鄱阳湖是中国最大的淡水湖，水量随季节性变化明显。为了研究不同水量对湖区微生物生理群和环境因子影响，采集了丰水期和枯水期鄱阳湖湖区水样，通过研究水体中生理菌群氮循环微生物、解磷细菌等数量和分布特征，分析菌群数量和总氮、总磷和溶解氧等指标相关性，揭示鄱阳湖丰水期和枯水期生理菌群变化规律。结果表明，4种氮循环微生物中，硝化细菌（Nitrobacteria）数量最高，所有样品超过3000 MPN·100 mL-1。氨化细菌（Ammonifying bacteria）、亚硝化细菌（Nitrosobacteria）和反硝化细菌（Denitrifying bacteria）数量较少，平均为975.11、45.68和127.51 MPN·100mL-1，样品之间差异明显。44%样品中大肠杆菌（Escherichia coli）数量低于20 MPN·100 mL-1，达到国家一级水标准，大肠杆菌为300 MPN·100 mL-1有23个，占总样品数30.67%。少数水体样品中解磷细菌（Phosphate-solubilizing bacteria）数量在20~80 CFU·mL-1，多数样品中没有检测到解磷细菌。底泥中存在较多解磷细菌，占异养细菌5%左右。水体中总氮（TN）与大肠杆菌、氨化细菌和亚硝化细菌成极显著正相关。枯水期反硝化细菌数量明显高于丰水期，其它生理菌群则明显下降，温度是主要影响因素。鄱阳湖水质基本保持良好，没有出现大面积富营养化，大肠杆菌、氨化细菌和亚硝化细菌可以作为鄱阳湖夏季总氮污染的主要指标微生物。%Poyang Lake is the largest freshwater lake in China. The limnology of Poyang Lake is strongly affected by seasonal differences in the water level.To study the relationship between the physiological microorganisms, environmental factors and different water level, water samples in Poyang Lake were collected during wet and dry seasons, aiming to study the amount and distribution of physiological microorganisms related with nitrogen-cycling (including ammonifying bacteria, denitrifying bacteria, nitrobacteria, nitrosobacteria) and Escherichia coli determined with the Most Probable Number (MPN) method. The relationship between microbial amount and total nitrogen (TN), total phosphorus (TP), dissolved oxygen (DO) and other indicators were analyzed, and the change rule of physiological microorganisms during wet and dry seasons in Poyang Lake were revealed. The results showed that the highest bacteria amount in four kinds of nitrogen-cycling microorganisms wasnitrobacteria, and the amount of all samples exceeded 3000 MPN·100 mL-1.Ammonifying bacteria,denitrifying bacteria,nitrosobacteria in Poyang lake had a less average amount of 975.11 MPN·100 mL-1, 45.68 MPN·100 mL-1, 127.51 MPN·100 mL-1respectively, with significant differences between all samples. The amount ofEscherichia coli in the 44% samples was less than 20 MPN·100 mL-1, which met the national water standards of grade A. The sample numbers with the amount of Escherichia coli of 300 MPN·100mL-1 was 23, which was 30.67% in the total numbers. The amount of solubilizing-P bacteria in only a few water samples was 20~80 CFU·mL-1, but it was not detected in the most water samples. There were a lot of solubilizing-P bacteria in sediments, which almost accounted for 5% in all heterotrophic bacteria. Total nitrogen (TN) and Escherichia coli, ammonifying bacteria, nitrosobacteria were kept highly significant positive correlation. Denitrifying bacteria in dry seasons was significantly higher than that in wet seasons, whereas the amount of other physiological microorganisms significantly decreased, in which the temperature was the main factor. Water quality of Poyang Lake remains in good condition, and there is no large-scale eutrophication. Escherichia coli,ammonifying bacteria and nitrosobacteria can be acted as the key indicators for total nitrogen (TN) pollution in Poyang lake during wet seasons.
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