Methane oxidation produces biomass that is a potential source of particulate carbon for consumers, and is in addition to photosynthetic production. We assessed methanotrophy and photosynthetic production under differing conditions of light and methane concentration. We measured methane oxidation and photosynthesis in gravel sediments from adjacent shaded and unshaded stretches of 15 chalk rivers in southern England, and also i...

Due to a combination of local methanogenesis and high background concentrations in the groundwater, water in the River Lambourn is 51 times supersaturated with methane (162 nmol CH 4 L −1 ). Pore‐water concentrations of methane in the gravels of the riverbed were much lower throughout the year (71 nmol CH 4 L −1 ), suggesting significant methane oxidation. To investigate the potential for methane oxidation as a novel chemosynt...

We measured the δ 13 C values of dominant primary consumers and their potential food sources in a groundwater‐fed lowland river. The δ 13 C of most consumers, such as Gammarus and Simulium , reflected that of the dominant forms of photosynthetic production, whereas the cased larvae of two caddis flies ( Agapetus and Silo ) were consistently 13 C depleted (mean δ 13 C: ‐41.2% and ‐40.4%, respectively) throughout the year. The r...