Automated in-situ dark chamber system for parsing open channel and sediment-associated aerobic respiration in rivers and streams

Abstract:

River corridor systems are known to be important biogeochemical reactors, with significant contributions to large-scale carbon and nutrient cycles. Recent modeling suggests that the open channel and the surrounding sediments contribute to total river corridor respiration in highly variable proportions, and as a function of stream order. It has remained difficult, however, to separate these contributions in the field. We present an automated, battery-powered system of pumps, valves, and oxygen sensors that carries out nightly in-situ dark-bottle incubations. The rates gleaned from these incubations, combined with estimates of total system respiration and gas exchange using existing inverse models, allow the parsing of total system respiration between open channel and sediment-associated processes on a daily basis over long periods of time at low cost and labor.