Effect of weir impoundments on methane dynamics in a river.

We measured CH concentration, CH oxidation in the water column and total CH emissions to the atmosphere (diffusion and ebullition) in three weir impoundments and river reaches between them, in order to understand their role in river methane (CH) dynamics. Sediment samples were also collected to determine CH consumption and production potentials together with the contribution of individual methanogenic pathways. The CH surface water concentration increased 7.

Dominance of Methanosarcinales phylotypes and depth-wise distribution of methanogenic community in fresh water sediments of Sitka stream from Czech Republic.

The variation in the diversity of methanogens in sediment depths from Sitka stream was studied by constructing a 16S rRNA gene library using methanogen-specific primers and a denaturing gradient gel electrophoresis (DGGE)-based approach. A total of nine different phylotypes from the 16S rRNA library were obtained, and all of them were clustered within the order Methanosarcinales. These nine phylotypes likely represent nine new species and at least 5-6 new genera.