Bioecological Characteristics of Coral Habitats around Moonsom, Cheju Island, Korea: II. Community Dynamics of Phytoplankton and Primary Productivity

Algae > Volume 15(1); 2000 > Article

Algae 2000;15(1): 37-47.

Joon-Baek Lee, Jong-Hun Choa, Dong-Woo Kang, You-Bong Go and Bong-Cheol Oh

ABSTRACT

Community dynamics of phytoplankton and primary productivity have been investigated bimonthly from February 1997 to December 1997 in the coastal area around Moonson of the southern Cheju Island, which is well-known for soft coral habitats in Korea. Average water temperature was 18.5degree C, being stratified from May to September by the seasonal thermocline, while vertically homogeneous in the winter. Euphotic depths ranged seasonally from 18.9 m to 45.9 m (average 33.7 m). Chlorophyll a concentrations varied from 0.02 to 0.92 μg·l super(-1). Standing crops of phytoplankton ranged from 2 x 10 super(3) to 3.9 x 10 super(5) cells·l super(-1), showing a peak only in the spring. Diatoms occupied 67.5% of the total standing crops, while phytoflagellates, were predominated with 36.6% and 38.7% in June, respectively. There was four dominant species in the study area. Chaetoceros socialis Lauder dominated in inshore but Patalia sulcata (Ehrenberg) Cleve in offshore. In October, Skeletonema costatum (Greville) Gran dominated the whole area. Daily primary productivity varied from 32.3 to 364.9 mgC·m super(-2)·day super(-1) (average 180.7mgC·m super(-2)·day super(-1)). Contribution of nanoplakton (

Key words: Cheju Island, community dynamics, Moonson, nanoplankton, phytoplankton, primary producivity