초록
인천 연안 표영생태계의 미세생물 먹이 망에서 부유천생동물의 역할을 파악하기 위하여 시미세생물의 현종량과 성장률을 측정하고, 종속영양 편모충류와 섬모충류의 포식능력을 연구하였다. 종속영양 편모충류와 섬모충류의 여과율과 먹이섭취율은 형광 표지 박테리아(FLB)를 이용한 방법과 자연해시료를 분리 배양하는 방법에 의하여 연구 하였다. 본 조사시에 인천 연안수역의 박테리아 현존량은 0.7~1.5$\times$10/SUP 6/ cell. ml/SUP -1/, 종속영양 편모충류의 현종량은 1,680~2,180 cell.ml/SUP -1/, 독립영양 편모류의 현존량은 1.090~2,180 cell.ml/SUP -1/, 섬모충류의 현존량은 3,600~ 5,700 cell.ml/SUP -1/였다. 박테리아의 평균 성장률은 0.015~0.025 h/SUP -1/,섬모 충류의 성장률은 0.021 h/SUP -1/로 전반적으로 느린 편이었다. 종속 영양편모충류의 박테리아에 대한 포식률은 평균 0.055 h/SUP -1/로 높게 나타나고, 섬모충류의 종속영 양 편모류에 대한 포식률도 0.057 h/SUP -1/로 높게 나타났으나 독립영양 편모류에 대 한 포식률은 0.019 h/SUP -1/로 낮게 나타났다. 종속영양 편모충류의 박테리아에 대한 여과율과 섭취율은 각각 3.6~61.8 nl/SUP -1/.HFL.h/SUP -1/,6~52BAC.HFL.h/SUP -1/로 FLB를 이용하였을 때 낮게 나타나고 자연 개쳬군을 이용하였을 때 높게 나타나 며 박테리아 군집에 큰 영향을 주었다. 우점부유섬모충류인 Tintinnopsis sp의 평균여 과율은 3.2~4.6ul.CIL/SUP -1/.h/SUP -1/, 섭취율은 5~6 cells.CIL/SUP -1/. h/SUP -1/로 인천연안수역 편모류 현존량의 17-20%를 섭취하는 것으로 나타나고 해야 간조 시보다 만조 시에 다소 높게 나타났다.
To clarify the role of protozooplankton in the microbial food web of Inchon coastal ecosystem, the grazing capacities and growth rates of heterotrophic flagellated (HFL) and ciliates were investigated. We measured the growth rates of bacteria, HFL, autotrophic flagellated (AFL) and ciliates using reverse flow (RF) filter set and obtained the clearance rates and ingestion rates of HFL and dilates by fluorescent labelled bacteria (FLB) method and isolation culture method from natural seawater of Inchon coastal area. The standing crops of bacteria, HFL, AFL and ciliates in this study area were 0.7∼1.5${\times}$10/SUP 6/ cells$.$ml/SUP -1/ 1,680∼2,180 cells$.$ml/SUP -1/, 1,090∼2,180 cells$.$ml, and 3,600∼5,700 cells$.$l/SUP -1/, respectively. The mean growth rates of bacteria, HFL, AFL and ciliates were 0.039 h/SUP -1/, 0.032∼0.033h/SUP -1/, 0.015∼ 0.025h/SUP -1/and 0.021h/SUP -1/, respectively. The growth rates of protozooplankton of Inchon coastal waters were relatively low. Mean grazing rate of HFL, AFL and ciliates were0.039 h/SUP -1/, 0.032∼0.033h/SUP -1/,0.015∼ 0.025h/SUP -1/and 0.021h/SUP -1/, respectively. The growth rates of protozooplankton of Inchon coastal waters were relatively low. Mean grazing rate of HFL on bacteria was 0.055h/SUP -1/. Mean grazing rates of ciliates on HFL was relatively high of 0.057 h/SUP -1/, while the grazing rate of ciliates on AFL was low of 0.019h/SUP -1/. The clearance rates and ingestion rates of HFL on bacteria were 3.6∼61.8nl$.$HFL$.$h/SUP -1/ and 6∼52 BAC. HFL$.$h/SUP -1/ respectively. FLB grazing experiment showed low values, while natural bacteria experiment showed high value meaning high grazing pressure on total bacteria. The clearance rates and ingestion rates of Tintinnopsis sp., dominant ciliates in Inchon coastal waters, were 3.2∼4.6 ul$.$CIL/SUP -1/$.$h/SUP -1/ and 5∼6 cells$.$CIL/SUP -1/$.$h/SUP -1/ respectively, showing higher values in the high tide than low tide. The ingestion rates of ciliates implies that ciliate took up 17∼20% of total nanoflagellates of Inchon coastal waters.
