Satellite monitoring of the Black Sea ecological risk areas

Abstract

Results of multiyear monitoring of zones of persistent ecological risk in the Black Sea are presented. These ones are most affected by oil pollution, raised concentration of suspended particulate matter and harmful algae bloom. Studies are based on satellite remote sensing data obtained over the Black Sea from 2000 to 2017 from radar sensors ERS-2 SAR, Envisat ASAR, Sentinel -1A, -B, Radarsat 2, TerraSAR-X; visible and infrared data from Envisat MERIS, Landsat-5 TM, Landsat-7 ETM+, Landsat-8 OLI, MSI Sentinel-2A and Terra/Aqua Modis. An analysis of radar data indicated areas most affected by ship spills of bilge waters. Greatest polluted area were found along the main ship routes, near biggest ports and at sites of anchor positions. It is necessary to separate anthropogenic oil pollution and oil-containing slicks caused by natural hydrocarbon seeps including mud volcanoes, natural gas and oil outflows from the sea bottom, and gas hydrates. The geographical distribution of these slicks is defined by their permanent locations that well correlate with locations of natural hydrocarbon seeps from the sea bottom in this region. Areas characterized by increased concentration of suspended particulate matter were revealed at maps compiled from Envisat MERIS, MSI Sentinel-2A data and Landsat colour composites. Among the most notable ones are river plume zones, first of all, those of the Danube River and mountain rivers of Georgia. Results of satellite data processing were used for detecting impacts of various natural factors, such as precipitation, rivers flows, wind-driven water circulation and vortex activity, on suspended matter proliferation. Mapping of zones of maximum propagation of suspended solids in different seasons was performed for the examined areas. Eutrophication has recently become a very important problem worldwide. It is true also for the Black Sea, especially for its western part.