New optode applications for partitioning river corridor respiration

While river corridors are widely understood to be important locations for organic carbon processing, it remains unclear where in the river corridor this processing primarily takes place, how variable processing rates are in space and time, and what conditions provide the primary drivers of spatial and temporal variability. One of the major reasons for this large knowledge gap is the lack of tools and techniques available. We demonstrate several novel approaches centered around dynamic oxygen sensing in river corridors.

Currently, assessing the rate at which a small sediment or water sample consumes oxygen is a highly manual process, requiring expensive repetition of sensing technology. We propose a high throughput laboratory system that can determine oxygen consumption rate for many sediment and water samples at a time with low cost and effort. This allows the broad interrogation of river corridor sediments, as well as the application of a wide variety of experimental treatments.

In addition to high-throughput, we lack systems to generate continuous long-term datasets of river channel respiration rates. The dark-bottle method is well-known but requires significant fieldwork and provides only single-point-in-time measurements. We propose an automated dark-bottle incubation system for long term, in-situ river channel respiration measurement.

Finally, riverbed oxygen conditions are highly variable in space and time. This variation is notoriously difficult to capture in the field with a high degree of spatial resolution. We propose an advanced high-resolution vertical oxygen profiler which can be installed in a riverbed and will capture dissolved oxygen conditions at very high spatial and temporal resolutions.

Together, these new techniques and technologies will allow for a leap forward in river corridor research.