The mixotrophic marine ciliate Mesodinium rubrum possesses a highly modified algal endosymbiont as a nutrition source for the species. Accordingly, we assumed that the species can reflect the ecotoxicity on marine producer (as phytoplankton) and consumer (as zooplankton) both. A series of experiments were conducted to identify the potential of the species as a standard test species for marine ecotoxicological study. The comparison of species sensitivity on reference toxic materials was made using potassium dichromate for phytoplankton and copper chloride for zooplankton. The ciliate revealed the highest sensitivity on both reference materials among the seven test species including phytoplankton, benthic copepod and rotifer species. The toxicity end point of the species was 72hr-EC50=1.52 mg/L (as potassium dichromate) estimated by population growth inhibition (PGI), which is more sensitive than the most sensitive phytoplankton Skeletonema costatum (72hr-EC50=3.05 mg/L). As comparison to rotifer, it also revealed higher sensitivity on copper chloride; 72hr-EC50=0.38 mg/L for ciliate and 48hr-EC50=0.48 mg/L for rotifer. Also, the elutriate toxicity test of various ocean disposal wastes were conducted to identify the potential of ciliate toxicity test application using industrial waste sludges. The toxicity of leather processing waste sludge was highest on the ciliate, followed by dyeing waste sludge and dye production waste sludge as an increasing order of toxicity. 72h-EC50 of ciliate PGI test was 1.83% and that of S. costatum 3.84% for leather waste sludge which showed highest toxicity. The toxicity test results also revealed that the highest sensitivity was observed on ciliate species on ocean disposed sludge wastes. Also, ciliate toxicity test well discriminated the degree of toxicity between sludge sources; 72h-EC50 values were 1.83% for leather processing waste sludge, 16.75% for dye production waste sludge and 27.75% for textile production waste sludge. Even the laboratory culture methods of the species were not generally established yet, the species has high potential as the standard test species for marine toxicity test in terms of the dual reflection of phyto- and zooplankton toxicity from single test, sensitivity and test replicability.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 시험생물
  2.2. 시험용액의 제조
  2.3. 독성실험
  2.4. 자료분석
 3. 결 과
  3.1. 표준독성물질을 이용한 민감도 실험
  3.2. 해양 배출 오염물질을 이용한 적용 실험
 4. 고 찰
 참 고 문 헌

• 안경호(국립수산과학원 갯벌연구소) | Kyoung Ho An (Tidal Flat Research Institute, NFRDI)
• 박경수(안양대학교 해양생명공학과) | Gyung Soo Park (Department of Marine Biotechnology, Anyang University) Corresponding Author
• 이승민(국립수산과학원 서해수산연구소) | Seung Min Lee (West Sea Fisheries Research Institute, NFRDI)