| 摘要: |
| 1997年11—12月(枯水期), 1998年8月和10月(丰水期), 对长江从金沙江至河口干流和主要支流、湖泊入江口总氮、总溶解氮、总有机氮等进行调查。结果表明, 长江水中各种形态氮的浓度, 枯水期明显高于丰水期, 支流明显高于干流；长江TN和TDN在枯、丰期具有基本类似的迁移变化过程；DIN是长江水中TDN的主要存在形式, 丰水期TDN的迁移变化主要取决于DIN；TDN是长江水中TN的主要存在形式, TN的迁移变化主要取决于TDN或者由DIN和TON共同决定；丰水期各种形态的氮中只有有机氮比较容易为悬浮颗粒物质所吸附；长江干流枯水期TDN浓度与长江径流呈较好的线性正相关关系；枯水期TN、丰水期TN和TDN浓度与长江径流的正相关主要发生在上游,这与长江水中氮主要来自于面源有关。
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| 关键词: 总氮,有机氮,分布变化,迁移,长江 |
| DOI：10.11693/hyhz200306001001 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目,49876020号;中国科学院“九五”重点资助项目,KZ952-S1-421号;国务院三峡工程建设委员会资助项目,SX(97)-11-4号 |
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| DISTRIBUTION, VARIATION AND REMOVAL PATTERNS OF TOTAL NITROGEN AND ORGANIC NITROGEN IN THE CHANGJIANG RIVER |
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SHEN Zhi-Liang, LIU Qun, ZHANG Shu-Mei
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Key Laboratory of Marine Ecology and Environmental Science, Institute of Oceanology,The Chinese Academy of Sciences
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| Abstract: |
| Nitrogen content increase by several times in Changjiang River and its estuary Over the past 40 years has been a major concern of oceanographers home and abroad. In this paper, the distribution and removal patterns of total nitrogen, total dissolved nitrogen and organic nitrogen were studied in the mainstream and the mouths of major tributaries and lakes in the Changjiang River from Jinshajiang River to the mouth during November and December, 1997 (dry season) and in August and October 1998 (flood season), to provide the basic data and a scientific basis for further research of biogeochemistry of N in the Changjiang River and its estuary.
The concentrations of various forms of N in the Changjiang River water were obviously higher in the dry season than in the flood season and higher in the tributaries than in the mainstream. The lowest concentrations of various forms of N in the dry and flood seasons(second low for TON in the flood season) were found in Panzhihua, because of less pollution in the Jinshajiang River. Their concentrations obviously increased in the upper reaches and had a smaller variation in the middle and lower reaches, and the concentrations in the mainstream were affected by the tributaries. In the tributaries, high concentrations of N were found in the Huangpujiang, Hanshui and Jialingjiang Rivers and low values in the Yalongjiang River, Poyanghu Lake and Dongtinghu Lake in the dry season; in the flood season, high values were in the Huangpujiang, Wujiang and Jialingjiang Rivers and low values in the Yalongjiang River, Poyanghu Lake and Dongtinghu Lake. The removal and variation patterns of TN and TDN in the dry season were respectively similar to the flood season. DIN was the main form of TDN in the Changjiang River, and the removal and variation of TDN was mainly determined by DIN. TDN was the main form of TN in the Changjiang River, and the removal and variation of TN was mainly determined
by TDN or DIN and TON that was almost 50% of TN concentration. The negative relationships between TN, TON and TSM respectively in the flood season show that only organic N could be absorbed by suspended matter in various forms of N. Apositive relationship between TDN concentration and the runoff in the Changjiang River mainstream was found for the dry season. The significant positive relationships between TN concentration in the dry, TN, TDN concentrations in the flood season and the runoff respectively were mainly in the upper reaches, due to the fact that N in the Changjiang River water mainly comes from non-point sources, e.g., precipitation and agriculture non-point sources N lost from fertilizer and soil. In the upper reaches, a large difference of human activity along the river leads to the difference of the concentration of non-point sources N. However, in the middle and lower reaches, because of in significant differences in population and agricultural production etc., the difference of N concentration is small.
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| Key words: Total nitrogen, Organic nitrogen, Distributions and variations, Removal, Changjiang River |
