The Effect of Arsenic Exposure on Feeding Habits of Hermit Crabs

Contaminants that affect marine ecosystems have origins from processes associated with mining and the burning of fossil fuels. This study examines the degree to which arsenic concentrations affect the feeding patterns of hermit crabs to suggest the extent of impact the substance has on a marine ecosystem. Exploring the relationship between the amounts of arsenic exposed to hermit crabs and the amount retained defines the bioavailability of arsenic. The study also aims to correlate the arsenic concentrations in the tissue and the mass of consumed pellet after two weeks of exposure. We hypothesize that when the hermit crabs are exposed to Arsenic, they will consume less pellet than before exposure and will retain a higher concentration of arsenic. We expect to see a linear relationship when plotting consumed pellet as a function of arsenic retention. The sixteen crabs are selected from a larger group on the criteria of completing continuous 30 minutes of feeding. All crabs are captured from the same tide pool. After completing the initial feeding test, crabs are placed in control or Arsenic jars. They are observed and left undisrupted for two weeks. After this, a final10 min feeding test takes place, recording the mass of their meal. The crabs are frozen using liquid nitrogen until they are ready for digestion in 70% nitric acid solution. Although the experiment is still in process, a statistically significant difference in the mass of pellet consumed has been established between in an exposed crab (lower) than a control crab (higher). The experiment is still looking to perfect the feeding test and thus find a concrete difference between mass consumed in a feeding test and concentration of arsenic