The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

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Title: The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources
Authors: Ritson, JP
Brazier, RE
Graham, NJD
Freeman, C
Templeton, MR
Clark, JM
Item Type: Journal Article
Abstract: Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought-tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that peat DOC that had been exposed to oxygen was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on the amount of DOC production from vegetation litters; however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought-tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed post-drought is due entirely to soil microbial processes and DOC solubility rather than litter layer effects. Long-term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas pulses related to drought may be observed in peat soils and are likely to become more common in the future. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch blocking to raise water tables.
Issue Date: 16-Jun-2017
Date of Acceptance: 8-May-2017
ISSN: 1726-4189
Publisher: European Geosciences Union (EGU)
Start Page: 2891
End Page: 2902
Journal / Book Title: Biogeosciences
Volume: 14
Copyright Statement: © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License (
Sponsor/Funder: Engineering & Physical Science Research Council (E
Funder's Grant Number: 144356 (EP/N010124/1)
Keywords: Science & Technology
Life Sciences & Biomedicine
Physical Sciences
Geosciences, Multidisciplinary
Environmental Sciences & Ecology
Meteorology & Atmospheric Sciences
04 Earth Sciences
05 Environmental Sciences
06 Biological Sciences
Publication Status: Published
Appears in Collections:Civil and Environmental Engineering

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