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

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

The action “UNBIAS: UNravelling BIvAlve Shell Chemistry” aims to improve our understanding of the mineralization of mollusk shells and how shell composition can function as an archive of changes in the shallow marine environment. Shells and skeletons of marine organisms (such as corals or mollusks) are widely used as archives for reconstructing climate and environmental change in Earth’s past. These carbonates preserve in rocks, serving as “time capsules” containing information on climate millions of years ago. Mollusk shells are particularly suitable for this because, like tree rings, they grow incrementally, depositing layers of carbonate. The composition of these layers reflects the environment in which the animals grew and how that environment changed throughout the seasons or even at the scale of days. This type of information is exceedingly rare in geology, since most rocks and minerals grow very slowly and therefore only yield information on a timescale of thousands to millions of years. We can therefore take “snapshots” of climate and environment from fossil shells of animals that lived during warm periods in the past to learn about the effect of global warming on our seasons or even on weather phenomena. These highly precise climate reconstructions help us to create better models for projecting climate of the future and informing policymakers about the effects of anthropogenic climate change under various future climate scenarios. However, we do not know precisely how mollusks build shells and how their shell composition depends on the environment. Therefore, UNBIAS tests new methods to characterize the chemistry of mollusk shells and link changes in this chemistry to variability in their environment. Through a combination of growth experiments, in which modern bivalves (e.g. mussels, oysters and cockles) are grown under controlled conditions, and chemical measurements in fossil bivalve shells from past greenhouse periods, UNBIAS aims to improve our understanding of shell formation in mollusks and subsequently apply the lessons learned from modern mollusks to produce more accurate reconstructions of climate in the past.

Data: CORDIS, © European Union