Caister Academic Press

Climate Change and Nitrogen Turnover in Soils and Aquatic Environments

Gero Benckiser
from: Climate Change and Microbial Ecology: Current Research and Future Trends (Second Edition) (Edited by: Jürgen Marxsen). Caister Academic Press, U.K. (2020) Pages: 327-390.

Abstract

Many more than 10,500 soil types link the bio-, geo-, aqua- with the atmosphere. After the invention of technical N2-fixation (TNF) by Haber and Bosch (H-B) the BNF (biological N2-fixation) input was almost doubled and the bio-, geo-, and aquaspheres are now the largest greenhouse gas flux drivers (CO2, CH4, NH3, NO, N2O) on Earth. After introduction of NH4+ by BNF and TNF and its conversion to NO3- by autotrophic nitrifying bacteria and archaea, denitrifying bacteria, archaea, and fungi together with plants as gas conduits return after reduction of the oxidized N species NO3- and NO2- the gaseous N species NO, N2O and N2 to the atmosphere. The almost doubled N-input after H-B invention enables farmers to nearly approach Nature's high productivity, which is based on N shortage and biodiversity, by monocultures, often surpassing plant N demand and soil N buffer capacity. In consequence, increasing amounts of NO3- flow towards the groundwater and CO2, CH4, and N2O emissions enhance the atmospheric temperature. Particularly Western Asian and Northern African regions with characteristic low and unpredictable rainfall, long dry seasons, scarce water resources, rural poverty, high dependence on limited cropping/livestock agriculture, and low levels of technological adaptations have to suffer under greenhouse gas effects. In approaching Nature's productivity achievements and being successful in food security and stabilizing ecosystem functioning, farmers and industry TNF product designers must understand (a) the mechanisms behind the individual genes holding promise of a better N absorption by an adapted germplasm and (b) how pollution costs are reducible. On both aspects scientist are doing concentrated research and on the concerned progress in aquatic and soil ecosystems nitrogen cycling this chapter is focussing read more ...
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