Effects of Artificial Acidification on the Growth of Periphyton

Abstract

Acidification caused an increase in periphyton growth in large enclosures in the littoral zone of Lake 223. Diatomeae decreased in relative abundance above [H⁺] = 10⁻⁶ mol/L, and were replaced by filamentous Chlorophyta. The genus Mougeotia, dominant in many acidified Scandinavian lakes, was the most tolerant of high acidity. Fewer species and lower species diversity were observed at higher [H⁺]. Although increases in standing crop were observed, there were no corresponding increases in production. The abundance of invertebrates and microbiota were also unaffected by hydrogen ion concentration.Key words: lake acidification, periphyton, microcosms, acid rain