해창만의 생물해양학적 환경특성. 1. 식물플랑크톤 군집의 계절변동 및 분포 특성

Distributional Characteristics and Seasonal Fluctuations of Phytoplankton Community in Haechang Bay, Southern Korea

남해 중앙부에 위치하는 해창만의 식물플랑크톤 군집은 비교적 다양한 생물종에 의해 군집을 이루고 있으나, 출현 세포 밀도는 매우 낮은 특징을 보였다. 특히, 계절적으로는 여름과 가을에 높은 세포 밀도를 나타내고 있는 반면, 봄에 낮은 세포 밀도를 나타내나, 식물플랑크톤 군집은 연중 중심목 규조류에 의해 지배되고 있었다. 그러나, Chl-a량의 분포와 관련하여, 식물플랑크톤에 의한 해창만의 기초생물 잠재생산력은 연중 매우 높은 것으로 판단되며, 미소 또는 극미소 플랑크톤에 대한 점유율이 높을 것으로 추정되었다.

The obseuations on the seasonal fluctuations of phytoplankton community in Haechang Bay of the Korean southern sea were carried out during four seasons from 1997 to 1998. A total of 77 species of phytoplankton including 10 freshwater species, belonging to 51 Benera was identified. Seasonal succession of dominant species was evident in Haechang Bay; Chaetoceros cunisetus, Skeletonema costatum, Eurampia zodiacus, Dictyocha fibula and Ceratium furca in summer, C. curisetus in autunm, C. cunisetus Rhizosoienia setigera and E. zodiacus in winter and S. costatum in spring. The phytoplankton community in Haechang Bay showed various species composition and was occupied with centric diatoms all the year round, Densities of the phytoplankton cell number by the samples of Haechang Bay ranged from $8.4{\times}10^3\;cells/l\;to\;2.0{\times}10^5\;cells/l$ with the mean value of $9.2{\times}10^4\;cells/l$ in summer, from $3.2{\times}10^3\;cells/l\;to\;4.6{\times}10^6\;cells/l$ with mean of $6,2{\times}10^4\;cells/l$ in autumn, from $8.4{\times}10^3\;cells/l\;to\;4.3{\times}10^4\;cells/l$ with mean $2.2{\times}10^4\;cells/l$ in winter and from $1.0{\times}\;10^3\;cells/l to\;4.6{\times}10^4\;cells/l$, with mean of $1.1{\times}10^4\;cells/l$ in spring. Phytoplankton standing crops fluctuated with an annual mean of $4.7{\times}10^4 cells/l$ between the lowest value of $1.0{\times}10^3\;cells/l$ in spring and the highest value of $4.6{\times}10^5 cells/l$ in autumn, That is, phytoplankton standing crops was high in summer and autumn, while it was very low in winter and spring.