Author: Susan Elizabeth Boehme
Publisher:
ISBN:
Category :
Languages : en
Pages : 288

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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722851057
Category :
Languages : en
Pages : 46

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Book Description
To investigate the relationship between sigma(CO2) delta(C-13) values and rates of the dominant remineralization processes at the organic-rich field site of Cape Lookout Bight, NC, the isotopic composition of porewater sigma(CO2) was measured on a seasonal basis. The sigma(CO2) delta(C-13) values varies seasonally in response to changes in rates of sulfate reduction and methanogenesis, the dominant remineralization processes at this site. A tube incubation experiment was also performed to determine the isotopic signature of the sigma(CO2) produced by sulfate reduction and methanogenesis. The delta(C-13) of the sigma(CO2) produced in the sulfate reduction zone determined from the tube incubation was -14.3 plus or minus 1.9, a value enriched in C-13 relative to the labile organic fraction. The C-13-enrichment may be caused by low rates of methanogenesis occurring in the sulfate reduction zone. The delta(C-13) of the sigma(CO2) produced in the methanogenic zone was estimated to be +44 per mil, whereas the co-produced methane was -65 per mil. The fractionation factor for CO2 reduction was calculated to be 1.055, a value in agreement with previous estimates at this site. The measured concentration and delta(C-13) of the sigma(CO2) at Cape Lookout was closely reproduced by a diagenetic model using the measured rates of sulfate reduction and sigma(CO2) production, and the isotopic signature of the sigma(CO2) production in the two biogeochemical zones. Boehme, Susan E. Unspecified Center ...

Author: S. E. Boehme
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Jeffrey Todd Gelwicks
Publisher:
ISBN:
Category : Acetates
Languages : en
Pages : 452

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Book Description

Author: Marc J. Alperin
Publisher:
ISBN:
Category : Biogeochemical cycles
Languages : en
Pages : 262

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Book Description

Author: Ronald S. Oremland
Publisher: Springer Science & Business Media
ISBN: 1461528127
Category : Science
Languages : en
Pages : 881

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Book Description
Certain trace gases in the atmosphere are able to absorb electromagnetic energy from the reflection of solar radiation from the Earth's surface. These gases have been increasing steadily and there is concern that they will change global climatic conditions by warming the atmosphere--the so-called ``greenhouse effect.'' Many of these gases originate from biological systems. The Biogeochemistry of Global Change discusses the role of radiative trace gases in this process. The disciplines covered in the book include microbiology, geochemistry, atmospheric chemistry, plant physiology, oceanography and limnology, and soil science. This diversity allows for cross-fertilization, achieving a better understanding of the complex mechanisms for biological and chemical formation, the destruction of trace gases, and the manipulation of ecosystems. Some of the topics covered include: biological mechanisms of formation and destruction of various ``greenhouse'' gases (such as methane, nitrous oxide, carbon dioxide, dimethylsulfide, and chlorofluorocarbons); the outward and consumptive flux of trace gases from marine and terrestrial systems (including anthropogenic sources); global trace gas modeling studies; the atmospheric physical and chemical reactions of trace gases; and the environmental significance of various trace gases in ancient and current atmospheres. The Biogeochemistry of Global Change provides both reviews and primary source material for active researchers in this field and for microbiologists and atmospheric chemists.

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 568

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Book Description

Author: C. Marjorie Aelion
Publisher: CRC Press
ISBN: 1420012614
Category : Science
Languages : en
Pages : 466

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Book Description
Enhanced analytical capabilities and separation techniques, improved detection limits, and accessibility of instrumentation have led to massive strides in the use of isotopes to assess microbial processes in surface and subsurface sediments. Considering the rapid growth of research and commercial interest in stable isotope and radioisotope applicat

Author: Horst D. Schulz
Publisher: Springer Science & Business Media
ISBN: 3540321438
Category : Science
Languages : en
Pages : 583

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Book Description
Since 1980 a considerable amount of scientific research dealing with geochemical processes in marine sediments has been carried out. This textbook summarizes the state-of-the-art in this field of research providing a complete representation of the subject and including the most recent findings. The topics covered include the examination of sedimentological and physical properties of the sedimentary solid phase. A new chapter describes properties, occurrence and formation of gas hydrates in marine sediments. The textbook ends with a chapter on model conceptions and computer models to quantify processes of early diagenesis.

Author: Tyler Johnston
Publisher:
ISBN: 9781321083835
Category : Biogeochemistry
Languages : en
Pages : 82

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Book Description
Previous studies conducted at Georgetown Lake have identified increasing concentrations of dissolved inorganic carbon (DIC) near the bottom of the lake and this DIC was also isotopically heavier (delta13C- DIC) than in the upper reaches of the water column. Based on this observation methane production was suspected to be occurring, since acetoclastic methanogenesis produces isotopically depleted CH4 and enriched CO2.