The status of phosphorus of a calcareous flush at Bakethin Reservoir, Northumberland

In order to assess the status of phosphorus of a calcareous flush at Bakethin reservoir, Northumberland, chemical analyses of the concentration of phosphorus in the water and the phosphatase activity of cyanobacteria, Nostoc and Rivularia, as well as the bryophytes, Drepanocladus revolvens and Cratoneuron commutatum, were performed. Concentrations of total filterable phosphorus ranged from 0.11 to 11.35 μg I(^1) and filtrable reactive phosphorus ranged from below detection to 10.55 μg I(^1) No statistical difference was determined in concentrations of phosphorus at different sites in the flush, but a significant difference was determined between different sampling dates, at <0.05. Phosphatase activity in the cyanobacteria, Rivularia and Nostoc, varied between different sites and different dates. Nostoc showed a consistently higher rate of phosphatase activity than Rivularia. Activity in both the cyanobacteria showed no correlation between filtrable reactive and filtrable organic content of the water. Phosphatase activity in the bryophytes, Drepanocladus revolvens and Cratoneuron commutatum, had its pH maximum in the acidic range. Activity also varied between sampling dates and between different species.