Consideration of dissolved organic carbon flux reduces estimated wetland carbon losses in response to warming
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SOILS, SEC 1 • SOIL ORGANIC MATTER DYNAMICS AND NUTRIENT CYCLING • SHORT ORIGINAL COMMUNICATION
Consideration of dissolved organic carbon flux reduces estimated wetland carbon losses in response to warming Hongyang Chen 1
&
Changming Fang 1 & Ming Nie 1
Received: 14 April 2020 / Accepted: 27 August 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Purpose Wetland gaseous carbon (C) emissions have been widely used to evaluate temperature sensitivity of soil organic carbon (SOC) decomposition (indicated by Q10). However, dissolved organic carbon (DOC) flux as an important pathway for soil solidphase organic carbon losses has seldom been considered in such estimations, which may introduce bias in predictions of wetland soil C-climate feedback. Hence, this study aimed to explore whether and how the temperature sensitivity of wetland SOC decomposition is affected by DOC flux. Materials and methods We carried out an anaerobic microcosm experiment using diverse wetland soils to assess the feedback of wetland SOC decomposition to temperature change with and without considering DOC flux. Results and discussion The contribution of DOC flux to wetlands SOC decomposition at a low temperature was significantly (p < 0.05) higher than that at a high temperature. Q10 values of wetland SOC decomposition rates were significantly (p < 0.05) overestimated, by an average of 8%, when DOC was not considered. However, this overestimation was not significant (p > 0.05) for low-SOC wetland soils. In addition, the overestimation for alkaline wetland soils was much higher than that of acid wetland soils, with a significantly (p < 0.01) positive correlation between the ratios of Q10 (gaseous C emissions) to Q10 (SOC decomposition) and soil pH across all wetland soil samples. Conclusions Our finding suggested that the sensitivity of wetland SOC decomposition to temperature change might be overestimated if DOC flux is not considered, especially in alkaline or high-SOC soils. Thus, C-climate models should incorporate DOC flux when predicting wetland C loss in response to warming. Keywords Dissolved organic carbon . Greenhouse gases . Global warming . Q10 . Soil organic carbon decomposition
1 Introduction Wetlands play an important role in global carbon (C) cycles (Davidson and Janssens 2006; Fenner and Freeman 2011; Responsible editor: Zucong Cai Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11368-020-02767-0) contains supplementary material, which is available to authorized users. * Ming Nie [email protected] 1
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Coastal Ecosystems Research Station of the Yangtze River Estuary, Institute of Biodiversity Science, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, China
Abril et al. 2013). Despite covering 4–6% of the terrestrial land surface, wetlands are estimated to account for one-third of global soil organic carbon (SOC) storage (Mitra et al. 2005;
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