Supply of nutrients in bulk precipitation to the Upper Lagan catchment

Abstract

Studies of the supply of nutrients from atmospheric sources have been common in Britain and the United States but little similar research has been undertaken in Ireland. In the present study monthly inputs in bulk precipitation were calculated for the 1976/77 water year in a 3 km2 headwater portion of the River Lagan catchment. Nutrient values were observed to fluctuate from month to month, usually reflecting rainfall amount. The effects of atmospheric scavenging were noted for months which followed several consecutive weeks of dry weather. Dry fallout, originating from outside the catchment, was thought to be an important contributor of phosphate. Nitrate and potassium were other nutrients considered to have predominantly terrestrial sources; sodium, magnesium, and to a lesser extent calcium, having marine origins