Distribution Patterns and Community Assembly Processes of Eukaryotic Microorganisms in Tibetan Plateau Proglacial Lakes at Different Emergence Stages

Abstract. Proglacial lakes are rapidly expanding due to climate change and glacier retreat. Eukaryotic microorganisms play a crucial role in the biogeochemical cycles of these lakes. However, there is limited understanding of the formation processes of eukaryotic microbial communities and their responses to material cycling in proglacial lakes, which are land reservoirs and new habitats for biological evolution of glacier meltwater, particularly in proglacial lakes at different developmental stages. This study investigates the distribution patterns and community assembly process of eukaryotic microbes in high altitude proglacial lakes, formed during different periods (i.e., 1990s, 2000s and post-2010), located on the central Tibetan Plateau. Using 18S rDNA gene amplification sequencing, in conjunction with neutral community model and a null model, we analyze the spatial dynamics and assembly processes of eukaryotic microbial communities. Our results reveal significant spatial heterogeneity community structure. Characterized by a pronounced geographical distance-decay pattern that intensifies with the age of the proglacial lake, indicating stronger symbiotic relationships and biological nesting. For proglacial lakes formed at different times, ecological shifts account for approximately 80 % of the observed community variations. Water temperature was the primary environmental factors influencing the formation of eukaryotic microbial communities. This study provides valuable data on the distribution patterns and assembly processes of eukaryotic microbial communities in emerging proglacial lakes, enhancing our understanding in the trajectories of eukaryotic microbial communities’ formation in high altitude glacier lakes in the context of climate change, and offering insights into the mechanisms that sustain eukaryotic microbial diversity in extreme environments.