title: Manganese in the upper Severn mid-Wales.
abstract: The concentrations of manganese (Mn) in the Upper River Severn (the Plynlimon catchments) are examined in relation to rainfall, cloud water, throughfall, stemflow and stream water concentrations where there is over 20 years of monitoring data available. Manganese concentrations are particularly low in rainfall and cloud water, with maximum concentrations occurring under low volumes of catch due to atmospheric "washout" of contaminants and dry deposition. There is strong Mn enrichment in throughfall and stemflow and this is probably linked to cycling through the vegetation. Manganese in the streams and groundwaters are primarily supplied from within-catchment sources. The highest concentrations occur within the tree canopy probably due to element cycling and in groundwaters due to mobilisation from the rock. Manganese concentrations in streams are at their lowest during spring and summer following long dry spells, with rapid increases following subsequent rain. There is no clear long-term trend in Mn concentration in the streams although there are increases in Mn concentrations for years when there is extensive felling of spruce plantation forest and in 1995 following a more extensive dry period. New high resolution monitoring picks up the effects of the rising limb of the hydrograph when concentrations rapidly increase, diurnal patterns during summer low-flow periods and contrasting dynamics between moorland and forested catchments.
authors: Centre for Ecology and Hydrology, Lancaster. Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK.
authors: A P
authors: AP
authors: Rowland
authors: C
authors: C
authors: Neal
authors: B
authors: B
authors: Reynolds
authors: M
authors: M
authors: Neal
authors: A J
authors: AJ
authors: Lawlor
authors: D
authors: D
authors: Sleep
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring; D016468:Forestry / Q000706:statistics & numerical data; D060587:Groundwater / Q000737:chemistry; D007700:Kinetics; D016014:Linear Models; D008345:Manganese / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D014852:Wales; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data; D014887:Weather
chemical_list: D014874:Water Pollutants, Chemical; D008345:Manganese