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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
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| 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 |
| Authors: | Takano, Shinya Browse this author | | Sugimoto, Atsuko Browse this author →KAKEN DB | | Tei, Shunsuke Browse this author →KAKEN DB | | Liang, Maochang Browse this author | | Shingubara, Ryo Browse this author | | Morozumi, Tomoki Browse this author | | Maximov, Trofim C. Browse this author |
| Issue Date: | 10-Oct-2019 |
| Publisher: | PLOS |
| Journal Title: | PLOS ONE |
| Volume: | 14 |
| Issue: | 10 |
| Start Page: | e0223720 |
| Publisher DOI: | 10.1371/journal.pone.0223720 |
| Abstract: | 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 1m 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-equilibriumconditions, 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. |
| Rights: | http://creativecommons.org/licenses/by/4.0/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/78619 |
| Appears in Collections: | 環境科学院・地球環境科学研究院 (Graduate School of Environmental Science / Faculty of Environmental Earth Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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