“…As the interface between land and ocean, continental mar-gins comprise a key juncture in the carbon cycle (Bianchi et al, 2018), provide crucial habitats for unique marine ecosystems (Levin and Sibuet, 2012), support a major fraction of the worlds fisheries (Worm et al, 2006) and participate in exchange processes with the interior ocean (Dunne et al, 2007;Jahnke, 1996;Rowe et al, 1994). These ocean settings and their underlying sediments are also amongst those most vulnerable to change (Keil, 2017) through direct perturbations such as contaminant and nutrient discharge from land; loci of intense resource extraction, such as bottom trawling (Pusceddu et al, 2014) and mineral and hydrocarbon recovery (e.g., Chanton et al, 2015); and indirect effects such as ocean warming (Roemmich et al, 2012), acidification (Feely et al, 2008;Orr et al, 2005) and local or large-scale deoxygenation (Diaz and Rosenberg, 2008;Keeling et al, 2010). Such influences may change not only the amount of carbon sequestered in marine sediments but also its character, with radiocarbon serving as a key metric to detect such change.…”