Evaluation of oxygen consumption and gross production rate in natural and artificial tidal flats in Ago [Japan] bay

The oxygen consumption rates and gross primary production rates in artificial (with dredged sediment) and natural tidal flats of three types (i.e., estuary, foreshore, and unused wetland) were estimated using light and dark in situ benthic chamber methods. The gross primary production rate correlated with photon flux density and chlorophyll a concentration in the sediment. After the construction of the artificial tidal flat by mixing with dredged sediment, chlorophyll a concentration increased from 15.8 μg · g-1-wet to 28.3 μg · g-1-wet, and the biomass of macrobenthos also increased from 24.0 g · 0.2 m-2 to 109 g · 0.2 m-2. The oxygen consumption and gross primary production rates increased from 0.47 to 1.8 gO2 · m-2 · d-1 and from 1.1 to 1.9 gO2 · m-2 · d-1 respectively.