Methylphosphonate (MPn) metabolism has been proposed to be an aerobic source of methane in surface oceanic waters. Previous work by Daniela del Valle, C-MORE post-doctoral fellow in the laboratory of Prof. David Karl, has shown that even though microbes are able produce methane from dissolved MPn in the ocean, this process is not a significant source of methane at Station ALOHA. However, this w...

Natural marine hydrocarbon seeps on continental margins today represent a small source of methane in the global atmosphere budget, which is dominated by anthropogenic sources and contributions from wetlands in the tropics and northern high latitudes. In glacial times with lowered sea level, exposed seeps must have vented directly to the atmosphere and the portion of methane that was formerly di...

Anammox (anaerobic ammonium oxidation) is an environment-friendly and cost-efficient nitrogen-removal process currently applied to high-ammonium-loaded wastewaters such as anaerobic digester effluents. In these wastewaters, dissolved methane is also present and should be removed to prevent greenhouse gas emissions into the environment. Potentially, another recently discovered microbial pathway,...

A unique set of geochemical pore-water data, characterizing the sulfate reduction and uppermost methanogenic zones, has been collected at the Blake Ridge (offshore southeastern North America) from Ocean Drilling Program (ODP) Leg 164 cores and piston cores. The δ13C values of dissolved CO2 (ΣCO2) are as 13C-depleted as –37.7‰ PDB (Site 995) at the sulfate-methane interface, reflecting a substan...

Early diagenetic dolomite beds were sampled during the Ocean Drilling Programme (ODP) Leg 201 at four reoccupied ODP Leg 112 sites on the Peru continental margin (Sites 1227/684, 1228/680, 1229/681 and 1230/685) and analysed for petrography, mineralogy, dC, dO and Sr/Sr values. The results are compared with the chemistry, and dC and Sr/Sr values of the associated porewater. Petrographic relatio...

Evaluating the importance of natural marine hydrocarbon seeps to global methane budgets requires correctly predicting the gas fraction lost by the seep bubbles during transit through the water column. In the Santa Barbara Channel, California, three widely differing seeps (depth, flux, oiliness) were visited and observations were made of seep gas partial pressures, Pi, near the surface for alkan...

Widespread seepage of methane from seafloor sediments offshore Svalbard close to the landward limit of the gas hydrate stability zone (GHSZ) may, in part, be driven by hydrate destabilization due to bottom water warming. To assess whether this methane reaches the atmosphere where it may contribute to further warming, we have undertaken comprehensive surveys of methane in seawater and air on the...

To clarify the mechanisms of methane transport from the rhizosphere into the atmosphere through rice plants (Oryza sativa L.), the methane emission rate was measured from a shoot whose roots had been kept in a culture solution with a high methane concentration or exposed to methane gas in the gas phase by using a cylindrical chamber. No clear correlation was observed between change in the trans...

Hierarchical flower-like ZnO nanorods, net-like ZnO nanofibers and ZnO nanobulks have been successfully synthesized via a surfactant assisted hydrothemal method. The synthesized products were characterized by X-ray powder diffraction and field emission scanning electron microscopy, respectively. A possible growth mechanism of the various hierarchical ZnO nanostructures is discussed in detail. G...

This study analyzed cored sediments retrieved from sites distributed across a transect of the Lei-Gong-Hou mud volcanoes in eastern Taiwan to uncover the spatial distributions of biogeochemical processes and community assemblages involved in methane cycling. The profiles of methane concentration and carbon isotopic composition revealed various orders of the predominance of specific methane-rela...