A Study on Red Tide Control with Loess Suspension

Abstract

As one of the red tide control method, montmorillonite was used to eliminate the causative organisms in Korea and Japan. We assayed the loess to replace the montmorillonite because it distribute in large quantity and nearby the red tide occurrence in South Coast of Korea. By using the mixture of loess and coal ashes, we examined the decreasing level of nutrients such as ammonia and phosphate, the elimination of causative organisms as a chlorophyll a content, and the harmful effect on aquaculture orgarnisms in cage culture farms. Half of the ammonium and phosphate was adsorbed by the loess particles, but only of ammonium was adsorbed by the coal ashes particles. In water column test, the particles of loess and coal ashes were settled down by in 20 minutes, the red tide organisms was eliminated by after 2 hours in 1,000 ppm of loess suspension, but the organisms were eliminated only by the same concentration of coal ashes. The harmful test of fishes and invertbrates, we observed any other negative effects of test animals than a tint deceleration in yellowtail.