Hotchkiss, Erin听1
1听Biological Sciences, Virginia Tech
Despite much research identifying inland waters as active players in the carbon cycle, the relative role of hydrologic transport and听in situ听transformations in controlling carbon fluxes and fate along aquatic continua is still uncertain. Further, conclusions about the function of aquatic ecosystems in altering terrestrial carbon inputs still largely depend on where we draw our ecosystem boundaries,听i.e., the spatial scale of measurements used to assess the rates and processes controlling organic matter transformations. Because most studies do not integrate mechanisms with larger-scale carbon flux patterns, quantifying organic carbon (OC) transformations within freshwaters is a necessary step toward a broader knowledge of the dynamic processes controlling OC fluxes and fate. Here I will highlight how we can use stream metabolism, CO2, and OC fluxes to estimate: (1) What is the distance OC travels in river networks before being consumed and respired as CO2听(i.e., OC spiraling)? (2) What proportion of stream CO2听is derived from respiration on land, upstream, or within a stream reach? (3) How might we estimate thresholds in the transition of freshwater ecosystems from dominantly process-controlled ecosystems to systems functioning primarily as pipes and chimneys? I will present a data-informed framework for future considerations of integrated carbon transport, transformations, and fate when scaling patterns and processes within aquatic networks.