Impact of the climate change on hydrodynamic seabed stressors

How will climate change affect the composition of the seabed? Ongoing climate change impacts nearly every area of our oceans. While coastal impacts of flooding and erosion are well studied, less attention has been paid to the impact of increased storminess and regional sea level rise on the seafloor, its sediments, and the benthic habitats which rely on it. Making use of a set of 3D hydrodynamic and wave models, and CMIP5 climate projections, we investigate and quantify the drivers of seafloor stresses. Our study maps the potential for grain size mobilisation in current and future projections, highlighting areas where seabed composition is likely to change in future. Sea level rise not only alters absolute water depth but also modifies current stresses by shifting the phase and magnitude of the tides. Rising sea levels also reduce exposure of the seabed to ocean waves. However, increased storm intensity in a warming world will lead to more frequent periodic disturbance of an otherwise increasingly immobile seabed. These predicted changes and their expected impact on the benthic environment are discussed in the context of the increasing anthropogenic activity in the marine environment and the associated challenges in marine spatial management.