Riparian shading controls instream spring phytoplankton and benthic algal growth

Halliday, S.J.; Skeffington, R.A.; Wade, A.J.; Bowes, M.J. ORCID: https://orcid.org/0000-0002-0673-1934; Read, D.S. ORCID: https://orcid.org/0000-0001-8546-5154; Jarvie, H.P.; Loewenthal, M.. 2016 Riparian shading controls instream spring phytoplankton and benthic algal growth. Environmental Science: Processes and Impacts, 18 (6). 677-689. https://doi.org/10.1039/c6em00179c

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Official URL: http://dx.doi.org/10.1039/C6EM00179C

Abstract/Summary

Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010–2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually suppressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1039/c6em00179c
UKCEH and CEH Sections/Science Areas:	Rees (from October 2014)
ISSN:	2050-7887
NORA Subject Terms:	Earth Sciences Ecology and Environment Chemistry
Date made live:	29 Jul 2016 08:59 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/514062

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1039/c6em00179c

UKCEH and CEH Sections/Science Areas:

Rees (from October 2014)

ISSN:

2050-7887

NORA Subject Terms:

Earth Sciences
Ecology and Environment
Chemistry

Date made live:

29 Jul 2016 08:59 +0 (UTC)