Coral-macroalgae interactions and productivity
The “biodiversity-productivity paradox” on coral reefs: Disentangling the influence of macroalgae on reef-building coral productivity
2020-2024: German Academic Scholarship Foundation / Studienstiftung des deutschen Volkes
Ph.D. Stipend of Jana Vetter, M.Sc.
Biodiversity and ecosystem productivity are closely linked. Coral reefs are the most biodiverse marine ecosystems making them productivity hotspots of ecological and economical significance. Importantly, high biodiversity alone does not always lead to high productivity (“biodiversity-productivity paradox”).
Anthropogenic stressors, in particular global warming and eutrophication have led to shifts from stony coral to the dominance of other organism groups (e.g., macroalgae), with negative consequences on species diversity and ecosystem services. Most research to date has focused on the competition for space between these two organism groups. But water mediated interaction effects between stony corals and macroalgae in shaping their productivity are largely unknown.
This project aims to measure physiological effects that are mediated without contact between stony corals and macroalgae. For this, we measure physiological responses (e.g., calcification, photosynthesis, and photosynthetic efficiency) and assess water mediated substances related to changes in the productivity of the organisms. In a second step, we will validate the aquarium findings through in situ measurements of coral-macroalgae communities in the coral reef. Based on measurements of reefs with different proportions of stony corals and macroalgae we will establish a productivity balance for coral reefs with contrasting ecological states (dominance of stony corals or macroalgae). The results will lead to a better understanding of the underlying biotic interactions in contrasting biodiversity-productivity scenarios.
Listen to the german project description by Jana Vetter:
Hören Sie sich die deutsche Projektbeschreibung von Jana Vetter an:
- 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.