| 深圳茅洲河下游柱状沉积物中碳氮同位素特征 |
| 摘要点击 3655 全文点击 937 投稿时间：2017-04-28 修订日期：2017-08-10 |
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| 中文关键词 碳氮同位素 总氮 有机质 C/N 沉积物 |
| 英文关键词 carbon and nitrogen isotope total nitrogen organic matter carbon-nitrogen ratio sediment |
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| 中文摘要 |
| 对茅洲河下游12根沉积物柱状样中总氮（TN）、有机质（OM）、C/N值、δ15N、δ13C含量进行了测定，分析探讨了茅洲河下游及其主要支流沙井河沉积物中氮和有机质的分布特征及来源.结果表明，沉积物中TN平均含量为1815.37 mg·kg-1，OM平均含量为22401.68 mg·kg-1，与太湖和巢湖流域相比，研究区内TN和OM含量均处于较高水平，且随深度增加变化均较大.茅洲河下游沉积物中δ15N、δ13C含量范围为2.20‰~32.78‰、-27.53‰~-21.95‰，平均值分别为6.78‰、-25.41‰；C/N值范围为0.49~18.23；δ13C随深度变化较为平缓，而δ15N、C/N值随深度增加波动较大.研究区来源分析表明：C3植物与合成化肥为茅洲河下游表层沉积物（0~40 cm）的主要来源；藻类是深层沉积物与支流沙井河沉积物中有机质的主要来源.茅洲河下游表层沉积物（0~40 cm）中的氮素主要来源于无机化肥与土壤有机氮，深层沉积物与支流沙井河沉积物中的氮素主要来源于土壤流失和土壤有机氮. |
| 英文摘要 |
| Based on the determinations of total nitrogen (TN), organic matter (OM), carbon-nitrogen ratio (C/N), δ15 N, and δ13 C on 12 sediment cores, the distribution characteristics and the sources of nitrogen and organic matter were analyzed in sediments from the lower reaches and main tributaries of the Maozhou River. The results showed that the average concentrations of total nitrogen (TN) and organic matter (OM) were 1815.37 mg·kg-1 and 22 401.68 mg·kg-1, respectively, in the Maozhou River sediments, which were higher than in TaihuLake and ChaohuLake. The levels of TN and OM in the study area were high and varied greatly with the increase of depth. The δ15 N content in the sediments of the MaozhouRiver downstream ranged from 2.20 ‰ to 32.78 ‰, while the δ13 C content ranged from -27.53 ‰ to -21.95 ‰. The average concentrations of δ15 N and δ13 C were 6.78 ‰ and -25.41 ‰. Moreover, the C/N ratio ranged from 0.49 to -18.23. The δ13 C varied slightly with the increase of depth, while δ15 N and C/N varied greatly. A source analysis in the study area indicated that C3 plants and chemical fertilizer were the main sources in the surface sediments (0-40 cm) downstream of the Maozhou River. Furthermore, algae were the main sources of organic matter in the deep sediments downstream of the Maozhou River and in tributary sediments of the Shajing River. Nitrogen in the surface sediments (0-40 cm) downstream of the Maozhou River mainly comes from inorganic fertilizer and soil organic nitrogen, while nitrogen in the Maozhou River deep sediments and Shajing River sediments mainly come from soil erosion and soil organic nitrogen. |
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