Project: Determining metabolic carbon incorporation rate in fish carbonates and its implications for the global carbon cycle

NSF abstract:
The Earth’s carbon cycle is linked by processes that transfer carbon between the ocean, atmosphere, living organisms, and sediments. Carbonate mineral production in the ocean connects these important carbon pools and is a key process in the global carbon cycle. Marine fish release significant amounts of carbonate minerals and organic carbon to the oceans each year. Yet the role of marine fish in the global carbon cycle remains poorly understood. To better understand this role, this project will study carbonate minerals produced by several species of marine fish, including deep sea and open ocean fish species. Results from the study will improve estimates of the amount and composition of carbonate that marine fish produce each year. The project is expected to provide essential new insights about the interactions between the oceans, marine fish, and the global carbon cycle. This project supports the work of an early career female scientist. Education opportunities include hands-on training for two PhD students, 3 Masters of Professional Science Student Interns and several undergraduate researchers. Graduate students will receive in-depth training on science writing through a week-long workshop with a professional writer. Scientists associated with the project will host workshops with high school students and teachers. Teaching materials and scientific results will be shared through open-access online repositories, annual outreach events, social media, as well as professional conferences and publications.

Marine bony fish were initially estimated to contribute 3-15% of global new carbonate production in the oceans each year, making fish a fundamental influence on the oceanic alkalinity budget and Earth’s global carbon cycle. However, technological advancement has shown that global fish biomass is likely to be significantly larger than previously appreciated, and the impact of this increased fish biomass on global carbonate production rates has yet to be evaluated. Significant knowledge gaps regarding the composition of fish contributions coupled with uncertainty regarding production magnitude currently preclude their inclusion in fully coupled carbon-climate models. This project will address these knowledge gaps by refining production rate estimates and conducting detailed compositional analyses of carbonate minerals (ichthyocarbonate) produced by several species of marine fish, including fast-swimming epipelagic and mesopelagic species. Scientists involved in this study will conduct a series of controlled experiments to constrain production rate under varying environmental conditions and will employ a stable carbon isotope mass balance to define the origin of carbon in ichthyocarbonate, including dietary carbon and dissolved inorganic carbon in seawater. The study will provide scalable relationships between metabolic rate, ichthyocarbonate production rate, and the incorporation of dietary carbon into ichthyocarbonate. The study will use an interdisciplinary approach to enhance understanding of carbon cycling between the atmosphere and the oceans driven by marine fish. Broader impacts of this project include support for an early career female faculty member, training of future STEM workforce in three degree tracks, and the development of science-aligned educational materials that will be disseminated to high-school students and teachers through workshops, the Science Education Resource Center (SERC) repository, as well as annual events hosted at the university, including Diversity in Marine Science Day and Women in Marine Science Day.

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.