Seasonal variations in snowmelt-driven river stage on the Colorado River drives strong redox fluctuations across a ~80-cm vertical portion of the riverbed, and results in the assembly of a unique ‘hyporheic’ microbiome
Significance and Impact
Biogeochemical fluctuations in the hyporheic zone are impacted by changes in snowmelt. An understanding of these dynamics is critical for predicting fluxes of metals, carbon, and other nutrients from this reactive hotspot
- Strong changes in snowmelt-driven river stage altered patterns of hyporheic mixing in the Colorado River, adjacent to the Rifle site.
- This mixing modulated redox fronts in the riverbed, with greater dissolved iron concentrations at shallower depths during periods of low river discharge
- Dynamic mixing and geochemical conditions in a ~80-cm vertical section of the riverbed resulted in a microbial community that was distinct from those in river water and groundwater
Danczak RE, AH Sawyer, KH Williams, JC Stegen, C Hobson, and MJ Wilkins. 2016. Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments. Journal of Geophysical Research – Biogeosciences. 121: 2976-2987, DOI: 10.1002/2016JG003527