The Scaling Relationship for the Length of Tributaries to Lakes

Abstract

Globally, the length of tributaries to lakes varies from 0 to more than 15,000 km, but scaling relationships describing this aspect of lake‐river connectivity are lacking. In this study, we describe a simple theoretical scaling relationship for tributary length based on the principle of line intercepts of topographic features, and test this theory using data from Scandinavia. Tributary length increases by 73% for each doubling of lake area. This pattern reflects the relationship between catchment and lake area, and is modified by inlet frequency, junction angle, and lake shape—factors related to specific geologic and hydrologic processes. The theory is precise (r2 = 0.74), with low bias (mean error is 14% of mean tributary length) when the characteristic junction angle (∼76°) is estimated statistically. Our study bridges the gap between geomorphic and large‐scale statistical relationships to provide simple rules for understanding complex patterns of lake‐river connectivity.

Magnitude and Origin of CO2 Evasion From High‐Latitude Lakes

“…By combining both high‐frequency estimates of CO 2 flux and NEP, we quantified source contribution to the annual CO 2 air‐water flux from 14 lakes in subarctic Sweden. These systems have varying catchment conditions, such as drainage ratio (i.e., the ratio between catchment and lake area, a proxy for catchment inputs as it is related to the extent of (riverine) input from watersheds to lakes (Seekell et al., 2022)), and vegetation cover (e.g., percent forest cover), leading to distinct hydrological inputs, carbon processing times, and DOC concentrations. This variability allowed us to compare the effects of DOC concentration, drainage ratio and vegetation cover on magnitude, and sources of CO 2 evasion to evaluate the potential role of hydrology and terrestrial export in controlling annual CO 2 air‐water flux.…”