A centennial record of fluvial organic matter input from the discontinuous permafrost catchment of Lake Torneträsk

High-latitude regions are underlain by the most organic carbon (OC)-rich soils on earth and currently subject to intense climate warming, potentially increasing remobilization and mineralization of soil OC. Sub-Arctic Scandinavia is located on the 0°C mean annual isotherm and is therefore particular...

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Bibliographic Details
Published in:Journal of Geophysical Research: Biogeosciences
Main Authors: Vonk, Jorien, Alling, Vanja, Rahm, Lars, Mörth, Magnus, Humborg, Christoph, Gustafsson, Örjan
Format: Article in Journal/Newspaper
Language:English
Published: Linköpings universitet, Tema vatten i natur och samhälle 2012
Subjects:
n-alkanes
TOC
radiocarbon
d13C
sediment
climate warming
subarctic
Natural Sciences
Naturvetenskap
Arctic
Torneträsk
Climate change
permafrost
Subarctic
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79924
https://doi.org/10.1029/2011JG001887
Description
Summary:High-latitude regions are underlain by the most organic carbon (OC)-rich soils on earth and currently subject to intense climate warming, potentially increasing remobilization and mineralization of soil OC. Sub-Arctic Scandinavia is located on the 0°C mean annual isotherm and is therefore particularly vulnerable to climate change. This study aimed to establish a baseline for soil OC release over the past century into Lake Torneträsk, the largest lake in sub-Arctic Scandinavia, through bulk geochemical and molecular radiocarbon analyses in chronologically constrained sediment cores. Our results suggest a dominance of peat-derived terrestrial OC inflow. We show that the annual terrestrial OC inflow to the lake is ∼12 times higher than the in-lake produced particulate OC, and consists for a large part (ca. 60%) of old OC from deep reservoirs in the catchment. The sedimentary record shows signs of increasing inflow of more degraded terrestrial matter since ∼1975, as indicated by increasing %TOC concentrations, a lower δ13C value and lower TOC:TN ratios. Based on simultaneous changes in local climate and reported signs of permafrost degradation (e.g., active layer deepening, mire/peat erosion), the observed changes in the sedimentary record of Scandinavia's largest mountain lake likely reflect a climate warming-induced change in terrestrial OC inflow.

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