Contrasting response of microeukaryotic and bacterial communities to the interplay of seasonality and local stressors in shallow soda lakes

Seasonal envir onmental v ariation is a leading dri v er of micr obial planktonic comm unity assemb l y and inter actions. How ever, departur es fr om usual seasonal tr ends ar e often r e ported. To understand the r ole of local str essors in modifying seasonal succession, we sampled fortnightl y, thr oughout thr ee seasons, fiv e nearby shallow soda lakes exposed to identical seasonal and meteorological c hanges. We c har acterised their micr oeukar yotic and bacterial communities by amplicon sequencing of the 16S and 18S rRN A gene , r especti v el y. Biological inter actions w er e inferr ed by anal yses of synchr onous and time-shifted interaction networks, and the keystone taxa of the communities were topologically identified. The lakes showed similar succession patterns during the study period with spring being c har acterised by the r elev ance of trophic interactions and a certain level of community stability followed by a more dynamic and v aria b le summer-autumn period. Adaptation to gener al seasonal c hanges happened thr ough shar ed cor e micr obiome of the lakes. Stochastic events such as desiccation disrupted common network attributes and introduced shifts from the prevalent seasonal trajectory. Our results demonstrated that, despite being extreme and highly variable habitats, shallow soda lakes exhibit certain similarities in the seasonality of their planktonic communities, yet local stressors such as droughts instigate deviations from pr ev alent tr ends to a gr eater extent for micr oeukar yotic than for bacterial comm unities.