Persistent Blooms of Diatoms Stephanodiscus hantzschii f. tenuis and S. parvus in the Naktong River

Algae > Volume 10(2); 1995 > Article

Algae 1995;10(2): 91-96.

Kyung-Je Cho, Jae-Gi Shin

Department of Biology, Inje University

ABSTRACT

Seasonal variations of Stephanodiscus population were monitored with 1~4 week interval for recent 4 years to elucidate the population dynamics and the water pollution of the Naktong River. Small and tiny stephanoid diatoms persistently predominate the phytoplankton community over extensive periods of six months from November to April of nest year in the Naktong River. Its bloom has annually regular periodicity. Maximum abundance ranged from 4.05 × 10 super(4) cells/ml to 10.92 × 10 super(4) cells/ml and their dominance ranged from 16% to 100% (mean 65%) of total phytoplankton cells. The optimum water temperature for Stephanodiscus growth and bloom ranged from 0℃ to 15℃. Stephanodiscus diatom populations are comprised of mainly S. hantzschii f. tenuis (Hust.) Hakansson et Stoermer and S. parvus Stoermer et Hakansson S. hantzschii f. tenuis is a dominant component comprising above 80% relative abundance of total stephanoid population and S. parvus is a sub-dominant. The abundance of S. parvus was relatively higher in spring than in other season, occassionally accounting for above 50% of population. Other small Stephanodiscus or Cyclostephanos diatom were observed with low abundance and frequency. Stephanoid diatoms have occurred with broad geographical distribution from Kumho River to lower region of the Naktong River. Their algal abundances coincided with the eutrophic status of water in the Naktong River. It is supposed that Stephanodiscus would be a representative indicator for water pollution monitoring of the Naktong River.

Key words: Stephanodiscus hantzschii f. tenuis, S. parvus, cyclostephanoid diatom, eutrophication