Experiments using an artificial stream to investigate the seasonal growth of chalk-stream algae

Marker, A.F.H. and Casey, H. (1983) Experiments using an artificial stream to investigate the seasonal growth of chalk-stream algae. In: Fifty-first annual report for the year ended 31st March 1983. Ambleside, UK, Freshwater Biological Association, pp. 63-75. (Annual Report, Freshwater Biological Association, Ambleside)

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Abstract

Research into the production ecology of chalk streams using a large artificial recirculating stream is described. Physical chemical processes including calcium and inorganic phosphate levels, and exchange of gaseous carbon dioxide in both a simple closed system and a circulating system with gravel substrate have been monitored in both light and dark conditions. Further experiments were concerned with the seasonal changes in algal growth over the gravel substrate with constant water velocities and replenishment. The algal population, composed mainly of the diatoms Achnanthes minutissima, Meridion circulare, Nitzschia fonticola and Synedra ulna reached a peak in mid May and declined rapidly during June. Concentrations of phosphate phosphorus fell as the diatoms grew but was not thought to limit growth. Silicate concentrations followed the diatom cycle closely but never fell below 0.8 mg/l Si. It is possible that one of the nutrients may have been limiting the rate of growth due to steep diffusion gradients through the algal mat. In the last summer and autumn a hard calcareous crust composed of the green alga Gongrosira incrustans and the blue green alga Homeothrix varians , developed. The channel stream is compared with the natural conditions found in chalk streams.

Item Type: Book Section
Title: Experiments using an artificial stream to investigate the seasonal growth of chalk-stream algae
Personal Creator/Author:
CreatorsEmail
Marker, A.F.H.
Casey, H.
Title of Book: Fifty-first annual report for the year ended 31st March 1983
Refereed: No
Series Name: Annual Report, Freshwater Biological Association, Ambleside
Page Range: pp. 63-75
Date: 1983
Publisher: Freshwater Biological Association
Place of Publication: Ambleside, UK
Issuing Agency: Freshwater Biological Association
Uncontrolled Keywords: Algae; Fresh water; Growth; Phosphates; Population dynamics; Seasonal variations; Silicates; Achnanthes minutissima; Meridion circulare; Synedra ulna; Annual report
Subjects: Biology
Ecology
Item ID: 5190
Depositing User: Mrs Christine Davey
Date Deposited: 10 May 2011 17:05
Last Modified: 29 Sep 2011 15:14
URI: http://aquaticcommons.org/id/eprint/5190

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