Xie Gui-Juan, Gong Yi, Zhu Fu-Cheng, Liu Chang-Li, Lu Bao-Wei, Deng Hui, Tang Xiang-Ming
College of Biology and Pharmaceutical Engineering, West Anhui University, Lu'an 237012, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Huan Jing Ke Xue. 2023 Apr 8;44(4):2052-2061. doi: 10.13227/j.hjkx.202206018.
Organic aggregates (OA) are the important circulation hub of matter and energy in aquatic ecosystems. However, the comparison studies on OA in lakes with different nutrient levels are limited. In this study, spatio-temporal abundances of OA and OA-attached bacteria (OAB) in oligotrophic Lake Fuxian, mesotrophic Lake Tianmu, middle-eutrophic Lake Taihu, and hyper-eutrophic Lake Xingyun were investigated in different seasons during 2019-2021 using a scanning electron microscope, epi-fluorescence microscope, and flow cytometry. The results showed that:① the annual average abundances of OA in Lake Fuxian, Lake Tianmu, Lake Taihu, and Lake Xingyun were 1.4×10, 7.0×10, 27.7×10, and 16.0×10 ind·mL, whereas the annual average abundances of OAB in the four lakes were 0.3×10, 1.9×10, 4.9×10, and 6.2×10 cells·mL. The ratios of OAB:total bacteria (TB) in the four lakes were 30%, 31%, 50%, and 38%, respectively. ② OA abundance in summer was significantly higher than that in autumn and winter; however, the ratio of OAB:TB in summer was approximately 26%, which was significantly lower than that in the other three seasons. ③ Lake nutrient status was the most important environmental factor that affected the abundance variations of OA and OAB, accounting for 50% and 68% of the spatio-temporal variations in OA and OAB abundances. ④ Nutrient and organic matters were enriched in OA, especially in Lake Xingyun; the proportions of particle phosphorous, particle nitrogen, and organic matters in this lake were as high as 69%, 59%, and 79%, respectively. Under the circumstance of future climate change and the expansion of lake algal blooms, the effects of algal-originated OA in the degradation of organic matters and nutrient recycling would be increased.
有机聚集体（OA）是水生生态系统中物质和能量的重要循环枢纽。然而，关于不同营养水平湖泊中OA的比较研究有限。在本研究中，于2019 - 2021年不同季节，使用扫描电子显微镜、落射荧光显微镜和流式细胞仪，对贫营养的抚仙湖、中营养的天目湖、中富营养的太湖和超富营养的星云湖中的OA及附着在OA上的细菌（OAB）的时空丰度进行了调查。结果表明：①抚仙湖、天目湖、太湖和星云湖的OA年平均丰度分别为1.4×10、7.0×10、27.7×10和16.0×10个·mL，而这四个湖泊中OAB的年平均丰度分别为0.3×10、1.9×10、4.9×10和6.2×10个细胞·mL。四个湖泊中OAB与总细菌（TB）的比例分别为30%、31%、50%和38%。②夏季OA丰度显著高于秋季和冬季；然而，夏季OAB与TB的比例约为26%，显著低于其他三个季节。③湖泊营养状况是影响OA和OAB丰度变化的最重要环境因素，分别占OA和OAB丰度时空变化的50%和68%。④营养物质和有机物在OA中富集，尤其是在星云湖；该湖中颗粒态磷、颗粒态氮和有机物的比例分别高达69%、59%和79%。在未来气候变化和湖泊藻华扩张的情况下，藻类来源的OA在有机物降解和营养物质循环中的作用将增强。
