scholarly journals A modeling case for high atmospheric oxygen concentrations during the Mesozoic and Cenozoic

Geology ◽  
2016 ◽  
Vol 44 (12) ◽  
pp. 1023-1026 ◽  
Author(s):  
Benjamin J.W. Mills ◽  
Claire M. Belcher ◽  
Timothy M. Lenton ◽  
Robert J. Newton
Keyword(s):  
Atmospheric Oxygen ◽  
Oxygen Concentrations

Reduction of acetylene by stationary cultures of free-living Rhizobium sp. under atmospheric oxygen levels

1976 ◽  
Vol 22 (7) ◽  
pp. 949-952 ◽  
Author(s):  
William R. Evans ◽  
Donald L. Keister
Keyword(s):  
Atmospheric Oxygen ◽  
Maximal Activity ◽  
Free Living ◽  
Oxygen Levels ◽  
Specific Activities ◽  
Rhizobium Sp ◽  
Oxygen Concentrations

The reduction of acetylene to ethylene by stationary (non-shaking) cultures of free-living rhizobia under atmospheric oxygen levels has been demonstrated. Under these conditions the development of the activity is inhibited by 10 mM NH4Cl and about 20% of oxygen is required for maximal activity. When the stationary cultures were shaken, oxygen concentrations of 1% and higher were found to be inhibitory. Specific activities of 20 and 40 nmol of acetylene reduced h−1 mg−1 protein were observed.

scholarly journals AVALIAÇÃO QUÍMICA DE LENHOS CARBONIZADOS DE Araucaria columnaris SOB DIFERENTES CONCENTRAÇÕES DE OXIGÊNIO COMO COMPARATIVO DE ANÁLISE DE charcoal FÓSSIL

Química Nova ◽  
2020 ◽  
Author(s):  
Fernanda Marder ◽  
Daniela Lara ◽  
André Jasper ◽  
Eduardo Ethur ◽  
Dieter Uhl ◽  
...  
Keyword(s):  
Climate Change ◽  
Environmental Changes ◽  
Atmospheric Oxygen ◽  
Firing Process ◽  
Chemical Evaluation ◽  
Fossil Coal ◽  
The Face ◽  
Life Trajectory ◽  
Carbonized Wood ◽  
Oxygen Concentrations

CHEMICAL EVALUATION OF Araucaria columnaris CARBONIZED WOODS UNDER DIVERSE OXYGEN CONCENTRATIONS AS COMPARATIVE ANALYSIS OF FOSSIL charcoal. In the face of environmental changes concerns, the study of climate change becomes essential to understand the life trajectory of planet earth. For this purpose, this work seeks to understand climate change and fluctuations in the amount of atmospheric oxygen across geological ages, carbonizing the Araucaria columnaris wood in varying oxygen concentrations, and comparing them to the fossil coal from Quiteria Outcrop. In this study, pyrolysis of Araucaria columnaris wood occurred with the use of TGA, under an atmosphere of 21% and 30% O2, analyzed in FTIR, distinguishing the constituent compounds of the wood. Multivariate analysis of the mains components (PCA) was applied, for data crossing. There is a distinction between carbonized wood and fossil charcoal, the charcoal burning temperature as well as the atmospheric oxygen composition being inconclusive. However, FTIR results indicate that the amount of oxygen has an influence on the degradation of the wood, and samples at 450 °C have greater similarities with fresh wood. Thus, it was observed that the temperature and the burning time are the main factors of the fires, being that the amount of oxygen available in the atmosphere influences the firing process.

scholarly journals Response to Comment on "Long-term climate forcing by atmospheric oxygen concentrations"

Science ◽  
2016 ◽  
Vol 353 (6295) ◽  
pp. 132-132 ◽  
Author(s):  
C. J. Poulsen ◽  
C. Tabor ◽  
J. White
Keyword(s):  
Atmospheric Oxygen ◽  
Climate Forcing ◽  
Oxygen Concentrations
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