Microbial production and uptake of nitric oxide in soil

Abstract

SUMMARYFluxes of NO from three different soils have been studied by a flow-through system in the laboratory as a function of gas flow rate, of NO mixing ratio, and of incubation conditions. The dependence of net NO fluxes on gas flow rates and on NO mixing ratios could be described by a simple model of simultaneous NO production and NO uptake. By using this model, rates of gross NO production, rate constants of NO uptake, and NO compensation mixing ratios could be determined as function of the soil type and the incubation condition. Gross NO production rates were one to two orders of magnitude larger under anaerobic than under aerobic conditions. NO uptake rate constants, on the other hand, were only 5-8 times larger so that the compensation mixing ratios of NO were in a range of about 1600-2200 ppbv under anaerobic and of about 50-600 ppbv under aerobic conditions. The different soils exhibited similar NO uptake rate constants, but the gross NO production rate and compensation mixing ratio was significantly higher in an acidic (pH

Identification of nitric oxide reductase activity in Rhodobacter capsulatus: the electron transport pathway can either use or bypass both cytochrome c2 and the cytochrome bc1 complex

“…This gas is a product of microbial nitrification and denitrification (Goretski & Hollecher, 1988;Carr et al, 1989;Zafiriou et al, 1989;Rende et al, 1989). Furthermore, it is formed during chemical processes such as the decomposition of nitrite in soils and the combustion of fossil fuels (Logan, 1983).…”

“…capsulatus encounters such molecules in its natural habitats and that therefore nitric oxide reductase may be present. Furthermore, the toxicity of nitric oxide, coupled with the evidence of its extensive production in some environments (Rende et al, 1989), suggests that it may be advantageous to possess nitric oxide reductase activity. The present paper describes strains of R .…”

Measurements of nitrogen oxides and ozone fluxes by eddy covariance at a meadow: evidence for an internal leaf resistance to NO<sub>2</sub>

“…It is now well established that soil biogenic NO emission depends on several factors, such as the amount of soil moisture, soil temperature, and soil nitrogen (Remde et al, 1989;Remde and Conrad, 1991;Ludwig et al, 2001;Laville et al, 2009). Ozone is deposited to terrestrial ecosystems through dry deposition (Fowler et al, 2009).…”

The influence of tillage on NO and N2O fluxes under spring and winter barley

“…Nitric oxide is a byproduct of the nitri®cation pathway (Hutchinson & Brams 1992), but also a direct intermediate in the denitri®cation pathway. Although, denitri®cation can produce up to twice as much NO as nitri®cation (Remde et al 1989), the net release of NO from soil is greatly in¯uenced by the gas phase diffusivity in soil and the rate of NO consumption by denitri®ers. It is therefore likely that the lower gas diffusivities created by the direct drilling system will diminish the emission of NO.…”