Temperature and moisture are minor drivers of regional-scale soil organic carbon dynamics

González-Domínguez, B., Niklaus, P. A., Studer, M. S., Hagedorn, F., Wacker, L., Haghipour, N., Zimmermann, S., Walthert, L., McIntyre, C. and Abiven, S. (2019) Temperature and moisture are minor drivers of regional-scale soil organic carbon dynamics. Scientific Reports, 9(1), 6422. (doi: 10.1038/s41598-019-42629-5) (PMID:31015496) (PMCID:PMC6478928)

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Abstract

Storing large amounts of organic carbon, soils are a key but uncertain component of the global carbon cycle, and accordingly, of Earth System Models (ESMs). Soil organic carbon (SOC) dynamics are regulated by a complex interplay of drivers. Climate, generally represented by temperature and moisture, is regarded as one of the fundamental controls. Here, we use 54 forest sites in Switzerland, systematically selected to span near-independent gradients in temperature and moisture, to disentangle the effects of climate, soil properties, and landform on SOC dynamics. We estimated two SOC turnover times, based on bulk soil 14C measurements (τ14C) and on a 6-month laboratory soil incubation (τi). In addition, upon incubation, we measured the 14C signature of the CO2 evolved and quantified the cumulated production of dissolved organic carbon (DOC). Our results demonstrate that τi and τ14C capture the dynamics of contrasting fractions of the SOC continuum. The 14C-based τ14C primarily reflects the dynamics of an older, stabilised pool, whereas the incubation-based τi mainly captures fresh readily available SOC. Mean site temperature did not raise as a critical driver of SOC dynamics, and site moisture was only significant for τi. However, soil pH emerged as a key control of both turnover times. The production of DOC was independent of τi and not driven by climate, but primarily by the content of clay and, secondarily by the slope of the site. At the regional scale, soil physicochemical properties and landform appear to override the effect of climate on SOC dynamics.

Item Type:Articles
Additional Information:We thank the Swiss National Science Foundation (project-no. 143026) for funding this study in the frame of the National Research Programme 68. (http://www.nrp68.ch/en).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mcintyre, Dr Cameron
Authors: González-Domínguez, B., Niklaus, P. A., Studer, M. S., Hagedorn, F., Wacker, L., Haghipour, N., Zimmermann, S., Walthert, L., McIntyre, C., and Abiven, S.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Scientific Reports
Publisher:Nature Publishing Group
ISSN:2045-2322
ISSN (Online):2045-2322
Copyright Holders:Copyright © 2019 The Authors
First Published:First published in Scientific Reports 9(1):6422
Publisher Policy:Reproduced under a Creative Commons License

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