| 夏季闽江CDOM的空间分布与降解特征 |
| 摘要点击 3797 全文点击 1336 投稿时间：2018-06-02 修订日期：2018-07-03 |
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| 中文关键词 闽江 有色溶解有机质(CDOM) 三维荧光光谱-平行因子分析 微生物降解 光降解 |
| 英文关键词 Minjang River chromophoric dissolved organic matter (CDOM) EEMs-PARAFAC microbial degradation photodegradation |
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| 中文摘要 |
| 利用三维荧光光谱-平行因子分析技术（EEMs-PARAFAC）以及微生物和光降解实验等方法，分析夏季闽江下游-河口区有色溶解有机质（CDOM）的组成、分布及其降解特征.结果表明，闽江下游-河口区CDOM存在三类荧光组分：类腐殖质、类酪氨酸和类色氨酸；类腐殖质是河段CDOM的主要荧光组分，在河口区随着盐度增加主要的荧光组分逐渐变为类蛋白质.CDOM的丰度变化呈现出明显的空间分布格局：河段CDOM的吸收系数a（280）较低，进入市区后有所增加，到了郊区呈现下降的趋势，而在河口区迅速下降；保守估计福州市区对闽江CDOM的贡献为8%.河段a（280）易被微生物降解和光降解，降解率分别为（28±8）%和（44±7）%，其生物可利用性和光化学活性远高于受海源CDOM影响的河口区；类腐殖质、类酪氨酸和类色氨酸荧光组分在河段具有较高的光化学活性，降解率分别为（75±0.5）%、（58±21）%和（73±3）%，但不易被微生物降解，而且在28 d微生物培养后出现类腐殖质的累积. |
| 英文摘要 |
| The composition, distribution, and degradation of chromophoric dissolved organic matter (CDOM) in the lower reach and estuary of the Minjiang River were analyzed using fluorescence excitation-emission matrices-parallel factor analysis (EEMs-PARAFAC) and microbial and photochemical degradation experiments. The results show that there are three types of fluorescence components in the study area:humic-like, tyrosine-like, and tryptophan-like. The humic-like components are the main components in the river zone, while the protein-like components become dominant with increasing salinity in the estuary. The change of the CDOM abundance shows a notable spatial distribution pattern. The absorption coefficient a(280) of CDOM is lower in the river, increases after entering the urban area, shows a decreasing trend in the suburbs, and rapidly declines in the estuary. A conservative estimate of the contribution of the Fuzhou urban area to the CDOM of the Minjiang River is 8%. The a(280) in the river is susceptible to microbial and photochemical degradation and the degradation percentages are (28±8)% and (44±7)%, respectively. The bioavailability and photochemical reactivity of a(280) are much higher in the river than in the estuary. The humic-like, tyrosine-like, and tryptophan-like components show a higher photochemical reactivity in the river, with degradation percentages of (75±0.5)%, (58±21)%, and (73±3)%, respectively. The fluorescent components are not labile with respect to microbial degradation and humic-like components are accumulated after 28 days of microbial culture. |
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