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- Creator:
- Loyd, Sean
- Description:
- Major hydrocarbon accumulations occur in traps associated with salt domes. Whereas some of these hydrocarbons remain to be extracted for economic use, significant amounts have degraded in the subsurface, yielding mineral precipitates as byproducts. Salt domes of the Gulf of Mexico Basin typically exhibit extensive deposits of carbonate that form as cap rock atop salt structures. Despite previous efforts to model cap rock formation, the details of subsurface reactions (including the role of microorganisms) remain largely unknown. Here we show that cap rock mineral precipitation occurred via closed-system sulfate reduction, as indicated by new sulfur isotope data. 13C-depleted carbonate carbon isotope compositions and low clumped isotope-derived carbonate formation temperatures indicate that microbial, sulfate-dependent, anaerobic oxidation of methane (AOM) contributed to carbonate formation. These findings suggest that AOM serves as an unrecognized methane sink that reduces methane emissions in salt dome settings perhaps associated with an extensive, deep subsurface biosphere.
- Resource Type:
- Article
- Campus Tesim:
- Fullerton
- Department:
- Department of Geological Sciences
- Creator:
- Rosa, Daniele
- Description:
- Terrestrial and atmospheric chemistry is affected by allocation patterns in plants. Experimental results show that environmental factors including water, nitrogen, light and atmospheric CO2 affect plant biomass productivity and allocation. Various global vegetation models describe the cycling of carbon and water between land and atmosphere using terrestrial processes and biomass allocation schemes. The latter still have great margins for improvement in terms of dynamic responses to atmospheric CO2. Based on new results from experiments involving plants growing at double atmospheric CO concentrations, a dynamic allocation scheme is applied to the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ-DGVM) with the objective of reproducing the observed ecosystem productivities and structural changes in a elevated CO2 environment. The allocation scheme is based on the definition of apparent environmental resources for which levels are determined by linear perturbation of actual resources induced by elevated CO2.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Humboldt
- Department:
- Mathematical Modeling