What is the process called when ammonia is converted to nitrite by bacteria in aquatic systems?

What is the process called when ammonia is converted to nitrite by bacteria in aquatic systems?

• A. Photosynthesis
• B. Respiration
• C. Nitrification
• D. Fermentation

Answer: (C)

Nitrification is the process you’re asking about. It’s an aerobic microbial sequence that begins with ammonia-oxidizing bacteria converting ammonia (NH3) into nitrite (NO2−), with Nitrosomonas often cited as a classic example. This sets the stage for the next step, where nitrite-oxidizing bacteria convert NO2− into nitrate (NO3−). Together, these steps comprise nitrification, a key part of the nitrogen cycle in aquatic systems and an important way that ammonia is detoxified, though it can raise nitrate levels. The other processes don’t fit: photosynthesis uses light to build sugars, respiration uses oxygen to release energy from organic matter, and fermentation occurs anaerobically to generate energy without an external electron acceptor.

Nitrification is the process you’re asking about. It’s an aerobic microbial sequence that begins with ammonia-oxidizing bacteria converting ammonia (NH3) into nitrite (NO2−), with Nitrosomonas often cited as a classic example. This sets the stage for the next step, where nitrite-oxidizing bacteria convert NO2− into nitrate (NO3−). Together, these steps comprise nitrification, a key part of the nitrogen cycle in aquatic systems and an important way that ammonia is detoxified, though it can raise nitrate levels.

The other processes don’t fit: photosynthesis uses light to build sugars, respiration uses oxygen to release energy from organic matter, and fermentation occurs anaerobically to generate energy without an external electron acceptor.