气候变化领域集成服务门户(CCPortal): Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia

CCPortal

DOI	10.5194/tc-10-1449-2016
	Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia
	Paul Overduin P.; Wetterich S.; Günther F.; Grigoriev M.N.; Grosse G.; Schirrmeister L.; Hubberten H.W.; Makarov A.
发表日期	2016
ISSN	19940416
卷号	10 期号:4
英文摘要	Coastal erosion and flooding transform terrestrial landscapes into marine environments. In the Arctic, these processes inundate terrestrial permafrost with seawater and create submarine permafrost. Permafrost begins to warm under marine conditions, which can destabilize the sea floor and may release greenhouse gases. We report on the transition of terrestrial to submarine permafrost at a site where the timing of inundation can be inferred from the rate of coastline retreat. On Muostakh Island in the central Laptev Sea, East Siberia, changes in annual coastline position have been measured for decades and vary highly spatially. We hypothesize that these rates are inversely related to the inclination of the upper surface of submarine ice-bonded permafrost (IBP) based on the consequent duration of inundation with increasing distance from the shoreline. We compared rapidly eroding and stable coastal sections of Muostakh Island and find permafrost-table inclinations, determined using direct current resistivity, of 1 and 5%, respectively. Determinations of submarine IBP depth from a drilling transect in the early 1980s were compared to resistivity profiles from 2011. Based on borehole observations, the thickness of unfrozen sediment overlying the IBP increased from 0 to 14 m below sea level with increasing distance from the shoreline. The geoelectrical profiles showed thickening of the unfrozen sediment overlying ice-bonded permafrost over the 28 years since drilling took place. We use geoelectrical estimates of IBP depth to estimate permafrost degradation rates since inundation. Degradation rates decreased from over 0.4mg-1 following inundation to around 0.1g-1 at the latest after 60 to 110 years and remained constant at this level as the duration of inundation increased to 250 years. We suggest that long-term rates are lower than these values, as the depth to the IBP increases and thermal and porewater solute concentration gradients over depth decrease. For the study region, recent increases in coastal erosion rate and changes in benthic temperature and salinity regimes are expected to affect the depth to submarine permafrost, leading to coastal regions with shallower IBP. © 2016 Author(s).
学科领域	benthic environment; coastal erosion; coastal zone; deep drilling; geoelectric field; permafrost; sea level; sea surface salinity; shallow water; shoreline change; Arctic Ocean; Laptev Sea; Siberia
语种	英语
scopus关键词	benthic environment; coastal erosion; coastal zone; deep drilling; geoelectric field; permafrost; sea level; sea surface salinity; shallow water; shoreline change; Arctic Ocean; Laptev Sea; Siberia
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119620
作者单位	Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Potsdam, Germany; Mel'Nikov Permafrost Institute, SBRAS, Yakutsk, Russian Federation; Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation
推荐引用方式 GB/T 7714	Paul Overduin P.,Wetterich S.,Günther F.,et al. Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia[J],2016,10(4).
APA	Paul Overduin P..,Wetterich S..,Günther F..,Grigoriev M.N..,Grosse G..,...&Makarov A..(2016).Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia.Cryosphere,10(4).
MLA	Paul Overduin P.,et al."Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia".Cryosphere 10.4(2016).