The ability to obtain energy via the oxidation of reduced sulfur compounds (e. g., H2S) is widespread among prokaryotes (both Bacteria and Archaea). Unfortunately, the nature of the major reaction end product has what effect on the immediate environment?

a. drastically lower the pH
b. produces reactive oxygen species
c. raise the salinity
d. produce anoxic conditions
e. depletes available nitrogen

Explanation:

H2S is inorganic molecule, and bacteria that gain energy from inorganic molecules are called chemolithotrophs. Sulfur oxidizing bacteria basically oxidize H2S to gain energy.

It is also true that, not all bacteria are sulfur oxidizing. There are many different types of bacteria with different ways of getting energy. They can do photosynthesis, oxidize iron, oxidize hydrogen, etc.

Some bacteria oxidize H2S because they have no direct access to sunlight.

In these bacteria, H2S is used instead of water. This drastically lower the pH.