Methane Metabolism in a Temperate Swamp

Abstract

Comparisons between in situ CH4 concentration and potential factors controlling its net production were made in a temperate swamp. Seasonal measurements of water table level and depth profiles of pH, dissolved CH4, C02, 029 S042-, N03-, formate, acetate, propionate, and butyrate were made at two adjacent sites 1.5 to 2 m apart. Dissolved CH4 was inversely correlated to 02 and, in general, to N03-and so42-, potential inhibitors of methanogenesis. At low water table levels (August 1992), maximal CH4 (2 to 4 ,uM) occurred below 30 cm, whereas at high water table levels (October 1992) or under flooded conditions (May 1993), CH4 maxima (4 to 55 ,uM) occurred in the top 10 to 20 cm. Higher CH4 concentrations were likely supported by inputs of fresh organic matter from decaying leaf litter, as suggested by high acetate and propionate concentrations (25 to 100 ,uM) in one of the sites in fall and spring. Measurements of potential CH4 production (and consumption) showed that the highest rates generally occurred in the top 10 cm of soil. Soil slurry incubations confirmed the importance of organic matter to CH4 production but also showed that competition for substrates by nonmethanogenic microorganisms could greatly attenuate its effect.

Ecosystem–atmosphere exchange of CH4 and N2O and ecosystem respiration in wetlands in the Sanjiang Plain, Northeastern China

“…Saarnio et al (2007) summarized the measurements of CH 4 in Southern Finland and reported that the ombrotrophic mire emitted 5 AE 4 g C m À2 yr À1 CH 4 , in accordance with our results in the SI wetlands (4.36 AE 1.79 g C m À2 yr À1 ). The annual CH 4 flux from the SS wetland ecosystem is 0.21 AE 0.10 g C m À2 yr À1 , which falls in the range summarized by Roehm (Table 3) but is dramatically smaller than the reported flux from temperate swamps in Quebec, Canada, as 1.21 g C m À2 yr À1 (Amaral & Knowles, 1994); the reason may lie in the higher productivity of forest swamps compared with SS (Mitsch & Gosselink, 1993). The ecosystem respirations for PI wetlands are also consistent with the dataset derived from the literature for wetlands around the world (Roehm, 2005).…”

Growth of methanotrophs in methane and oxygen counter gradients

“…In the simplest case where growth depends only on the supply rates of two spatially separated substrates, localization of biomass can be determined mathematically 114,151. It is likely that, in some cases, this factor explains the spatial distribution of methanotrophic activity in nature [3,6]. However, other factors often affect this distribution, such as N-limitation in the water column of lakes [18].…”

Localization of methane consumption and nitrification activities in some boreal forest soils and the stability of methane consumption on storage and disturbance

“…Methane was determined by GC with flame ionization detection [Amaral and Knowles, 1994]. Nitrate and nitrite were analyzed by capillary electrophoresis [Amaral and Knowles, 1994] on samples passed through 0.2-/•m filters. Soil pH was determined on 1:5 soil:distilled water slurries using an Accumet p H meter (Fisher Scientific).…”