Humic lake acidification experiment. Status pr September 1990, one week before start of the treatment

Abstract

An important conclusion from the acid rain research during the late 1970's and the early 1980's, was that humic substances (HS) in the water affected the response of acid rain. HS acts as a modifier on both the chemical composition and on the biological activity of acidified surface water. The Humex project will, by artificial acidification of a whole catchment, study the role of HS on the acidification and the role of acidification on the biological properties of HS. In fall 1988, a dystrophic lake was divided in two halves by a plastic curtain, from the middle of the natural outlet to the opposite side. During the following two years, through September 1990, the water chemistry of the two lake halves has been monitored and a number of scientists from Europe and North America have been studying the organic matter and the biota in the water, and in the catchment area prior to the artificial acidification, which started October 6th 1990.