Nitrogen is an element that is essential for growth and reproduction in all living things. It is found in amino acids that make up proteins and nucleic acids that comprise the hereditary material of life. Nitrogen comprises about 80% of the Earth's atmosphere and although it is common and plentiful, only a specialized group of bacteria, and industrial fertilizer manufacture can "fix" this largely inert compound into biologically useful nitrogen compounds. How does man alter the naturally occurring nitrogen cycle and in turn, impact other cycles on Earth?Nitrogen fertilizer is applied inefficiently and as a result, about 80% of the nitrogen in applied fertilizer is never incorporated into plants, but rather pollutes rivers and lakes causing uncontrolled algal growth. NOx gases released into the atmosphere contribute to the production of acid rain. Agricultural soilmanagement is the largest source of N2O emissions in the U. S.In coastal marine systems, increases in nitrogen runoff often lead to anoxic conditions and dead zones. Burning fossil fuels, using synthetic nitrogen fertilizers and cultivation of legumes are all detrimental to the nitrogen cycle. Globally, about 70% of total N2O emissions come from human activities