Final answer:
The primary sulfur source for the newly discovered bacteria is hydrogen sulfide, which these bacteria oxidize during anoxygenic photosynthesis to obtain energy.
Step-by-step explanation:
The primary sulfur source for the newly discovered bacteria is hydrogen sulfide. Bacteria and other microorganisms play a crucial role in the sulfur cycle, with many bacteria using sulfate, coming from the decomposition of dead organisms, as a source of sulfur. However, some specialized bacteria, such as purple sulfur bacteria from the genus Chromium, perform anoxygenic photosynthesis where they oxidize hydrogen sulfide as an electron donor to obtain energy and grow. These microorganisms typically live in anaerobic (oxygen-free) water environments and rely on sulfur compounds, such as hydrogen sulfide, which they convert into elemental sulfur or sulfuric acid.