Student Research Projects

Filter Feeding Responses in Lamellibranch Bivalves and Global Warming Conditions: Can it Be Detected by the Hemocytes?

Student Ashley Sibley, 17
Faculty Mentor(s)
Department Earth and Environmental Sciences
Course Biology 489: Undergraduate Research


The Earth is expected to see more changes in its climate within a century due to increased carbon dioxide concentrations and other greenhouse gases. Though efforts have been made to reduce and eliminate emissions, marine life will still be severely affected due to the expected rises in ocean temperatures, ocean acidification, increased salinity levels, and decreased oxygen levels. One of many groups of marine organisms to be severely affected is bivalves. Bivalves have a significant impact on many economies because they are a great food source, and their shells have many uses. Bivalves play a significant ecological role in cleaning the aquatic environment due to their filter feeding rates. Aside from their ecological and economical roles, bivalves are intriguing due to their various evolutionary adaptations. Many Species have evolved a lamellibranch gill that is utilized for both filter feeding and respiration. The purpose of this experiment is to determine how increased temperature affects filter feeding in the lamellibranch bivalve Geukensia demissa. Filter feeding rates will be indirectly determined by measuring water clarity with a spectrophotometer. Hemolymph from the bivalves will also be extracted, and the number of haemocytes will be calculated to determine if an increase in temperature causes reductions in hemocyte production due to stress. The haemocytes may indirectly correlate with how efficiently Geukensia demissa is filter feeding. Dissolved oxygen of the testing area will also be determined to indirectly quantify respiration. Preliminary results from absorbance values indicate that Geukensia demissa does not filter feed as efficiently in temperature 10 degrees above ambient conditions. Additionally, the number of haemocytes decreases with an increase in temperature and decrease in filter feeding.


VWC Undergraduate Research Grant