State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; College of Water Sciences, Beijing Normal University, Beijing, 100875, PR China.
Environ Res. 2023 Dec 1;238(Pt 1):117129. doi: 10.1016/j.envres.2023.117129. Epub 2023 Sep 12.
Anthropogenic landcover could rise nutrient concentrations and impact the characteristics and bioavailability of dissolved organic matter (DOM) in a river network. Exploring the interactions between DOM and microbials might be conducive to revealing biogeochemistry behaviors of organic matter. In this study, synchronous fluorescence spectra (SFS) with Gaussian band fitting and two-dimensional correlation spectroscopy (2D-COS) were employed to identify DOM fractions and reveal their interactions with bacterial communities. DOM was extracted from a river network under eco-agricultural rural (RUR), eco-residential urban (URB), eco-economical town (TOW), and eco-industrial park (IND) regions in Jiashan Plain of eastern China. The overlapping peaks observed in the SFS were successfully separated into four fractions using Gaussian band fitting, i.e., tyrosine-like fluorescence (TYLF), tryptophan-like fluorescence (TRLF), microbial humic-like fluorescence (MHLF), and fulvic-like fluorescence (FLF) materials. Across all four regions, TRLF (44.79% ± 7.74%) and TYLF (48.09% ± 8.85%) were the dominant components. Based on 2D-COS, variations of TYLF and TRLF were extremely larger than those of FLF in RUR-TOW. However, in URB-IND, the former exhibited lower variations compared to the latter. These suggested that FLF be likely derived continuously from lignin and other residue of terrestrial plant origin along the river network, and TYLF and TRLF be originated discontinuously from domestic wastewater in RUR-TOW. By high-throughput sequenced OTUs, the number of organisms in RUR-TOW could be higher than those in URB-IND, while genes associated with carbohydrate metabolism were lower in former than those in the latter. According to co-occurrence networks, microbes could promote the production of TYLF and TRLF in RUR-TOW. In contrast, microbial communities in URB-IND might contribute to decompose FLF. The obtained results could not only reveal interactions between DOM fractions and bacterial communities in the river network, but this methodology may be applied to other water bodies from different landscapes.
人为土地覆被可能会提高营养物质浓度，并影响河网中溶解有机物质 (DOM) 的特征和生物可利用性。探索 DOM 与微生物之间的相互作用可能有助于揭示有机物的生物地球化学行为。在这项研究中，采用同步荧光光谱（SFS）和二维相关光谱（2D-COS）来识别 DOM 分数并揭示它们与细菌群落的相互作用。从中国东部嘉善平原的生态农业农村（RUR）、生态住宅城市（URB）、生态经济城镇（TOW）和生态工业园区（IND）地区的河网中提取 DOM。使用高斯带拟合将 SFS 中观察到的重叠峰成功分离成四个分数，即酪氨酸样荧光（TYLF）、色氨酸样荧光（TRLF）、微生物腐殖质样荧光（MHLF）和富里酸样荧光（FLF）物质。在所有四个区域中，TRLF（44.79%±7.74%）和 TYLF（48.09%±8.85%）是主要成分。基于 2D-COS，RUR-TOW 中 TYLF 和 TRLF 的变化明显大于 FLF。然而，在 URB-IND 中，前者的变化比后者小。这表明 FLF 可能是由陆地植物来源的木质素和其他残余物连续产生的，而 TYLF 和 TRLF 则是由 RUR-TOW 中的生活污水不连续产生的。通过高通量测序 OTUs，RUR-TOW 的生物数量可能高于 URB-IND，而前者与碳水化合物代谢相关的基因则低于后者。根据共现网络，微生物可以促进 RUR-TOW 中 TYLF 和 TRLF 的产生。相比之下，URB-IND 中的微生物群落可能有助于分解 FLF。研究结果不仅可以揭示河网中 DOM 分数与细菌群落之间的相互作用，而且这种方法还可以应用于来自不同景观的其他水体。
