Abstract
The experimental study was conducted with model equipment in order to assess influence of benthic biota on organic matter dynamics in tidal flat. In the experiment, four different biota ecosystems were prepared; shaded system, unshaded system, unshaded and polychaete released system, and unshaded and bivalve released system. Throughout the experiment, the amount of organic matter in sediment tended to increase. The accumulation rate of organic matter was different among the systems. The accumulation rate was greatly higher in shaded system than the other unshaded systems. This result suggests that the effect of benthic microalgae on bacterial organic matter degradation with its supplying oxygen and extracellular matabolite was much greater than that of macrobenthos. Filter feeding by bivalve inhibited the accumulation of organic matter in sediment, which was attributed to decreasing deposition, and respiration and the growth of bivalve. Moreover, bivalve predominance enhanced the productivity of attached algae because of activation of PO4-P regeneration by bivalve.
