Boogie Flux: Incorporating Low-cost, Rapidly Deployable CO2 Chambers into Multi-scale Aquatic Flux Studies

Despite their disproportionate impact on global carbon flux and carbon budgets, wetlands are investigated insufficiently, with few studies that consider the influence of differentiated ecophysiological variables. Multi-scale and multi-method approaches are needed to tackle the complexities of these systems. Remote sensing can provide the measurements needed to make detailed, landscape level maps of ecological function, on the plant functional type and species level. Stationary flux towers have been a leading technology in estimating CO2 flux, but they integrate over large areas and cannot distinguish the individual contribution of different wetland plant functional types and open water. This shortcoming can be potentially overcome by deploying floating CO2 chambers, which can be used to capture variability within the flux tower footprint as well as the study site. We thus adapted low-cost chambers, which were previously created for soil applications, to float on water with the aid of a boogie board. These rapidly re-deployable "boogie flux" meters were tested in the Sacramento San-Joaquin Delta by comparing CO2 flux measurements between open water regions and areas with submerged vegetation of varying canopy densities and heights. Particular attention has been paid to challenges that arise due to sensor sensitivity and platform stability on rough estuarine waters. Areas of submerged vegetation were identified using maps of aquatic plant functional types derived from satellite and airborne imagery. Combining these maps with boogie flux measurements serves as an estimate of vertical CO2 contributions partitioned between open water and submerged vegetation. It also is the baseline measurement of an intended time series capturing the changes of CO2 flux relative to the vegetation phenological cycle. This combination between remote sensing and high spatial frequency field measurements will support characterizing the spatio-temporal influence of different ecological partitions on CO2 flux, potentially assisting in management decisions regarding wetland ecosystem sustainability and restoration for climate change mitigation.