Print Email Facebook Twitter Predicting the survival of coral reefs Title Predicting the survival of coral reefs: A biophysical modelling approach Author Hendrickx, Gijs (TU Delft Civil Engineering and Geosciences) Contributor Herman, Peter M. J. (mentor) Dijkstra, Jasper (mentor) Pietrzak, Julie (graduation committee) Luijendijk, Arjen (graduation committee) Degree granting institution Delft University of Technology Programme Civil Engineering | Hydraulic Engineering Date 2020-04-16 Abstract KEY POINTS (I) A biophysical model framework (BMF) for corals is developed in which four environmental factors are included: (1) light; (2) hydrodynamics; (3) temperature; and (4) acidity. (II) The full feedback loop between corals and their environment forms the core of this model framework, where the morphological development is new and closes the feedback loop. (III) The developed BMF predicts the coral response to environmental input via (mainly) process-based relations within the accuracy of climate projections. (IV)- The BMF supports both the deep reef refugia hypothesis and the turbid reef refugia hypothesis. (V) The BMF contributes to the development of protection and recovery programs and is not site-specific. (VI) The BMF is developed for long-term predictions - in the order of decades to centuries - but runs on daily averages and is therefore applicable for assessing the response of corals on shorter time-scales; such as months to years. SUMMARY The increasing pressure on Earth’s ecosystems due to climate change becomes more and more evident. These pressures are especially visible at coral reefs. Therefore, a good understanding of the biophysical mechanisms controlling these ecosystems is needed, so that accurate predictions of their survival can be made. Such an understanding is also needed to develop efficient recovery and protection programs vital to the maintenance of these ecosystems. Because the research on marine ecosystems is relatively young and the phenomenon of coral bleaching is yet to be fully understood, there is no comprehensive framework in which the complex interactions between corals and their environment are combined. In this study, a biophysical model is developed in which four environmental factors are included in a feedback loop with the coral’s biology: (1) light; (2) hydrodynamics; (3) temperature; and (4) acidity. Literature from multiple disciplines is combined to find the interdependencies between the corals and their environment. These relations include coral growth, coral bleaching, storm damage, and recruitment/recolonization of corals. For the connection with the hydrodynamics, a coupling is made between the biological model developed here and Delft3D-FM. The composed biophysical model is a big leap forward in understanding the world of coral reefs, as it is the first construction of a model framework including four environmental factors in which the hydrodynamics are included in the feedback loop. Furthermore, it creates the ability to assess recovery and protection programs based on the four aforementioned environmental factors; e.g. the susceptibility of coral bleaching can be reduced by increasing the attenuation of light through the water column. Because more environmental factors have a role to play in the coral dynamics, the framework is constructed such that these can be added relatively easily. Subject Biophysical modelCoral reefsProcess-based modellingDelft3D flexible mesh To reference this document use: http://resolver.tudelft.nl/uuid:e211380e-3f92-4afe-b371-f1e87b0c3bbd Part of collection Student theses Document type master thesis Rights © 2020 Gijs Hendrickx Files PDF 20200409_Thesis_online.pdf 35.75 MB Close viewer /islandora/object/uuid:e211380e-3f92-4afe-b371-f1e87b0c3bbd/datastream/OBJ/view