Search for: All records

Abstract Gas transfer velocity () controls gas fluxes between aquatic ecosystems and the atmosphere. In streams, is controlled by turbulence and, thus, local hydrology and geomorphology. Resultantly, variability in can be large and modeling from physical parameters can have large uncertainty. Here, we leverage a large dataset of estimates derived from tracer‐gas experiments in 22 US streams across a range of discharges. Our analysis shows that was highly variable both spatially across and temporally within streams, with estimates of spanning three orders of magnitude. Overall, scaled with discharge in steep streams due to relatively high stream power, but not in low‐slope streams, where stream power was relatively low even at high flows. Understanding how responds to stream discharge in a wide variety of streams is key to creating temporally and spatially resolved estimates of biogeochemical processes in streams. 

Abstract The design of infrastructure used for deploying water quality sensors can potentially impact data quality. Despite this, sensor infrastructure design has not been well discussed in the peer‐reviewed literature. Here, we present side‐by‐side measurements from two contrasting designs; a “monopod” consisting of a strut driven into the streambed and a downrigger suspended from an “overhead cable.” We collected measurements over an approximately 6‐month period from two wadeable stream monitoring sites within the National Ecological Observatory Network. In general, we observed minimal differences between measurements, suggesting both designs to be viable options from a data quality perspective under normal operating conditions. However, the monopod design was more susceptible to coming out of the water during low stage and burial by sedimentation. While more expensive and logistically complex to install, the overhead cable design exhibited greater survivability, adjustability, and serviceability. We discuss additional design considerations and potential modifications that we hope will prove useful to other researchers in instrumenting their own sites.