2023 AMSS Abstract Book

Arctic | Lower Trophic Levels

Effects of increased temperature on sediment community oxygen consumption and individual respiration rates at a long-term mooring site as part of the US Synoptic Arctic Survey Presenter: Christina Goethel , cgoethel@umces.edu, Jacqueline Grebmeier , jgrebmei@umces.edu, University of Maryland Center for Environmental Science Bottom water temperatures in the Bering and Chukchi Seas have been increasing in recent years and are predicted to continue to increase. In addition to food availability, water temperature is one of the primary drivers for the dominant macrofaunal species found in benthic communities in these regions. As part of the United States contribution to the Synoptic Arctic Survey, ten sediment cores and six individuals of dominant bivalves, Macoma calcarea and Ennucula tenuis , were collected at the Chukchi Ecosystem Observatory mooring array in the northeastern Chukchi Sea aboard the US Coast Guard Cutter Healy in September 2022. Five cores and three individual bivalves were held in a climate control room set at 4°C and the other five cores and three individual bivalves were held in a climate control room set at -1°C. Oxygen concentrations (µmol/L) were measured in the cores using a PreSens oxygen meter over a 20-hour period with additional measurements taken at the 6 and 12-hour marks. Individual bivalves were kept in 100 mL airtight jars and oxygen concentrations (µmol/L) were measured every minute for approximately 48-hours using a FireSting oxygen probe. Preliminary results demonstrate that cores held at 4°C had higher oxygen consumption rates (mmol O2 m-2 day-1) than those held in the -1°C incubator. A similar pattern was seen in the individual M. calcarea and E. tenuis, where individuals held at the higher temperature had a higher respiration rate. These results are consistent with previous studies conducted in the northern Bering Sea and the southeastern Chukchi Sea in July and indicate the potential for higher benthic carbon cycling with projected warming bottom water temperatures associated with climate warming.

Alaska Marine Science Symposium 2023 152

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