Since the nitrogen cycle is typically associated with plants because of the nitrogen-fixing bacteria that live on plant roots, this process is independent of aerobic respiration. Instead, the nitrogen cycle involves the process of nitrogen-fixing, ammonification (through which ammonium is converted to nitrites), nitrification (through which nitrites are converted to nitrates), and assimilation from plants and/or denitrification through denitrifying bacteria that return nitrogen to the atmosphere as N2.
Therefore, the correct answer to this question is aerobic respiration.