<em>Reduction of sulfur compounds and the release of hydrogen sulfide is happening here.</em>
<u>Explanation:</u>
Sulfur is an important element in the sulfur cycle. Sulfur compounds can be found on earth in various forms. They can be found in mineral rocks and organic matter. It is the <em>work of bacteria to reduce sulfur</em> compounds and convert them to sulfides.
There are different types of bacteria that reduce various sulfur containing compounds. They are <em>sulfate-reducing bacteria, sulfur-reducing bacteria, sulfite reducing bacteria etc.</em> In a swamp there is low oxygen availability and organic matter decays in this condition.
<em>The sulfate reducing bacteria oxidizes the organic matter and releases Hydrogen sulfide.</em>
<span>In the middle archaeologists have uncovered many early human communities which were lost to time many ages ago, of these communities two notable ones are the Jericho and Catal Huyuk.</span>