Evaluation of Diatom Growth Potential in Midstream and Downstream Nakdong River

doi:2006.21.2.229

Algae > Volume 21(2); 2006 > Article

Algae 2006;21(2): 229-234. doi: https://doi.org/10.4490/algae.2006.21.2.229

Young Ho Kwon¹, Jung Kwan Seo¹^*, Sang Won Park² and Sang Yong Yang¹

¹Nakdong River Environment Research Center National Institute of Environmental Research, Koryoung 717-873, Korea
²Department of Environmental Science Keimyung University, Daegu 704-701, Korea

ABSTRACT

For the test organism of algal growth potential (AGP), the diatom in the genus Stephanodiscus which cause blooms in the Nakdong River was used instead of generally used strains of Selenastrum, Microcystis, or Anabaena. AGP results indicated that all the samples in the Nakdong River except for that from the Nakdan Bridge site were eutrophic state. Furthermore, the sample from Kumho River site was hypertrophic state. In the main stream Nakdong River, the value of AGP was lowest at the upstream Nakdan Bridge site and was highest at Koryoung Bridge site which is just downstream of Kumho River confluent point indicating the seriousness of pollution contributed by the Kumho River to the Nakdong River. Changes in the concentration of nutrients before and after the AGP tests and inter-relationship among the nutrients indicated that the growth of the Stephanodiscus in the AGP tests were mostly affected by the nitrate, silicate and phosphate. The limiting nutrient was identified by the nutrient addition experiments and the results showed that phosphate was the limiting nutrient for the growth of Stephanodiscus in the tested samples.

Key words: AGP, diatom, Nakdong River, nutrients