Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA.
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, 80309, USA.
J Microbiol. 2019 Oct;57(10):852-864. doi: 10.1007/s12275-019-8668-8. Epub 2019 Aug 3.
Recent work suggests that microbial community composition in high-elevation lakes is significantly influenced by microbes entering from upstream terrestrial and aquatic habitats. To test this idea, we conducted 18S and 16S rDNA surveys of microbial communities in a high-alpine lake in the Colorado Rocky Mountains. We compared the microbial community of the lake to water entering the lake and to uphill soils that drain into the lake. Utilizing hydrological and abiotic data, we identified potential factors controlling microbial diversity and community composition. Results show a diverse community entering the lake at the inlet with a strong resemblance to uphill terrestrial and aquatic communities. In contrast, the lake communities (water column and outlet) showed significantly lower diversity and were significantly different from the inlet communities. Assumptions of neutral community assembly poorly predicted community differences between the inlet and lake, whereas "variable selection" and "dispersal limitation" were predicted to dominate. Similarly, the lake communities were correlated with discharge rate, indicating that longer hydraulic residence times limit dispersal, allowing selective pressures within the lake to structure communities. Sulfate and inorganic nitrogen and phosphorus concentrations correlated with community composition, indicating "bottom up" controls on lake community assembly. Furthermore, bacterial community composition was correlated with both zooplankton density and eukaryotic community composition, indicating biotic controls such as "top-down" interactions also contribute to community assembly in the lake. Taken together, these community analyses suggest that deterministic biotic and abiotic selection within the lake coupled with dispersal limitation structures the microbial communities in Green Lake 4.
最近的研究表明，高海拔湖泊中的微生物群落组成受到来自上游陆地和水生栖息地的微生物的显著影响。为了验证这一观点，我们对科罗拉多落矶山脉的一个高海拔湖泊中的微生物群落进行了 18S 和 16S rDNA 调查。我们将湖泊中的微生物群落与进入湖泊的水以及流入湖泊的上坡土壤进行了比较。利用水文和非生物数据，我们确定了控制微生物多样性和群落组成的潜在因素。结果表明，在入口处有一个多样化的群落进入湖泊，与上坡陆地和水生群落具有很强的相似性。相比之下，湖泊群落（水柱和出水口）的多样性明显较低，与入口群落明显不同。中性群落组装的假设很难预测入口和湖泊之间的群落差异，而“可变选择”和“扩散限制”被预测为主要因素。同样，湖泊群落与排放量呈正相关，表明较长的水力停留时间限制了扩散，使湖泊内的选择压力能够塑造群落。硫酸盐和无机氮磷浓度与群落组成相关，表明“自上而下”的控制对湖泊群落组装起作用。此外，细菌群落组成与浮游动物密度和真核生物群落组成相关，表明“自上而下”的生物控制（如捕食作用）也会对湖泊中的群落组装产生影响。总之，这些群落分析表明，湖泊内的确定性生物和非生物选择以及扩散限制共同塑造了格林湖 4 号的微生物群落。
