river breath
n.— «As the material decomposes and is eaten by organisms including insects and fish, and as river conditions change, carbon dioxide is release, or degassed, from surface waters. The resulting “river breath,”…turns out to be a significant downstream movement of carbon fixed by the forest.» —“Tropical streams, rivers ‘exhaling’ millions of tons more CO2 than thought” by Sandra Hines University of Washington Office of News and Information Apr. 10, 2002. (source: Double-Tongued Dictionary)