Monthly Member Meetings

Reading clams like tree rings: what bivalve shells can tell us about the world

               Just like trees, the shells of bivalve mollusks (like clams, oysters, and scallops) grow sequentially, and their growth rings can be studied to understand the past environment. Growth increments can be deposited yearly, fortnightly (every two weeks), daily, or sub-daily.  The isotopic and trace elemental chemistry of the growth rings can change subtly through time, reflecting environmental conditions during growth. Growth rates and shell chemistry have been analyzed in a variety of species to reconstruct marine paleoenvironments, like North Atlantic Ocean temperature and productivity over hundreds of years, as well as sea ice dynamics in Antarctica. Shell growth and chemistry can also provide insight into human behavior like seasonality of diets at archeological sites and can be used to verify the origins of commercial shellfish harvesting.

                Dr Kelly Cronin will share with us her studies of modern Molluscan studies in North Carolina as well as her sclerochronology of Antarctic scallops. She is an Assistant Professor of Geology at Perimeter College of Georgia State University.

Images below are of molluscan shells from the Environmental Archaeology web pages from the Florida Museum of Natural History about Sclerochronology,

https://www.floridamuseum.ufl.edu/envarch/research/methods/sclerochronology/