Introduction
The food webs and production of rivers and streams have been very widely studied and are firmly viewed as being based on the twin resources of allochthonous detritus (both particulate and dissolved, derived from terrestrial plants) and autochthonous primary production, with only the balance between the two being contentious.
It would be very surprising indeed if methane turned out to be a substantial third source of energy to river ecosystems as recently proposed for lakes (Jones & Grey 2011).
Nevertheless, we have demonstrated that macroinvertebrate (particularly Trichoptera; caddis flies) biomass may comprise up to 30% methane-derived carbon in chalk rivers (Trimmer et al 2009), although it is rather difficult to see why they use this alternative chemosynthetic basal resource when such rivers are so conventionally productive.
Our current Natural Environment Research Council funded research focuses on establishing how common a phenomenon is the use of methane-derived carbon in rivers, the processes controlling the degree of use, and how far it is transferred through the food web.
