7 - PhD-exchange for Hilde Cecilie Trannum

At Laboratoire d'Océanologie Biologique de Banyuls there has been developed a new experimental approach to measure sediment reworking rates in two dimensions with a high degree of time resolution. The technique is based on thin aquaria, luminophores, time lapse photography and image analysis. We want to apply this technique to investigate how drill cuttings have the potential to change the bioturbation-potential of selected species. Earlier studies have suggested that changes in the sediment reworking rat e of the entire community largely result from changes in the sediment reworking rate of a few dominant species. Thus, bioturbation experiments on single species will contribute highly relevant information on the particular mechanisms that are responsible for effects of drill cuttings on benthic species, and would be a highly valuable supplement to the experiments on community level that have been carried out so far in the project. The setup also offers an opportunity to study temporal changes in the biotu rbation potential of benthic species after a discharge has taken place. This information may then be used in parameterization of the ParTrack-model, in addition to its value in its own right.