BIOC63H3 Lecture Notes - Lecture 9: Carl Bosch, Fritz Haber, Nitrogen Fixation
18 Nov 2013
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Nh3, nh4, haber-bosch, microbial fixation: nox no, no2, fossil fuel combustion, lightning, eutrophication (n deposition) Lightning creates huge pressure and high temperatures that can turn unreactive nitrogen to reactive nitreogen in the soil. Soil bacteria can incorporate n in their own cells for. Excrete it back into the soil in form of nitrate. Needed to run hb reaction: german chemist fritz haber and carl bosch 1909, high pressure 200-400 atm, high temp 400-600 c. 1: use fossil fuels to drive the expensive reaction, these conditions are usually only otherwise produced by lightning. Humans have more than doubled global n input. Natural fixation 100 tg of n/year: more than doubled now thanks to humans, no longer a closed cycle. Nitrogen overload decrease in plant diversity: once the n threshold was reached, d rotundifolia"s population decreased significantly. N overload vs. global biodiversity hotspots decreased.
