Monthly Determinations of the Concentrations of Sodium, Potassium, Magnesium and Calcium in the Rain and in Pools on the Silver Flowe National Nature Reserve

In 1959 the series of ombrotrophic mires in the valley of the Cooran Lane known as the Silver Flowe were declared a National Nature Reserve and in 1964 a programme of work on the mires was begun at the University of Hull. The Cooran Lane runs through a N-S orientated valley between the Merrick and Kells ranges in Kirkcudbrightshire, Scotland. The Silver Flowe complex of mires has been described in some detail by Ratcliffe & Walker (1958). Between 1967 and 1970 work was carried out on the mire which Ratcliffe & Walker called Brishie bog (Nat. Grid ref. NX 477834) and between 1970 and 1973 on that which they named Craigeazle bog (Nat. Grid ref. NX 476810). In connection with this work it was necessary to visit the sites at monthly intervals and this provided an excellent opportunity to obtain data on the total inputs of various inorganic ions with the rain. In a paper dealing with sites in the English Lake District, Gorham (1955) states 'ion concentrations similar to or a little greater than those of the rain have been observed in pools on raised or blanket bogs' but Chapman (1965) working on Coom Rigg moss in Northumberland found that the mean concentrations of five ions at various sites on this bog were about four times the mean concentrations in the rain. On Bog Hill, in the Moor House Nature Reserve, Gorham (1956) collected water samples from several pools in May and August and found marked differences in ion concentrations between pools and between times of the year. It therefore seemed worth while to sample several pools on the Silver Flowe bogs in an attempt to obtain a comprehensive record of the variation in concentration of ions between pools and from month to month over the year as a whole. Chapman (1965) has shown that a considerable volume of water flows through the upper few centimetres of Coom Rigg moss and Boatman & Tomlinson (1973) have shown that water moves just below the surface of Brishie bog into the pools. During passage through the peat it is likely that ions are adsorbed on to the peat colloids and absorbed by plants. By comparing the mean monthly concentrations of ions in the pools with those in the monthly rain collections and, subsequently, by comparing the ratio of one to the other for the different ions, an estimate has been obtained of the relative amounts of different ions removed from the water while passing through the peat. Rain and pool water samples were collected at the Brishie site in 1969 and at the Craigeazle site between the beginning of July 1971 and the end of June 1972.