Dynamical carbonate depositional system of the Exumas, Bahamas | Photo: Hildegard Westphal

The effect of environmental change

Most modern tropical marine ecosystems are strongly oligotrophic and are dominated by photosymbiotic and photic organisms accompanied by heterotrophic organisms. Observed and predicted disturbances of such ecosystems by eutrophication, acidification, and other factors, are known or assumed to shift the biological community towards a different equilibrium. This has consequences on the ecosystem services coastal protection and habitat provision. In order to gain a better understanding of the effects of changing environmental parameters, field studies are being undertaken in areas of natural or anthropogenic extremes. These field studies serve as analogues for scenarios predicted for the future. They are complemented by laboratory experiments in the MAREE where single or combined parameters are changed under controlled conditions.

Regional and global environmental changes are altering the chemistry of the ocean, sometimes at rates exceeding those in historical and recent geological records. These alterations may affect the health of marine organisms, and may lead to shifts in biological communities which can manifest in changed sedimentation patterns.

Carbonate secreting organisms play an important role in tropical ecosystems as they are able to shape their environment by building frameworks and providing habitats. Their role in coastal protection and for resource management is essential in particular in densely populated coastal areas. The carbonate sedimentology group focuses on the effect of environmental change on calcification and carbonate sediment production. Also we use carbonate sediments as archives of the biotic composition of ecosystems in order to characterize the status and the change of such systems.

Environmental changes in tropical ecosystems, especially in densely populated areas, also include increased inputs of pollutants from different sources such as industries and oil spills. We analyse organic pollutants and heavy metals in water, sediments and marine organisms in order to also characterize the pollution status of tropical coastal and marine ecosystems.