Nitrogen in the environment

• Nitrogen is an essential component of many organic molecules such as DNA, RNA and proteins, the building blocks of life.  Air is the major reservoir of nitrogen that constitutes 79% of nitrogen gas (N2). Although the majority of the air we breathe is N2, most of this is unavailable for use. This is because of the strong triple bond between the N atoms in the N2 molecules that make it relatively inert. Therefore, in order for the plants and animals to use nitrogen, N2 gas must be converted to either ammonium (NH4+) or nitrate (NO3-) or organic nitrogen such as urea - (NH3)2CO.
• Nitrogen (N), a macronutrient, is most frequently found limiting for plant growth. This is due to the continual loss of nitrogen from the reserve of combined or fixed nitrogen, which is present in soil and available for use by plants. It is continually depleted by such processes as microbial denitrification, soil erosion, leaching, chemical volatilization, and most important, removal of nitrogen-containing crop residues from the land. The nitrogen reserve in agricultural soils must therefore be replenished periodically in order to maintain an adequate (non-growth limiting) level for crop production. This replacement of soil nitrogen is generally accomplished by the addition of chemically fixed nitrogen in the form of commercial inorganic fertilizers or by the activity of biological nitrogen fixation (BNF) systems.
• Nitrogen is a versatile element that exists in both organic and inorganic forms as well as in many different oxidation states. The movement of nitrogen between the atmosphere, biosphere, and geosphere is described in the nitrogen cycle (Figure 1), one of the major biogeochemical cycles.

Exploring the nitrogen cycle, microbial diversity and plant biotechnology

A workshop was held on April 28, 2007. The purpose of this workshop was to provide high school science teachers with useful exercises to convey basic scientific concepts to your students.