scholarly journals Dissimilatory Nitrate/Nitrite Reduction Processes in River Sediments Across Climatic Gradient: Influences of Biogeochemical Controls and Climatic Temperature Regime

2019 ◽  
Vol 124 (7) ◽  
pp. 2305-2320 ◽  
Author(s):  
Xiaofei Li ◽  
Jordi Sardans ◽  
Lijun Hou ◽  
Dengzhou Gao ◽  
Min Liu ◽  
...  
Keyword(s):  
Temperature Regime ◽  
River Sediments ◽  
Nitrite Reduction ◽  
Climatic Gradient ◽  
Climatic Temperature ◽  
Reduction Processes

scholarly journals Effects of Sulfamethoxazole and 2-Ethylhexyl-4-Methoxycinnamate on the Dissimilatory Nitrate Reduction Processes and N2O Release in Sediments in the Yarlung Zangbo River

2020 ◽  
Vol 17 (6) ◽  
pp. 1822 ◽  
Author(s):  
Huiping Xu ◽  
Guanghua Lu ◽  
Chenwang Xue
Keyword(s):  
High Altitude ◽  
Nitrate Reduction ◽  
River Sediments ◽  
Nitrogen Transformation ◽  
Emerging Pollutants ◽  
15N Tracer ◽  
Ammonium Oxidation ◽  
Reduction Processes ◽  
Dissimilatory Nitrate Reduction ◽  
Yarlung Zangbo River

The nitrogen pollution of rivers as a global environmental problem has received great attentions in recent years. The occurrence of emerging pollutants in high-altitude rivers will inevitably affect the dissimilatory nitrate reduction processes. In this study, sediment slurry experiments combined with 15N tracer techniques were conducted to investigate the influence of pharmaceutical and personal care products (alone and in combination) on denitrification and the anaerobic ammonium oxidation (anammox) process and the resulting N2O release in the sediments of the Yarlung Zangbo River. The results showed that the denitrification rates were inhibited by sulfamethoxazole (SMX) treatments (1–100 μg L−1) and the anammox rates decreased as the SMX concentrations increased, which may be due to the inhibitory effect of this antibiotic on nitrate reducing microbes. 2-Ethylhexyl-4-methoxycinnamate (EHMC) impacted nitrogen transformation mainly though the inhibition of the anammox processes. SMX and EHMC showed a superposition effect on the denitrification processes. The expression levels of the denitrifying functional genes nirS and nosZ were decreased and N2O release was stimulated due to the presence of SMX and/or EHMC in the sediments. To the best of our knowledge, this study is the first to report the effects of EHMC and its mixtures on the dissimilatory nitrate reduction processes and N2O releases in river sediments. Our results indicated that the widespread occurrence of emerging pollutants in high-altitude rivers may disturb the nitrogen transformation processes and increase the pressure of global warming.

Symbiotic Stars at Optical, Infrared and Radio Wavelengths

1979 ◽  
Vol 46 ◽  
pp. 125-149 ◽  
Author(s):  
David A. Allen
Keyword(s):  
Temperature Regime ◽  
Type Star ◽  
Stellar Systems ◽  
Symbiotic Stars ◽  
Lower Excitation ◽  
Definition Of ◽  
Original Type

No paper of this nature should begin without a definition of symbiotic stars. It was Paul Merrill who, borrowing on his botanical background, coined the termsymbioticto describe apparently single stellar systems which combine the TiO absorption of M giants (temperature regime ≲ 3500 K) with He II emission (temperature regime ≳ 100,000 K). He and Milton Humason had in 1932 first drawn attention to three such stars: AX Per, CI Cyg and RW Hya. At the conclusion of the Mount Wilson Ha emission survey nearly a dozen had been identified, and Z And had become their type star. The numbers slowly grew, as much because the definition widened to include lower-excitation specimens as because new examples of the original type were found. In 1970 Wackerling listed 30; this was the last compendium of symbiotic stars published.

SYSTEM ANALYSIS OF GEOLOGICAL-AND-PRODUCTION DATA FOR PREDICTION TEMPERATURE REGIME OF GAS WELLS OPERATION USING A GEOLOGO-TECHNOLOGICAL MODEL

2015 ◽  
pp. 56-61
Author(s):  
A. V. Kustyshev ◽  
A. V. Krasovskii ◽  
E. S. Zimin ◽  
D. A. Tatarikov
Keyword(s):  
Process Parameters ◽  
Temperature Regime ◽  
System Analysis ◽  
West Siberia ◽  
Production Data ◽  
Gas Wells ◽  
Method Of Calculation ◽  
Technological Model

An algorithm has been developed, and a method of calculation of wellhead temperature in gas wells has been realized based on the geologo-technological model. The developed method enables to calculate the forecast process parameters taking into consideration the temperature regime of gas wells. The method was tested using the above mentioned model of the Cenomanian deposit of one of West Siberia fields. The results of these calculations have been later taken into account in designing the deposit development.

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