駕莫灣 北部海域의 海洋環境과 植物플랑크톤 群集의 變動特性: 1. 植物플랑크톤 群集의 季節動態와 赤潮原因生物

Seasonal dynamics of phytoplankton community and red tide organisms in the northern Kamak bay, southern Korea

In order to study on the seasonal dynamics of phytoplankton and the occurrence of red tide organisms, the present study was carried out in the Northern Kamak Bay of Southern Korea during the period from January to November, 1991. Eighty-one species were identified belonging to 4 divisions, 6 orders, and 46 genera. Thirteen species including seven dinoflagellates, Prororcentrum dentatum, P. glacile, Gyrodinium falcatum, G. fissum, Pheopolykrikos hartmannii, Katodinium rotundatum, Oxytoxum scolopax, one diatom, Neodelphineis pelagica, one blue-green alga, Trichodesmium erythraeum, two silicoflagellates, Distephanus speculum, Ebria tripartita, one chloromonad, Chattonella sp., and one euglenoid, Etreptiella gymnastica, are new records in this study area. The structure of phytoplankton communities are composed of diatoms through the year, and dinoflagellates during warm seasons. Predominant species in the study area four centric diatoms, Skeletonema costatum during the whole year, Eucampia zodiacus in early spring, Leptocylindrus danicus in spring, Chaetoceros diadema in fall, and three pennate diatoms, Asterionella glacialis, Nitzschia longissima, and Pseudonitzschia pungens. Phytoplankton standing crop was generally high in winter and spring and low in summer and fall, range from 2.8×103 cells/ℓ in September to 5.2×106 cells/ℓ in february. Red tide organisms occured frequently in warm seasons, when low salinity, high temperature and high concentration of phosphate. The causative organisms of red tide in the study area were Prorocentrum triestinum, P. dentatum, Gymnodinium sanguineum, Noctiluca scintillans, Dictyocha fibula, S. costatum, H.akashiwo and Mesodinium rubrum.