Aquatic chemistry and humic substances in bog lakes in Latvia

Chemical composition of 19 bog lakes in Latvia has been studied. Peculiarities of chemical composition and their influence on community structure have been analysed as the main factors considering aquatic humic substances (AHS). AHS isolated from bog waters shows principally different elemental, functional and spectral characteristics, and also acidity, from humic substances isolated from other water bodies (eutrophic and mesotrophic) and reference humic samples. The observed differences are due to the dependence of humus properties on biological processes and pollution levels in the water bodies.