SPP 527 - Subproject: Controls on stable isotope fractionation of alkaline earth metals in cultured corals

Basic data for this project

Description

The chemical and isotopic compositions of coral skeletons are well considered archives for paleoenvironmental reconstructions, since important knowledge about dynamics of past climate change is derived from coral-based records. However, there are still open questions regarding biomineralisation and element incorporation into the coral hard tissues. Recent developments in the analysis of stable isotope ratios of metals offered the opportunity to gain further insights into biomineralisation. While initial results on Ca, Mg and Sr stable isotope fractionation in corals indicate promising fractionation patterns in response to environmental changes like temperature and carbonate chemistry as well as new insights into biomineralisation, more systematic work is required to better understand the processes governing element and isotope fractionation mechanisms and to allow for a reliable exploitation as paleo-environmental indicator. Our understanding would benefit in particular from work on samples grown under well-defined environmental conditions, like for instance from laboratory cultures. In this project we plan to conduct systematic empirical calibrations on stable isotope fractionation of the alkaline earth metals Ca, Mg and Sr in corals grown in controlled laboratory experiments. Based on these results we will develop a model for element and isotope fractionation processes in corals. In a further step our findings will be validated on recent and fossil environmental samples.