Interactions between soft and stony corals during phase shifts
The effect of soft corals and phase shifts on reef-building coral productivity – a negative feedback loop?
2020-2023: Heinrich-Böll Foundation / Heinrich-Böll Stiftung
Ph.D. Stipend of Kara E. Engelhardt, M.Sc.
Coral reef are among the most biodiverse ecosystems on Earth and they belong to the ecosystems most affected by climate change. Climate change and in particular global warming and marine heat waves have led to mass mortality of stony corals often resulting in so-called 'phase shifts', where the stony coral skeleton is overgrown by fast-growing opportunistic organisms like soft corals. However, it is largely unknown how indirect effects on productivity may lead to a negative feedback loop during phase shifts, when soft corals start to overgrow stony corals.
The main aims of this project are:
The results of this research will lead to a better understanding of the processes underlying phase shifts from stony coral-dominated reefs to the dominance of other organism groups such as soft corals. Further this research will deepen our understanding of the changes in productivity and energy transfer between competing organisms in coral reefs and help to uncover hidden feedback loops during phase shifts.
The main aims of this project are:
- To measure the interaction effects between stony corals & soft corals on their productivity during scenarios of simulated phase shifts
- To explore the role of contact-free mechanisms in mediating these interactions
- To measure the productivity of coral reefs with different proportions of stony corals and soft corals in order to establish a productivity balance for coral reefs and understand changes in productivity during phase shifts.
The results of this research will lead to a better understanding of the processes underlying phase shifts from stony coral-dominated reefs to the dominance of other organism groups such as soft corals. Further this research will deepen our understanding of the changes in productivity and energy transfer between competing organisms in coral reefs and help to uncover hidden feedback loops during phase shifts.
Highlighted publications
- Engelhardt KE, Vetter J, Wöhrmann-Zipf F, Dietzmann A, Proll FM, Reifert H, Schüll I, Stahlmann M, Ziegler M. 2023. Contact-free impacts of sessile reef organisms on stony coral productivity. Communications Earth & Environment 4:396. 10.1038/s43247-023-01052-5
- Wiederkehr F, Engelhardt KE, Vetter J, Ruscheweyh H-J, Salazar G, O’Brien J, Priest T, Ziegler M, Sunagawa S. 2025. Host-level biodiversity shapes the dynamics and networks within the coral reef microbiome. ISME Communications:ycaf097. 10.1093/ismeco/ycaf097.