Soils in the Lena River Delta serve as a large Carbon storage

Lead Author Sebastian, Zubrzycki
Institution Contact Institute of Soil Science, Center for Earth System Research and Sustainability, Universität Hamburg Allende-Platz 2 20146 Hamburg, Germany Tel: +49 40 42838-8185 Fax: +49 40 42838-2024
Co-Authors Evgeny Abakumov, Department of Applied Ecology, Saint-Petersburg State University, St. Petersburg, Russia Aleksei Desiatkin, Institute for Biological Problems of Cryolithozone, SB RAS, Yakutsk, Russia Lars Kutzbach and Eva-Maria Pfeiffer, 1 Institute of Soil Science, Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, Germany
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.6 Strategies for ecosystem services and sustainable environmental management of soils and contaminated areas in the Arctic
Datetime Wed, Sep 14, 2016 01:15 PM - 01:30 PM
Presentation Type Oral
Abstract text The largest Arctic delta, the Lena River Delta extends over an area of 32,000 km² and likely holds more than half of the entire soil organic carbon (SOC) mass stored in the seven major deltas in the northern permafrost regions. Around 60 % of the Lena River Delta region consists of true Holocene deltaic units: a river terrace dominated by wet-sedge-polygons covered by a soil-complex of Glacic Aquiturbels and Typic Historthels, and active floodplains covered mainly by sand dominated soils as Psammentic Aquorthels and Typic Psammorthels. The mean SOC stocks for the upper 100 cm on both units were estimated at 29 kg m 2 ± 10 kg m 2 at the river terrace and at 14 kg m 2 ± 7 kg m 2 on the floodplains. For the depth of 100 cm, the total SOC storage of the Holocene river terrace was estimated at 121 Tg ± 43 Tg, and the SOC storage of the active floodplains was estimated at 120 Tg ± 66 Tg. The mass of SOC stored within the observed seasonally thawed layer was estimated at about 127 Tg assuming an average maximum thawed layer depth of 50 cm. The SOC mass which is stored in the perennially frozen ground below 50 cm soil depth, which is excluded from intense biogeochemical exchange with the atmosphere, was estimated at 113 Tg. The mean nitrogen (N) stocks for the upper 1 m of soils were estimated at 1.2 kg m 2 ± 0.4 kg m 2 for the Holocene river terrace and at 0.9 kg m 2 ± 0.4 kg m 2 for the active floodplain levels, respectively. Considering projections for deepening of the seasonally thawed layer up to 120 cm in the Lena River Delta within the 21st century, these large carbon storages could become increasingly available for decomposition and mineralization processes.
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