Gulf of Alaska | Lower Trophic Levels MASTER’S POSTER PRESENTATION
Influence of glacial recession on high-latitude intertidal communities Presenter: Maddi Mcarthur , mgmcarthur@alaska.edu, University of Alaska Fairbanks Brenda Konar , bhkonar@alaska.edu, University of Alaska Fairbanks Schery Umanzor , sumanzor@alaska.edu, University of Alaska Fairbanks Julie Schram , jbschram@alaska.edu, University of Alaska Southeast
Climate warming is increasing the rate of glacial recession in high latitude coastal environments, which is likely having significant, ecosystem-wide impacts. As glacial cover declines, the resulting increase in sediment-laden freshwater entering coastal watersheds may also alter water temperature, salinity, dissolved oxygen, turbidity, photosynthetically active radiation, and carbonate chemistry. The goal of this study is to determine how receding glaciers impact high- latitude intertidal community variability via the response of a dominant ecosystem engineer, the Pacific blue mussel Mytilus trossulus . Evidence suggests that shifting environmental conditions associated with climate change may cause physiological stress on mussels, weakening the byssal threads that attach them to the substrate. If byssal threads weaken, a cascading effect could occur where their detachment results in a decrease in overall community resilience. This study’s objectives are to 1) examine the influence of glacial recession on mussel byssal thread tenacity in situ , and 2) determine if observed site-level differences in byssal thread tenacity are related to seasonal and interannual variation in intertidal community structure. This study is taking place within five watersheds experiencing 0-60% glacial cover, which all receive differing amounts of glacial meltwater input. In each watershed, the force required to remove individual mussels from the substrate by breaking byssal threads was recorded in summer 2022. To document seasonal and interannual intertidal community variability, biomass and percent cover data were collected from May to September 2019-2022. Preliminary results show site-level differences in mussel byssal thread tenacity, and that the site with the highest level of glacial influence contains mussels with the lowest byssal thread tenacities on average. Although site-level differences exist in intertidal community biomass seasonal and interannual variation, the site with the highest level of glacial influence experiences the least variability. These early findings provide insight into how mussels are influenced by glacial recession and improve our understanding of how entire intertidal communities respond to the same changing conditions.
Alaska Marine Science Symposium 2023 131
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