Microbiome of the Hanford 300A oxic subsurface sediments

The Hanford 300 Area is an unconfined aquifer containing an extensive uranium plume resulting from prior disposal of nuclear fuel fabrication wastes. The site is adjacent to the Columbia River. Changes in river stage result in intrusion of surface water into the subsurface, increasing groundwater elevation and altering the chemical composition and flow velocity of the local environment. Within the established Integrated Field Research Challenge site, the upper layer of the subsurface consists of high porosity Hanford formation, which is oxic. At ~17m, the sediment transitions to the fine-grained, lower porosity Ringold formation, and there is an associated redox transition zone, below which sediments are anoxic.

汉福德300区为一处非承压含水层（unconfined aquifer），因过往核燃料制造废料的处置作业形成了大范围铀污染羽流（uranium plume）。该场地紧邻哥伦比亚河（Columbia River），河流水位变化会引发地表水向地下侵入，抬升地下水位并改变局部环境的化学成分与流速。在已划定的集成野外研究挑战（Integrated Field Research Challenge）站点内，地下上层为高孔隙度汉福德地层（Hanford formation），处于氧化（oxic）环境；在约17米深度处，沉积物过渡为细粒、低孔隙度的林戈尔德地层（Ringold formation），伴随形成氧化还原过渡带（redox transition zone），该过渡带下方的沉积物均处于缺氧（anoxic）环境。