Title
The potential of coastal ecosystems to mitigate the impact of sea-level rise in shallow tropical bays
Author
Keyzer, L.M. (TU Delft Environmental Fluid Mechanics)
Herman, P.M.J. (TU Delft Environmental Fluid Mechanics) 
Smits, B.P. (Deltares)
Pietrzak, J.D. (TU Delft Environmental Fluid Mechanics)
James, R.K. (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)
Candy, A.S. (TU Delft Environmental Fluid Mechanics; NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)
Riva, R.E.M. (TU Delft Physical and Space Geodesy)
Bouma, T.J. (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)
van der Boog, C.G. (TU Delft Environmental Fluid Mechanics)
Katsman, C.A. (TU Delft Environmental Fluid Mechanics)
Slobbe, D.C. (TU Delft Physical and Space Geodesy)
Zijlema, M. (TU Delft Environmental Fluid Mechanics)
van Westen, R.M. (Universiteit Utrecht)
Dijkstra, H.A. (Universiteit Utrecht)
Date
2020
Abstract
Shallow tropical bays in the Caribbean, like Orient Bay and Galion Bay in Saint Martin, are often sheltered by coral reefs. In the relatively calm environment behind the reefs, seagrass meadows grow. Together, these ecosystems provide valuable ecosystem services like coastal protection, biodiversity hotspots, nursery grounds for animals and enhancing tourism and fisheries. However, sea-level rise imperils these ecosystems and the services they provide because of changing hydrodynamic conditions, with potential effects on the interdependencies between these ecosystems. By means of a hydrodynamic model that accounts for the interaction with vegetation (Delft3D Flexible Mesh), the impact of sea-level rise (0.87 m in 2100) is investigated for three scenarios of future reef development (i.e. keep-up, give-up and catch-up). If coral reefs cannot keep up with sea-level rise, the wave height and flow velocity increase significantly within associated bays, with the wave height doubling locally in case of eroding reefs in our model simulations. Since the presence of seagrass strongly depends on the hydrodynamic conditions, the response of seagrass to the future hydrodynamic conditions is projected using a habitat suitability model that is based on a logistic regression. The spatial character of the bays determines the response of seagrass. In Orient Bay, which is deeper and partly exposed to higher waves, the seagrass will likely migrate from the deeper parts to shallow areas that become suitable for seagrass because of the surf zone moving landward. In contrast, the conditions for seagrass worsen in Galion Bay for the catch-up and give-up scenario; due to the shallowness of this bay, the seagrass cannot escape to more suitable areas, resulting in significant seagrass loss. It is shown that healthy coastal ecosystems are able to limit the change in hydrodynamic conditions due to sea-level rise. Therefore, preserving these ecosystems is key for ensuring the resilience of shallow tropical bays to sea-level rise and maintaining their ecosystem services.
Subject
Coral reefs
Habitat suitability model
Hydrodynamic modelling
Sea-level rise
Seagrass
Shallow tropical bays
To reference this document use:
http://resolver.tudelft.nl/uuid:d71ed57c-f1a1-44c5-8db1-f9e56fe0395d
DOI
https://doi.org/10.1016/j.ecss.2020.107050
ISSN
0272-7714
Source
Estuarine, Coastal and Shelf Science, 246
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2020 L.M. Keyzer, P.M.J. Herman, B.P. Smits, J.D. Pietrzak, R.K. James, A.S. Candy, R.E.M. Riva, T.J. Bouma, C.G. van der Boog, C.A. Katsman, D.C. Slobbe, M. Zijlema, R.M. van Westen, H.A. Dijkstra