Quasi-Permanent Sources of Film Pollution of the Sea Surface in the Sea of Marmara

The work examines the manifestation of quasi-permanent sources of oil slick structures in the Sea of Marmara based on analysis of Sentinel-1 C-SAR radar and Sentinel-2 MSI and Landsat-8, -9 OLI optical satellite data. An area of regular occurrence of these sources in the northwestern part of the water area was identified, and the slick structures associated with them were mapped using radar images. A comparison of the discovered slicks with the topography of the seabed of the study area was carried out and it was noted that their most frequent manifestation is observed in the zone of the depth slope and above the plateau between deep-sea basins, which corresponds to the data of acoustic sounding of gas intrusions. Typical forms of manifestation are considered, and estimates of spatial characteristics of slick structures and their maximum lifetime are made. Based on the results of the analysis of optical satellite images, examples are given with changes in the reflectance of the water–film system. For a case with optically “thick” film, a method for estimating the volume of contamination is proposed.