Institute of Aquatic Ecology, Centre for Ecological Research, H-1113 Budapest, Hungary.
National Multidisciplinary Laboratory for Climate Change, Centre for Ecological Research, H-1113 Budapest, Hungary.
FEMS Microbiol Ecol. 2023 Aug 22;99(9). doi: 10.1093/femsec/fiad095.
Seasonal environmental variation is a leading driver of microbial planktonic community assembly and interactions. However, departures from usual seasonal trends are often reported. To understand the role of local stressors in modifying seasonal succession, we sampled fortnightly, throughout three seasons, five nearby shallow soda lakes exposed to identical seasonal and meteorological changes. We characterised their microeukaryotic and bacterial communities by amplicon sequencing of the 16S and 18S rRNA gene, respectively. Biological interactions were inferred by analyses of synchronous 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 characterised by the relevance of trophic interactions and a certain level of community stability followed by a more dynamic and variable summer-autumn period. Adaptation to general seasonal changes happened through shared core microbiome 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 prevalent trends to a greater extent for microeukaryotic than for bacterial communities.
季节环境变化是浮游微生物群落组装和相互作用的主要驱动因素。然而，通常的季节性趋势经常会偏离。为了了解本地胁迫因子在改变季节性演替中的作用，我们在三个季节中每两周采样一次，共采集了五个附近的暴露于相同季节性和气象变化的浅层苏打湖。我们通过扩增子测序分别对 16S 和 18S rRNA 基因进行了微真核生物和细菌群落的特征描述。通过同步和时间滞后相互作用网络分析推断了生物相互作用，并拓扑识别了群落的关键类群。在研究期间，这些湖泊表现出相似的演替模式，春季以营养相互作用的相关性和一定程度的群落稳定性为特征，随后是更为动态和多变的夏季-秋季。通过湖泊共享的核心微生物组适应一般季节性变化。干旱等随机事件破坏了常见的网络属性，并导致偏离普遍季节性轨迹的转变。我们的研究结果表明，尽管是极端且高度可变的栖息地，浅层苏打湖的浮游微生物群落的季节性仍具有一定的相似性，但干旱等局部胁迫因子对微真核生物群落的偏离趋势比细菌群落更为明显。
