Collaborative research: the role of zooplankton in mercury biomagnification in arctic environments

The National Science Foundation Division of Polar Programs awarded the University of Alaska Anchorage $208,192 on August 1, 2026, under the Polar Programs assistance listing (CFDA 47.078) to conduct collaborative research on zooplankton's role in mercury biomagnification in Arctic marine environments.

The research project characterizes zooplankton communities and quantifies mercury concentrations in seawater, sediments, phytoplankton, and zooplankton along the central and western Aleutian Islands to explain spatial variation in total mercury concentrations affecting Steller sea lions, a federally recognized endangered population in the western Aleutian Islands whose mercury levels have doubled over the past decade. The project integrates physical, chemical, and biological oceanography with genomics, focusing on the hypothesis that gut microbiomes of key zooplankton species produce significant amounts of methylmercury that enter marine food webs and expose sea lions and other marine life to this toxic compound. The research identifies mercury exposure pathways in common prey species and addresses how mercury moves through the marine food web—a concern for local Arctic residents whose subsistence practices and cultural heritage depend on marine resources.

Performance occurs in Anchorage, Alaska with a period of performance from August 1, 2026, through July 31, 2029.

Abstract

Mercury is a heavy metal that occurs in the ocean because of human activities and natural processes. Once in the marine environment, mercury can be transformed into methylmercury, a highly toxic compound that poses severe health risks to humans, animals, and ecosystems. Over the past decade, mercury levels in steller sea lions from the western aleutian islands - a federally recognized endangered population - have doubled. This increase is especially critical in pups, whose mercury levels now surpass established safety thresholds for mammals in some locations. Furthermore, mercury accumulation in steller sea lions and other marine life varies regionally across the central aleutian islands. The outcomes of this project will provide new information about how and where toxic mercury concentrations are increasing across the aleutian archipelago. Understanding how toxic mercury moves through the marine food web is especially critical for local arctic residents, whose subsistence practices, cultural heritage, and well-being are closely tied to marine resources. This project will integrate physical, chemical, and biological oceanography with genomics to identify the drivers of spatial variation in total mercury concentrations in the aleutian islands. Specifically, IT will focus on the common prey species that serve as pathways of mercury exposure to steller sea lions. We hypothesize that the GUT microbiomes of key zooplankton species produce significant amounts of methylmercury, thereby providing a source of this toxin in food webs. The main objectives of this project are to, 1) characterize the zooplankton communities along the central and western aleutian islands with known differences in biotic total mercury concentrations, and to 2) quantify mercury concentrations in seawater, sediments, phytoplankton, and zooplankton, and determine how the observed spatial variation is influenced by zooplankton community composition and physical oceanographic conditions. This project will train multiple graduate students and provide critical data on the health of species that are important to local arctic communities. 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.- subawards are not planned for this award.