Esthwaite Water - United Kingdom
UK ECN Site. Esthwaite Water is a natural lake situated in a glacial valley and is generally agreed to be the most productive or eutrophic lake in the English Lake District. It lies approximately 65 m above sea level and has an area of 1 km2 and a maximum depth of 15.5 m. The average retention time is 90 days. The catchment area is 17.1 km 2 and the hills are composed geologically of Bannisdale slates and grits. The surrounding land is used chiefly for agricultural purposes and forestry. The lake is a grade 1 Site of Special Scientific Interest and has been a designated "Ramsar" site since November 1991. The diverse aquatic invertebrate fauna includes a number of species with restricted distributions in Britain, one of which is the flatworm, Bdellocephala punctata. The slender naiad, Najas flexilis, which is listed as Nationally Scarce, has been found in Esthwaite Tarn. Artificial enrichment of the lake occurs by input from the Hawkshead Sewage Treatment Works (which has operated a continuous programme of phosphate stripping since 1989) and originally from effluents from the fish farm which used to be situated towards the south of the lake. The lake undergoes summer stratification with oxygen depletion regularly below 7 m and sometimes as shallow as 5 m. The phytoplankton tends to be dominated by diatoms in spring and by cyanobacteria for much of the summer.
General Characteristics, Purpose, History
Lake ecological monitoring and research. Research on Esthwaite Water has been closely linked to that on Windermere with its origins in the work of W H Pearsall who started his studies of the English Lake District just before the First World War. A national facility for biological research on freshwaters was established in 1929 with a base established on the shores of Windermere in 1931 when a small group of scientists began research in earnest. Work continued throughout the Second World War and in 1950, the laboratory with its 41 staff was transferred to Ferry House and then the main laboratory was relocated to buildings on Lancaster University site in 2003. Before 1970, research carried out was primarily of a fundamental nature as progress was made to understand some of the key processes controlling freshwater ecosystems. Subsequently, there was a shift towards more applied work whilst continuing with a core element of fundamental research. Data collected includes, amongst others, water temperatures, dissolved oxygen levels, nutrients, flora and fauna information. The long-term data are used to reveal long-term trends of ecosystem functions and services provided as affected by climate change.
Affiliation and Network Specific Information