Oxygen fluxes of enclosed reef epibiota communities

Enclosed chamber experiments have a long history in the examination of respiration and the production rates of single species in the laboratory, but also of corals, algae, and soft-bottom communities in the field. We incubated single concrete blocks (20×20×40 cm) from the Poole Bay artificial reef, supporting a mixed algal and faunal community, in a clear acrylic chamber on the seabed under dark and light conditions. Oxygen concentrations were monitored and the epibiota removed for biomass determination of the different taxonomic groups present. For summer experiments (temperature 16–19°C), linear relationships were found between the mass of epibiota (ash-free dry weight) and dark respiration and between the mass of algae and net oxygen production. Average respiration (at 20°C) was 41±3 μmol O 2 g AFDW −1 h −1 and average algae grass production was 276±27 μmol O 2 g AFDW −1 h −1 . The relationship of these instantaneous measures of oxygen flux to longer term reef epibiota production is discussed.