Microbial carbon mineralization in tropical lowland and montane forest soils of Peru

Whitaker, Jeanette ORCID: https://orcid.org/0000-0001-8824-471X; Ostle, Nicholas; McNamara, Niall P. ORCID: https://orcid.org/0000-0002-5143-5819; Nottingham, Andrew T.; Stott, Andrew W.; Bardgett, Richard D.; Salinas, Norma; Ccahuana, Adan J.Q.; Meir, Patrick. 2014 Microbial carbon mineralization in tropical lowland and montane forest soils of Peru. Frontiers in Microbiology, 5, 720. 13, pp. 10.3389/fmicb.2014.00720

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Abstract/Summary

Climate change is affecting the amount and complexity of plant inputs to tropical forest soils. This is likely to influence the carbon (C) balance of these ecosystems by altering decomposition processes e.g. ‘positive priming effects’ that accelerate soil organic matter mineralization. However, the mechanisms determining the magnitude of priming effects are poorly understood. We investigated potential mechanisms by adding 13C labelled substrates, as surrogates of plant inputs, to soils from an elevation gradient of tropical lowland and montane forests. We hypothesised that priming effects would increase with elevation due to increasing microbial nitrogen limitation, and that microbial community composition would strongly influence the magnitude of priming effects. Quantifying the sources of respired C (substrate or soil organic matter) in response to substrate addition revealed no consistent patterns in priming effects with elevation. Instead we found that substrate quality (complexity and nitrogen content) was the dominant factor controlling priming effects. For example a nitrogenous substrate induced a large increase in soil organic matter mineralization whilst a complex C substrate caused negligible change. Differences in the functional capacity of specific microbial groups, rather than microbial community composition per se, were responsible for these substrate-driven differences in priming effects. Our findings suggest that the microbial pathways by which plant inputs and soil organic matter are mineralized are determined primarily by the quality of plant inputs and the functional capacity of microbial taxa, rather than the abiotic properties of the soil. Changes in the complexity and stoichiometry of plant inputs to soil in response to climate change may therefore be important in regulating soil C dynamics in tropical forest soils.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.3389/fmicb.2014.00720
UKCEH and CEH Sections/Science Areas:	UKCEH Fellows Shore
ISSN:	1664-302X
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - Official URL link provides full text
Additional Keywords:	soil organic matter, microbial community composition, decomposition, respiration, priming, cloud forest, ecosystem function
NORA Subject Terms:	Ecology and Environment Biology and Microbiology
Date made live:	19 Jan 2015 11:54 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/509032

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