| 混合层深度对藻类生长的影响研究 |
| 摘要点击 5464 全文点击 2369 投稿时间：2012-11-20 修订日期：2013-02-15 |
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| 中文关键词 混合层 水华 真光层/混合层 藻类 光照 |
| 英文关键词 mixing layer water bloom euphotic layer/mixing layer algae light |
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| 中文摘要 |
| 三峡水库蓄水后,支流库湾频繁暴发水华. 为研究水华暴发关键因子,以临界层理论为指导,于2012年初冬季,在香溪河野外观测站建立围隔实验系统,研究水体混合对藻类生长的影响机制. 围隔水下深度按梯度布设,表底掺混均匀,并注入由浮游动物网过滤的低Chl-a浓度的香溪河河水. 结果表明, Zeu/Zmix(真光层深度与混合层深度之比)＞1的围隔藻类生长迅速并暴发水华,Chl-a浓度最高达到90 mg·m-3,反之生长缓慢. 临界层理论适用于本实验,Zeu/Zmix也存在一个临界值,低于临界值浮游植物生长会受光限制而不易暴发水华; 在临界层理论的基础上,分析得藻类净初级生产力与Zmix存在负相关关系,即Zmix越小藻类净初级生产力越大. |
| 英文摘要 |
| Frequent blooms have been observed in tributary bays of the Three Gorges Reservoir since its initial filling. In order to identify the primary factor controlling water blooms, some experiments were conducted based on the critical depth theory. In the winter of early 2012, the enclosures on Xiangxi River were built to investigate the mechanism of mixing layer depth(Zmix) on algal growth. The length of the enclosures under water was changed in gradient,and the water of each enclosures was injected from Xiangxi River, in which the algal concentration was low and the zooplanktons were filtered out,and then the water was mixed evenly. The results showed that the algae grew quickly in the enclosures with Zeu/Zmix(the favorable ratio of euphotic depth to mixing depth)＞1, and the maximum density of chlorophyll-a(Chl-a) reached 90 mg·m-3, otherwise the algae grew slowly. The critical depth theory was appropriate for the experiment,and there was a critical value of Zeu/Zmix. Water bloom will not break out if the Zeu/Zmix is below the critical value. Based on the critical depth theory,it was found that there was a negative correlation between algal net primary productivity and Zmix,the lower the Zmix,the greater the net primary productivity. |
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