Comparison of assembly mechanisms and community stability between free-living and particle-associated microbial communities in lakes from different biogeographical regions

Lakes, aquatic ecosystems within a terrestrial ecosystem, are biological hotspots of the global carbon cycle and host huge biodiversity and interactions. They also provide essential ecosystem services that benefit human society. Within lakes, planktonic microorganisms are key players in the aquatic food webs, mainly contributing to energy capture and element cycling. During summer months, many temperate lakes undergo stratification, forming a warm upper layer and a colder, and sometimes anaerobic deeper layer. Global warming is expected to increase the extent and duration of this stratification in many lakes, potentially impacting the abundance, diversity, and seasonal dynamic of free-living and particle-associated bacterial communities within these distinct water layers. In this study, we investigated the bacterial communities of four typical karstic deep-water lakes during two years in the stratified and mixed periods. The aim was to demonstrate geographic distribution patterns of bacterial communities in different seasons and lakes, understand the dominant microbial community assembly processes and drivers, and explore bacterial community co-occurrence patterns and functional diversity of communities in the studied environment. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project IDs JMF-2112-10, JMF-2301-04, and JMF-2304-04.