The export of particles from the surface to the deep ocean affects nutrient distributions, sustains mesopelagic and bathypelagic organisms, and, ultimately, contributes to controlling the Earth’s climate [Trull et al., 2008]. Despite the importance of this process, however, modern estimates of global carbon export vary between 5 and 12 Pg C yr−1 [Laws et al., 2000; Henson et al., 2011]. This large range of variation reflects an ignorance arising from lack of observations and from substantial disagreement among the different methods and assumptions used to estimate the magnitude of export. To predict how oceanic carbon uptake will evolve in the future and to interpret past records of CO2, we need to understand

the factors that control the uncertainty of our current estimates of global carbon export.