| 冰封状态下达里湖冰-水中浮游细菌群落结构差异 |
| 摘要点击 2528 全文点击 683 投稿时间：2020-09-22 修订日期：2020-10-29 |
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| 中文关键词 冰封 元素迁移 浮游细菌 结构 达里湖 |
| 英文关键词 frozen element migration bacterioplankton community Dali Lake |
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| 中文摘要 |
| 细菌是湖泊生态环境、物质能量循环的关键参与者.为了解寒旱区湖泊冰封状态下上部水体中浮游细菌群落结构变化特征，于2019年1月中旬，在内蒙古达里湖进行了15个取样点处的湖冰底层、冰下表层水等样品（"底冰"和"表水"）的采集与分析.结果表明，在门类水平上，达里湖底冰中浮游细菌群落多样性比表水中略低，且优势浮游细菌门类的相对含量出现明显冰-水差异.虽然底冰和表水中优势浮游细菌门类均由Proteobacteria、Actinobacteria、Cyanobacteria、Bacteroidetes、Verrucomicrobia、Planctomycetes、Tenericutes及Gemmatimonadetes等组成，但Proteobacteria的相对含量在底冰中平均达到63.64%，而表水中的平均相对含量下降到26.75%，明显小于Actinobacteri的平均相对含量（39.10%）.再者，由于冰封过程中"冷冻浓缩"作用导致氮（N）、磷（P）等元素迁移幅度不同，促使底冰和表水中Proteobacteria和Actinobacteria等优势细菌门类相对含量存在明显的差异响应，导致主要浮游细菌属种的相对含量出现冰-水明显不同.整体上，总磷（TP）和溶解性总磷（DTP）等变化成为影响底冰中优势细菌门类结构变化的环境因子，而溶解态无机磷（DIP）和氨氮（NH4+-N）等变化成为影响表水中优势细菌门类结构变化的环境因子.显然，不同形态N、P元素的迁移幅度等成为影响冰封状态下湖泊表层水体中浮游细菌结构差异的主要影响因素，这也将为进一步分析寒旱区湖泊水生态环境提供基础数据. |
| 英文摘要 |
| Bacteria are the key components of water ecosystems, and play important roles in material and energy cycle processes. To understand the changes in the bacterioplankton community in frozen lakes, we collected 15 "bottom ice" samples and 15 "surface water" samples under the ice sheet from Dali Lake, which is an inland closed lake in the Inner Mongolia Plateau. Combined with comparisons of the physicochemical proxies between "bottom ice" and "surface water" samples, the phylum community characteristics of the bacterioplankton were analyzed in detail. Although the bacterioplankton were mainly comprised of Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, and 11 other phyla in the "bottom ice" and "surface water", the average relative abundances of the dominant planktonic bacteria were clearly different. For example, the average relative abundance of Proteobacteria was approximately 63.64% in the "bottom ice" samples, but decreased to approximately 26.75% in the surface water samples, which was visibly smaller than the relative abundance of Actinobacteria with an average value of approximately 39.10%. We concluded that the changes in the contents of nutrient elements and physicochemical proxies must be the primary factors influencing the changes in the bacterioplankton community in the frozen Dali Lake. The changes in the physicochemical proxies could have been responsible for the changes in the bacteria community in the "bottom ice" and "surface water". Otherwise, the different physiological characteristics of the planktonic bacteria phyla caused the different responses to the changes in the contents of the nutrient elements and physicochemical proxies in the frozen lake. For example, the major bacterioplankton phyla were mainly influenced by the changes in total phosphorus and dissolved total phosphorus in the "bottom ice" and by the changes in dissolved inorganic phosphorus and ammonia nitrogen in the "surface water". The results will provide basic data to analyze the lake ecological environment in Northern China. |
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