Exploring biological influence on offshore sandwave length

Biological activity at the seabed is known to have a significant influence on bottom dynamics and morphology. This paper explores the influence of biological activity on sand wave dimensions by adapting the input parameters of an idealized sandwave model (Besio et al., 2006). Once the prediction capability of the model is analyzed by means of a comparison of the theoretical predictions with different field data in the Belgium Continental Shelf, the values of the physical parameters are changed (the critical bed shear stress is lowered because of the burrowing activity of surface deposit feeders and the ripple height is lowered because of tube building worms) and the trends of the wavelength as function of the parameters are analyzed. The results show that the predicted wavelengths are closer to the observed values if biological activity is included in the model. Once the significant influence of biological activity on sandwave dimensions is shown, future research should focus on a better parameterization of biological activity in order to improve the reliability of the long-term morphodynamic predictions, especially in marine environments with large biological activities.