| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | August 17, 2021 |
| Latest Amendment Date: | January 8, 2025 |
| Award Number: | 2049294 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Henrietta Edmonds
hedmonds@nsf.gov (703)292-7427 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2021 |
| End Date: | August 31, 2025 (Estimated) |
| Total Intended Award Amount: | $494,208.00 |
| Total Awarded Amount to Date: | $494,208.00 |
| Funds Obligated to Date: |
FY 2022 = $163,318.00 FY 2023 = $170,071.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
8622 DISCOVERY WAY # 116 LA JOLLA CA US 92093-1500 (858)534-1293 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
CA US 92093-0244 |
| 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): |
PHYSICAL OCEANOGRAPHY, Chemical Oceanography |
| Primary Program Source: |
01002223DB NSF RESEARCH & RELATED ACTIVIT 01002324DB 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
Understanding the mechanisms that determine when and how the ocean takes up carbon from the atmosphere is important to our fundamental knowledge of ocean biogeochemistry and to our ability to model future climate. Air-sea fluxes of oxygen are also relevant to climatic variability, and surface oxygen can act as a tracer of biological carbon production and export as well as of important physical processes. The Kuroshio Extension region of the northwest Pacific Ocean is an area of strong carbon dioxide uptake and a site of wintertime watermass formation, with Subtropical Mode Water formed to the south of the Kuroshio Extension and lighter and denser Central Mode Water formed to the north. These mode waters then sink below the surface, moving carbon dioxide to the ocean interior. There are very few wintertime vertical profiles of any carbon system parameter in these mode water formation regions and no fully resolved winter or annual cycles of measurements. In this project, the investigators will deploy robotic profiling floats to make these needed measurements. They will combine the float data with numerical modeling to advance understanding of mode water formation and air-sea fluxes of carbon dioxide and oxygen in this important region. This proposal will fund an early career scientist and expand expertise in and capability for biogeochemical profiling float operations at the University of Hawai?i, providing a foundation for future work in autonomous biogeochemical platforms. This proposal will fund a graduate student in their Ph.D. work and multiple summer undergraduate researchers. Students will gain exposure to the complementary fields of marine chemistry, ocean physics, and climate models.
The team will investigate carbon and oxygen budgets in the northwest Pacific from the following: new float observations of oxygen, nitrate, and estimated dissolved inorganic carbon; longer-term float temperature and salinity observations for water mass analysis; and model output. They will deploy biogeochemical Argo floats capable of measuring pH in the heart of the Subtropical and Central Mode Water formation regions in the Kuroshio Extension to provide vertical profiles of oxygen, nitrate, and, especially, estimates of dissolved inorganic carbon. They will use these observations to both calculate the drivers of air-sea carbon dioxide and oxygen fluxes and to validate model output for further analysis. Western boundary currents, such as the Kuroshio Extension, are areas of significant carbon dioxide uptake, but the relative importance of biology and physics to that uptake and its variability on large temporal and spatial scales is not well understood. The project has three main goals: (1) to determine what fraction of the CO2 and O2 uptake in the North Pacific is the result of mode water formation and subduction, (2) to determine how the physical and biological processes that drive air-sea fluxes vary spatially in the Kuroshio Extension region, and (3) to analyze the drivers of interannual and decadal variability of mode water formation and related gas fluxes in the Kuroshio Extension region and determine how that variability is linked to the larger climate system. The new observations will be evaluated in the larger context of multiple decades of observations from ships and almost two decades of physical observations from profiling floats. The team will use model output to diagnose physical drivers of air-sea fluxes and to link the observed mechanisms to longer-term variability and climate processes. The data collected will represent the first seasonally resolved profiles of oxygen, nitrate, and derived DIC in a western boundary current and will be of use to a broad community of researchers.
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.
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