lämmastikuringluses

lämmastikuringluses is the Estonian term for the nitrogen cycle, a crucial biogeochemical process that circulates nitrogen through the Earth's atmosphere, biosphere, and lithosphere. This cycle is essential for life as nitrogen is a key component of amino acids, proteins, and nucleic acids. The primary reservoir of nitrogen is the atmosphere, where it exists as nitrogen gas (N2), a form that most organisms cannot directly utilize.

The nitrogen cycle involves several key steps. Nitrogen fixation is the process by which atmospheric nitrogen is converted into ammonia (NH3) or related compounds. This can occur biologically, primarily by certain bacteria and archaea, or abiotically through lightning or industrial processes. Once fixed, nitrogen can be assimilated by plants and microorganisms.

Ammonification is the decomposition of organic nitrogen compounds into ammonia by decomposers. Nitrification is the conversion of ammonia to nitrites (NO2-) and then to nitrates (NO3-) by nitrifying bacteria. Nitrates are the form of nitrogen most readily absorbed by plants. Denitrification, carried out by denitrifying bacteria, converts nitrates back into nitrogen gas, returning it to the atmosphere and completing the cycle. Human activities, such as the use of fertilizers and combustion, significantly impact the natural nitrogen cycle, leading to environmental issues like eutrophication.