신구저수지의 1차 생산 및 지방산 생성속도 결정을 위한 13C 추적자 활용 연구

Abstract

An Application of 13C Tracer f。r the Determination of Primary Prod uctivity and Fatty Acid Production Rate in Shingu Reservoir. Lee, Yeonjung, Min-Seob Kim, Kyung-Hoon Shin* and Soon-Jin Hwang1 (Department of Environmental Marine Sciences, Hanyang University, Ansan 425-791, Korea; 1Department of Environmental Science, Konkuk University, Seoul 143-701, Korea)

The in situ incubation experiment was carried out using 13C tracer to determine pri­ mary productivity and fatty acid production rate in the shallow, eutrophic Shingu reservoir on 4th July. Particulate organic matter (POM) accounted for 76% in sus­ pended particulate matter (SPM), and average concentration of chlorophyll-a was 89

µg L 1 in the euphotic layer. Total amount of chlorophyll-a (Chl-a), primary pro­ ductivity and Chl-a specific productivity in euphotic layer were 112 mg Chl-a m-2,

3.53 g C m-2 d-1, 32 mg C mg Chl-a-1 d-1, respectively. The fatty acid composition in newly produced organic matter and suspended organic matter didn’t show any

significant difference, demonstrating that autochthonous organic matter should be a major source of POM pool. In addition, the fatty acids of bacterial origin were increased through extracellular release of newly photosynthesized DOC, and closely coupled with bacterial assimilation. This result suggests that organic carbon should be actively cycled through the microbial loop in Shingu reservoir in summer.