Ammonium ions (NH₄⁺) are converted to nitrate (NO₃⁻) and nitrite (NO₂⁻) through a process called nitrification.

Here's a breakdown of the process:

1. Nitrification

* Step 1: Oxidation of Ammonium to Nitrite

* Bacteria: *Nitrosomonas* and other related bacteria.

* Reaction: NH₄⁺ + 1.5O₂ → NO₂⁻ + 2H⁺ + H₂O

* Step 2: Oxidation of Nitrite to Nitrate

* Bacteria: *Nitrobacter* and other related bacteria.

* Reaction: NO₂⁻ + 0.5O₂ → NO₃⁻

In Summary:

* Nitrification is a biological process that occurs in soil and water.

* Specialized bacteria perform the oxidation steps, using oxygen to convert ammonium to nitrite and then to nitrate.

* This process is crucial for the nitrogen cycle, making nitrogen available to plants and other organisms.