As our society continues to develop highly desirable coastal areas due to their economic viability, erosion becomes a principle problem faced by all communities residing there. A popular technique used to deal with increased erosion is to construct oyster reefs to reduce sediment loss. The purpose of this study was to assess the effects of manmade oyster reefs on sediment composition of estuarine shorelines. This study aimed to assess the possible environmental impacts constructing these reefs may have on sediment composition in order to contribute to the environmental evaluation of implementing this technique as a standard erosion preventative. We took 32 five-centimeter sediment cores from each of four points around two small oyster reefs and from two control sites: one before and one after the reefs in accordance with the longshore current. From these samples we measured bulk density, particle size, and total carbon. We hypothesized that the oyster reefs would cause bulk density to be lower than the control sites, but that total carbon would be higher in the area surrounding the reefs. We expected particle size to be smaller around the reefs, and the control site past the reefs was expected to have variables with intermediate values.
Results/Conclusions
We found a significant difference in bulk density and porosity between the reef sites and the control sites. Significant differences were seen between different reef positions as well, confirming that the more protection received by the oyster bar, the lower the bulk density and porosity of the sample. This result is most likely due to how the longshore current and wave action interact with the shoreline. Contrary to our hypotheses, there were no significant differences between the two controls in bulk density, and there were no significant differences in carbon content between any of the sites. Further research may elucidate the effects of changing sediment composition in the estuary on infaunal and benthic organismal population and productivity, and along with our results can inform current and future erosion management programs.