Effects of CO2, Light, and Invasive Amphipod Herbivory on Eelgrass (Zostera marina)

• Main Author: Christian Robert Hart Tettelbach
• Other Authors: Katharyn Boyer, Karina Nielsen, Brent Hughes
• Format: Master Thesis
• Language: English
• Published: San Francisco State University 2021
• Subjects: Ocean acidification
• Online Access: https://hdl.handle.net/20.500.12680/2v23w133n

Human-mediated changes, including ocean acidification, reduced light availability, and grazing by the invasive amphipod, Ampithoe valida, are expected to influence the health of San Francisco Bay's native seagrass Zostera marina (eelgrass). A mesocosm experiment and feeding assay testing the relative and interactive effects of these factors found eelgrass responded negatively to low light conditions and A. valida consumption of plants, as predicted. Surprisingly, increased CO2 did not enhance eelgrass biomass, even under a light level set to mimic ambient conditions in San Francisco Bay. This suggests light was insufficient across the experiment to permit a positive CO2 response. These findings especially emphasize the negative effects of low light on eelgrass performance and highlight that seagrass benefits associated with ocean acidification may be tempered in the midst of physiological constraints. https://doi.org/10.46569/20.500.12680/2v23w133n