Sediments and functional traits: Applying a functional trait approach to assess marine macrobenthic function

In this doctoral thesis, I investigate how the ecological function of sediment-living animals, such as cockles and worms, is affected by environmental pollution, changes in their habitat, and the arrival of new species. The functions of the sediment-living organism are important for ecosystems such as the Wadden Sea since they can affect the substrate properties and also are an important food source for birds and fishes. To investigate their function, I analyzed what kind of animal characteristics (a.k.a biological traits), like behavior and body shape, are related to different environmental conditions, such as polluted and non-polluted sites. I found out that analyzing the diversity of biological traits can give you a lot of new information about what is going on in marine ecosystems. The main conclusions of my thesis are: (1) Analyzing animal traits can improve your ability to detect the harmful effects of marine pollution; (2) Environmental variation like changes in seagrass densities can greatly affect the kinds of biological traits you can find in marine sediment-living communities; (3) With the arrival of new species, completely new biological traits can be introduced in sediment-living communities; (4) Some species also can affect the function of other organisms by facilitating their occurrence. For example, seagrasses favor the occurrence of burrowing shrimps and worms. In short, focusing on biological traits can give you an informative picture of the functioning of sedimentary marine ecosystems like the ones we have in the Wadden Sea.