Morphology and Ecology of Peridinium bipes var. occultatum Lindem.(Dinophyceae) Forming Freshwater Red Tides in Korean Dam Reservoirs

Abstract

Water blooms can be defined as the phenomenon occurring when phytoplankton, protists, and microorganisms increase abruptly to great numbers or accumulate biologically or physically, causing the color of the water to change and harming other organisms (Lee 1999; MOMAF 2000). The term red tide refers to the phenomenon of by which water bodies turn red due to the high numbers of Dinophyceae In recent times, repeated occurrences of freshwater red tides in domestic dam reservoirs, including Imha dam reservoir, have caught the attention of scientists, and in the years 2003 and 2004 serious red tides occurred in dam reservoirs all over the country, including Sangsa, Chuam, Gucheon and Miryang dam reservoirs, causing great worries not just to ecologists, but through all levels of society in Korea (KOWACO 2003). Korean freshwater red tides have been reports by Kim et al. (1987), Kang et al. (1989) and Ahn (1990). However, the first two were in fact very short abstracts rather than dissertations or reports, and the report by Ahn (1990) simply conducted research on the bacterial variation caused by red tides rather than the red tide itself. Thus we can say that there have been no actual Korean research projects directly examining freshwater red tides. Also, because the research projects mentioned above were all conducted on Soyang dam reservoir, it is also true that the amount of research done is much limited to be able to achieve complete understanding of the phenomenon of freshwater red tides in Korean dam reservoirs as a whole. However, work such as the investigation on the classification and the genotypic analysis of the organisms that cause freshwater red tides in Chuam dam reservoir, Sangsa dam reservoir and the Togyo dam reservoir by Ki et al. (2005a, b) showed that, in recent times, research on freshwater red tides in Korea has been gradually progressing. Nevertheless, research on the present level of freshwater red tide incidents and their causes is still insufficient. Therefore, it is critical that we examine the seriousness and causes of freshwater red tides in the dam reservoirs where they occur, devise appropriate countermeasures against freshwater red tides and investigate the subsequent hindrances to utilization of water resources, such as conducting bioassays Algae Volume 21(4): 433-443, 2006