A ‘gilledʹ benthic chamber for extended measurement of sediment-water fluxes

A benthic chamber has been developed that utilizes an artificial ‘gillʹ to maintain close to ambient dissolved oxygen concentrations within the chamber. The ‘gillʹ consists of approximately 12.8 m of silicone tubing through which chamber water is pumped by a controlled submersible peristaltic pump. Via turning this pump on and off, benthic oxygen demand can be determined at various times after deployment; ambient oxygen levels over the sediment can be manipulated so that the influences of hypoxic and anoxic conditions can be determined. Because the tubing is impermeable to charged ions, long-term deployments, at close to ambient internal oxygen levels, also make possible the measurement of fluxes of dissolved components whose fractional rate of change is much less than that of oxygen.