Comparison of Eelgrass Pathogen Density and Temperature and Salinity Levels in Drakes Estero and Tomales Bay
By: Andrea Hoppe and Taylor Pantiga
Department: Ecology
Faculty Advisor: Dr. C. Sarah Cohen
Eelgrass, Zostera marina, is an aquatic angiosperm and foundation species that grows submerged in marine, estuarine, and coastal ecosystems (Sullivan et al. 2013). As a foundation species, it provides multiple ecosystem services, such as habitats for fisheries species, shoreline stabilization, and blue carbon storage. Global populations of Z. marina have been declining for a multitude of reasons, one of which is a net slime mold and the focus of this study, Labyrinthula zosterae. This pathogen infects eelgrass and initiates “seagrass wasting disease” (Brakel et al. 2017). Various environmental variables are known to influence the severity of pathogen infection, though salinity (McKone et al. 2009) and temperature (Brakel et al. 2019) are known to be highly influential. Changes in salinity and temperature due to climate change are also expected to create conditions favorable for pathogen infections. The pathogen is chronically present in north-central California and has been documented at sites in the Bay Area, including Keller Beach, Crown Beach, Richardson Bay, Sacramento Landing, and Drakes Estero (Atkinson et al. 2021). Drakes Estero underwent thorough eelgrass restoration from August 2016 to May 2017 (Becker et al. 2020). Understanding more about the pathogen’s presence in Drakes Estero will provide information that is essential to the restoration project while providing insights into disease interactions within eelgrass beds. This project aims to observe eelgrass pathogen density in Drakes Estero and Tomales Bay while comparing the severity of pathogen infections to the temperature and salinity levels of the field sites.