GGR214H5 Chapter Notes - Chapter 2: Nitrogen Fixation, Denitrification, Water Cycle
Document Summary
Protects life from harmful radiation from the sun. Concentration remain the same on century timescales, large residence time. 78 % nitrogen, 21 % oxygen, 0. 93% argon. Concentration vary over time and space, small residence time. Residence time: average amount of time that a substance might be expected to remain in the atmosphere or any of the other spheres of the earth atmosphere system. The atmosphere is a reservoir with sources and sinks sources are inputs to a reservoir sinks are outputs from a reservoir. Converts nitrogen into forms that organisms can use: bacteria, lightning, source. Denitrification: bacteria converts fixed nitrogen into n2 or nitrous oxide (n2o, n2o is eventually converted back into n2 by photodissociation. Respiration: carbohydrates and oxygen produce energy, co2 and h2o. Decomposition: organic material or carbohydrate is decomposed: bacteria consumes oxygen and produces carbon dioxide, in the absence of oxygen anaerobic decomposition is performed.
