폐쇄생태계 내 용존산소에 미치는 동물플랑크톤 인위적 가입 효과

Abstract

In order to understand role of zooplankton aggregation affecting alteration in the dissolved oxygen (DO) concentration, we artificially enhanced zooplankton abundance by net towing. Thus, present study was designed to monitor the effect of N. scintillans blooms on the DO concentration by introduction of enclosed polyethylene bags (220 liter) during two weeks. DO concentration in experimental bags varied between 4.00 and 5.56 mg L-1 which is very low when compared to the ambient water(6.03 and 8.68 mg L-1) and control bags(5.20 and 7.32 mg L-1). The most dominant species, N. scintillans, representing from 52.0 to 86.0 % of total abundance in the bags, ranged from 6 to 109 individuals L-1 in ambient water, from 35 to 489 individuals L-1 in control bags and from 237 to 791 individuals L-1 in experimental bags during the study period. The high abundance of N. scintillans in experimental bags stemmed from the artificial addition of the species by net towing. Based on the above results, DO concentration showed negative relationship with N. scintillans abundance. High abundance of N. scintillans was coincident with the low concentration of DO, whereas low abundance of N. scintillans was related to the relatively high concentration of DO. The result indicates that high abundance of N. scintillans affected negatively DO concentration in the enclosed bags.