2024 journal article
Gulf Stream mesoscale variabilities drive bottom marine heatwaves in Northwest Atlantic continental margin methane seeps
Communications Earth & Environment.
open access via doi.org (publisher)
Methane hydrates on continental margins sequester substantial amounts of methane. Ocean warming often triggers hydrate dissociation, influencing global climate and marine ecosystems. Here we use ocean reanalysis to investigate bottom marine heatwaves affecting methane seeps at the Northwest Atlantic continental margin. These heatwaves are driven by downward displacement of ocean subsurface isopycnals that brings anomalously warm water to the seafloor, which frequently lacked surface expressions. The isopycnal anomalies are generated by the interaction of Gulf Stream mesoscale activity and slope topography, including warm core ring intrusions and impingements at the tail of the Grand Banks. Once generated, the isopycnal anomalies propagate along the slope and affect the seep area via topographic Rossby waves, offering predictability for bottom marine heatwaves. A northward shift and increasing instability of the Gulf Stream has intensified bottom marine heatwaves at the seep area since 2009, and future climate change will likely exacerbate this trend. Since 2009, bottom marine heatwaves at the Northwest Atlantic continental margin, triggered by subsurface isopycnal anomalies, may have been affecting methane seeps, exacerbated by Gulf Stream mesoscale eddy activity and slope topography interactions, according to high-resolution ocean reanalysis and water mass analysis to investigate bottom marine heatwaves.