CHEN Fajin, CHEN Jianfang, JIA Guodong, JIN Haiyan, XU Jie, YANG Zhi, ZHUANG Yanpei, LIU Xizhen, ZHANG Haisheng. Nitrate δ15N and δ18O evidence for active biological transformation in the Changjiang Estuary and the adjacent East China Sea[J]. Acta Oceanologica Sinica, 2013, 32(4): 11-17. doi: 10.1007/s13131-013-0294-4
Citation:
CHEN Fajin, CHEN Jianfang, JIA Guodong, JIN Haiyan, XU Jie, YANG Zhi, ZHUANG Yanpei, LIU Xizhen, ZHANG Haisheng. Nitrate δ15N and δ18O evidence for active biological transformation in the Changjiang Estuary and the adjacent East China Sea[J]. Acta Oceanologica Sinica, 2013, 32(4): 11-17. doi: 10.1007/s13131-013-0294-4
CHEN Fajin, CHEN Jianfang, JIA Guodong, JIN Haiyan, XU Jie, YANG Zhi, ZHUANG Yanpei, LIU Xizhen, ZHANG Haisheng. Nitrate δ15N and δ18O evidence for active biological transformation in the Changjiang Estuary and the adjacent East China Sea[J]. Acta Oceanologica Sinica, 2013, 32(4): 11-17. doi: 10.1007/s13131-013-0294-4
Citation:
CHEN Fajin, CHEN Jianfang, JIA Guodong, JIN Haiyan, XU Jie, YANG Zhi, ZHUANG Yanpei, LIU Xizhen, ZHANG Haisheng. Nitrate δ15N and δ18O evidence for active biological transformation in the Changjiang Estuary and the adjacent East China Sea[J]. Acta Oceanologica Sinica, 2013, 32(4): 11-17. doi: 10.1007/s13131-013-0294-4
State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China;College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China
2.
State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China;Laboratory of Marine Ecosystem and Biogeochemistry of State Oceanic Administration, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China
3.
Key Laboratory of Marginal Sea Geology of Chinese Academy of Sciences, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
4.
Laboratory of Marine Ecosystem and Biogeochemistry of State Oceanic Administration, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China
5.
Division of Environment, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
The Changjiang Estuary has been considered as one of the most polluted estuaries in the world due to high nitrate (NO3-) input, especially in spring and summer. In this study, δ15N and δ18O of NO3-, along with other chemical parameters in this area, were measured in spring to evaluate NO3- biogeochemical processes. A simple two end-members mixing model was used to examine the relative contribution of the Changjiang River Diluted Water and marine water to NO3- sources in the Changjiang Estuary and the adjacent East China Sea. The isotopic signals show that NO3- behaved relatively and conservatively in Transect F and Transect P where assimilation was weak possibly due to vertical mixing, while active assimilation and weak nitrification occurred in Transect D. Spatial difference in assimilation was indicated by the ~1:1 enrichment of δ15N and δ18O in the three transects, while spatial difference in nitrification was reflected by deviations of δ15N and δ18O from assimilation line. Our results suggest that the input of the Changjiang River Diluted Water promoted NO3- assimilation possibly by stratifying the water column which favored the phytoplankton growth.
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