Water bodies can be polluted with sulfur compounds by direct discharge of
sulfur-contaminated (waste)waters, but also by acid deposition of sulfur com-pounds from the atmosphere. Sulfates can be emitted directly into the atmosphere,
for example, by sea salt aerosols or volcanic eruptions. Indirectly, H
2SO4is formed
following atmospheric SO
2and SO
3
emission (predominantly anthropogenic, see
Section I.A.5), thus leading to acid, sulfate-contaminated rain water. Precipitation
of this acid rain water causes acidification of surface waters and soils. This results
in a decrease of the species diversity and the vitality of many ecosystems. In
particular, oligotrophic, weakly buffered lakes are very sensitive to acidification