한국 남해연안역에서 야광충 최대 개체수 출현양상의 연간변이와 생태학적 중요성

Abstract

This study has been conducted as part of \\\\'Research Fishery Management Program\\\\' in the Jangmok bay faced with South Sea Institute of KORDI from 2001 to 2006. We surveyed the temporal dynamics of red-tide protozoan Noctiluca scintillans and the related environmental determinants for understanding the mechanisms controlling outbreaks of the red-tide organism in the southern coastal waters. Hydrographic data, nutrients, chlorophyll-a (chl-a) and N. scintillans were taken around daytime flood tide at intervals of 7-10 days from 2001 to 2006 from the pier of the Marine station in Jangmok bay.Present study revealed seasonal periodicity of the organism with maximal abundances in May-September, and with a relatively low but obvious peak in December/January from 2001 to 2005. Exceptionally, the maximal peaks of the species occurred in March/April, 2006, which the timing of peaks shifted earlier compared to other periods. The distinctive peaks of N. scintillans occurred commonly after the chl-a concentration increased accompanied with the nitrate concentration. Nitrate concentration varied with the surface salinity in the marine station during the study periods. N. scintillans showed high abundance (120,155 inds.m-3) after responding to the high concentration of chl-a under the range of 15-20°C in 2002. However, the highest abundance (132,426 inds.m-3) occurred after high chl-a concentration was found under the range of 8-13°C in 2006. Specifically, the first peaks of N. scintillans abundance in each year coincided with the chl-a concentration of net-sized phytoplankton (> 20㎛) rather than nano- and pico-sized phytoplankton. Exceptionally, the first peak of N. scintillans in winter was not coincident with chl-a concentration in 2003, which might be related with accumulation by drifting from oceanic waters. It suggested that enhanced abundances of N. scintillans stemmed from the functional response to chl-a and accumulation by drifting in the Marine station during