Biogeochemical cycles recycle water and natural elements throughout the biosphere to ensure that organisms do not run out of these substances. Thiobacillus denitrificans is a specialized species of bacteria that obtains its energy from carbon dioxide and inorganic nitrogen-containing compounds such as nitrates in its environment. It is used in the bioremediation of groundwater that contains excess nitrate. How does Thiobacillus denitrificans help bioremediate groundwater?