The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources
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Author(s)
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.
Date Issued
2017-06-16
Date Acceptance
2017-05-08
Citation
Biogeosciences, 2017, 14, pp.2891-2902
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 (https://creativecommons.org/licenses/by/3.0/)
the Creative Commons Attribution 3.0 License (https://creativecommons.org/licenses/by/3.0/)
Sponsor
Engineering & Physical Science Research Council (E
Grant Number
144356 (EP/N010124/1)
Subjects
Science & Technology
Life Sciences & Biomedicine
Physical Sciences
Ecology
Geosciences, Multidisciplinary
Environmental Sciences & Ecology
Geology
DRINKING-WATER TREATMENT
CLIMATE-CHANGE
LONG-TERM
CONSERVATION MANAGEMENT
INDUCED ACIDIFICATION
SPHAGNUM BOGS
BLANKET PEAT
LITTER
DECOMPOSITION
MATTER
Meteorology & Atmospheric Sciences
04 Earth Sciences
05 Environmental Sciences
06 Biological Sciences
Publication Status
Published