Water Resources Graduate Program, Oregon State University, Corvallis, OR, United States of America.
Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR, United States of America.
PLoS One. 2024 Sep 24;19(9):e0306896. doi: 10.1371/journal.pone.0306896. eCollection 2024.
Accurate characterization of the movement of water through catchments, particularly during precipitation event response, is critical for hydrological efforts such as contaminant transport modeling or prediction of extreme flows. Abiotic hydrogeochemical tracers are commonly used to track sources and ages of surface waters but provide limited details about transit pathways or the spatial dynamics of water storage and release. Alternatively, biotic material in streams is derived from thousands of taxa originating from a variety of environments within watersheds, including groundwater, sediment, and upslope terrestrial environments, and this material can be characterized with genetic sequencing and bioinformatics. We analyzed the stable water isotopes (δ18O and δ2H) and microbiome composition (16S rRNA gene amplicon sequencing) of the Marys River of western Oregon, USA during an early season storm to describe the processes, storage, and flowpaths that shape surface water hydrology. Stable water isotopes (δ18O and δ2H) typified an event response in which stream water is composed largely of 'old' water introduced to the catchment before the storm, a common though not well understood phenomenon. In contrast, microbial biodiversity spiked during the storm, consisting of early- and late-event communities clearly distinguishable from pre-event communities. We applied concentration-discharge (cQ) analysis to individual microbial taxa and found that most Alphaproteobacteria sequences were positively correlated (i.e., were mobilized) with discharge, whereas most sequences from phyla Gammaproteobacteria and Bacteroidota were negatively correlated with discharge (i.e., were diluted). Source predictions using the prokaryote habitat preference database ProkAtlas found that freshwater-associated microbes composed a smaller fraction of the microbial community during the stream rise and a larger fraction during the recession, while soil and biofilm-associated microbes increased during the storm and remained high during recession. This suggests that the "old" water discharged during the storm was likely stored and released from, or passed through, soil- and biofilm-rich environments, demonstrating that this approach adds new, biologically derived tracer information about the hydrologic pathways active during and after this event. Overall, this study demonstrates an approach for integrating information-rich DNA into water resource investigations, incorporating tools from both hydrology and microbiology to demonstrate that microbial DNA is useful not only as an indicator of biodiversity but also functions as an innovative hydrologic tracer.
准确描述水在集水区中的运移，特别是在降水事件响应期间，对于水文工作至关重要，例如污染物运移模拟或极端流量预测。非生物水文地球化学示踪剂常用于追踪地表水的来源和年龄，但提供的有关传输途径或水存储和释放的空间动态的详细信息有限。或者，溪流中的生物物质源自流域内多种环境中的数千个分类群，包括地下水、沉积物和上坡陆地环境，并且可以通过遗传测序和生物信息学对其进行表征。我们分析了美国俄勒冈州西部玛丽斯河在早期季节风暴期间的稳定水同位素（δ18O 和 δ2H）和微生物组组成（16S rRNA 基因扩增子测序），以描述塑造地表水水文的过程、存储和流径。稳定水同位素（δ18O 和 δ2H）典型地代表了一种事件响应，其中溪流中的水主要由在风暴之前引入集水区的“旧”水组成，这是一种常见但尚未完全理解的现象。相比之下，微生物生物多样性在风暴期间飙升，包括明显区别于事件前群落的早期和晚期事件群落。我们将浓度-流量（cQ）分析应用于单个微生物分类群，并发现大多数α变形菌序列与流量呈正相关（即被迁移），而大多数γ变形菌和拟杆菌门的序列与流量呈负相关（即被稀释）。使用原核生物栖息地偏好数据库 ProkAtlas 进行源预测发现，在溪流上升期间，与淡水相关的微生物在微生物群落中所占的比例较小，而在衰退期间所占的比例较大，而土壤和生物膜相关的微生物在风暴期间增加并在衰退期间保持高位。这表明，在风暴期间排放的“旧”水可能是在土壤和生物膜丰富的环境中存储和释放的，或者是通过这些环境释放的，这表明这种方法增加了有关该事件期间和之后活跃的水文途径的新的、生物衍生示踪剂信息。总的来说，这项研究展示了一种将富含信息的 DNA 整合到水资源调查中的方法，结合了水文学和微生物学的工具，表明微生物 DNA不仅可用作生物多样性的指标，而且还可用作创新的水文示踪剂。
