Schwefelkreislaufschließung

Schwefelkreislauf refers to the biogeochemical cycle of sulfur through the Earth's atmosphere, lithosphere, hydrosphere, and biosphere. Sulfur is an essential element for all living organisms, playing a crucial role in the structure of proteins and enzymes.

The cycle begins with the weathering of rocks and minerals, releasing sulfate into the soil and water. Microorganisms, particularly bacteria, are central to the Schwefelkreislauf. Sulfate-reducing bacteria convert sulfate into hydrogen sulfide (H₂S) in anaerobic environments. This gas is then oxidized by other bacteria, such as sulfur-oxidizing bacteria, back into elemental sulfur or sulfate.

Volcanic activity and the burning of fossil fuels are significant sources of atmospheric sulfur compounds, primarily sulfur dioxide (SO₂). SO₂ can be returned to the Earth's surface through acid rain, which can acidify lakes and damage forests. In the atmosphere, SO₂ can be further oxidized to sulfate aerosols, which can influence climate by scattering sunlight.

Plants absorb sulfate from the soil and incorporate it into organic compounds. When organisms die, decomposers break down their organic matter, releasing sulfur back into the environment. Animals obtain sulfur by consuming plants or other animals. The continuous movement and transformation of sulfur through these processes constitute the Schwefelkreislauf. Human activities, particularly industrial emissions, have significantly impacted the natural sulfur cycle by increasing the atmospheric concentration of sulfur compounds.