Russian Arctic - environmental geology and coastal processes
Dr. Daria Ryabchuk
The marginal seas of the Russian Arctic – Barents, White, Kara, Laptev, East Siberian and Chukchi seas – cover an area (about 4 620 000 km2). Among the main environmental geological problems of the area permafrost melting (in contest of methane emission and its impact on climate change), coastal erosion (especially high-rate thermal erosion) and local sediment pollution should be mentioned. The entire coast east to the Pechora Sea (eastern Barents Sea) is located in the permafrost zone. Offshore, areas of continuous, discontinuous and insular submarine permafrost can be observed. Acceleration permafrost melting leads first of all onshore but also offshore to increasing methane emission, and problem of coastal erosion The total length of Russian Arctic marginal seas’ coastline is about 40000 km (24200 km shoreline of mainland and 14100 km of islands). More than 15000 km (or 38%) are eroding and retreating. On coasts composed of easily erodible Quaternary deposits (the Laptev Sea, the East Siberian Sea, the northern coast of Yamal Peninsula in the Kara Sea) the rate of shoreline retreat reaches 3-12 m/year as a result of thermal erosion. Shores consisted of unconsolidated sediments within permafrost areas show the highest erosion rates (up to 15-20 m/year). Since 2011, the Russian Research Geological Institute (VSEGEI) has conducted nearshore and coastal monitoring of White Sea and the Russian parts of the Barents and the Baltic Sea. Result of monitoring show close links between offshore geology, tectonics, and geomorphology with trends and rates of coastal erosion/accumulation. Uplifting coasts of Western Barents and White Sea located within Baltic Crystalline Shield do not suffer from coastal erosion, contrary to coast of Pechora Sea. It is important to mention, that coastal geological hazards can be considered to be climate-dependent, with a comprehensive understanding of the main trends of climate change being important for prediction and mitigation of future damage to coastal infrastructure and the elaboration of adaptation strategies. Coasts and bottom sediments of Western Arctic are higher polluted compared to Eastern Arctic where coast and sediment pollution can be observed just within local “hot spots”. In general, marine and coastal environment of the Eastern Russian Baltic Sea demonstrate low level of contamination. One of the most polluted areas in the Russian Arctic is a Kola Bay, where all kind of technogenic objects (from sunken vessels to household waste) can be found, and the bottom sediments are loaded with very high concentrations of hazardous substances, e.g. heavy metals.
