Resazurin tracer data from experiments in Colorado (2018) and Iowa (2019)

Studies in ecohydrology focusing on hydrologic transport argue that longer residence times across a stream ecosystem should consistently result in higher biological demand for carbon, nutrients, and oxygen. This consideration inadvertently disregards the potential for biologically mediated reactions to be limited by stoichiometric imbalances. Based on the relevance and co-dependences between hydrologic exchange, stoichiometry, and biological uptake, and acknowledging the limited amount of field studies available to determine their net effects on the retention and export of resources, we quantified how microbial respiration is controlled by the interactions and supply of essential nutrients needed (C, N, P) in a headwater stream in Colorado, USA, and in an agricultural canal in Iowa. At each site, we conducted two rounds of experiments, each consisting of four sets of continuous injections of Cl as a conservative tracer, resazurin as a proxy for aerobic respiration, and one of the following nutrient treatments: a) N, b) NC, c) NP, and d) CNP. Nutrient treatments were treated as known system modifications to alter metabolism, and statistical tests indicated the relationships between hydrologic transport metrics and respiration metrics.

This dataset includes conservative and reactive tracer data, as well as discharge values observed during the experiments. It also includes the tracer masses injected and the date and duration of the injections.