Event Website
http://www.bates.edu/mt-david-summit.xml
Start Date
1-4-2011 1:45 PM
End Date
1-4-2011 3:00 PM
Description
Bivalve shells record environmental conditions during shell deposition. We determined the growth history of the commercially important soft-shell clam Mya arenaria by examining annual lines in the chondrophore and related interannual variation in growth to regional and local environmental conditions. In addition to annual growth lines it is also possible to observe annual spawning checks; differentiating between these lines increases the resolution with which we detect interannual growth variation. We collected M. arenaria from Maquoit Bay, Maine, and used them to create an annual index of growth for 21 years, 1990 to 2011. M. arenaria growth over time can be modeled using the Von Bertalanffy growth function. Pairing each modeled year of growth to its corresponding measured year of growth allows us to correct for ontogenetic variation and generate a Standard Growth Index. We then related variations in growth to regional climate oscillations such as the North Atlantic Oscillation and local factors such as air temperature, water temperature, and precipitation. Preliminary results suggest summer air temperature is the best predictor of M. arenaria growth rates, responsible for about two thirds of interannual growth variation, while precipitation has no significant effect on growth. Once the relationships between environmental conditions and M. arenaria growth are established and quantified, we can use fossil specimens to reconstruct past environmental conditions.
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Interannual Growth Rate Variation in the Soft-Shell Clam, Mya arenaria, and Its Relationship to Temperature Differences at Maquoit Bay, ME
Bivalve shells record environmental conditions during shell deposition. We determined the growth history of the commercially important soft-shell clam Mya arenaria by examining annual lines in the chondrophore and related interannual variation in growth to regional and local environmental conditions. In addition to annual growth lines it is also possible to observe annual spawning checks; differentiating between these lines increases the resolution with which we detect interannual growth variation. We collected M. arenaria from Maquoit Bay, Maine, and used them to create an annual index of growth for 21 years, 1990 to 2011. M. arenaria growth over time can be modeled using the Von Bertalanffy growth function. Pairing each modeled year of growth to its corresponding measured year of growth allows us to correct for ontogenetic variation and generate a Standard Growth Index. We then related variations in growth to regional climate oscillations such as the North Atlantic Oscillation and local factors such as air temperature, water temperature, and precipitation. Preliminary results suggest summer air temperature is the best predictor of M. arenaria growth rates, responsible for about two thirds of interannual growth variation, while precipitation has no significant effect on growth. Once the relationships between environmental conditions and M. arenaria growth are established and quantified, we can use fossil specimens to reconstruct past environmental conditions.
http://scarab.bates.edu/mt_david_summit/MDS2011/02Poster/5