Identifying Sources of Organic Matter to Benthic Organisms in the Beaufort and Chukchi Outer Continental Shelves

Benthic invertebrate communities are an essential ecosystem component in Arctic food webs, however the proportional contributions of different sources of organic matter (marine, terrestrial, or microbial production) that sustain benthic organisms in the Arctic are unclear. This project provided a better understanding of the organic matter sources consumed by benthic organisms, using a state-of-the-art essential amino acid (EAA) “fingerprinting” approach. The EAA “stable isotope fingerprints” were analyzed from soft tissues and shells of clams from three regions of the Arctic marine environment: Hanna Shoal, Chukchi Sea, and the Beaufort Sea. EAA isotope fingerprints were also analyzed from primary producers in order to be able to resolve taxon-specific signatures. Analytical results from clams and primary producers were statistically compared and differentiated from EAA fingerprints derived from microbial and terrestrial carbon sources. In Hanna Shoal and Chukchi Sea, phytoplankton and terrestrial derived EAAs made the greatest proportional contributions to benthic invertebrates. Bacteria made up the next highest proportion of bivalve EAAs in Hanna Shoal. In contrast to Hanna Shoal and Chukchi Sea, the results from Beaufort Sea indicated a greater contribution of EAAs from sources other than phytoplankton and terrestrial organic matter. Most notably, there appeared to be a greater contribution of bacterial and macroalgal sources of EAAs in this region.

USD: $246,082

2016-10-01 → 2019-06-07