Bubble Stripping as a Tool to Reduce High Dissolved CO2 in Coastal Marine Ecosystems

High dissolved CO₂ concentrations in coastal ecosystems are a common occurrence due to a combination of large ecosystem metabolism and long residence times. Many of the socially, commercially, and recreationally important species may have adapted to this natural variability over time. However, eutrophication and ocean acidification may be perturbing the water chemistry beyond the bounds of tolerance for these organisms. We are currently limited in our ability to deal with the geochemical changes unfolding in our coastal ocean. This study helps to address this deficit of solutions by introducing bubble stripping as a novel geochemical engineering approach to reducing high CO₂ in coastal marine ecosystems. We use an empirically validated numerical model to find that air/sea gas exchange rates within a bubbled system are 1-2 orders of magnitude higher than within a non-bubbled system. By coupling bubbling-enhanced ventilation to a coastal ecosystem metabolism model, we demonstrate that strategically timed bubble plumes can mitigate exposure to high CO₂ under present-day conditions and that exposure mitigation is enhanced in the more acidic conditions predicted by the end of the century. ­The Fifth Assessment Report of the Intergovernmental Panel on Climate Change emphasizes the need to both adapt to and mitigate the effects of climate change and ocean acidification. We believe shallow water bubble stripping could be one approach for reducing high CO₂ conditions in coastal ecosystems and should be added to the growing list of engineering approaches intended to increase coastal resilience in a changing ocean.