Salinization of inland freshwater is one of the future global ecological and environmental challenges, threatening the safety of drinking water and the quality of industrial and agricultural water. Previous research suggests that salinity is the main factor shaping the microbial community in water bodies, and changes in salinity directly or indirectly cause changes in the structure of aquatic ecosystems. The salinity fluctuations in inland water bodies of subtropical coastal cities will change with the increase of extreme weather events, such as heavy rainfall, and will have an impact on the composition and function of planktonic bacterial communities.

Planktonic bacteria usually have two ways of life - free living bacteria and particle attached bacteria. Free living bacteria mainly utilize dissolved organic matter in water bodies; Attached bacteria usually colonize the surface of particulate matter, forming biofilms that play a role in the degradation and remineralization of particulate organic matter. Planktonic bacteria play a role in the element cycling and energy flow of freshwater ecosystems. Therefore, revealing the response process and mechanism of the stability of planktonic bacterial communities to interference is important for predicting the dynamics and functional changes of bacterial communities in the context of future environmental changes. However, there is currently a relative lack of research on the stability of planktonic bacterial communities under salinity fluctuations, and there are no reports on the differences and mechanisms of community stability between free living and attached bacteria under salinity fluctuations.

The Water Ecological Health Research Group of the Institute of Urban Environment, Chinese Academy of Sciences has established a long-term positioning ecological observation and research station in the largest landscape water body (Xinglinwan Reservoir) in Jimei District, Xiamen, Fujian Province. The team explored the stability of free and attached bacterial communities under the background of salinity fluctuations using high-throughput sequencing technology and multivariate statistical methods based on a high-frequency (twice sampled per week) time series dataset for three consecutive years.

The results showed that with the increase of water salinity, the stability of the composition of free and attached bacterial communities showed an increasing trend, and their α Diversity is showing a decreasing trend. Comparative analysis shows that under high salinity and low variation scenarios, the stability of attached bacterial communities is higher than that of free living bacteria; Under low salinity and high variability scenarios, the stability of free living bacterial communities is higher than that of attached bacteria. Furthermore, studies have shown that bacterial traits (such as genome size and rare species interaction intensity) and rainfall driven environmental factors (such as salinity and particulate matter) may jointly lead to differences in the stability of free and attached bacterial communities under different salinity scenarios. This study preliminarily reveals the inherent relationship between rainfall, salinity, and the stability of planktonic bacteria, providing basic data and scientific basis for the ecological management, protection, and restoration of shallow water lakes and reservoirs in subtropical cities under climate change conditions.

The related research findings are titled Community stability of free living and particle attached bacteria in a subtropical reserve with salinity fluctuations over 3 years, and are published in Water Research. The research work was supported by the National Natural Science Foundation of China and the STS Program of Chinese Academy of Sciences in Fujian Province.

Paper link:论文链接



Stability of free and attached bacterial communities in urban reservoirs under the background of salinity fluctuations