Abstract
Seagrasses provide a variety of ecosystem services, including sediment
stabilization, sediment accretion, improving water quality through
trapping suspended sediments, and storing carbon and nutrients. Sharp
declines in eelgrass (Zostera marina) abundance at South Slough have
prompted efforts to understand eelgrass stressors in the estuary.
Sediment characteristics including organic matter, carbon content, grain
size distribution, bulk density, and porosity were investigated along
with eelgrass metrics at several sites along the estuarine salinity
gradient. These data were used to study the sediment characteristics of
intertidal eelgrass beds in the South Slough estuary, how
characteristics vary between sites along the salinity gradient, and to
determine the relationship of sediment characteristics and eelgrass
abundance. Results show that eelgrass was present at sites characterized
by high percent sand and low percent silt/clay, low porosity and high
bulk density, and low organic matter and carbon content. Eelgrass was
absent from sites characterized by low percent sand and high percent
silt/clay, high porosity and low bulk density, and high organic matter
and carbon content. These results suggest that fine sediment may be one
stressor contributing to changes in intertidal eelgrass distribution in
the South Slough estuary. This study can help inform eelgrass
restoration efforts in South Slough, especially regarding habitat
suitability and site selection.