Dissolved organic nutrient uptake by riverine phytoplankton varies along a gradient of nutrient enrichment

Mackay, E.B. ORCID: https://orcid.org/0000-0001-5697-7062; Feuchtmayr, H.; De Ville, M.M.; Thackeray, S.J. ORCID: https://orcid.org/0000-0003-3274-2706; Callaghan, N. ORCID: https://orcid.org/0000-0003-0273-6161; Marshall, M.; Rhodes, G. ORCID: https://orcid.org/0000-0003-0488-3843; Yates, C.A.; Johnes, P.J.; Maberly, S.C. ORCID: https://orcid.org/0000-0003-3541-5903. 2020 Dissolved organic nutrient uptake by riverine phytoplankton varies along a gradient of nutrient enrichment. Science of the Total Environment, 722, 137837. 14, pp. 10.1016/j.scitotenv.2020.137837

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Official URL: http://dx.doi.org/10.1016/j.scitotenv.2020.137837

Abstract/Summary

The concentration of dissolved organic matter (DOM) in freshwaters is increasing in large areas of the world. In addition to carbon, DOM contains nitrogen and phosphorus and there is growing concern that these organic nutrients may be bioavailable and contribute to eutrophication. However, relatively few studies have assessed the potential for dissolved organic nitrogen (DON) or dissolved organic phosphorus (DOP) compounds to be bioavailable to natural river phytoplankton communities at different locations or times. Temporal and spatial variations in uptake, relative to environmental characteristics were examined at six riverine sites in two contrasting catchments in the UK. This study also examined how the uptake by riverine phytoplankton of four DON and four DOP compounds commonly found in rivers, varied with concentration. Total nitrogen (TN) and phosphorus (TP) concentrations, the proportion of inorganic nutrient species, and nutrient limitation varied temporally and spatially, as did the potential for DON and DOP uptake. All eight of the DOM compounds tested were bioavailable, but to different extents. Organic nutrient use depended on the concentration of the organic compound supplied, with simple compounds (urea and glucose-6-phosphate) supporting algal growth even at very low concentrations. DON use was negatively correlated with the TN and ammonia concentration and DOP use was negatively correlated with soluble reactive phosphorus (SRP) and dissolved organic carbon (DOC) concentration. The evidence indicates that DOM in rivers has been overlooked as a potential source of nutrients to phytoplankton and therefore as an agent of eutrophication.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.scitotenv.2020.137837
UKCEH and CEH Sections/Science Areas:	Soils and Land Use (Science Area 2017-) Water Resources (Science Area 2017-)
ISSN:	0048-9697
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	dissolved organic nitrogen, dissolved organic phosphorus, DOM, eutrophication, freshwater, nutrient limitation
NORA Subject Terms:	Ecology and Environment
Date made live:	25 Mar 2020 14:15 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/527326

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.scitotenv.2020.137837

UKCEH and CEH Sections/Science Areas:

Soils and Land Use (Science Area 2017-)
Water Resources (Science Area 2017-)

ISSN:

0048-9697

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

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

Additional Keywords:

dissolved organic nitrogen, dissolved organic phosphorus, DOM, eutrophication, freshwater, nutrient limitation