Tracking climate-driven changes of water masses and fluxes in polar regions using acoustics.

Climate warming increases glacial melt in polar environments, altering the pressure on extensive networks of nutrient-rich fluids and climate-changing gases below the surface and connecting from land to sea. The increased transport of these fluids and gases to the marine environment has been observed in polar regions, but such processes remain difficult to detect and monitor. To that purpose, water-column acoustic measurements have proven extremely effective, allowing the detection, identification and quantification of fine changes in oceanography, stratified turbulence and mixing at large scales. Here, we highlight recent visualisations of such anomalous acoustic features in polar regions collected on broadband split-beam systems ranging from 12 to 200 kHz. This allowed us to perform fine analysis of water masses and near-seafloor features. By coupling these acoustic with profiles of chemical properties of the water column and multi-disciplinary datasets, we interpret those, including meltwater, subglacial plumes, and seafloor seeps. These observations show the potential of using water-column acoustics in the context of long-term monitoring changes in those regions, with the potential to capture short and long-term variations in sensitive areas to better understand those rapidly changing environments.