College of Bioscience and Biotechnology, Hunan Agriculture University, 1# NongdaRoad, Changsha, 410128, Hunan, China; Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Hunan University of Arts and Science, Changde, 415000, Hunan, China.
College of Bioscience and Biotechnology, Hunan Agriculture University, 1# NongdaRoad, Changsha, 410128, Hunan, China; School of Life Science, Hunan Normal University, Changsha, 410000, Hunan, China.
Harmful Algae. 2018 Jul;77:18-28. doi: 10.1016/j.hal.2018.05.008. Epub 2018 Jun 5.
The frequent occurrence of Microcystis aeruginosa blooms benefit from the dormant Microcystis cells, which will be recruited from sediment into overlying water to form a dominant population and algal blooms when external environmental conditions are suitable. Previous studies have unveiled factors involved in M. aeruginosa recruitment and bloom initiation, including nutrition, illumination, temperature, and hydrodynamic force. In this study, three dominant benthic bacterial species isolated from Lake Chongtian with frequent blooms-forming were identified through next generation sequencing (NGS) techniques, and laboratory experiments were conducted on the recruitment of dormant M. aeruginosa cells via co-culture with these bacteria at 10 °C, 15 °C, 20 °C and 25 °C. The results showed that the bacterial strains in sediment proliferated quickly before recruitment of dormant M. aeruginosa cells, subsequently significantly promoted the recruitment of dormant M. aeruginosa via allelochemical (metabolite) production, lower N:P values and lower dissolved oxygen concentrations in the sediment-water interface, and enhanced photosynthesis of M. aeruginosa cells. Furthermore, dormant M. aeruginosa was recruited from sediment at 10 °C when bacterial activity was present, but not recruited when bacterial activity was absent. At 15 °C,20 °Cand 25 °C, there were no remarkable differences in the recruitment rate of dormant M. aeruginosa cells among all bacterial groups, although their recruitment rate were significantly higher than that at 10 °C.These findings suggested that, under laboratory conditions, three benthic bacteria not only had a great influence on promoting the recruitment of dormant M. aeruginosa cells under desirable temperatures, but also can spur recruitment of dormant M. aeruginosacells from sediment at lower temperature (10 °C).
铜绿微囊藻水华的频繁发生得益于休眠的铜绿微囊藻细胞，这些细胞在适宜的外部环境条件下会从沉积物中被招募到上层水体中，形成优势种群并引发水华。先前的研究揭示了与铜绿微囊藻的招募和水华起始有关的因素，包括营养、光照、温度和水动力。在这项研究中，通过下一代测序（NGS）技术从频繁形成水华的滇池中分离出三种优势底栖细菌，在 10°C、15°C、20°C 和 25°C 下，通过与这些细菌共培养来研究休眠铜绿微囊藻细胞的招募。结果表明，在休眠铜绿微囊藻细胞被招募之前，沉积物中的细菌迅速繁殖，随后通过产生化感物质（代谢物）、降低沉积物-水界面的 N:P 值和溶解氧浓度，以及增强铜绿微囊藻细胞的光合作用，显著促进了休眠铜绿微囊藻的招募。此外，当存在细菌活性时，休眠铜绿微囊藻会从沉积物中在 10°C 时被招募，但当不存在细菌活性时则不会被招募。在 15°C、20°C 和 25°C 时，所有细菌组的休眠铜绿微囊藻细胞的招募率没有显著差异，尽管它们的招募率明显高于 10°C。这些发现表明，在实验室条件下，三种底栖细菌不仅在适宜温度下对促进休眠铜绿微囊藻细胞的招募有很大影响，而且还可以在较低温度（10°C）下从沉积物中刺激休眠铜绿微囊藻细胞的招募。
