Meeting Abstract
The ribbed mussel Geukensia demissa, can filter the total volume of water in a salt marsh twice a day. Making the salt marsh the most invaluable natural water purification system in the world. Ribbed mussels are found on raised portions of the marsh sediment called mounds. Mounds store water, reduce soil salinity stress, have a high organic content and promote cordgrass (Spartina alterniflora) growth. However, salt marshes are threatened by a variety of natural and anthropogenic factors. Rising temperatures may be altering the positive effect ribbed mussels and cordgrass have on each other. The purpose of this study was to examine the relationship between these two species in a saltmarsh at Tybee Island, Georgia. At this site, cordgrass height and density vary with distance from a winding tributary off of Tybee Creek. In addition, a road cuts through the high marsh. Four mounds located in the high marsh close to the tributary and four located in the mid marsh further away from the tributary were surveyed from spring through fall 2018. Spartina height and density and ribbed mussel abundance were determined on each mound. Temperature was monitored by placing one temperature logger in the high marsh and another in the mid marsh. Data from loggers indicate that the number of days when temperatures were above 110°F was higher in the high marsh than the mid marsh. Despite higher temperatures and proximity to the road, cordgrass density and height, and ribbed mussel abundance in the high marsh increased significantly over time. Mean mussel abundance in the high marsh was 39 ± 2 and in the mid marsh was 27± 2. The proximity to the tidal creek may have a positive effect on cordgrass growth which in turn lowered the temperatures and provided suitable shelter for ribbed mussels.
