Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia

The warming trend in the Arctic region is expected to cause drastic changes including permafrost degradation and vegetation shifts. We investigated the spatial distribution of ice content and stable isotopic compositions of water in near-surface permafrost down to a depth of 1 m in the Indigirka Riv...

Descripción completa

Detalles Bibliográficos
Autores principales: Takano, Shinya, Sugimoto, Atsuko, Tei, Shunsuke, Liang, Maochang, Shingubara, Ryo, Morozumi, Tomoki, Maximov, Trofim C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6786563/
https://www.ncbi.nlm.nih.gov/pubmed/31600327
http://dx.doi.org/10.1371/journal.pone.0223720
_version_ 1783458087392247808
author Takano, Shinya
Sugimoto, Atsuko
Tei, Shunsuke
Liang, Maochang
Shingubara, Ryo
Morozumi, Tomoki
Maximov, Trofim C.
author_facet Takano, Shinya
Sugimoto, Atsuko
Tei, Shunsuke
Liang, Maochang
Shingubara, Ryo
Morozumi, Tomoki
Maximov, Trofim C.
author_sort Takano, Shinya
collection PubMed
description The warming trend in the Arctic region is expected to cause drastic changes including permafrost degradation and vegetation shifts. We investigated the spatial distribution of ice content and stable isotopic compositions of water in near-surface permafrost down to a depth of 1 m in the Indigirka River lowlands of northeastern Siberia to examine how the permafrost conditions control vegetation and microtopography in the Taiga–Tundra boundary ecosystem. The gravimetric water content (GWC) in the frozen soil layer was significantly higher at microtopographically high elevations with growing larch trees (i.e., tree mounds) than at low elevations with wetland vegetation (i.e., wet areas). The observed ground ice (ice-rich layer) with a high GWC in the tree mounds suggests that the relatively elevated microtopography of the land surface, which was formed by frost heave, strongly affects the survival of larch trees. The isotopic composition of the ground ice indicated that equilibrium isotopic fractionation occurred during ice segregation at the tree mounds, which implies that the ice formed with sufficient time for the migration of unfrozen soil water to the freezing front. In contrast, the isotopic data for the wet areas indicated that rapid freezing occurred under relatively non-equilibrium conditions, implying that there was insufficient time for ice segregation to occur. The freezing rate of the tree mounds was slower than that of the wet areas due to the difference of such as soil moisture and snow cover depends on vegetation and microtopography. These results indicate that future changes in snow cover, soil moisture, and organic layer, which control underground thermal conductivity, will have significant impacts on the freezing environment of the ground ice at the Taiga–Tundra boundary in northeastern Siberia. Such changes in the freezing environment will then affect vegetation due to changes in the microtopography of the ground surface.
format Online
Article
Text
id pubmed-6786563
institution National Center for Biotechnology Information
language English
publishDate 2019
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-67865632019-10-19 Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia Takano, Shinya Sugimoto, Atsuko Tei, Shunsuke Liang, Maochang Shingubara, Ryo Morozumi, Tomoki Maximov, Trofim C. PLoS One Research Article The warming trend in the Arctic region is expected to cause drastic changes including permafrost degradation and vegetation shifts. We investigated the spatial distribution of ice content and stable isotopic compositions of water in near-surface permafrost down to a depth of 1 m in the Indigirka River lowlands of northeastern Siberia to examine how the permafrost conditions control vegetation and microtopography in the Taiga–Tundra boundary ecosystem. The gravimetric water content (GWC) in the frozen soil layer was significantly higher at microtopographically high elevations with growing larch trees (i.e., tree mounds) than at low elevations with wetland vegetation (i.e., wet areas). The observed ground ice (ice-rich layer) with a high GWC in the tree mounds suggests that the relatively elevated microtopography of the land surface, which was formed by frost heave, strongly affects the survival of larch trees. The isotopic composition of the ground ice indicated that equilibrium isotopic fractionation occurred during ice segregation at the tree mounds, which implies that the ice formed with sufficient time for the migration of unfrozen soil water to the freezing front. In contrast, the isotopic data for the wet areas indicated that rapid freezing occurred under relatively non-equilibrium conditions, implying that there was insufficient time for ice segregation to occur. The freezing rate of the tree mounds was slower than that of the wet areas due to the difference of such as soil moisture and snow cover depends on vegetation and microtopography. These results indicate that future changes in snow cover, soil moisture, and organic layer, which control underground thermal conductivity, will have significant impacts on the freezing environment of the ground ice at the Taiga–Tundra boundary in northeastern Siberia. Such changes in the freezing environment will then affect vegetation due to changes in the microtopography of the ground surface. Public Library of Science 2019-10-10 /pmc/articles/PMC6786563/ /pubmed/31600327 http://dx.doi.org/10.1371/journal.pone.0223720 Text en © 2019 Takano et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Takano, Shinya
Sugimoto, Atsuko
Tei, Shunsuke
Liang, Maochang
Shingubara, Ryo
Morozumi, Tomoki
Maximov, Trofim C.
Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia
title Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia
title_full Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia
title_fullStr Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia
title_full_unstemmed Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia
title_short Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga–Tundra boundary in the Indigirka River lowlands, northeastern Siberia
title_sort isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the taiga–tundra boundary in the indigirka river lowlands, northeastern siberia
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6786563/
https://www.ncbi.nlm.nih.gov/pubmed/31600327
http://dx.doi.org/10.1371/journal.pone.0223720
work_keys_str_mv AT takanoshinya isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia
AT sugimotoatsuko isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia
AT teishunsuke isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia
AT liangmaochang isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia
AT shingubararyo isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia
AT morozumitomoki isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia
AT maximovtrofimc isotopiccompositionsofgroundiceinnearsurfacepermafrostinrelationtovegetationandmicrotopographyatthetaigatundraboundaryintheindigirkariverlowlandsnortheasternsiberia