OBSERVATIONS ON THE CHANGES IN NITRATE CONCENTRATIONS ALONG STREAMS IN 7 UPLAND MOORLAND CATCHMENTS IN NORTHEAST SCOTLAND

River water has been sampled under baseflow conditions in both summer and winter at c. 250-m intervals along the length of each of seven riv ers in northeast Scotland, and the nitrate contents have been determin ed. The resultant data have been examined in the context of the nitrog en saturation hypothesis, Capacity of the catchment soils to retain ni trate was generally minimal in winter. Although biological uptake of n itrate was evident in summer, in the upper part of each catchment subs tantial nitrate leaching still occurred. The phenomenon was most marke d in water draining from hill peats, except where these were conspicuo usly waterlogged. The results are discussed in the context of possible nitrogen saturation effects on upper catchment slopes.