Isoscapes as tools for assessing water sources in the River Ob watershed

Lead Author Pertti, Ala-aho
Institution Contact University of Aberdeen Address: B32, St Mary's, Geography & Environment, School of Geosciences, Elphinstone Road, University of Aberdeen, Aberdeen AB24 3UF, Scotland
Co-Authors Pertti Ala-aho, University of Aberdeen, Scotland; Chris Soulsby, University of Aberdeen, Scotland; Sergey Kirpotin, Tomsk State University, Russia; Oleg Pokrovsky, University of Toulouse, France; Rinat Manasypov, Tomsk State University, Russia; Sergey Loiko, Tomsk State University, Russia; Doerthe Tetzlaff, University of Aberdeen, Scotland
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.3 Siberian Inland Waters: Vulnerability to Global Change and Human Impact
Datetime Thu, Sep 15, 2016 11:00 AM - 11:15 AM
Presentation Type Oral
Abstract text Western Siberia Lowland (WSL) is undergoing changes in permafrost extent which are likely to modify atmospheric carbon emission and lateral export of carbon to the sea from peat deposits. The main driver for the changes is global warming, but the mechanisms controlling the pathways of freshly released carbon typically relate to inland rivers and lakes. To outline the changes in the carbon fluxes, the hydrology of this remote and data-scarce lowland area needs to be better understood.

Stable water isotopes (O18 and deuterium) can be used as tracers to infer the sources, residence times and connectivities between different water stores. We present an extensive dataset for stable water isotopes (n=604) sampled in 2014 and 2015 from the river network of the Ob basin including significant tributaries and the main stem of the Ob. Samples also include a unique subset from supra-permafrost soil solutions and thermokarst lakes and ponds. Sample locations span the longitude of 73-88E and latitude of 56-68N covering a spectrum of permafrost free to continuous permafrost areas. The dataset is supplemented with precipitation and snow isotope data from other observation networks and studies.

The dataset allows the first attempt to build ‘isoscapes’ outlining the typical water isotope signatures and their variabilities in different hydrological storages (rivers, lakes, soils, snow) for western Siberia. Hydrological and geographical data such as river discharge, catchment area, permafrost extent, lake and bog coverage, and latitude will be used to seek explanatory factors for the isotopic variability. We expect the analysis to lead to an improved conceptual understanding of water flow paths in this vast lowland area, which is important for estimating changes in the closely interlinked carbon fluxes.
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