ABSTRACT:

This article provides supporting information for JAWER article "Dissolved oxygen concentration profiles in the hyporheic zone through the use of a high-density fiber optic measurement system" (https://doi.org/10.1080/23249676.2019.1611495). It gives additional details about sourcing, constructing and controlling the DO measurement system. Sample AutoHotKey ® scripts are presented. Additionally, sample calculations are presented for the evaluation of flowline residence time. Finally, additional details are provided to describe conditioning of the flume water, initiating the bacterial communities and preparation and consumption of the carbon amendments to support the metabolic activities of the microbial communities.

ABSTRACT:

Nitrous oxide (N2O) is a potent greenhouse gas that, over the past several decades , has been increasing its forcing potential for atmospheric warming. An estimated 10% of all anthropogenically generated N2O is emitted from streams and rivers. These emissions are strongly correlated to ammonium and nitrate runoff from agricultural and industrial processes. However, not all impacted steams emit N2O. Reeder et al. (2018) showed that the flow of surface water and its interaction with stream bed morphology exerts control over the biological processes that are the primary source of (N2O) emissions from rivers and streams. A mathematical model that predicts which flowlines have the correct properties to produce and emit N2O is presented. The data provided in this contribution includes: (1) spatially distributed nitrous oxide measurements from a large-scale, long-term flume experiment, (2) KDO data used in the Tau_tilde transform, (3) data to calculate N2O fluxes through the hyporheic, (4) calculated residence times through the hyporheic and (5) compiled data for the averaged N2O/Tau profiles.

Reference:
Reeder, W. J., Quick, A. M., Farrell, T. B., Benner, S. G., Feris, K. P., Marzadri, A., & Tonina, D. (2018). Hyporheic source and sink of nitrous oxide. Water Resources Research, 54. https://doi.org/10.1029/2018WR022564

ABSTRACT:

Dissolved oxygen concentrations and consumption rates are a primary indicator of bioactivity levels in the hyporheic zone (HZ) of streams and rivers. Conventional wisdom has held that bioactivity levels in the hyporheic zone were generally homogeneous and primarily controlled by nutrient (carbon) supplies. In this view, variations in bioactivity levels are driven by spatial heterogeneity of nutrient resources. Reeder et al. (2018) demonstrated that hyporheic hydraulics exert primary control over bioactivity levels in the HZ. Variations in aerobic respiration rates are a linear function of the hyporheic flow velocity. The data provided in this contribution includes: (1) bed surface and pressure profiles along with validation data for the bedforms used in a large-scale, long-term flume experiment, (2) spatially and temporally distributed hyporheic dissolved oxygen measurements, (3) calculated fluxes through the hyporheic, (4) calculated and measured residence times through the hyporheic and (5) calculated dissolved oxygen consumption rate constants (KDO).

Reference:
Reeder, W. J., A. M. Quick, T. B. Farrell, S. G. Benner, K. P. Feris, and D. Tonina Spatial and Temporal Dynamics of Dissolved Oxygen Concentrations and Bioactivity in the Hyporheic Zone, Water Resources Research, doi: 10.1002/2017WR021388.