BEDFORMS, INTERNAL WAVES, AND SCOUR PROCESSES: MORPHODYNAMIC BEHAVIOR ON THE CONTINENTAL SHELF OF THE NORTHERN BLACK SEA

The Black Sea basin presents an ideal laboratory for investigating the morphodynamic interplay between response (morphology) and force (processes) associated with shelf sedimentation. Recent studies along the perimeter of the basin have documented the existence of a complex, heterogeneous seafloor composed varyingly of sand, gravel, silt, and clay. The patchwork seabed facies support acoustically sharp contacts between areas with large bedforms and adjacent areas with subdued morphology similar to sorted bedforms. The documentation of these phenomena is novel in the northern Black Sea. Similar bedform features have been documented in other Black Sea regions and hypothesized to be associated with paleoshorelines.

Of particular note is the apparent association between the occurrence of distinct, active bedform areas and a zone of breaking internal waves across the continental shelf. In this tideless basin, internal waves have been observed, but a direct observational link between the hydrodynamics (internal waves, wind waves, and currents) and the morphological responses (scour marks, ripples, and suspended sediment) has not been documented.

Various geophysical datasets are utilized to establish the spatial patterns of facies and bedform types in the area. In addition, a mini-benthic tripod, complete with an acoustic Doppler current profiler (ADCP), a rotary fanbeam sonar, and a conductivity-temperature sensor was deployed to record seabed dynamics in response to changing forcing conditions. Further morphological, hydrodynamic, and environmental characterization information comes from simultaneous autonomous underwater vehicle (AUV) surveys. Together the fixed tripod and mobile AUV datasets provide a complementary basis for deciphering the processes responsible for the observed seafloor morphology.