미세조류 먹이생물에 의한 담수산 섬모충 Stentor roeselii의 생장율과 섭식률

Abstract

A heterotrich ciliate Stentor roeselii was isolated from Pal’tang reservoir in Korea and the strain was maintained successfully in laboratory. The optimal temperature and pH for S. roeselii growth were 25∼30 ℃ and pH 7∼9. Stentor roeselii dominantly ingested the small sized (2∼5μm) FLP among the size spectra of natural assemblage FLP. As the result of growth experiments on six algal preys such as cyanobacteria (Aphanothece sp., Microcystis aeruginosa, Synechocystis sp.), green algae (Chlorella vulgaris, Coelastrum sp.), and diatom (Stephanodiscus hantzschii), Aphanothece sp. induced higher growth rate of Stentor roeselii than other algal species. Hence Aphanothece sp. was supplied to the culture system as the best prey source for the stable culture maintenance.Growth, ingestion, and clearance rates of S. roeselii on five phytoplankton species (three cyanobacteria species Aphanothece sp., Microcystis aeruginosa (NIES 44), Microcystis aeruginosa (NIES 298) and two diatom species Stephanodiscus hantzschii, Cyclotella meneghiniana) which have caused harmful algal blooms in Pal’tang reservoir were measured. Maximum growth rates (μmax) of S. roeselii were 0.165∼0.334 d-1, and maximum ingestion rates (Imax) were 10∼437 ngC predator-1 d-1 on the cyanobacteria, and 1524∼3798 ngC predator-1 d-1 on the diatom. Also, maximum clearance rates (Cmax) of S. roeselii were 55∼294 μl predator-1 d-1. I max was comparable or higher than the maximum ingestion rates previously reported on the other ciliates. Based on the present results, it is suggested that a heterotrich ciliate S. roeselii may be applied as one of suitable predator to control freshwater algal blooms.