한강수계 (漢江水系) 인공호에서의(人工湖) 요소분해속도 비교연구 = Comparative Investigation of the Urea Degradation in Reservoirs of the Han River System

다국어 초록 (Multilingual Abstract)

The in situ rate of urea degradation was measured in the euphotic zone of three reservoirs located in the Han River System, The daily rate of urea degradation(i. e., sum of the incorporation rate of urea carbon into the particulate organic matter and the liberation rate of urea carbon into the water as carbon dioxide) in surface water was 14μmol urea·m^-3.day^-1 in Lake Soyang, 43μmol urea ·m^-3.day^-1 in Lake Chungju and 49μmol urea·m^-3.day^-1 in Lake Paldang. There was no change at various depths. The greater part of urea degradation took place during the the phase of carbon dioxide liberation. In the light, an appreciable amount of urea degradation was incorporated into phytoplankton cells, but this was extremely low in the dark condition. High correlation coefficients were obtained between urea degradation rate and photosynthesis or photosynthetic carbon assimilation rate by unit amount of chlorophyll-a. The residence time of urea in surface water was respectively estimated as 9, 2 and 9 days in Lakes Soyang, Chundu and Paldang. The present results suggest that in reservoirs the urea degradation occurred in connection with photosynthetic activity and that its has an important contribution as one of the nitrogen source for phytoplankton population. The brief residence time of urea indicates that the urea is a rapidly recycled from of biogeochemical parameter.