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Soil organic matter biochemistry and potential susceptibility to climatic change across the forest-tundra ecotone in the Fennoscandian mountains

La bioquímica de la materia orgánica del suelo y su susceptibilidad potencial al cambio climático a través de áreas de transición del bosque de tundra en las montañas Fennoscandinas

Sjögersten, Sofie and Turner, Benjamin L. and Mahieu, Nathalie and Condron, Leo M. and Wookey, Philip A. (2003) Soil organic matter biochemistry and potential susceptibility to climatic change across the forest-tundra ecotone in the Fennoscandian mountains. Global Change Biology. 9:759-772.

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We studied soil organic carbon (C) chemistry at the mountain birch forest-tundra ecotone
in three regions of the Fennoscandian mountain range with comparable vegetation cover
but contrasting degrees of continentality and latitude. The aim of the study was to
identify functional compound classes and their relationships to decomposition and
spatial variation across the ecotone and latitudinal gradient. Solid-state 13C nuclear
magnetic resonance (CPMAS 13C NMR) was used to identify seven functional groups
of soil organic C: alkyls, N-alkyls, 0-alkyls, acetals, aromatics, phenolics and carboxyls.
N-alkyls, 0-alkyls and acetals are generally considered labile substrates for a large
number of saprotrophic fungi and bacteria, whilst phenolics and aromatics are mainly
decomposed by lignolytic organisms and contribute to the formation of soil organic
matter together with aliphatic alkyls and carboxyls. All soils contained a similar proportional
distribution of functional groups, although relatively high amounts of N-alkyls,
0-alkyls and acetals were present in comparison to earlier published studies, suggesting
that large amounts of soil C were potentially vulnerable to microbial degradation. Soil
organic matter composition was different at the most southerly site (Dovrefjell, Norway),
compared with the two more northerly sites (Abisko, Sweden, and Joatka, Norway), with
higher concentrations of aromatics and phenolics, as well as pronounced differences in
alkyl concentrations between forest and tundra soils. Clear differences between mountain
birch forest and tundra heath soil was noted, with generally higher concentrations of
labile carbon present in tundra soils. We conclude that, although mesic soils around the
forest-tundra ecotone in Fennoscandia are a potential source of C to the atmosphere in a
changing environment, the response is likely to vary between comparable ecosystems in
relation to latitude and continentality as well as soil properties especially soil nitrogen
content and pH.

Item Type: Article
NWISRL Publication Number: 1109
Subjects: Soil > Chemistry
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:50
Last Modified: 08 Nov 2016 15:46
Item ID: 167