Elevated CO2 Levels do not Affect the Shell Structure of the Bivalve Arctica islandica from the Western Baltic

摘要

Shells of the bivalve Arctica islandica are used to reconstruct paleo-environmental conditions (e.g. temperature) viaudbiogeochemical proxies, i.e. biogenic components that are related closely to environmental parameters at the time of shelludformation. Several studies have shown that proxies like element and isotope-ratios can be affected by shell growth andudmicrostructure. Thus it is essential to evaluate the impact of changing environmental parameters such as high pCO2 andudconsequent changes in carbonate chemistry on shell properties to validate these biogeochemical proxies for a wider rangeudof environmental conditions. Growth experiments with Arctica islandica from the Western Baltic Sea kept under differentudpCO2 levels (from 380 to 1120 matm) indicate no affect of elevated pCO2 on shell growth or crystal microstructure,udindicating that A. islandica shows an adaptation to a wider range of pCO2 levels than reported for other species.udAccordingly, proxy information derived from A. islandica shells of this region contains no pCO2 related bias.