The relative importance of oxygen for root-associated methanotrophy was examined by using sediment-free, intact freshwater marsh plants (Pontederia cordata and Sparganium eurycarpum) incubated in split chambers. The root medium contained approximately 100 (mu)M methane. Methane oxidation was calculated from the difference between methane loss from chambers in the presence and absence of 1 mM 1-...

Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 106 tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (<100 m water depth), methane released from the seafloor may reach the atmosphere and potentially amplify global ...

Continental freshwater systems have now been shown to be globally significant sources of methane, but there are still large uncertainties associated with freshwater methane fluxes. Studies to date have mainly focused on either ebullition of bubbles originating from sediments or on diffusive fluxes of dissolved methane across the air–water interface. We examined the potential influence of a new ...

We investigated the effect of dissolved organic carbon (DOC) on hypolimnetic metabolism (accumulation of dissolved inorganic carbon (DIC) and methane (CH4)) in 21 lakes across a gradient of DOC concentrations (308 to 1540 !mol C L). The highly colored nature of the DOC in these lakes suggests it is mostly of terrestrial origin. Hypolimnetic methane accumulation was positively correlated with ep...

[1] Huge quantities of CH4 are stored in marine sediment in the form of methane hydrate, bubbles, and dissolved CH4 in pore water. Here I discuss the various pathways for methane to enter the ocean and atmosphere, including: (i) Methane hydrate dissolution or dissociation as it rises through seawater. The dissociation rate can be 2 to 3 orders of magnitude greater than the dissolution rate. (ii...

An isobaric flow loop added to the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) is being investigated as a means of rapidly forming methane hydrate in watersaturated sand from methane dissolved in water. Water circulates through a relatively warm source chamber, dissolving granular methane hydrate that was pre-made from seed ice, then enters a colder hydrate growth chamber wher...

The alluvial aquifer adjacent to Norman Landfill, OK, provides an excellent natural laboratory for the study of anaerobic processes impacting landfill-leachate contaminated aquifers. We collected groundwaters from a transect of seven multilevel wells ranging in depth from 1.3 to 11 m that were oriented parallel to the flow path. The center of the leachate plume was characterized by (1) high alk...

Abstract Various anaerobic processes have been explored for the energy-efficient treatment of municipal wastewater. However, dissolved methane in effluent appears to be a barrier towards energy and carbon neutrality wastewater treatment. Although several recovery methods developed, their engineering feasibility economic viability not yet assessed holistic manner. In this perspective, we thus in...

The existence of strong absorption bands of singly deuterated methane (CH3D) at wavelengths where normal methane (CH4) absorbs comparatively weakly could enable remote measurement of D/H ratios in methane ice on outer solar system bodies. We performed laboratory transmission spectroscopy experiments, recording spectra at wavelengths from 1 to 6 μm to study CH3D bands at 2.47, 2.87, and 4.56 μm,...

A correction to this paper has been published: https://doi.org/10.1007/s10661-021-08983-6