Arctic | Lower Trophic Levels UNDERGRADUATE POSTER PRESENTATION Investigating the critical thermal maximum of Pacific Arctic bivalves Presenter: Sophia Garms , sngarms@smcm.edu Christina Goethel , cgoethel@umces.edu Jacqueline Grebmeier , jgrebmei@umces.edu, University of Maryland Center for Environmental Science Changing sea-ice extent and warming seawater temperatures are physical factors contributing to a shift within the biological community composition in the Pacific Arctic. This research is focused on identifying the critical thermal maximum (CTM) of bivalve species in the Distributed Biological Observatory (DBO) regions in the Chukchi Sea. Bivalves are dominant prey for benthivorous predators, therefore the results of this study are particularly important as they affect the rest of the food chain. Species of Macoma spp . bivalves are common globally, making them a good sample choice. Understanding how the genus responds in the rapidly changing Arctic could allow for new information on the resilience of the genus in other regions experiencing rising temperatures. Here, we collected samples from three stations in DBO regions 3 (SE Chukchi Sea) and 4 (NE Chukchi Sea). Samples were collected aboard the Canadian Coast Guard Ship Sir Wilfrid Laurier as part of the annual July Canadian Three Oceans/DBO cruise. We assessed how individual M. calcarea responded to rising seawater temperatures in an artificial environment based on two acclimation periods: 48 hours and three weeks. Preliminary experimentation was completed shipboard shortly after the samples were collected to study individuals in water collected at sea and to investigate a short acclimation period. Secondary post-cruise experiments were conducted on live bivalves that had been returned from sea and placed in a climate control room in Solomons, MD. For all experiments, we put single clams into 100mL airtight jars, and FireSting oxygen probes were placed randomly into four of the 20 containers to monitor declining oxygen levels throughout experimentation with temperature variations. The temperature probe was placed randomly to monitor rising water temperature levels throughout experimentation, controlled by increasing the temperature of the refrigerator. Preliminary results show that M. calcarea bivalves in an acclimation period of 48 hours had a CTM of roughly 15.69°C, and roughly 22°C in an acclimation period of three weeks. Interestingly, a second bivalve, Astarte borealis, that was maintained and acclimated to an artificial environment for seven years in a climate control room, was also able to survive a 22°C temperature. These results demonstrate that bivalve species may be able to tolerate higher temperatures, indicating that they may be able to adapt to warming bottom seawater temperatures and decli
Alaska Marine Science Symposium 2023 144
Made with FlippingBook flipbook maker