Acidity controls on dissolved organic carbon mobility in organic soils



Evans, Chris D, Jones, Tim G, Burden, Annette, Ostle, Nick, Zielinski, Piotr, Cooper, Mark DA, Peacock, Mike ORCID: 0000-0002-3086-2854, Clark, Joanna M, Oulehle, Filip, Cooper, David
et al (show 1 more authors) (2012) Acidity controls on dissolved organic carbon mobility in organic soils. GLOBAL CHANGE BIOLOGY, 18 (11). pp. 3317-3331.

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Abstract

<jats:title>Abstract</jats:title><jats:p>Dissolved organic carbon (<jats:styled-content style="fixed-case">DOC</jats:styled-content>) concentrations in surface waters have increased across much of <jats:styled-content style="fixed-case">E</jats:styled-content>urope and <jats:styled-content style="fixed-case">N</jats:styled-content>orth <jats:styled-content style="fixed-case">A</jats:styled-content>merica, with implications for the terrestrial carbon balance, aquatic ecosystem functioning, water treatment costs and human health. Over the past decade, many hypotheses have been put forward to explain this phenomenon, from changing climate and land management to eutrophication and acid deposition. Resolution of this debate has been hindered by a reliance on correlative analyses of time series data, and a lack of robust experimental testing of proposed mechanisms. In a 4 year, four‐site replicated field experiment involving both acidifying and deacidifying treatments, we tested the hypothesis that <jats:styled-content style="fixed-case">DOC</jats:styled-content> leaching was previously suppressed by high levels of soil acidity in peat and organo‐mineral soils, and therefore that observed <jats:styled-content style="fixed-case">DOC</jats:styled-content> increases a consequence of decreasing soil acidity. We observed a consistent, positive relationship between <jats:styled-content style="fixed-case">DOC</jats:styled-content> and acidity change at all sites. Responses were described by similar hyperbolic relationships between standardized changes in <jats:styled-content style="fixed-case">DOC</jats:styled-content> and hydrogen ion concentrations at all sites, suggesting potentially general applicability. These relationships explained a substantial proportion of observed changes in peak <jats:styled-content style="fixed-case">DOC</jats:styled-content> concentrations in nearby monitoring streams, and application to a <jats:styled-content style="fixed-case">UK</jats:styled-content>‐wide upland soil p<jats:styled-content style="fixed-case">H</jats:styled-content> dataset suggests that recovery from acidification alone could have led to soil solution <jats:styled-content style="fixed-case">DOC</jats:styled-content> increases in the range 46–126% by habitat type since 1978. Our findings raise the possibility that changing soil acidity may have wider impacts on ecosystem carbon balances. Decreasing sulphur deposition may be accelerating terrestrial carbon loss, and returning surface waters to a natural, high‐<jats:styled-content style="fixed-case">DOC</jats:styled-content> condition.</jats:p>

Item Type: Article
Uncontrolled Keywords: acidity, dissolved organic carbon, organic soil, peat, podzol, soil carbon, sulphur
Divisions: Faculty of Science and Engineering > School of Environmental Sciences
Depositing User: Symplectic Admin
Date Deposited: 02 Aug 2022 08:40
Last Modified: 27 Oct 2023 18:45
DOI: 10.1111/j.1365-2486.2012.02794.x
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3160177