Soil organic matter characteristics in surficial permafrost sediments on Herschel Island, Yukon Territory, Canada


Contact
Michael.Fritz [ at ] awi.de

Abstract

Recent mobilisation of soil organic matter (SOM) in permafrost of the northern high latitudes is thought to have a significant impact on the carbon balance in the atmosphere. However, the environmental processes which influence SOM accumulation and remobilisation still need to be investigated more accurately. This study investigates the quantity and quality of SOM on Herschel Island in the western Canadian Arctic in relation to various landscape characteristics. To reach this goal, soil moisture, total organic carbon (TOC) and total nitrogen (TN) contents, stable carbon isotopes (∂¹³C) and TOC/TN ratios (C/N) were determined on 128 samples from twelve sediment cores reaching up to 250 cm depth. Drilling locations were chosen based on morphology, vegetation and soil properties and supported by satellite imagery and air photos. Seasonal thaw depths (active layer depths) correlate with ground disturbance and vegetation cover and lie between 20 and 100 cm. Well-preserved SOM is accumulated in the active layer and subjacent ice-rich permafrost of wet polygonal tundra. Uplands, hummocky tussock tundra and alluvial fans cover more than 50 % of the island and show heterogeneous SOM storage characteristics with considerable TOC contents being limited to the active layer. Disturbed areas with slope gradients greater than 6° show strong SOM degradation with low TOC contents throughout the active layer and permafrost strata. Linear regression and principal component analysis (PCA) shows that a decreasing SOM content is driven by increasing ground disturbance and reduced vegetation cover. Improved drainage decreases the preservation of SOM in the active layer. Future deepening of the active layer because of increasing temperatures and ground disturbance will remobilise SOM stored in ice-rich permafrost. This might increase carbon dioxide and methane emissions from permafrost landscapes.



Item Type
Conference (Poster)
Authors
Divisions
Primary Division
Programs
Primary Topic
Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
GeoBerlin2015 - Dynamic Earth from Alfred Wegener to today and beyond. Annual Meeting of DGGV and DMG, 04 Oct 2015 - 07 Oct 2015, Berlin, Germany.
Eprint ID
38826
DOI 10.2312/GFZ.LIS.2015.003

Cite as
Baltruschat, S. , Fritz, M. , Obu, J. , Lantuit, H. and Hinderer, M. (2015): Soil organic matter characteristics in surficial permafrost sediments on Herschel Island, Yukon Territory, Canada , GeoBerlin2015 - Dynamic Earth from Alfred Wegener to today and beyond. Annual Meeting of DGGV and DMG, Berlin, Germany, 4 October 2015 - 7 October 2015 . doi: 10.2312/GFZ.LIS.2015.003


Download
[img]
Preview
PDF
book_of_abstracts_geoberlin_2015.pdf

Download (12MB) | Preview
Cite this document as:

Share


Citation

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item