Study of permafrost formations degradation in East Siberia coastal zone (subsequent to the results of expeditions of 2014–2016)

• Main Authors: M. N. Grigoriev, М. Н. Григорьев
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Государственный научный центр Российской Федерации Арктический и антарктический научно-исследовательский институт 2017
• Subjects: НИС «Остров Самойловский»; East Siberian Sea; submarine permafrost; ice-covered banks thermoabrasion; export of organic matter; retreat of the shore; the research station “Ostrov Samoilovsky”; Восточно-Сибирское море; подводная мерзлота; льдистые берега; термоабразия; вынос органического материала; отступление берегов; Laptev Sea; Arctic; Ice; laptev; lena river; permafrost; Siberia
• Online Access: https://www.aaresearch.science/jour/article/view/103; https://doi.org/10.30758/0555-2648-2017-0-1-89-96

The noticeable changes in cryological complex (submarine permafrost formations, ice-covered banks) in the coastal zone of the Laptev and East Siberian Seas are accompanied by export of organic matter into the sea. The degradation of subaqueous permafrost formations roof rock has been observed. The average cover rate fall for the entire period of thawing is in the range of millimeters to 40 centimeters per year. Cryogenic relief-forming processes (termoabroziya, thermoerosion, etс.) on the Eastern Siberia Sea coast lead to a reduction of coastal land annually by 10–11 km2. The average rate of shore retreat is 5.1m / year and not more than 10m / year. The maximum values can reach 25 m / year. The acceleration of thermoabrasive shores destruction occurred in the period from 2000 to 2009. The sediment and organic matter flowing down to the Laptev Sea and East Siberian Sea is 62 and 90 million tons of precipitation and 1.6 and 2.4 million tons of organic carbon per year. The expedition studies in 2016 on the basis of the research station “Ostrov Samoilovsky” included drilling, GPR survey on the drilling profiles at the Lena River delta. Drilling depth is 24 meters. When drilling of underflow thawed soil through the water column of 7–9 m, the long-term (about an hour) methane outburst was observed.