Meeting Abstract
As the climate warms, organisms endure rapid environmental changes and are susceptible to physiological damage that may force them to modify their thermal limits by either shifting their range distributions or being outcompeted by other species. Marine intertidal organisms, specifically, face unique challenges of oxygen limitation and aerial exposure, and it is up to us to understand how they might respond to such conditions and identify important biomarkers that can be used to recognize when an organism may be in jeopardy. Heart rate, is one physiological response, that is well-studied for investigating whole-organismal responses and can explain an organisms critical thermal limit. Furthermore, measurements of enzymatic activity of lactate dehydrogenase (LDH) can infer anaerobic metabolism and be indicative of stress. Thus, we hypothesize that the cardiac performance and subcellular activity of the invasive Mediterranean mussel (Mytilus galloprovincialis) will increase as temperature increases in both intertidal and subtidal populations. While exposing subtidal and intertidal mussels to varying temperatures (8-28 °C) at a ramping rate of 4 °C hr-1 we measured heart rate every hour and assessed LDH activity for each temperature treatment. For the submerged subtidal population of mussels, preliminary data suggests heart rate slowly increases as seawater temperature increase, while aerial exposed mussels reached a maximum rate at 12-16 °C. These measurements will begin to elucidate whether organisms have the capacity to deal with a changing climate and the physiological mechanisms that drive whole-organismal responses, while providing additional insight into the possible mechanisms that allow this non-native species to tolerate vastly different habitats and outcompete native species.
