Nitrogen cycle evolution

Beaumont V. and Robert F. (1998) Nitrogen isotopic composition of organic matter from Precambrian cherts new keys for nitrogen cycle evolution Bull. Soc. Geol. Fr. 169(2), 211-220. 

Falkowski, P.G. 1997 Evolution of the nitrogen cycle and its influence on the biological sequestration of C02 in the ocean. Nature 387 272-275. 

Aber, J. D. (1992). Nitrogen cycling and nitrogen saturation in temperate forest ecosystems. Trends in Ecology and Evolution, 1, 220-3. 

More recently, electrochemical methods have been used to bring about a controlled reduction of the dialkylhydrazide compounds formulated above, and the whole system has been cyclized, as shown in Scheme 4/ This ppens the way for the production of amines directly from coordinated dinitrogen, without the intermediacy of ammonia. It suggests a possible electrochemical cycle for the production of ammonia, too, but until recently this has not been a feasible route, because reduction of the hydrazine derivative ( NNHj stage) always led to the evolution of hydrogen rather than to the reduction of the compound and loss of the bromide, as occurs in the alkylated-nitrogen cycle. 

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