Succession of the plankton community during coastal reclamation with the solid wastes.

Abstract

The plankton community was investigated in the pond constructed on the coast line of Kitakyushu City, Northern Kyushu, Japan, where various kinds of solid wastes such as soil from land source, domestic wastes, and industrial wastes, had been dumped from 1980 to 1987. The cell density of phytoplankton continued to increase gradually and red tides were observed from 1983. The plankton community was predominated by several species of diatoms, dinoflagellates, Cryptophyceae, green algae, filamentous bacterium, ciliates, and rotifers. Some of them occurred continuously or cyclically during certain periods. Closing to the end of reclamation, a phototrophic red sulfur bacterium Thiocapsa roseopersicina predominated twice and discolored the water to purple-brown. At the first time, phytoplankton almost disappeared from the pond but retrieved after a few months, and at the second time phytoplankton occurred abundantly with the phototrophic bacterium. Thus, in the case of this pond, the specific phyto-and zooplankton adapting to the water quality seem to have appeared one after another during almost whole time of this investigation. A large amount of plankton was suggested to play an important role in the self-purification of the water quality in the pond, and the pond acts as an oxidation pond for the polluted water caused by the solid wastes dumped.