University of Amsterdam
Research
Research in my lab focuses on how climate and environmental change impact reef-building corals. Coral reefs are biodiversity hotspots of immense socio-economic importance; yet, warming and acidifying oceans as well as environmental degradation severely threaten reefs and the ecosystem services they provide for millions of people worldwide. By integrating eco-physiological, stable isotope, trace element and biogeochemical analyses, we aim to provide insights into the mechanisms and traits that enable resistance to multiple climate change stressors and promote the adaptive capacity of corals in a changing ocean.
Multiple climate change stressors
Coral reefs are highly sensitive to multiple climate change stressors. Ocean warming and marine heatwaves lead to coral bleaching which can cause coral mortality on regional to global scales. At the same time, ocean acidification reduces the calcification rates of many coral species, impacting the ability of reefs to grow and keep up with sea level rise. Last but not least, low dissolved oxygen events (hypoxia) represent an emerging threat to coral reefs because they can ‘suffocate’ corals and other reef organisms, leading to tropical dead zones. While the individual impacts of ocean warming and acidification are well-studied, the effects of hypoxia on coral physiology remain largely unknown. Furthermore, these stressors do not occur in isolation and both bleaching and hypoxia events are increasing under climate change. Our research therefore focuses on the impacts of combined and repeated stressors on coral health and resilience.
The role of environmental history
The environmental history of organisms strongly influences their resistance to abiotic stress, including climate change, yet this is rarely taken into account when predicting coral responses to future climate scenarios. Environmental variability, in particular, has the potential to increase organism resistance to stress but this mechanism is poorly understood in corals. While there is strong evidence that variable environments increase coral heat and often also acidification tolerance, this is unknown for hypoxia tolerance. In addition, environmental variability does not always increase stress tolerance and can even have negative effects but the underlying reasons are largely unknown. We therefore investigate how multiple co-varying stressors affect coral resistance to heat, acidification and hypoxia and which variability regimes are most effective in increasing coral stress tolerance. To do so, we compare populations across strong environments gradients in the field and expose them to controlled stress tests and different variability regimes in lab-based mesocosm experiments.
Extreme reef environments as natural laboratories
Extreme reef environments can serve as natural laboratories to study how corals respond to extreme temperature, pH and dissolved oxygen levels, including those predicted to occur under future climate scenarios. In contrast to laboratory experiments, they provide the opportunity to investigate how corals can gain tolerance to suboptimal environmental conditions in situ and over ecologically realistic time scales. These extreme environments include locations where corals persist under chronic extreme conditions, such as reefs occurring near CO2 vents, or under highly fluctuating conditions where regular exposure to environmental extremes is punctuated by periods of relief. Our research takes place in extreme reef environments in both the Indo-Pacific and the Caribbean, such as macrotidal reefs in NW Australia and semi-enclosed bays in Curaçao and Bocas del Toro, Panama.
Other research interests
Phenotypic plasticity and its role in facilitating resistance to climate change
Fitness trade-offs involved in coral multi-stress tolerance
Interactions between global and local stressors
Coral calcification mechanisms, particularly in the context of ocean acidification and warming
Coral skeletal geochemical proxies, especially boron-based proxies
