Comparisons were made between benthic nutrient fluxes in a shallow marine
embayment measured by a sophisticated automated benthic chamber device and a
much simpler design. Both devices have similar chamber dimensions. The
sophisticated design can be deployed by line from a vessel, incorporates an
sealed waterproof computer, uses one chamber and all operations are fully
programmable; dissolved oxygen concentrations are electronically monitored
every 6 min and stored by the computer. The simpler design incorporates three
opaque and three clear chambers per site to investigate small-scale sediment
differences and the effect of benthic photosynthetic production on fluxes;
dissolved oxygen concentrations are electronically monitored every 10 min.
within all chambers and stored in a data logger; the deployment and recovery
and sampling operations other than for DO require the use of divers. Except
where sediments differ greatly over a few metres, both chamber devices deliver
similar results and indicate the consistency of the technique regardless of
the design. The simpler design is limited by the need for diver deployment and
sampling. An automated chamber array is recommended as the best way of
measuring ‘patchy’ sediments
Analysis of environmental issues related to small-scale hydroelectric development. VI. Dissolved oxygen concentrations below operating dams
