Skip to main content
Dryad

Newport Bay water quality and eelgrass bed stability

Data files

Jul 25, 2022 version files 26.55 KB

Abstract

Eelgrass (Zostera spp.) is a marine flowering plant found in coastal regions worldwide and provides critical habitat, nutrient cycling, and shoreline buffering to ecosystems. Populations are declining in many of these regions due to the negative impacts poor water quality has on light availability and photosynthesis. The Lower Newport Bay (LNB) in Southern California is a heavily developed recreational harbor and estuarine habitat supporting species from varying taxa, including eelgrass. To understand the impact water quality has on eelgrass persistence in LNB, we selected four sites with long-term stable eelgrass populations and four sites with transitional eelgrass populations to collect weekly measurements of weather conditions, light availability, and water quality parameters. Through repeated measure ANOVAs using date as a between factor, we found that stable eelgrass beds had significantly higher light availability, dissolved oxygen concentrations, and bluer water on the Forel-Ule scale. We fit a linear mixed effect model using the log of turbidity, log of chlorophyll, and log of eelgrass bed depth as fixed effects with depth nested in site as random effects, found it to be the best fit model using AIC (Akaike Information Criterion), and found that depth and turbidity are significant predictors of light availability. These results indicate that turbidity, rather than chlorophyll concentration, has a greater impact on light availability and eelgrass health in LNB. This pilot project provides a foundation for future research and recommendations for eelgrass conservation in LNB, and suggests that runoff contributing to higher turbidity may be a leading cause of unhealthy eelgrass beds.