Intense summer floods may induce prolonged increases in benthic respiration rates of more than one year leading to low river dissolved oxygen

Hutchins, M.G. ORCID: https://orcid.org/0000-0003-3764-5331; Harding, G.; Jarvie, H.P. ORCID: https://orcid.org/0000-0002-4984-1607; Marsh, T.J.; Bowes, M.J. ORCID: https://orcid.org/0000-0002-0673-1934; Loewenthal, M.. 2020 Intense summer floods may induce prolonged increases in benthic respiration rates of more than one year leading to low river dissolved oxygen. Journal of Hydrology X, 8, 100056. 10, pp. 10.1016/j.hydroa.2020.100056

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Official URL: https://doi.org/10.1016/j.hydroa.2020.100056

Abstract/Summary

The supply of readily-degradable organic matter to river systems can cause stress to dissolved oxygen (DO) in slow-flowing waterbodies. To explore this threat, a multi-disciplinary study of the River Thames (UK) was undertaken over a six-year period (2009–14). Using a combination of observations at various time resolutions (monthly to hourly), physics-based river network water quality modelling (QUESTOR) and an analytical tool to estimate metabolic regime (Delta method), a decrease in 10th percentile DO concentration (10-DO, indicative of summer low levels) was identified during the study period. The assessment tools suggested this decrease in 10-DO was due to an increase in benthic heterotrophic respiration. Hydrological and dissolved organic carbon (DOC) data showed that the shift in 10-DO could be attributed to summer flooding in 2012 and consequent connection of pathways flushing degradable organic matter into the river. Comparing 2009–10 and 2013–14 periods, 10-DO decreased by 7.0% at the basin outlet (Windsor) whilst median DOC concentrations in a survey of upstream waterbodies increased by 5.5–48.1%. In this context, an anomalous opposing trend in 10-DO at one site on the river was also identified and discussed. Currently, a lack of process understanding of spatio-temporal variability in benthic respiration rates is hampering model predictions of river DO. The results presented here show how climatic-driven variation and urbanisation induce persistent medium-term changes in the vulnerability of water quality to multiple stressors across complex catchment systems.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.hydroa.2020.100056
UKCEH and CEH Sections/Science Areas:	Pollution (Science Area 2017-) Water Resources (Science Area 2017-) UKCEH Fellows
ISSN:	2589-9155
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	flood, respiration, dissolved oxygen, river, water quality model, metabolism
NORA Subject Terms:	Hydrology
Date made live:	26 May 2020 13:43 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/527812

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.hydroa.2020.100056

UKCEH and CEH Sections/Science Areas:

Pollution (Science Area 2017-)
Water Resources (Science Area 2017-)
UKCEH Fellows

ISSN:

2589-9155

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

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

Additional Keywords:

flood, respiration, dissolved oxygen, river, water quality model, metabolism