Alpine Ecosystem Observation and Experiment Station of Gongga Mountain, The Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, #9, Block 4, Renminnanlu Road, Chengdu, 610041, China.
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
Environ Sci Pollut Res Int. 2018 Feb;25(6):5740-5751. doi: 10.1007/s11356-017-0824-2. Epub 2017 Dec 11.
The construction of the Three Gorges Reservoir (TGR) as well as the development of local industry and agriculture not only had tremendous impacts on the environment but also affected human health. Although water, soil, and air in the TGR have been well studied for environmental risk assessment, very little information is available on benthic sediments and microorganisms. In this study, sedimentary samples were collected along the main stream of the TGR to examine microbial phospholipid fatty acids (PLFA) and relevant variables (e.g., nutrients and heavy metals) after the full operation of the TGR. The results showed that there were prominent trends (increase or decrease) of sedimentary PLFAs and properties from downstream to upstream. Bacteria-specific PLFA decreased toward the dam, while fungi-specific PLFA did not show any significant trend. The PLFA ratio of fungi to bacteria (F/B) increased along the mainstream. The total PLFA concentration, which represents the microbial biomass, decreased significantly toward the dam. Upstream and downstream sampling points were clearly distinguished by PLFA ordination in the redundancy analysis (RDA). That finding showed microbial PLFAs to have an obvious distribution pattern (increase or decrease) in the TGR. The PLFA distribution was markedly controlled by nutrients and heavy metals, but nutrients were more important. Moreover, among nutrients, Bio-P, NH-N, NO-N, and DOC were more important than TP, TN, TOC, and pH in controlling PLFA distribution. For heavy metals, Tl, V, Mo, and Ni were more important than Zn, Cu, Cd, and Pb. These findings suggested that Tl, V, Mo, and Ni should not be ignored to guard against their pollution in the TGR, and we should pay attention to them and make them our first priority. This study highlighted that the construction of the TGR changed riverine environments and altered microbial communities in sediments by affecting sedimentary properties. It is a reminder that the microbial ecology of sediment as an indicator should be considered in assessing the eco-risk of the TGR.
三峡水库的建设以及当地工农业的发展不仅对环境产生了巨大影响，还影响了人类健康。尽管已经对三峡水库的水、土、气进行了充分的环境风险评估研究，但有关底栖沉积物和微生物的信息却很少。本研究采集了三峡水库干流的沉积物样本，以研究三峡水库完全蓄水后的沉积物微生物磷脂脂肪酸（PLFA）及相关变量（如养分和重金属）。结果表明，从下游到上游，沉积物 PLFA 和性质呈现出显著的变化趋势（增加或减少）。细菌特异性 PLFA 向大坝方向减少，而真菌特异性 PLFA 没有表现出任何明显的趋势。真菌与细菌的 PLFA 比值（F/B）沿主流增加。代表微生物生物量的总 PLFA 浓度显著向大坝方向减少。冗余分析（RDA）中的 PLFA 排序清楚地区分了上游和下游采样点。这一发现表明，微生物 PLFA 在三峡水库中有明显的分布模式（增加或减少）。PLFA 的分布明显受到养分和重金属的控制，但养分更为重要。此外，在养分中，生物磷（Bio-P）、氨氮（NH-N）、硝氮（NO-N）和溶解性有机碳（DOC）比总磷（TP）、总氮（TN）、总有机碳（TOC）和 pH 对 PLFA 分布的控制更为重要。对于重金属，Tl、V、Mo 和 Ni 比 Zn、Cu、Cd 和 Pb 更为重要。这些发现表明，在三峡水库中，不应忽视 Tl、V、Mo 和 Ni 的污染，应注意它们，并将其作为首要任务。本研究强调，三峡水库的建设通过影响沉积物性质改变了河流环境，改变了沉积物中的微生物群落。这提醒我们，在评估三峡水库的生态风险时，应考虑沉积物微生物生态学作为指标。
