2. 1. Hydrogen sulfide gas is released into the atmosphere › Volcanic eruptions and hot springs › Decay of sulfur-containing materials 2. Marine algae produce dimethyl sulfide that enters the atmosphere 3. Sulfur Dioxide enters the atmosphere › Volcanoes › Reaction of dimethyl with oxygen › Combustion of fossil fuels ; raises the amount of acid deposition 4. Sulfur reacts with oxygen; the result is sulfur trioxide 5. Sulfur trioxide react with water forming sulfuric acid › Produces fog and acid rain 6. Organisms use sulfur to make proteins 7. Plants take in sulfate salts from the soil 8. Organisms eat the plants taking in the sulfur and release it when they decompose. › Some goes back into soil some goes into the atmosphere

3.  Acid rain resulting from the sulfur dioxide released into the atmosphere has greatly impacted the biosphere.  Acid rain causes an increase in the amount of acid in the soil which limits plant growth. When these plants die off or aren’t as abundant it causes herbivores to lack their food source. And this carries onto the consumers that eat herbivores because now these consumers are missing their food. This chain reaction then trickles through the food web.  When there is an increase in acid rain, some organisms cannot tolerate it and end up dying. Then other organisms who feed off of these animals are deprived of their food source.

4.  Oil and coal fired power plants, metal smelters, and burning of fuel oils to heat houses releases sulfur dioxide(SO2) into the air. › SO2 is oxidized to sulfate in the air as sulfuric acid, which is a major part of acid rain  Acid rain gets into lakes, rivers, and streams and lowers the pH of the water which will negatively effect the life that exists in the water. › Many organisms cannot handle the acidic water › Humans are unable to use for fishing and recreation  The SO2 in the air can cause harm to human health. › Respiratory diseases  Acid rain damages forests because it takes nutrients that are necessary for plants to survive.

5.  The most significant effect humans have had on the sulfur cycle is through the production of sulfur dioxide from our day to day anthropogenic activities such as… › Industrial processes › Combustion of fossil fuels › Mining of metals (Cu) › Internal combustion engine  The sulfur dioxide released from these activities is a main component of acid rain.

7.  www.cengage.com/biology/discipline_content/animat ions/sulfur_cycle.html www.cengage.com/biology/discipline_content/animat ions/sulfur_cycle.html  www.science.jrank.org www.science.jrank.org  AP Book: Friedland and Relyea Environmental Science for AP*  www3.epa.gov/acidrain/effects/surface_water.html  www.clean-air-kids.org www.clean-air-kids.org