Turnover of labile and recalcitrant soil carbon differ in response to nitrate and ammonium deposition in an ombrotrophic peatland

Currey, Pauline M.; Johnson, David; Sheppard, Lucy J.; Leith, Ian D.; Toberman, Hannah; Van Der Wal, Rene; Dawson, Lorna A.; Artz, Rebekka R.E.. 2010 Turnover of labile and recalcitrant soil carbon differ in response to nitrate and ammonium deposition in an ombrotrophic peatland. Global Change Biology, 16. 2307-2321.

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The effects of 4 years of simulated nitrogen deposition, as nitrate (NO3 ) and ammonium (NH4 1), on microbial carbon turnover were studied in an ombrotrophic peatland. We investigated the mineralization of simple forms of carbon using MicroRespt measurements (a multiple substrate induced respiration technique) and the activities of four soil enzymes involved in the decomposition of more complex forms of carbon or in nutrient acquisition: Nacetyl- glucosaminidase (NAG), cellobiohydrolase (CBH), acid phosphatase (AP), and phenol oxidase (PO). The potential mineralization of labile forms of carbon was significantly enhanced at the higher N additions, especially with NH4 1 amendments, while potential enzyme activities involved in breakdown of more complex forms of carbon or nutrient acquisition decreased slightly (NAG and CBH) or remained unchanged (AP and PO) with N amendments. This study also showed the importance of distinguishing between NO3 and NH4 1 amendments, as their impact often differed. It is possible that the limited response on potential extracellular enzyme activity is due to other factors, such as limited exposure to the added N in the deeper soil or continued suboptimal functioning of the enzymes due to the low pH, possibly via the inhibitory effect of low phenol oxidase activity.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 2 - Biogeochemistry and Climate System Processes
UKCEH and CEH Sections/Science Areas: Billett (to November 2013)
ISSN: 1354-1013
Additional Keywords: Whim bog, carbon turnover, enzyme activity, nitrogen deposition, peatland, substrate-induced respiration
NORA Subject Terms: Botany
Agriculture and Soil Science
Biology and Microbiology
Atmospheric Sciences
Date made live: 16 Feb 2011 14:43 +0 (UTC)

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