Question

thiobacillus denitrificans is a species of bacteria that obtains its energy from carbon dioxide and inorganic compounds such as nitrogen in its environment. it is used in bioremediation (natural cleansing) of groundwater that contains excess nitrate, allowing the nitrates to be removed. through what process does thiobacillus denitrificans help bioremediate groundwater?

nitrification

denitrification

nitrogen fixation

decomposition

Explanation:

1. Analyze each process:

• Nitrification: Converts ammonia to nitrate, which would increase nitrate, not remove it.
• Denitrification: Bacteria convert nitrates into nitrogen gas, removing nitrates from the environment (like groundwater here). The bacterium is Thiobacillus denitrificans (name includes "denitrificans"), hinting at denitrification.
• Nitrogen fixation: Converts atmospheric nitrogen to ammonia, not related to nitrate removal.
• Decomposition: Breaks down organic matter, not focused on nitrate removal.

1. Match the bacterium's action (removing nitrate) to denitrification, where nitrates are reduced to nitrogen gas and removed.

Answer:

B. denitrification