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The ecology of Bassenthwaite Lake (English Lake District)

Thackeray, Stephen; Maberly, Stephen; Winfield, Ian. 2006 The ecology of Bassenthwaite Lake (English Lake District). Ambleside, Freshwater Biological Association, 80pp. (Freshwater Forum, 25).

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Abstract/Summary

Bassenthwaite Lake is, in many ways, different from the other major lakes in the English Lake District: it is the most northerly, the shallowest, has the largest catchment and the shortest mean retention time. There is also considerable temporal variation in lake level. Although the lake is surrounded by rich lowland soils, the catchment is dominated by upland moor and improved pasture, underlain by four dominant soil types: well drained loam with bare rocks and scree, shallow acid upland peat, fine loam and thick acidic peat soils. The supply of catchment-derived sediment, and its recycling within the lake, has serious implications for water quality and for the ecology of this site. These sediments largely comprise inorganic material, and are believed to originate mainly from the high fells and the floodplain of the River Derwent. Typically the lake thermally stratifies between May and September, and is mixed for the remainder of the year. However, the lake is only ever weakly stratified and episodic mixing events influence the ecology of the lake, by increasing the concentration of oxygen at depth and resuspending sediment in shallow water. Palaeolimnological reconstruction of long-term changes in total phosphorus concentration has revealed that, over the past 250 years, the lake has become increasingly eutrophic, with increases in phosphorus concentration being particularly dramatic in the late 1970s and early 1980s. Though tertiary sewage treatment was implemented at Keswick (the principal town in the catchment) in 1995, there has been only a slight reduction in phosphorus concentration in the lake. At present, diffuse sources contribute more to the total phosphorus load than do point sources and it is suspected that efficient internal recycling of a relatively modest sediment store, caused by wind-driven resuspension, may be one reason for the limited reduction in phosphorus availability.

Item Type: Publication - Book
Programmes: CEH Programmes pre-2009 publications > Biodiversity > CC01A Detection and Attribution of Change in UK and European Ecosystems
CEH Sections: _ Ecosystem Assessment & Forecasting
Additional Information. Not used in RCUK Gateway to Research.: For full text click on Official URL link
NORA Subject Terms: Ecology and Environment
Related URLs:
Date made live: 23 Sep 2008 14:20
URI: http://nora.nerc.ac.uk/id/eprint/3149

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