UNLOCKING NORTH ATLANTIC AND ARCTIC OCEAN CLIMATE DYNAMICS WITH SHELL GROWTH AND GEOCHEMISTRY IN NORTHERN NORWAY

Understanding of physical and chemical ocean/atmosphere dynamics in recent centuries is critical for refining global climate models and developing robust regional climate forecasts. Annually resolved and absolutely dated long-term records from the extratropical oceans are limited, contributing to an incomplete understanding of Arctic climate change. The development of such records, especially from polar regions, is therefore critical to improving our understanding of large-scale climate dynamics and interactions. The long-lived marine bivalve proxy, Arctica islandica, has vast potential to gain insight into the impacts of regional climate variability on benthic marine ecology in northern Norway. Specifically, we evaluate the potential to use shell growth and geochemical records derived from a master shell chronology as a proxy archive for marine climate conditions. Shells were collected live in 2009, 2013, and 2014 from the islands of Ingøy and Rolvsøy in 6 m water depth. A master shell growth chronology constructed from these shells documents highly synchronous shell growth at Ingøy during the last century. Combining shell growth information with oxygen isotope measurements collected from annual increments yields an annually-resolved, multi-proxy record of environmental conditions. A relatively strong inverse relationship is observed between the shell-based multiproxy record and North Atlantic sea surface temperatures (1972-2011). The spatial pattern of correlation resembles that of the North Atlantic Current, indicating that large-scale ocean surface current dynamics play a role in regulating ecosystem processes and thus shell growth in northern Norway. These results suggest that further development of the multiproxy record will be useful for understanding North Atlantic and Arctic climate variability for the past several centuries.