Meeting Abstract
Phyllaplysia taylori, a sea hare found in eelgrass beds along the Pacific coast, is an integral part of eelgrass ecosystems, consuming light-obstructing epiphytic growth from leaf blades. Estuarine eelgrass beds are ecologically important habitats that provide ecosystem services including carbon sequestration and sediment stabilization. Current efforts to re-establish these beds in the San Francisco Estuary make it necessary to understand which parts of the bay can host healthy P. taylori populations. This is especially important considering future climatic scenarios, which will amplify the natural daily and annual fluctuations of temperature and salinity that already occur throughout the bay. P. taylori individuals exposed for two weeks to predicted future high temperature and salinity scenarios were hypothesized to have significantly higher respiration and epiphyte grazing rates than individuals exposed to current scenarios, indicating the metabolic costs of temperature and salinity stress. High mortality rates were observed at the lowest salinity of 24ppt, and average grazing rates were 73% higher in individuals exposed to 27ppt than individuals exposed to 33ppt, indicating higher levels of stress and increased energy requirements at low salinities, and establishing a low salinity threshold. Continued experiments will use an orthogonal design to determine the effects of combined temperature and salinity stress. This study will help inform eelgrass restoration throughout San Francisco Bay by indicating the impacts of increased temperature and salinity fluctuations on the relationship between P. taylori and eelgrass bed health.
