Establishing the Lifespan of the Marine Bivalve, Astarte borealis, From the White Sea, Russia using Isotope Sclerochronology: Implications for Biological Consequences of Climate Change

Shells of the marine bivalve, Astarte, are uniquely suited to investigate links between environmental/climate change and biological consequences because of their change in size and biogeographic distribution through time. For example, are their corresponding changes in lifespan and biogeographic distribution depending on warm vs. cold climate states? Does warm vs. cold climate state result in longer or shorter lifespans? Early studies of Astarte have documented a decrease in shell size through geologic time. Modern specimens are much smaller than those from mid-Pliocene at similar latitudes. To begin to approach this question of changing lifespan through time, we must first decipher ontogenetic changes in shell growth of modern specimens. Data collected using isotope sclerochronology on modern specimens of Astarte borealis from the White Sea, Russia indicate that individuals have an average age of 32 years (± 5.6 years) with a maximum of 47 years (± 2.5 years). Non-annual disturbance lines have also been found in the outer layer of the shell and their identification allows for more accurate age counts.