Cajetan Neubauer
Please report errors in award information by writing to: awardsearch@nsf.gov.
