Climate variability drives watersheds along a transporter-transformer continuum

Abstract

We examined how climate variability affects the mobilization of material from six watersheds. We analyzed one to seven years of high-frequency sensor data from a temperate ecosystem and a tropical rainforest. We applied a windowed analysis to correlate concentration-discharge (C-Q) behavior with climate anomalies, providing insight into how hydrological and biogeochemical processes change in response to climate variability. Positive precipitation anomalies homogenized the C-Q responses for dissolved organic matter, nitrate, specific conductance and turbidity, indicating that hydrological processes dominate the C-Q signal and watersheds act as “conveyor belts” of material. In contrast, drier and warmer conditions led to C-Q behavior associated with variation in solute concentration, suggesting that biogeochemical processes are a primary control on solute export and their response to flow. Results indicate that climate variability can move watersheds along a continuum from transporter-to-transformer of biologically active solutes and responses can potentially vary by biome.