Freshwater Umbrella Research 2004-7

WP 2: Nitrogen as a nutrient

Task 2.4 — Review the case for application of critical loads for nutrient N to UK freshwaters, with preliminary assessment of critical load exceedance

Empirical critical loads for nutrient N are provided in the CCE Mapping Manual for shallow softwater lakes and in some areas of the UK (e.g. northern Scotland) where such sites occur, total N deposition may exceed the published range (5-10 kg N ha-1 yr-1). In this Task we will examine existing datasets, review the nutrient N critical loads literature and employ the results of Tasks 2.1, 2.2 and 2.3 to assess the case for the application of nutrient N critical loads in the UK, including a characterisation of sites most likely to be exceeded.