My research focusses on the trajectories of tropical marine communities under high temperature and eutrophic conditions.
Tropical coral reefs are going through fundamental changes due to increase seawater temperature and nutrient load. Most studies have focused on the coral-to-algae dominated shift. It has been observed that other relevant groups such as sponges and cyanobacteria can also dominate the system. However, the mechanisms and conditions under which these groups will dominate are poorly understood. The overall aim of this project is to understand how community dominance shifts through a temperature and nutrient gradient and identify tipping points and processes leading to those changes. Using the unique environments of marine lakes -islands of seawater- and reefs of Indonesia, we will look into the current and past trajectories of benthic organisms. The current and past community structure, and environmental settings will be analyzed using a multifaceted approach: photoquadrats, 3D models, species metabarcoding, environmental DNA, and sediment cores.
Keywords
Tropical reefs, marine ecology, photogrammetry, community structure, paleoecology
Projectdescription
In recent decades, concerns have been raised that coral reefs are shifting from coral-dominated states to systems dominated by macroalgae. Meanwhile there is growing evidence that other benthic groups are increasing in abundance on coral reefs, in particular sponges and benthic cyanobacterial mats (BCMs, dense mats of diverse microbial consortia dominated by cyanobacteria).
Given global trends in increased water temperatures and eutrophication due to coastal development and runoff, BCMs and sponges may be more resilient to environmental change than corals, or even macroalgae, leading to possible shifts of dominance. The overall aim of this project is to understand how tropical marine species communities respond to past and current environmental change and identify possible shifts in dominance of benthic groups related to temperature and eutrophication gradients. Using a multifaceted approach including photogrammetry, genomics, and water quality analysis, I will study current and past benthic distribution patterns and dynamics of whole communities through three main components: Marine lakes: discrete marine communities replicated over space, under similar degrees of eutrophication while each lake differs in temperature, representing natural states of future climate change scenarios; Coral Reefs: natural eutrophication gradient, caused by runoff and other human activities, while maintaining similar temperatures among sites; Sediment cores: window into past biodiversity dynamics, as paleolimnology provides a useful approach to study how diversity has shifted over time and under what circumstances. Through our field-validated data, we will identify feedbacks and conditions that can set the stage for large community fluctuations under future scenarios predicted for climate change.
Keypublications
- Kornder N.A., Cappelletto J., Mueller B., Zalm M.J.L., Martinez S.J., Vermeij M.J.A., Huisman J., de Goeij J.M. 2021. Implications of 2D versus 3D surveys to measure the abundance and composition of benthic coral reef communities. Coral Reefs 40, 1137-1153. https://doi.org/10.1007/s00338-021-02118-6
- Martinez S.J., Cavada-Blanco F., Cappelletto J., Agudo-Adriani E., Croquer A. 2021. Distribution, abundance, and health indicators of the critically endangered coral species Acropora cervicornis in Los Roques National Park, 2014. Advances in Oceanography and Limmnology 12(2). https://doi.org/10.4081/aiol.2021.10005
- Cavada-Blanco F., Cappelletto J., Agudo-Adriani E., Martinez S.J., Rodriguez J.P., Croquer A. 2020. Status of the pillar coral Dendrogyra cylindrus in Los Roques National Part, Southern Caribbean. bioRvix. https://doi.org/10.1101/2020.09.15.297770