Nitrifying bacteria participate in the nitrogen cycle mainly by
a. Converting nitrogen gas to ammonia
b. Releasing ammonium from organic compounds, thus returning it to the soil
c. Converting ammonium to nitrate, which plants absorb
d. Incorporating nitrogen into amino acids and organic compounds

Verified step by step guidance

1. Understand the role of nitrifying bacteria in the nitrogen cycle. Nitrifying bacteria are crucial for converting nitrogen compounds into forms that plants can absorb.
2. Identify the specific process that nitrifying bacteria are involved in. They are primarily responsible for converting ammonium (NH₄⁺) into nitrate (NO₃⁻).
3. Recognize that this conversion is a two-step process: first, ammonium is oxidized to nitrite (NO₂⁻) by bacteria such as Nitrosomonas, and then nitrite is further oxidized to nitrate by bacteria such as Nitrobacter.
4. Consider the options given in the problem. Option c, 'converting ammonium to nitrate, which plants absorb,' directly describes the role of nitrifying bacteria.
5. Conclude that the correct answer is option c, as it accurately reflects the function of nitrifying bacteria in the nitrogen cycle.

Key Concepts

Nitrogen Cycle

The nitrogen cycle is a crucial ecological process that transforms nitrogen into various chemical forms, making it accessible to living organisms. It involves several stages, including nitrogen fixation, nitrification, assimilation, ammonification, and denitrification. Understanding this cycle is essential for comprehending how nitrogen moves through the environment and supports life.

Nitrifying Bacteria

Nitrifying bacteria are a group of microorganisms that play a vital role in the nitrogen cycle by converting ammonia into nitrites and then into nitrates. This process, known as nitrification, is essential for making nitrogen available to plants in a form they can absorb and utilize for growth. These bacteria are typically found in soil and aquatic environments.

Nitrate Absorption by Plants

Plants absorb nitrates from the soil as a primary source of nitrogen, which is crucial for synthesizing proteins and other essential compounds. Nitrates are the end product of nitrification, a process facilitated by nitrifying bacteria. This absorption is a key step in the nitrogen cycle, linking soil nutrient availability to plant growth and ecosystem productivity.