10.33591/NIOZ/EITBIE
Francisco, Flavio
Flavio
Francisco
Digital Object Identifier from Automated Test
NIOZ Royal Netherlands Institute for Sea Research
2019
NIOZ Royal Netherlands Institute for Sea Research in cooperation with Utrecht University
CC0 1.0
Asymmetrical morphological features are dynamic, given their migration rates, dimensions and flow separation that can occur at the lee slopes exceeding certain angles. Thus, the behavior of these bedforms, which include many tidal sand waves, are challenging to understand. Most experimental investigations regarding asymmetrical bedforms and behavior consider the riverine environment, and scarcely any information is available on sediment compositional changes along asymmetrical tidal sand waves despite their abundance offshore. Thus, Aan asymmetrical sand wave field located off the coast of the Island Texel in the North Sea. A research cruise was investigated undertaken in June and October 2017 to account for any intra - and inter - seasonal variability. Sediment samples were collected along a single transect that covered five complete sand waves to measure grain size characteristics composition and sediment permeability over at the different sections of the sand waves (e.g., trough, crest, stoss and lee slopes) of 4 sand waves. We found significant variations in both sediment parameters between these four units, with a difference in permeability of more than 2-fold in both seasons, as well as the range in median grain size exceeding 65 ??m., The morphological unitswhich can further be divided into two distinctdiscrete groups: stoss/crest and lee/trough. These results indicate a distinct sediment sorting process along the Texel sand waves over small spatial scales, which has could have large implications for biogeochemistry and benthic species distribution in these tidal sand wave fields.