Project: Resolving vertical trophic linkages between surface and deep pelagic food webs

NSF Award Abstract:
This CAREER award is advancing our understanding of connections between surface and deep water ocean food webs, which in turn has important implications for carbon cycling in the ocean. Although marine ecosystems deeper than 200 m encompass Earth’s largest single habitat, the food web relationships of deep-sea organisms are poorly resolved. The investigator is evaluating active transport by fishes, squids, crustaceans, and gelatinous animals that move organic matter from the more productive surface into deeper waters through feeding and diel vertical migration. She is using a combination of data on abundance and distribution of species with measurements of stable isotope biomarkers to understand trophic relationships and connect community composition and migratory behavior with food-web processes in the southern California Current ecosystem. The investigator is from a group traditionally underrepresented in science, and she has designed a comprehensive educational plan to train a more diverse, inclusive generation of seagoing biological oceanographers through hands-on field and research experiences. In addition to providing support for graduate and undergraduate students to participate directly in this research, the investigator is creating a novel and cohesive undergraduate curriculum involving a seagoing laboratory course to teach interdisciplinary field methods to conduct research on pelagic ecosystems and a seminar course highlighting Native and Indigenous knowledge alongside more traditional oceanographic research. The overall goal is to broaden participation in science by combining hands-on interdisciplinary research, mentoring, and expanding networks of minority and majority scientists.

This study centers around Vinogradov’s “ladder of migrations” as a conceptual framework, with the goal of understanding cumulative downward transport of organisms and organic matter to the deep ocean by overlapping vertical migrations and feeding. It is focusing on the role of micronekton, defined as ~2-20 cm fishes, cephalopods, crustaceans, and gelatinous animals, as active transporters of surface-derived organic matter across epipelagic, mesopelagic, and upper-bathypelagic layers in the southern California Current Ecosystem. One research cruise is sampling deep pelagic micronekton communities comprehensively and systematically and complements long-term data collected in the surface waters of this ecosystem. Depth-discrete MOCNESS tows are sampling organisms to assess micronekton abundance, biomass, and extent of diel vertical migrations to understand how relative compositions of taxa drive vertical connectivity. Analysis of bulk carbon and nitrogen stable isotopes and compound-specific isotopic analyses of amino acids (AA-CSIA) in organism tissue are providing quantitative assessments of deep-pelagic food webs and measuring the relative strength and composition of trophic linkages between surface and deeper water assemblages across distinct environmental gradients.

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.

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).