Kenneth H. Williams

TL;DR: The results of a 20-day microcosm experiment sought to better understand how natural organic matter fuels microbial communities within anoxic biogeochemical hot spots (NRZs) in a shallow alluvial aquifer at the Rifle (CO) site and highlight the complex nature of organic matter transformation in NRZs and the microbial metabolic pathways that interact to mediate redox status and elemental cycling.

TL;DR: In this paper, the authors quantify nitrogen fluxes and mass balances at a hillslope underlain by marine shale and find that, at this site, bedrock weathering contributes 78% of the subsurface reactive nitrogen, while atmospheric sources (commonly regarded as the sole sources of reactive nitrogen in pristine environments) account for only 22%.

TL;DR: In this article, open circuit potentials arising from variable redox conditions in the fluid local-toelectrodesurfaceselectrodicpotentialswere recorded for a pair of silver-silver chloride electrodes in a column experiment, whereby a natural wetland soil containing a known community of sulfatereducerswascontinuouslyfed with asulfate-richnutrient medium.

TL;DR: The results indicate that the redox-buffering capacity of reduced sediments can prevent U mobilization, but could be overcome as delivery rate or oxidant concentration increases, mobilizing U.