Daily variations of inorganic nutrients and plankton in Jangmok Bayduring summer 2003. II. Heterotrophic flagellates and ciliates.

Abstract

In order to understand the abundance and biomass of heterotrophic protists in Jangmok Bay, abiotic and biotic factors were daily measured from 14 July to 4 September, 2003. Heterotrophic protists consisted of mainly heterotrophic nanoflagellates (HNF), heterotrophic dinoflagellates (HDNF) and heterotrophic ciliates. The abundance of HNF, HDNF and HCI was in the range of 0.13 - 2.81x103 cells/l (767±582x103 cells/l), in the range of 0.13 - 55.5 x103 cells/l (9.38±100.1x103 cells/l), and in the range of 0.95 - 54.7x103 cells/l (6.17±8.07x10 cells/l) respectively. Their biomass was 0.02 - 12.4 ㎍C/l(1.8±2.3 ㎍C/l), 2.5 - 2918 ㎍C/l (243.0±523.3 ㎍C/l) and 2.04-115.8 ㎍C/l (20.1±20.0 ㎍C/l), respectively. Mean microbial carbon biomass (mean 644±580 ㎍C/l) was composed of 5.59 % bacteria, 1.83 % cyanobacteria, 25.13 % autotrophs (<20 ㎛), 0.39 % HNF, 23.67 HDNF, 3.93 HCI and 39.45 % diatoms and other phytoplankton groups. Of the microbial carbon biomass, heterotrophic protists made up about 92.4 % and the contribution of heterotrophic protists to the total carbon biomass varied daily in the bay. This study suggests that in Jangmok Bay heterotrophic protists might play an important role as consumers of bacteria & small phytoplankton and that the importance of heterotrophic protists might vary daily.