Greenhouse gas (GHG) emissions from oil and gas systems are an important component of the GHG emission inventory. To assess the carbon emissions from oilfield-produced water under atmospheric conditions correctly, in situ detection and simulation experiments were developed to study the natural release of GHG into the atmosphere in the Shengli Oilfield, the second largest oilfield in China. The ...

The diazotrophic cyanobacterium Trichodesmium is a significant contributor to marine nitrogen and carbon cycles and has been incorporated in biogeochemical ocean circulation models. To date, parameterization of light as a controlling factor for nitrogen fixation has been based on field observations, where factors other than light also affect Trichodesmium physiology. Here we present data on lig...

increasing the concentration of atmospheric carbon dioxide is the main factor for the climatic change having some harmful consequences for the human health while there is no considerable effort for decreasing this accelerated global problem, yet. kermanshah province located in the west of iran has about 1,200,000 ha rangeland which is dominated by astragalus sppas the more frequent shrub beinga...

biological soil crusts (bscs) result from an intimate association between soil particles and cyanobacteria, algae, fungi, lichens and mosses in different proportions which live on the surface, or immediately in the uppermost millimeters of soil. therefore bscs cover the ground surface as a coherent layer, and influence primary processes such as carbon and nitrogen fixation and hydrologic status...

Extremely small quantities of carbon monoxide in air inhibit nitrogen fixation by red clover plants inoculated with Rhizobium trifolii (Lind and Wilson, 1941). In preliminary trials with Azotobacter vinelandii Wyss (1941) found a similar inhibition at carbon monoxide concentrations about 10 times those required for the symbiotic system. We have made a detailed study of the inhibition of this az...

• In nitrogen (N)-limited systems, the response of symbiotic N fixation to elevated atmospheric [CO 2 ] may be an important determinant of ecosystem responses to this global change. Experimental tests of the effects of elevated [CO 2 ] have not been consistent. Although rarely tested, differences among legume species and N supply may be important. • In a field free-air CO 2 enrichment (FACE) ex...

During 198 1 we examined the diel variations of nitrogen fixation in Lake Valencia, Venezuela. Four species of heterocyst-bearing blue-green algae were common but subdominant in the phytoplankton. In samples taken from and incubated at 0.5 m, the rate of nitrogen fixation per unit volume of water was lowest at night (~6% of the maximum daytime rate), increased from dawn until early afternoon, a...