Geographical, seasonal, and depth variation in sinking particle speeds in the North Atlantic

• Main Authors: Villa Alfageme, María, Soto, Feliciano de, Ceballos Romero, Elena, Giering, Sarah, Le Moigne, Frederic, Henson, Stephanie, Mas, Jose Luis, Sanders, Richard
• Other Authors: Universidad de Sevilla. Departamento de Física Aplicada II, Universidad de Sevilla. Departamento de Física Aplicada I, Obra Social la Caixa
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU Publications 2020
• Subjects: North Atlantic
• Online Access: https://idus.us.es/handle//11441/98535

Particle sinking velocity is considered to bea controlling factor for carbon transport to the deep sea and thus carbon sequestration in the oceans. The velocities of the material exported to depth are considered to be high in high-latitude productive systems and low in oligotrophic distributions. We use a recently developed method based on the measurement of the radioactive pair 210Po-210Pb to calculate particlesinkingvelocitiesinthetemperateandoligotrophicNorthAtlanticduringdifferentbloomstages.Our estimates of average sinking velocities (ASVs) show that slowly sinking particles (<100md 1) contribute significantlytocarbon fluxatallthelocationsexceptinthetemperateregionsduringthebloom.ASVsappear tovarystronglywithseason,whichweproposeiscaused bychanges intheepipelagiccommunitystructure. Our results are the first field datato confirmthe long-standing theorythat particle sinkingvelocities increase with depth, with increases of up to 90% between 50 and 150m depth.