Question

When nitrate is reduced to dinitrogen gas (N2), nitrogen is removed from the ecosystem and returned to the atmosphere through a series of reactions collectively known as ______.

1) nitrogen fixation
2) denitrification
3) anammox reaction
4) All of the choices are correct.

Answer 1

The series of reactions that reduce nitrate to dinitrogen gas and return nitrogen to the atmosphere is known as denitrification, which is a key component of the global nitrogen cycle.

Step-by-step explanation:

When nitrate is reduced to dinitrogen gas (N2), nitrogen is removed from the ecosystem and returned to the atmosphere through a series of reactions known as denitrification.

This is a part of the nitrogen cycle, where nitrogen-fixing bacteria incorporate atmospheric nitrogen into the biosphere, and it is eventually returned back to the atmosphere through several processes.

Specifically, during denitrification, soil bacteria such as Pseudomonas and Clostridium convert nitrates (NO3-) into nitrogen gas (N2), completing the cycle and replenishing the atmosphere.

This process is crucial in regulating the global nitrogen cycle and involves intermediate steps such as ammonification and nitrification, where ammonium (NH4+) is converted to nitrites (NO2-) and then to nitrates (NO3-), before finally being converted into dinitrogen gas.