Upregulation of Heat Stress Genes of Ribbed Mussels in Exposed Areas of the Salt Marsh on Tybee Island, Ga.

Geukensia demissa, the ribbed mussel, is a keystone species of the eastern US coastline. Geukensia demissa is at risk of experiencing heat stress due to climate change. Ribbed mussels form aggregates at the base of cordgrass stems where they are less exposed to direct sun rays. Some mussels end up in areas of the mound which lack cordgrass and are directly exposed to temperatures that regularly exceed 36°C during the summer. In field measurements, exposed mussels had higher body temperatures (30.1 ± 1.8 °C) than less exposed mussels (28.4 ± 1.0 °C). If exposed mussels experience heat stress, then in response, the expression of heat stress genes such hsp70 and hsc70 may be upregulated. Four mussels from exposed areas and four from less exposed areas were collected. Total RNA isolation and quality assessment was performed on the gill tissues. Expression of hsp70 and hsc70 was determined using RT-qPCR. Results of initial analyses were inconclusive, as many of the mRNA transcripts assessed were not expressed. This could be due to degradation of RNA or inaccuracy of mRNA template sequences, as little information is available on Geukensia demissa’s genome. In the future, collected samples will be preserved more quickly and more genomic research conducted to alleviate error. Also, ELISA (enzyme-linked immunosorbent assay) will be utilized to measure the hsp70 protein