Reconstructing ultra-high resolution climate variability and symbiont bleaching in tropical corals: from past to present (EPIBLEACH II)

Figure 1: The Ocean2100 coral aquarium facility at Justus Liebig University Giessen (PI: Ziegler) that will be leveraged in EPIBleach II to expose corals to fully controlled simulated bleaching conditions.

The EPIBleach project aims to identify and test geochemical proxies of coral bleaching, to later apply these tools to fossil corals from our warm past periods. This research is motivated by the increasing occurrence and severity of bleaching events in tropical coral reefs, and brings together the expertise of three institutions: GEOMAR Kiel (PI. Anagnostou), Justus Liebig University Giessen (PI. Ziegler), and Senckenberg Research Institute and Natural History Museum Frankfurt (PI. Santodomingo). In EPIBleach II we focus on ground-truthing geochemical proxies of coral stress, bleaching, and resilience. Our first objective is to conduct controlled culture experiments that simulate long-term heat-driven coral bleaching and subsequent recovery from bleaching in a suite of key coral species typically used in both ecological and paleo-environmental studies, Porites and Stylophora. These experiments will allow us to explore variable geochemical responses to stress during coral bleaching, and to identify the most robust proxies to trace its progression. These proxies will then be applied to well-preserved corals from the Coral Triangle, spanning warmer geologic periods to further reconstruct heat stress, bleaching, recovery, and coral resilience through varying environmental conditions in the past. Our reconstructions will have two major contributions to the SPP2299/2: first, by reconstructing ultra-high resolution climate variability from tropical regions, including novel sub-seasonal marine records not previously explored; and second, by exploring the link between environmental/climatic change and reconstructed bleaching events in the past, as a function of background climate (e.g. Earth’s temperature), tropical coral species richness and coral diversification.

*Figure 2: Fossil corals of Miocene age (Indonesia): Porites specimen (left, scale 1 cm), corallites of Stylophora specimen under Scanning Electron Microscope (right, scale 1 mm).*

Principle Investigators

Eleni Anagnostou (GEOMAR, Kiel)

Maren Ziegler (Justus Liebig University Giessen)

Nadia Santodomingo (Senckenberg)

Project Scientist

N.N. (GEOMAR, Kiel)