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Nitrogen transport, transformation, and retention in the Three Gorges Reservoir: A mass balance approach
Author(s) -
Ran Xiangbin,
Bouwman Lex,
Yu Zhigang,
Beusen Arthur,
Chen Hongtao,
Yao Qingzhen
Publication year - 2017
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10568
Subject(s) - biogeochemical cycle , biogeochemistry , nitrate , denitrification , nitrogen cycle , nitrogen , cycling , sedimentation , hydrology (agriculture) , environmental chemistry , environmental science , particulates , nitrogen balance , nitrite , flux (metallurgy) , chemistry , geochemical cycle , sediment , geology , paleontology , geotechnical engineering , organic chemistry , archaeology , history
Abstract Dam construction in river systems affects the biogeochemistry of nitrogen (N), yet most studies on N cycling in reservoirs do not consider the transformations and retention of the different N species. This study addresses the N inputs, transport, transformations, and retention in the Three Gorges Reservoir (TGR) in the Changjiang River, the world largest water storage project, during its filling phase in 2004–2007. The results indicate that dissolved inorganic nitrogen (DIN) was the most abundant N form in the TGR and particulate N was only 2% to the total N flow and retention. About 34% of the dissolved organic nitrogen (DON), 64% of nitrite, and 44% of ammonia were retained by transformation within the TGR in 2007. Time‐series data show that about 8% of inflowing total dissolved N was lost by denitrification and sedimentation. Transformations of DON, nitrite and ammonia caused an increase of the nitrate load by 6%; and at the same time the DIN flux increased by 4% while the water moved through the TGR, which is the balance between formation and retention of DIN. The large contribution of biogeochemical transformations to nitrate loading in the TGR indicates the importance of internal processing for the river N species composition.