1. Fig. 3 Biophysical characteristics of gravel-bed floodplains.
Biophysical characteristics of gravel-bed floodplains. (A) Near-infrared image georeferenced with a high-resolution image showing classified temperatures of an upwelling location on a gravel-bed river floodplain. GW, groundwater. (B) Total abundance (±1 SD) (in cells per square centimeter) of substratum from cobbles at points of downwelling (n = 52), neutral (n = 19), and upwelling (n = 49) on a gravel-bed floodplain. Significant difference indicated by different letters above bars [P < 0.05, analysis of variance (ANOVA); P < 0.05, Tukey’s test]. (C) Stable isotope biplot for major invertebrate taxa (±1 SD). All taxa have d13C signatures that are more depleted than river dissolved or particulate organic matter. The extreme shift for some organisms is the likely contribution of methane through methanotrophs. Percent contribution of methane to those taxa in the hyporheic food web is shown in parentheses. (D) Relationship between groundwater recharge from the hyporheic zone on a gravel-bed floodplain stream reach and the number of bull trout redds (egg pockets) per stream reach. VHG, vertical hydraulic gradient.
F. Richard Hauer et al. Sci Adv 2016;2:e
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