State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China.
University of Chinese Academy of Sciences, Beijing, 100000, China.
BMC Microbiol. 2018 Nov 23;18(1):195. doi: 10.1186/s12866-018-1333-2.
Understanding the recovery of bacterial communities after extreme environmental disturbances offers key opportunities to investigate ecosystem resilience. However, it is not yet clear whether bacterial communities can rebound to their pre-disturbance levels. To shed light on this issue, we tracked the responses of bacterial communities during an extreme salinization-desalinization cycle.
Our results showed that salinization-up process induced an ecological succession, shifting from a community dominated by Betaproteobacteria to Gammaproteobacteria. Within the desalinization-down process, taxon-specific recovery trajectories varied profoundly, with only Gammaproteobacteria returning to their initial levels, of which Alphaproteobacteria was the most prominent member. The α-diversity indices gradually increased at oligosaline environment (0.03‰ to 3‰) and subsequently decreased profoundly at hypersaline condition (10‰ to 90‰). However, the indices did not return to pre-disturbance level along the previous trajectory observed during the desalinization. Approximately half of the original OTUs were not detected during desalinization, suggesting that the seed bank may be damaged by the hypersaline environment. Moreover, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) implied that the osmosensors' capacity of bacterial communities was also impaired by the hypersaline condition.
These results suggested that the bacterial communities showed a low recovery after the extreme salinization-desalinization cycle.
了解细菌群落在极端环境干扰后的恢复情况，为研究生态系统的恢复能力提供了重要机会。然而，目前尚不清楚细菌群落是否能够恢复到干扰前的水平。为了阐明这个问题，我们跟踪了细菌群落在极端盐化-淡化循环过程中的响应。
我们的研究结果表明，盐化过程引起了生态演替，从以β变形菌为主的群落转变为γ变形菌为主的群落。在淡化过程中，分类群特异性的恢复轨迹差异很大，只有γ变形菌恢复到初始水平，其中α变形菌是最主要的成员。在低盐环境（0.03‰至 3‰）中，α多样性指数逐渐增加，而在高盐环境（10‰至 90‰）中则显著降低。然而，这些指数并没有沿着淡化过程中之前观察到的轨迹恢复到干扰前的水平。大约一半的原始 OTUs 在淡化过程中未被检测到，这表明种子库可能受到高盐环境的破坏。此外，未观察状态重建的群落系统发育分析（PICRUSt）表明，细菌群落的渗透压传感器的能力也受到高盐环境的损害。
这些结果表明，细菌群落经历极端盐化-淡化循环后恢复能力较低。
