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Title: Assessment of the nutrient status and associated algal productivity of Malham Tarn, Yorkshire
Author: J.F. Talling
Document Type: Monograph
Concern about a possible increase in nutrients to Malham Tarn, N. Yorks, with biological consequences, led in 1982 to a previous commissioned FBA report to the Nature Conservancy Council. As a mainly desk-study, it assessed the chemical evidence then available. This strongly suggested an increase since 1960 in the winter nitrate content of the Tarn water, but the situation with respect to phosphorus - potentially the most influential enrichment - was uncertain. Quantitative recent information was lacking for several major sources of input and compartments of storage. Among the latter algal communities of the plankton and benthos are important, and are also indicators of biological response to nutrients. To remedy these deficiencies in knowledge, a field investigation was carried out from March 1985 to March 1987. The present Report describes and assesses its findings. The Tarn is treated as a chemical system of input, largely transient storage, and output; seasonal cycles of inflow and outflow concentrations are traced and compared with reference to the dynamics of algal biomass and averaged nutrient concentrations in the Tarn. Algal biomass in plankton and benthos is characterised for elemental composition, and the phytoplankton resolved into seasonally varying species components with distinct patterns of environmental response. Very rough estimates are attempted of the nutrient inputs from atmospheric precipitation, migrant birds, agricultural fertiliser, and domestic sewage. Internal nutrient loading is also considered. Finally the susceptibility to long-term change is discussed, partly with reference to older records.
Publisher: Freshwater Biological Association
Publication Date: 1987
Publication Place: Ambleside
Subject Keywords: NutrientsEutrophicationCatchment basinsBenthic environmentNutrient balanceBiomassPotassiumPhosphorusAtmospheric depositionFertilizersSewage
Geographic Keywords: Yorkshire
Extent: 37; + figures and tables
Total file downloads: 169

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