Nitrogen isotopic constraints on nutrient transport to the upper ocean

Abstract Ocean circulation supplies the surface ocean with nutrients that fuel global productivity. However, mechanisms and rates of water nutrient transport from deep to upper are poorly known. Here, we use nitrogen isotopic composition nitrate place observational constraints on Southern into pycnocline (roughly 1.2 km), as opposed directly ocean. We estimate 62 ± 5% phosphate originate Ocean. Mixing, advection, accounts for most gross input pycnocline. in net, mixing carries away Despite quantitative dominance transport, richness relies large-scale advective flow, through which nutrient-rich is converted nutrient-poor eventually flows North Atlantic.