The nitrogen isotope value in both ammonium and nitrate ion were determined at 9 stations during both June and August 2016, in order to understand the origin of DIN at the Han river. δ15N-NO3 and δ15N-NH4 values in 8 stations (CP, SB, MHC, P4, SJ, SBC, P2, SC) were no significant variation. However δ15N-NO3 and δ15N-NH4 values in KK (Kyeongan stream) showed significant different in comparison with 8 stations, with an apparent increase of nitrogen isotope values. These results indicate that antropogenic nitrogen source influence on KK station. Also the δ13C and δ15N isotope ratio of phytoplankton (Diatom and Cyanobacteria) in KK (Kyeongan stream) showed heavier values, compared to other study stations. These results indicate that nitrogen isotope value in phytoplankton effects by different nitrogen source in study sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the identification of dissolved inorganic nitrogen origin in aquatic environments.

서 론
 재료 및 방 법
  1. 조사지점
  2. 입자성 유기물 시료
  3. 식물플랑크톤
  4. 탄소 및 질소 안정동위원소 분석
  5. 킬달 (Kjedahl) 증류법
 결과 및 고 찰
  1. 암모니아성 질소 및 질산성 질소의 거동
  2. 식물플랑크톤의 안정동위원소비 변화
 적 요
 사 사
 REFERENCES

• 김민섭(국립환경과학원 환경측정분석센터, Environmental Measurement & Analysis Center, NIER;) | Kim, Min-Seob
• 이은정(국립환경과학원 한강물환경연구소, Han River Environment Research Center, National Institute of Environmental Research) | Eun-Jeong Lee
• 윤숙희(국립환경과학원 환경측정분석센터, Environmental Measurement & Analysis Center, NIER;) | Suk-Hee Yoon
• 임보라(국립환경과학원 환경측정분석센터, Environmental Measurement & Analysis Center, NIER;) | Bo-La Lim
• 박재선(국립환경과학원 환경측정분석센터, Environmental Measurement & Analysis Center, NIER;) | Jaeseon Park
• 박현우(국립환경과학원 환경측정분석센터, Environmental Measurement & Analysis Center, NIER;) | Hyunwoo Park
• 정현미(국립환경과학원 환경기반연구부, Fundamental Environment Research Department, NIER) | Hyen-Mi Chung
• 최종우(국립환경과학원 환경측정분석센터, Environmental Measurement & Analysis Center, NIER;) | Jong-Woo Choi Corresponding author