We found unprecedentedly high abundances of microbially produced CH4 in the anoxic deep waters of Lake Untersee, an oligotrophic, perennially ice-covered Antarctic freshwater lake. The maximum CH4 concentration (approaching 21.8 6 1.4 mmol L21) is one of the highest observed so far in a natural aquatic ecosystem. Although surficial lake sediments are the predominant source of CH4 in Lake Unters...

The laser methane detector (LMD) has been proposed as a method to characterize enteric methane (CH4) emissions from animals in a natural environment. To validate LMD use, its CH4 outputs (LMD-CH4), were compared against CH4 measured with respiration chambers (chamber-CH4). The LMD was used to measure CH4 concentration (μL/L) in the exhaled air of 24 lactating ewes and 72 finishing steers. In ew...

Changes in the hydrological conditions of coastal wetlands may potentially affect the role of wetlands in the methane (CH4) cycle. In this study, the CH4 production potential and emissions from restored coastal reed wetlands at different water levels were examined in eastern China at a field scale in two phenological seasons. Results showed that the total CH4 flux from reeds at various water le...

Aircraft observations of Asian outflow from the TRACE-P aircraft mission over the NW Pacific (March-April 2001) show large CH4 enhancements relative to background, as well as strong CH4-C2H6-CO correlations that provide signatures of regional sources. We apply a global chemical transport model simulation of the CH4-C2H6-CO system for the TRACE-P period to interpret these observations in terms o...

Although estimates of the annual methane (CH4) flux from agriculturally managed peatlands exist, knowledge of controls over the variation of CH4 at different time-scales is limited due to the lack of high temporal-resolution data. Here we present CH4 fluxes measured from May 2014 to April 2016 using the eddy covariance technique at an abandoned peatland pasture in western Newfoundland, Canada. ...

Methane (CH4) has a 28-fold greater global warming potential than CO2 over one hundred years. Atmospheric CH4 concentration has tripled since 1750. Anthropogenic CH4 emissions from China have been growing rapidly in the past decades, and contribute more than 10% of global anthropogenic CH4 emissions with large uncertainties in existing global inventories, generally limited to country-scale stat...

Boreal lakes can be ice covered for a substantial portion of the year at which time methane (CH4) can accumulate below ice. The amount of CH4 emitted at ice melt is partially determined by the interplay between CH4 production and CH4 oxidation, performed by methane-oxidizing bacteria (MOB). Yet the balance between oxidation and emission and the potential for CH4 oxidation in various lakes durin...

We have used fast time-resolved infrared spectroscopy to characterize a series of organometallic methane and ethane complexes in solution at room temperature: W(CO)5(CH4) and M(eta5-C5R5)(CO)2(L) [where M = Mn or Re, R = H or CH3 (Re only); and L = CH4 or C2H6]. In all cases, the methane complexes are found to be short-lived and significantly more reactive than the analogous n-heptane complexes...

[1] Reducing methane (CH4) emissions is an attractive option for jointly addressing climate and ozone (O3) air quality goals. With multidecadal full-chemistry transient simulations in the MOZART-2 tropospheric chemistry model, we show that tropospheric O3 responds approximately linearly to changes in CH4 emissions over a range of anthropogenic emissions from 0–430 Tg CH4 a 1 (0.11–0.16 Tg tropo...