The dynamic inter-relationship between acid rain and eutrophication in thesoil domain

This work recognises the widespread deterioration of the natural environmen t, and the continual emergence of sudden environmental changes resulting fr om complex non-linear interactions of apparently disparate phenomena. Incor porating contemporary views of complexity and evolution, this paper present s a dynamic complex systems model which displays the discontinuous and non- linear characteristics which emerge from the inter-relationships of two suc h phenomena - acid rain and eutrophication - within the soil domain. A desc ription is given of the chemical and hydrological sub-modules which provide the basis of this spatio-temporal model, and the inter-relationships betwe en the buffering of acid and the adsorption of phosphates by the soil. Vari ous representations of soil acidification, phosphate adsorption and hydrolo gy drawn from existing models and literature are used to address both the c hemical interactions and the spatial hydrological flows within the context of a river catchment. The resulting model can be easily applied to any chos en catchment due to the minimal data requirements and its generic represent ation. It may be utilised to describe non-point sources of phosphates as pa rt of assessments of potential eutrophication, overcoming some of the limit ations found in existing models, and provides the basis for the examination of Chemical Time Bomb (CTB) phenomena whereby the soil changes from being a phosphate sink to being a phosphate source.