Related Experiment Video
Updated: Jul 11, 2026

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
Published on: August 3, 2016
Effect of Water Chemistry and Hydrodynamics on Nitrogen Transformation Activity and Microbial Community Functional
Yuanyuan Liu1,2, Chongxuan Liu1,3, William C Nelson1
1Pacific Northwest National Laboratory , Richland, Washington 99354, United States.
Abstract:
Hyporheic zones (HZ) are active biogeochemical regions where groundwater and surface water mix. N transformations in HZ sediments were investigated in columns with a focus on understanding how the dynamic changes in groundwater and surface water mixing affect microbial community and its biogeochemical function with respect to N transformations. The results indicated that denitrification, DNRA, and nitrification rates and products changed quickly in response to changes in water and sediment chemistry, fluid residence time, and groundwater-surface water exchange. These changes were accompanied by the zonation of denitrification functional genes along a 30 cm advective flow path after a total of 6 days' elution of synthetic groundwater with fluid residence time >9.8 h. The shift of microbial functional potential toward denitrification was correlated with rapid NO3- reduction collectively affected by NO3- concentration and fluid residence time, and was resistant to short-term groundwater-surface water exchange on a daily basis. The results implied that variations in microbial functional potential and associated biogeochemical reactions in the HZ may occur at space scales where steep concentration gradients present along the flow path and the variations would respond to dynamic HZ water exchange over different time periods common to natural and managed riverine systems.
More Related Videos
06:52Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria
Published on: December 19, 2017
08:05Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Related Concept Videos
Metabolism of Chemolithotrophs
The Winogradsky Column
Microbes and the Nitrogen Cycle
Marine Microbial Ecology
Freshwater Microbial Ecology
Microbial Wastewater Treatment