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Microbial dynamics in a High Arctic glacier forefield: a combined field, laboratory, and modelling approach

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)5677-5696
Number of pages20
JournalBiogeosciences
Volume13
Issue number19
Early online date13 Oct 2016
DOIs
DateAccepted/In press - 26 Sep 2016
DateE-pub ahead of print - 13 Oct 2016
DatePublished (current) - Oct 2016

Abstract

Modelling the development of soils in glacier forefields is necessary in order to assess how microbial and geochemical processes interact and shape soil development in response to glacier retreat. Furthermore, such models can help us predict microbial growth and the fate of Arctic soils in an increasingly ice-free future. Here, for the first time, we combined field sampling with laboratory analyses and numerical modelling to investigate microbial community dynamics in oligotrophic proglacial soils in Svalbard. We measured low bacterial growth rates and growth efficiencies (relative to estimates from Alpine glacier forefields) and high sensitivity of bacterial growth rates to soil temperature (relative to temperate soils). We used these laboratory measurements to inform parameter values in a new numerical model and significantly refined predictions of microbial and biogeochemical dynamics of soil development over a period of roughly 120 years. The model predicted the observed accumulation of autotrophic and heterotrophic biomass. Genomic data indicated that initial microbial communities were dominated by bacteria derived from the glacial environment, whereas older soils hosted a mixed community of autotrophic and heterotrophic bacteria. This finding was simulated by the numerical model, which showed that active microbial communities play key roles in fixing and recycling carbon and nutrients. We also demonstrated the role of allochthonous carbon and microbial necromass in sustaining a pool of organic material, despite high heterotrophic activity in older soils. This combined field, laboratory, and modelling approach demonstrates the value of integrated model–data studies to understand and quantify the functioning of the microbial community in an emerging High Arctic soil ecosystem.

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    Rights statement: This is the final published version of the article (version of record). It first appeared online via EGU at http://www.biogeosciences.net/13/5677/2016/. Please refer to any applicable terms of use of the publisher.

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    Rights statement: This is the final published version of the article (version of record). It first appeared online via EGU at http://www.biogeosciences.net/13/5677/2016/. Please refer to any applicable terms of use of the publisher.

    Final published version, 809 KB, PDF document

    Licence: CC BY

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