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

Ritson, J. P., Brazier, R. E., Graham, N. J. D., Freeman, C., Templeton, M. R. and Clark, J. ORCID: https://orcid.org/0000-0002-0412-8824 (2017) The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources. Biogeosciences, 14 (11). pp. 2891-2902. ISSN 1726-4170 doi: 10.5194/bg-14-2891-2017

Abstract/Summary

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 this DOC was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on 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 more immediate effects are observed in peat soils. 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.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/68650
Identification Number/DOI	10.5194/bg-14-2891-2017
Refereed	No
Divisions	Interdisciplinary centres and themes > Ecosystems Science Science > School of Archaeology, Geography and Environmental Science > Earth Systems Science Science > School of Archaeology, Geography and Environmental Science > Department of Geography and Environmental Science Interdisciplinary centres and themes > Soil Research Centre
Publisher	Copernicus Publications
Download/View statistics	View download statistics for this item