Our understanding of nitrogen (N) and phosphorus (P) variability in forested stream systems with minimal disturbance is confounded by the complex interactions of hydrologic and biogeochemical controls. In this thesis, our studies evaluate the variability of stream water N and P in a forested, headwater system in the Oregon Coast...
We examined the spatial and temporal variability of stream carbon dioxide (CO₂) and the drivers of these variations in a headwater catchment. To examine temporal variation and drivers, we measured stream and hyporheic pCO₂ at high temporal resolution over 11 months in a 95.9-ha forested headwater catchment in the Western...
Small mountainous watersheds are disproportionate sources of land-derived particulate organic matter (POM) to long-term sinks like lake bottoms and the ocean. As such, these ecosystems are an essential component of the global carbon cycle. The burial of POM in lacustrine and marine sediments contributes to the drawdown of atmospheric CO2...
Stream functioning includes simultaneous interaction among solute transport, nutrient processing, and metabolism. Metabolism is measured with methods that have limited spatial representativeness and are highly uncertain. These problems restrict development of methods for up-scaling biological processes that mediate nutrient processing. We used the resazurin–resorufin (Raz-Rru) tracer system to estimate metabolism...
A “smart” tracer is a tracer that provides, directly or through measurement of its concentration or in combination with another compound, at least one “bit” more of information about the environment through which it travels than a conservative tracer. In this study we propose and present the chemical compound resazurin...
After three decades of active research in hydrology and stream ecology, the connection between solute transport, stream metabolism and nutrient dynamics is still unresolved. This existing gap obscures the functionality of stream ecosystems and how they interact with other landscape processes. To date, determining rates of metabolism is accomplished with...
Water transient storage zones are hotspots for metabolic activity in streams although the contribution of different types of transient storage zones to the whole-reach metabolic activity is difficult to quantify. In this study we present a method to measure the fraction of the transient storage that is metabolically active (MATS)...
The hyporheic zone is of great interest for stream ecologists because of its role in stream biogeochemical processing. Our study addresses the effects of leaf-litter inputs and varying discharge on surface–hyporheic water exchange and their possible consequences for the hyporheic zone biogeochemistry. Our study was conducted during autumn in Riera...
Quantification of the transient storage zone (A[subscript s]) has become critical in stream biogeochemical studies addressed to examine factors controlling nutrient uptake. It is expected that higher A[subscript s] may enhance the interaction between nutrients and biota and thus, increase nutrient uptake. However, results from the literature are controversial. We...
Small hydropower plants divert part of the water from wide and physically complex
stream channels with active hyporheic areas to narrow and hydraulically simple concrete canals,
and thus, might affect nutrient dynamics. We compared nutrient uptake in diversion canals and
in stream channels in the Leitzaran Stream (Basque Country, northern...