TO BREAK OR NOT TO BREAK: THE IMPACTS OF CLIMATE CHANGE ON SKELETAL FUNCTION OF MARINE CALCIFIERS (Invited Presentation)

The skeletons of marine calcifiers providing protection against the elements and predation. The 3D structure is a response to the environment in which these organisms grew and therefore may be altered by many environmental parameters. For example, in coralline algae, temperature and light availability affect growth rates, cellular structure and mineral chemistry (Mg/ Ca ratios), while physical parameters such as wave exposure are known to affect the overall 3D morphology. Therefore, skeletons are able to record past environments via their incremental growth or chemical composition. Assessing internal cellular structure and mineral chemistry changes in the skeleton provides an insight into how calcification of these organisms might be impacted by future climate change.

What is often overlooked is how changes to the skeleton may affect the function of the species in the ecosystem. For habitat forming marine calcifiers, like corals and coralline algae, their 3D structure and subsequently the structural integrity is vital to their ecosystem function.

Finite Element Analysis (FEA) allows us to assess form and function within biological organisms, by computing stress and strain within a model to points of failure. Using FEA, the internal structure of marine calcifiers such as coralline algae and benthic foraminifers have been interrogated for their response to global change. By applying this technique to the geological record, alteration of ecosystem function of these key habitat builders in response to environmental changes during the Palaeocene Eocene Thermal Maximum (PETM) have been assessed. Results show for coralline algae that increasing temperatures and CO₂ concentrations causes calcifying organisms to form weaker skeletons. Yet, large differences in skeletal function between contemporary species suggests that some species will be worse affected by future climate change, highlighting the importance of species-specific responses. By analysing changes in the internal structure, we can link changing environments to structural integrity and ultimately the ability to support biodiversity.