2023 132 ENV

Survey and Sequencing of Tunicate Species on the Outer Coast Adjacent to San Francisco Bay

By: Emily Chapman, Erika Ono-Kerns

Department: Biology

Faculty Advisor: Dr. C. Sarah Cohen

Tunicates are a common intertidal chordate. The species diversity has not been described on the outer coast adjacent to San Francisco Bay in over 50 years. Tunicates have a high degree of genetic diversity. We collected tunicates from 10 sites from Point Reyes to Pescadero Point, as well as a site in Humboldt County. While at these sites, photographic characterization of habitats and morphology was documented. For DNA sequence characterization (barcoding), DNA is extracted, and PCR is completed using the Cytochrome c oxidase I locus. There are two main goals for this project. The first is to characterize native colonial, social, and solitary tunicates of the outer coast adjacent to San Francisco. Second, we aim to characterize contemporary outer coast samples across diverse field sites and compare them morphologically to the historical collections within the California Academy of Sciences. This research provides a view of potential changes in the identity and distribution of invertebrate chordates along our central coast shoreline, including National Marine Sanctuaries and shorelines impacted by the outflow of a major estuary. Tunicate distributions provide an example of impacts that could represent a snapshot of the ecosystem as a whole, offering a small-scale look into estimates of long-term change.