Hou Z, Nelson W C, Stegen J C, Murray C J, Arntzen E, Crump A R, Kennedy D W, Perkins M C, Scheibe T D, Fredrickson J K, Zachara J M
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
Sci Rep. 2017 Sep 20;7(1):12006. doi: 10.1038/s41598-017-12275-w.
The hyporheic zone (HZ) is the active ecotone between the surface stream and groundwater, where exchanges of nutrients and organic carbon have been shown to stimulate microbial activity and transformations of carbon and nitrogen. To examine the relationship between sediment texture, biogeochemistry, and biological activity in the Columbia River HZ, the grain size distributions for sediment samples were characterized to define geological facies, and the relationships among physical properties of the facies, physicochemical attributes of the local environment, and the structure and activity of associated microbial communities were examined. Mud and sand content and the presence of microbial heterotrophic and nitrifying communities partially explained the variability in many biogeochemical attributes such as C:N ratio and %TOC. Microbial community analysis revealed a high relative abundance of putative ammonia-oxidizing Thaumarchaeota and nitrite-oxidizing Nitrospirae. Network analysis showed negative relationships between sets of co-varying organisms and sand and mud contents, and positive relationships with total organic carbon. Our results indicate grain size distribution is a good predictor of biogeochemical properties, and that subsets of the overall microbial community respond to different sediment texture. Relationships between facies and hydrobiogeochemical properties enable facies-based conditional simulation/mapping of these properties to inform multiscale modeling of hyporheic exchange and biogeochemical processes.
潜流带（HZ）是地表溪流与地下水之间活跃的生态交错带，研究表明，营养物质和有机碳的交换可刺激微生物活动以及碳和氮的转化。为了研究哥伦比亚河潜流带中沉积物质地、生物地球化学和生物活性之间的关系，对沉积物样本的粒度分布进行了表征以确定地质相，并研究了相的物理性质、当地环境的物理化学属性以及相关微生物群落的结构和活性之间的关系。泥沙含量以及微生物异养和硝化群落的存在部分解释了许多生物地球化学属性（如碳氮比和总有机碳百分比）的变异性。微生物群落分析显示，假定的氨氧化泉古菌和亚硝酸盐氧化硝化螺旋菌的相对丰度较高。网络分析表明，共同变化的生物群落与泥沙含量之间呈负相关，与总有机碳呈正相关。我们的结果表明，粒度分布是生物地球化学性质的良好预测指标，并且整个微生物群落的子集对不同的沉积物质地有反应。相与水生生物地球化学性质之间的关系使得能够基于相进行这些性质的条件模拟/绘图，从而为潜流交换和生物地球化学过程的多尺度建模提供信息。
