한강하류역에서 계절변화에 따른 규조류 군집의 아-우점종과 환경요인과의 관계

Abstract

To understand the environmental factors affecting the sub-dominant species at the lower part of the Han River in Korea, we have seasonally investigated the physico-chemical factors and phytoplankton assemblages from Feb. 2001 to Feb. 2002, and from Feb. 2004 to Feb. 2005. During the study, a total of 437 taxa which were composed of 203 diatoms, 169 green algae, 37 blue-green algae, 17 euglenoids, 5 dinoflagellates and 6 chrysophytes were identified; the number of species ranged from 15 species to 58 species, showing diversity in the summer season. Among the taxonomic groups composing of phytoplankton communities in the Han River, diatoms and Cyanobacteria occupied 73% and 14% of the total standing crops, respectively. Diatoms were dominant through the year in 2001 and 2004 and they showed spring and winter blooms. The sub-dominant species were Fragilaria crotonensis, Synedra acus, Aulacoseira granulata, Nitzschia palea, Aulacoseira granulata var. angustissima, Asterionella fomosa, Synedra ulna, Diatoma vulgare and Cymbella affinis; Six taxa could be significantly related to TDN; Fragilaria crotonensis and Synedra acus were correlated with TDN. Aulacoseira granulata occurred more abundantly at low TN concentrations. But Diatoma vulgare and Cymbella affinis did not show significant change related to the environmental factors.