Final answer:
Sulfur oxidizing bacteria oxidize sulfur compounds to generate energy, playing a key role in the biogeochemical cycling of sulfur and converting inorganic sulfur to sulfate in the sulfur cycle. The correct option is B.
Step-by-step explanation:
Sulfur oxidizing bacteria specialize in oxidizing sulfur compounds. These bacteria are crucial in the biogeochemical cycling of sulfur and can use sulfur compounds such as hydrogen sulfide (H2S), elemental sulfur (S0), and sulfite (SO32-) as electron donors to generate energy.
In environments like deep-ocean vents and sulfur springs, they play an important role in converting inorganic sulfur compounds to sulfate (SO42-), thus contributing to the sulfur cycle.
Phototrophic sulfur bacteria can perform anoxygenic photosynthesis, where sulfur compounds serve as electron donors instead of water, as in oxygenic photosynthesis. This process does not produce oxygen but rather forms sulfate.
In contrast, nonsulfur bacteria use organic compounds, such as succinate and malate, for photosynthesis. Whereas nitrifying and nitrogen-fixing bacteria play different roles in the nitrogen cycle, oxidizing nitrogen compounds into nitrites, nitrates, or incorporating nitrogen gas into organic compounds.