Effects of climate change on peatland reservoirs: a DOC perspective

Fenner, N.; Meadham, J.; Jones, T.; Hayes, F. ORCID: https://orcid.org/0000-0002-1037-5725; Freeman, C.. 2021 Effects of climate change on peatland reservoirs: a DOC perspective. Global Biogeochemical Cycles, 35 (7), e2021GB006992. 23, pp. https://doi.org/10.1029/2021GB006992

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Official URL: http://dx.doi.org/10.1029/2021GB006992

Abstract/Summary

Peatland reservoirs are global hotspots for drinking water provision and are likely to become more important as demand per capita rises and the climate changes. Dissolved organic carbon (DOC) is associated with harmful disinfection byproducts and reduced aesthetic quality, and its removal is the major treatment cost. Littoral zones are known to be disproportionately important for DOC production through macrophyte inputs, and such communities are predicted to expand with warming in northern regions. However, little is known about autochthonous DOC contributions and their response to climatic change. Here we exposed mesocosms to elevated CO2 (eCO2), warming and a combined treatment across a trophic gradient. Regression analysis indicated that while sediments, macrophytes, and phytoplankton are important DOC sources (P < 0.05), benthic algal biomass showed the strongest relationship with DOC (P < 0.05), suggesting it is an underestimated source. DOC removal indicators, namely phenol oxidase (depolymerization) and respiration (mineralization) were inversely related to DOC concentration in oligohumic (P < 0.05) and oligotrophic (P < 0.1) systems, suggesting heterotrophic processes are important in DOC removal. DOC concentrations increased across all systems (P < 0.05), irrespective of trophic status, due to increased photoautotrophic inputs (macrophyte, pelagic, and benthic algae) under eCO2, warming, and combined scenarios, with inhibited depolymerization and mineralization under eCO2, even when combined with warming (P < 0.05 and P < 0.05 excepting the oligo-mesotrophic reservoir P < 0.1 respectively). Increased DOC loads of all fractions, regardless of provenance, are predicted in a future climate and, thus, investment in techniques to remove a greater range of DOC fractions is proposed to help “future proof” drinking water supplies.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1029/2021GB006992
UKCEH and CEH Sections/Science Areas:	Soils and Land Use (Science Area 2017-)
ISSN:	0886-6236
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	algae, dissolved organic carbon, drinking water, macrophytes, phytoplankton
NORA Subject Terms:	Agriculture and Soil Science
Date made live:	22 Jul 2021 11:19 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/530764

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1029/2021GB006992

UKCEH and CEH Sections/Science Areas:

Soils and Land Use (Science Area 2017-)

ISSN:

0886-6236

Additional Information. Not used in RCUK Gateway to Research.:

Open Access paper - full text available via Official URL link.

Additional Keywords:

algae, dissolved organic carbon, drinking water, macrophytes, phytoplankton