The Influence of Materials Released from Lake Sediment on The Growth of Three Kinds of Algae.

Abstract

To investigate the influence of materials released from lake sediment on the flora of phytop1ankton, we cultured three algal species, the green algae Scenedesmus acutus, the cyanobacterium Microcystis aeruginosa and filamentous cyanobacterium Oscillatoria agardhii with water obtained from an elution experiment of lake sediment. The effect of materials released from sediment on the growth of algae clearly varied from species to species of algae. The growth of green algae S. acutus was influenced by nitrogen released from sediment, though nitrogen was not actually supplied from the sediment somuch. The growth of filamentous cyanobacterium O. agardhii was mainly influenced by phosphorus released from the sediment. On the other hand, the growth of cyanobacterium M. aeruginosa was influenced by some materials, which were not nitrogen and phosphorus. From the results of an incubation experiment with adding EDTA and past research reports, it was suggested that these materials were organic complexes of iron, which stability constants was high, and inhibited M. aeurignosa from getting iron. This is a new finding in the relation between algae and lake sediment, and indicates that organic matter as complex-ligand released from sediment is one of the important factors affecting the flora of phytoplankton.