Fine-scale Monitoring of Puget Sound Ecosystems Using Benthic Foraminifera

Continuing an ongoing project, researchers are developing a tool for monitoring Puget Sound’s health using benthic foraminifera.

Principal Investigator

Elizabeth Nesbitt, University of Washington, Department of Earth and Space Sciences


Benthic foraminifera, microscopic shelled protists, occupy the bottom of marine food chains. As a result, any human impacts on foraminifera will resonate through the ecosystem. This project continues ongoing Washington Sea Grant-funded research to refine the use of benthic foraminifera as a low-cost, reproducible tool for fine-scale assessments of ecological health and for monitoring benthic ecosystems. This tool will be tested in three of the most vulnerable areas of Puget Sound. Results will be shared with the general public and agencies working on pollution mitigation.

Research Updates

This project continued the work of previously funded Washington Sea Grant research pioneering the use of foraminifera as indicators for Puget Sound health. Researchers further developed a foraminiferal tool for ecosystem monitoring and applied the tool to individual embayments, from the San Juan Islands to the Eagle Harbor Superfund site and industrialized Commencement Bay. The tool employed multiple indicators, including the composition, density and diversity of the assemblages.

In heavily impacted embayments, foraminiferal assemblages showed low density and diversity, dominance by pollution-tolerant species, and large numbers of partially dissolved individuals. With efficacy established and findings published, this tool is now being applied to many parts of the Sound. Project members have demonstrated its operation to grade-school and college students and other local groups, advancing public knowledge of Puget Sound’s condition.