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Title: Shifts in the source and composition of dissolved organic matter in Southwest Greenland lakes along a regional hydro-climatic gradient
Authors: Osburn, Christopher L.
Anderson, Nicholas John
Stedmon, Colin A.
Giles, Madeleine E.
Whiteford, Erika J.
McGenity, Terry J.
Dumbrell, Alex J.
Underwood, Graham J.
Keywords: Arctic
Stable carbon isotopes
Issue Date: 2017
Publisher: American Geophysical Union © The Authors
Citation: OSBURN, C.L. ... et al, 2017. Shifts in the source and composition of dissolved organic matter in Southwest Greenland lakes along a regional hydro-climatic gradient. Journal of Geophysical Research: Biogeosciences, 122 (12), pp.3431-3445.
Abstract: Dissolved organic matter (DOM) concentration and quality were examined from Arctic lakes located in three clusters across south-west (SW) Greenland, covering the regional climatic gradient: cool, wet coastal zone; dry inland interior; and cool, dry ice-marginal areas. We hypothesized that differences in mean annual precipitation between sites would result in a reduced hydrological connectivity between lakes and their catchments and that this concentrates degraded DOM. The DOM in the inland lake group was characterized by a lower aromaticity and molecular weight, a low soil-like fluorescence, and carbon stable isotope (δ 13 C-DOC) values enriched by ~2‰ relative to the coastal group. DOC-specific absorbance (SUVA 254 ) and DOC-specific soil-like fluorescence (SUVF C1 ) revealed seasonal and climatic gradients across which DOM exhibited a dynamic we term “pulse-process”: Pulses of DOM exported from soils to lakes during snow and ice melt were followed by pulses of autochthonous DOM inputs (possibly from macrophytes), and their subsequent photochemical and microbial processing. These effects regulated the dynamics of DOM in the inland lakes and suggested that if circumpolar lakes currently situated in cool wetter climatic regimes with strong hydrological connectivity have reduced connectivity under a drier future climate, they may evolve toward an end-point of large stocks of highly degraded DOC, equivalent to the inland lakes in the present study. The regional climatic gradient across SW Greenland and its influence on DOM properties in these lakes provide a model of possible future changes to lake C cycling in high-latitude systems where climatic changes are most pronounced.
Description: This is an Open Access Article. It is published by American Geophysical Union under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/
Sponsor: UK Natural Environment Research Council. Grant Number: NE/NE/J022063/1
Version: Published
DOI: 10.1002/2017JG003999
URI: https://dspace.lboro.ac.uk/2134/32952
Publisher Link: https://doi.org/10.1002/2017JG003999
ISSN: 2169-8953
Appears in Collections:Published Articles (Geography and Environment)

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