Water Reuse and Desalination Center (WDRC), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Appl Environ Microbiol. 2012 Oct;78(19):6819-28. doi: 10.1128/AEM.01223-12. Epub 2012 Jul 13.
This study explores microbial community structure in managed aquifer recharge (MAR) systems across both laboratory and field scales. Two field sites, the Taif River (Taif, Saudi Arabia) and South Platte River (Colorado), were selected as geographically distinct MAR systems. Samples derived from unsaturated riverbed, saturated-shallow-infiltration (depth, 1 to 2 cm), and intermediate-infiltration (depth, 10 to 50 cm) zones were collected. Complementary laboratory-scale sediment columns representing low (0.6 mg/liter) and moderate (5 mg/liter) dissolved organic carbon (DOC) concentrations were used to further query the influence of DOC and depth on microbial assemblages. Microbial density was positively correlated with the DOC concentration, while diversity was negatively correlated at both the laboratory and field scales. Microbial communities derived from analogous sampling zones in each river were not phylogenetically significantly different on phylum, class, genus, and species levels, as determined by 16S rRNA gene pyrosequencing, suggesting that geography and season exerted less sway than aqueous geochemical properties. When field-scale communities derived from the Taif and South Platte River sediments were grouped together, principal coordinate analysis revealed distinct clusters with regard to the three sample zones (unsaturated, shallow, and intermediate saturated) and, further, with respect to DOC concentration. An analogous trend as a function of depth and corresponding DOC loss was observed in column studies. Canonical correspondence analysis suggests that microbial classes Betaproteobacteria and Gammaproteobacteria are positively correlated with DOC concentration. Our combined analyses at both the laboratory and field scales suggest that DOC may exert a strong influence on microbial community composition and diversity in MAR saturated zones.
本研究探讨了管理含水层补给（MAR）系统中微生物群落结构，涵盖实验室和野外两个尺度。选择了两个具有地理差异的野外场地，即塔伊夫河（沙特阿拉伯塔伊夫）和南普拉特河（科罗拉多州），作为 MAR 系统。采集了非饱和河床、饱和浅层渗透（深度 1 至 2 厘米）和中层渗透（深度 10 至 50 厘米）区的样本。还使用了代表低（0.6 毫克/升）和中（5 毫克/升）溶解有机碳（DOC）浓度的补充实验室规模的沉积物柱，进一步研究 DOC 和深度对微生物组合的影响。微生物密度与 DOC 浓度呈正相关，而在实验室和野外尺度上，多样性均呈负相关。通过 16S rRNA 基因焦磷酸测序，从每条河流的类似采样区获得的微生物群落，在门、纲、属和种水平上在系统发育上没有显著差异，这表明地理和季节的影响小于水地球化学性质。当将来自塔伊夫和南普拉特河沉积物的野外尺度群落归为一组时，主坐标分析显示，三个样本区（非饱和、浅层和中层饱和）以及 DOC 浓度均存在明显的聚类。在柱研究中也观察到了类似的深度和相应 DOC 损失的趋势。典范对应分析表明，微生物纲 Betaproteobacteria 和 Gammaproteobacteria 与 DOC 浓度呈正相关。我们在实验室和野外两个尺度上的综合分析表明，DOC 可能对 MAR 饱和区的微生物群落组成和多样性产生强烈影响。
