| 太湖入湖河流溶解性有机碳来源及碳水化合物生物可利用性 |
| 摘要点击 5093 全文点击 2360 投稿时间：2014-09-06 修订日期：2014-10-07 |
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| 中文关键词 溶解性碳水化合物 溶解性有机碳 来源 殷村港 陈东港 |
| 英文关键词 dissolved carbohydrates dissolved organic carbon sources Yincungang River Chendonggang River |
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| 中文摘要 |
| 以太湖流域西北部殷村港和陈东港两条入湖河流为研究对象,于2012年9月至2013年8月每月采集表层水体样品, 测定了水温、叶绿素a浓度和浮游细菌丰度,并分析了溶解性有机碳DOC(dissolved organic carbon)浓度及其碳稳定同位素特征值(δ13 CDOC)、紫外吸光度SUVA254(specific UV absorbance)以及溶解性碳水化合物浓度的变化规律. 结果表明,殷村港和陈东港δ13 CDOC变化范围为 -27.03‰±0.30‰~-23.38‰±0.20‰,以外源性碳为主. 浮游植物光合作用产物的释放和外源输入是河流中溶解性碳水化合物的主要来源. 两条入湖河流中多糖PCHO(polysaccharides)和单糖MCHO(monosaccharides)浓度在春夏季与秋冬季具有显著差异(P<0.01, n=12; P<0.01, n=12). 这与碳水化合物的来源及组分的可利用性有关. 秋冬季藻类消亡过程中释放的PCHO在低温下不易被降解,容易堆积,因此两条入湖河流总溶解性碳水化合物TCHO(total dissolved carbohydrates)以PCHO为主; 而在春夏季,随着温度升高,PCHO被微生物分解利用转化为MCHO, MCHO是TCHO中主要组分. |
| 英文摘要 |
| Surface water samples of Yincungang and Chendonggang Rivers were collected from September 2012 to August 2013 in Lake Taihu. Water temperature, Chlorophyll a and bacterial abundance were analyzed, as well as dissolved organic carbon (DOC) concentrations, stable carbon isotope of DOC (δ13 CDOC), specific UV absorbance (SUVA254) and dissolved carbohydrates concentrations. δ13CDOC ranged from -27.03‰±0.30‰ to -23.38‰±0.20‰, indicating a terrestrial source. Both the autochthonous and allochthonous sources contributed to the carbohydrates pool in the tributaries. Significant differences in PCHO (polysaccharides) and MCHO (monosaccharides) concentrations were observed between spring-summer and autumn-winter (P<0.01, n=12; P<0.01, n=12), which might be caused by the variation in the sources and bioavailability of carbohydrates. PCHO contributed a major fraction to TCHO (total dissolved carbohydrates) in autumn and winter, which could be explained by the accumulation of undegradable PCHO limited by the low water temperature; MCHO contributed a major fraction to TCHO in spring and summer, which might be caused by the transformation from PCHO by microbes at high water temperature. |
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