To establish the structural and lithological controls on gas hydrate distribution and to assess the potential energy resource and environmental hazards in the Indian Ocean, non-pressurized and pressurized cores were recovered from the Krishna-Godavari (K-G) and Mahanadi Basins offshore east India, and from an Andaman Sea site. The pore fluids were analyzed for: salinity, Cl, sulfate, sulfide, c...

Methane (CH4) is a powerful greenhouse gas that plays a prominent role in the terrestrial carbon (C) cycle, and is released to the atmosphere from freshwater systems in numerous biomes globally. Radiocarbon (14C) analysis can indicate both the age and source of CH4 in natural environments. In contrast to CH4 present in bubbles released from aquatic sediments (ebullition), dissolved CH4 in lakes...

Elemental analyses (H, N, C, O, S), bulk isotope analyses (C, N) and C content of pyrolysis products from Sphagnum moss, underlying peat from a bog and the bog water (Hohlohsee, Black Forest, Germany) were performed to identify humi®cation processes in the early diagenesis of peat formation and to determine the origin of dissolved organic matter (DOM) in the bog lake. Atomic ratios of bulk elem...

For many trace elements, continental margins are the location of intense exchange processes between sediment and seawater, which control their distribution in the water column, but have yet to be fully understood. In this study, we have investigated the impact of fluid seepage at cold seeps on the marine cycle of neodymium. We determined dissolved and total dissolvable (TD) concentrations for R...

Benthic fluxes of carbon dioxide (CO2) and methane (CH4) were evaluated in grass carp Ctenopharyngodon idella (G), silver carp Hypophthalmichthys molitrix (S), and bighead carp Aristichthys nobilis (B) polyculture systems, to which topmouth culter Erythroculter ilishaeformis (T), Pacific white shrimp Litopenaeus vannamei (P), or common carp Cyprinus carpio (C) were added. These systems, GSBT, G...

I present a numerical diffusion–advection-reaction model to simulate CO2 chemistry, d C, and oxidation of organic carbon and methane in sediment porewater. The model takes into account detailed reaction kinetics of dissolved CO2 compounds, H2O, H , OH , boron and sulfide compounds. These reactions are usually assumed to be in local equilibrium, which is shown to be a good approximation in most ...

Microorganisms have contributed significantly to subsurface energy resources by converting organic matter in hydrocarbon reservoirs into methane, the main component of natural gas. In this study, we consider environmental controls on microbial populations in coal-bearing strata of the Cherokee basin, an unconventional natural gas resource in southeast Kansas, USA. Pennsylvanian-age strata in th...

Methane hydrates were studied in systems containing aqueous dissolved surfactants oil emulsions with a volume ratio of 40/60. Two commercial surfactants, named synperonic PE/F127 and cetyltrimethylammonium bromide, evaluated at 0, 350, 700 1500 ppm. Experiments made by applying the cooling–heating path an isochoric high-pressure cell different initial pressures 5.5, 8.0, 10.0 12.0 MPa. The obta...

Methane is a powerful greenhouse gas, of which most produced by microorganisms in process called methanogenesis. One environment where methanogenic occur the deep biosphere. The biosphere comprises variety ecosystem settings; marine habitats such as subseafloor sediments, rock pore volumes within basalts, and terrestrial settings sedimentary rocks crystalline bedrock fracture networks. Microbia...