2.3 Allometric scaling relationships
Prior to calculating allometric scaling relationships, we calculated
cumulative values for respiration and HEFs as the sum of all reaches
upstream of a given reach (and inclusive of the reach), as visualized
for a watershed in Figure S2. We calculated allometric scaling
relationships as cumulative hyporheic aerobic respiration (g
CO2 d-1) against watershed area
(km2) following Wollheim et al. (2022). First, we
grouped reaches in each basin into 10 equally sized quantiles based on
cumulative HEF, which is an important control of hyporheic respiration
(Son et al. 2022). Within each quantile, a random subset of 50 reaches
representing the range of stream orders was selected via bootstrapping
and used to calculate slope, intercept, and R2 values
for the relationship between cumulative respiration and watershed area.
This process was then iterated 1000 times for each combination of bin
and basin to calculate average values and confidence intervals for
slope, intercept, and R2 values.