Honors College Theses

Steady heartbeat: Field and laboratory studies indicate unexpected resilience to high temperatures for the ribbed mussel Geukensia demissa

Ashlyn N. Smith Ms., Georgia Southern University


Salt marshes are important ecosystems found along the coast of Georgia. Salt marshes are hosts to diverse organisms that interact with each other to promote many ecosystem services, such as storm buffering and flooding, and absorption of excess nutrients. Among these diverse organisms is the ribbed mussel, Geukensia demissa. Mussels are a foundation species in this intertidal landscape, and without them the whole salt marsh would be negatively affected. The purpose of this investigation was to explore the thermal stress response of G. demissato rising temperatures. Mussels were collected from three locations that were landlocked, close to a road, and far away from a road on Tybee Island, Georgia. The presence of this road has greatly increased the temperature in the salt marsh. Thus, we hypothesize that mussels will have an increased heart rate with increased temperature. To test this hypothesis, the heartbeat of G. demissawere recorded using an IR sensor in laboratory and field experiments at reduced and elevated temperatures. Results showed that mussels from locations regularly experiencing elevated temperatures do not have an increased heart rate. However, mussels from locations that experience lower temperatures did. These results indicate that mussels are more resilient to higher temperatures than previously expected. This study is significant for marsh conservationists and scientists wishing to preserve and maintain the salt marsh, its ecosystem services.