Nitrogen Cycling in Alpine Watersheds
What is nitrogen ?
Nitrogen is one of the most abundant elements in our atmosphere, in fact it makes up almost 80% of the air that we breathe. Nitrogen can be found in most parts of our world, in different phases. Nitrogen is a gas in the atmosphere (N2), a solid nutrient in the soil (NH4+ and NO3-), a dissolved form in water, and can be in liquid form in man-made liquid nitrogen.
Do we need nitrogen?
All living things need nitrogen to survive. Nitrogen is an essential element in the basic building blocks of life; DNA, proteins, and amino acids.
Does nitrogen move or stay still?
Nitrogen is continuously cycling through our environment, between reservoirs. Reservoirs are different places that store nitrogen, like the atmosphere, ocean, surface waters, soils, and biota (all living things). Microbes (tiny living organisms) are essential to the nitrogen cycle, as they perform many jobs to keep nitrogen moving through the environment. Various natural processes enable this movement, including fixation, nitrification, denitrification, mineralization, assimilation, and leaching.
During nitrification, nitrifying bacteria convert ammonium (NH4+) to nitrite (NO2-) to nitrate (NO3-), a more usable form of nitrogen for plants.
Nitrogen compounds in various forms are taken up from soils by plants which are then used in the formation of plant and animal proteins.
When nitrogen is deposited on the ground, such as in the form of animal waste or dead plants, microbes process nitrogen through the process decay, returning nitrogen to the soils.
Excess nitrogen in soils can be carried away by runoff (water), which then enters surface waters downstream. Leaching leads to high levels of nitrogen in surface waters, causing algal blooms. Algal blooms cause anoxic conditions, which lead to fish kills and other environmental damage.
Some nitrogen moves from the water to the atmosphere as detrifying bacteria produce nitrogen gas. 80% of the Earth's atmosphere is nitrogen.