UNBIAS · UNravelling BIvAlve Shell chemistry: Advanced Techniques for Accurate Reconstructions of Sub-annual Climate

An important part of climate variability takes place at the sub-annual to decadal scale. However, climate reconstructions mostly focus on long-term trends (thousands to millions of years), while data of past, fast and short-term changes is limited. To calibrate climate models and extend our knowledge of the causes and effects of rapid climate change, archives recording higher resolution climate change are needed. Contrary to sedimentary records, bivalve shells record environmental conditions at a resolution of days to months. Conventional climate proxies in bivalve shells (stable isotopes and trace elements) depend on multiple physiological and environmental parameters, complicating the reconstruction of individual climate parameters. UNBIAS aims to develop new, more accurate tools for absolute reconstructions of climate parameters on a sub-annual scale from bivalve shells. Parameters influencing climate proxies will be disentangled by combining state-of-the-art trace element and microstructure analyses with the new powerful carbonate clumped isotope method, which reconstructs absolute temperature. These techniques are applied directly on cross sections through shells of Arctica islandica, Ostrea edulis and Cerastoderma edule. First, more accurate climate proxies will be developed by applying this interdisciplinary approach on bivalves grown in monitored North Sea environments. After development, these new proxies will first be applied to reconstruct sub-annual climate and environmental change over the past 500 years, recording human impact on North Sea environments. Finally, fossil bivalve shell records from the warm Miocene epoch highlight the effect of global warming on short-term climate variability. UNBIAS provides me with interdisciplinary skills and expertise from specialized institutes in the Benelux and Germany. It will offer me unique chances to gain experience in teaching, professional network and outreach, thus greatly enhancing my career opportunies.