Fig. 1: Conceptual model of allometric scaling.

Allometric scaling (d) of cumulative biogeochemical function (F) in river networks with increasing watershed area as determined by local areal process rates (y) and physical structure of river networks. A Scenarios describing the change in local process rate (as either mass surface area⁻¹ time⁻¹ or as length time⁻¹) in stream reaches (local areal process slope = m.local, b = constant, Eq. (2)) vs. watershed area draining to the stream location. B Scaling of cumulative benthic surface area vs. watershed area and stream length vs. watershed area, accounting for the entire upstream river network. Scaling of cumulative length and surface area can differ. C Examples of scaling of cumulative biogeochemical function over the entire river network (mass time⁻¹) with increasing watershed area (cumulative function slope = d, Eq. (1)) resulting from variation in both local process rates (A) and cumulative physical attributes of networks (B).