Li Wen-Bao, Yang Xu, Tian Ya-Nan, Du Lei
Inner Mongolia Key Laboratory of Water Resources Protection and Utilization, Inner Mongolia Agricultural University, Hohhot 010018, China.
Huan Jing Ke Xue. 2021 May 8;42(5):2276-2286. doi: 10.13227/j.hjkx.202009218.
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.
细菌是水生态系统的关键组成部分，在物质和能量循环过程中发挥着重要作用。为了解冰冻湖泊中浮游细菌群落的变化，我们从内蒙古高原的内陆封闭湖泊达里湖采集了15个“底冰”样本和15个冰盖下的“地表水”样本。结合“底冰”和“地表水”样本之间物理化学指标的比较，详细分析了浮游细菌的门类群落特征。尽管“底冰”和“地表水”中的浮游细菌主要由变形菌门、放线菌门、蓝细菌门、拟杆菌门和其他11个门类组成，但优势浮游细菌的平均相对丰度明显不同。例如，变形菌门在“底冰”样本中的平均相对丰度约为63.64%，但在地表水样本中降至约26.75%，明显低于放线菌门的相对丰度，放线菌门的平均值约为39.10%。我们得出结论，营养元素含量和物理化学指标的变化必定是影响冰冻达里湖浮游细菌群落变化的主要因素。物理化学指标的变化可能是“底冰”和“地表水”中细菌群落变化的原因。否则，浮游细菌门类的不同生理特征导致了对冰冻湖泊中营养元素含量和物理化学指标变化的不同反应。例如，主要的浮游细菌门类在“底冰”中主要受总磷和溶解性总磷变化的影响，在“地表水”中受溶解性无机磷和氨氮变化的影响。研究结果将为分析中国北方湖泊生态环境提供基础数据。
