| 长江流域着生藻类群落结构的空间格局及其生态评价 |
| 摘要点击 5161 全文点击 714 投稿时间：2021-11-22 修订日期：2021-12-29 |
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| 中文关键词 长江流域 着生藻类 群落结构 空间格局 生态评价 |
| 英文关键词 Yangtze River basin periphytic algae community composition spatial pattern ecological evaluation |
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| 中文摘要 |
| 在长江流域河流区域共布设了130个采样点开展着生藻类调查，范围涵盖了自长江源区至入海口的干流重点区域、八大一级支流和三峡支流.长江干流着生藻类密度从高到低依次为长江上游、长江源区、长江中下游和金沙江，整个干流自西向东着生藻类群落空间格局呈现硅藻门和蓝藻门交替占优的形式，硅藻（舟形藻）在干流具最大竞争优势，干流着生藻类群落分布与总氮、总磷和pH密切相关.长江支流中，三峡支流着生藻类密度显著高于八大一级支流，所有支流着生藻类群落主要为蓝藻门，蓝藻（鞘丝藻）在长江支流具最大竞争优势，支流着生藻类群落分布与溶解氧和pH密切相关.着生藻类的多样性分析及水生态评价显示，长江源区物种丰富度较低，但均匀度指数较高，因此是α多样性最高的区域，也是水生态评价较好的区域（β中污型）；长江中下游尽管评价也为β中污型，但着生藻类群落均匀度显著低于源区，导致其α多样性低于源区.水质评价显示长江流域各区域均为良好，但区域间的WQI指数仍具显著差异，而且其差异结果与水生态评价结果不一致，因此建议结合水生态和水质两种评价结果从而更全面地评价水生态系统健康. |
| 英文摘要 |
| To explore the periphytic algae community structure in the Yangtze River basin, samples were collected from 130 sampling sites, including the source to the estuary along the mainstream of the Yangtze River, eight primary tributaries, and the tributary of the Three Gorges area. The periphytic algae densities of different areas in the mainstream of the Yangtze River ranked from high to low were the upstream area, source area, middle and lower area, and the Jinsha River. The high periphytic algae density in the upstream area was associated with the shift in nutrition level, and the high periphytic algae density in the source area was associated with human activity. The spatial pattern of the periphytic algae community in the whole main stream from west to east presented the alternating dominance of Bacillariophyta and Cyanophyta; the Bacillariophyta (Navicula) had a competitive advantage in the main stream, and the distribution of the periphytic algae community was driven by total nitrogen, total phosphorus, and pH. For the tributary of the Yangtze River, the periphytic algae density in the Three Gorges tributary area was far higher than those in the eight primary tributaries; the periphytic algae community was dominated by Cyanophyta (Lyngbya), which had a competitive advantage in the tributaries of the Yangtze River. The distribution of the periphytic community was driven by dissolved oxygen and pH. According to the diversity analysis and assessment, the periphytic algae community in the source area showed lower species richness and higher evenness, thus leading to a high α-diversity and good assessment result (mesosaprobic zone). The middle and lower reaches of the Yangtze River also showed the same assessment result, the mesosaprobic zone. However, the community evenness of the middle and lower reaches was significantly lower than that of the source area, thus making the middle and lower reaches of the Yangtze River have a significantly lower α-diversity than that of the source area. All areas of the Yangtze River showed good water quality assessment; however, different areas had different WQI index numbers, and the assessment results of the WQI index were inconsistent with the results of the aquatic assessment. Therefore, a comprehensive assessment of aquatic ecosystem health should use both aquatic assessments and water quality assessments. |
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