Long-term changes of nitrogen and phosphorus loadings to a large lake in north-west Ireland

Lower Lough Erne is a large (109.5km(2)) eutrophic lake in north-west Irela nd. Nutrient data from 14 years in the period 1974 to 1997 are analysed for temporal trends. Over the period of observation, soluble reactive phosphor us loadings have increased by approximately 2.0 tonnes SRP yr(-1) so that b etween 1974 and 1997 the mean concentration of the inflow has increased fro m 15 to 33 mu g SRP 1(-1). The increase is probably caused by diffuse agric ultural sources. There is no temporal trend in inorganic nitrogen inputs. b ut the total nitrogen and total Kjeldhal N both show a weak upward trend wi th time. (C) 2000 Elsevier Science Ltd. All rights reserved.