Abstract. Particulate concentrations of the 14 Rare Earth Elements (PREE), yttrium, and 232-thorium were measured in 200 samples collected in the epipelagic (ca. 0–200 m) and mesopelagic (ca. 200–1500 m) zones of the North Atlantic during the GEOVIDE cruise (May/June 2014, R/V Pourquoi Pas?, GEOTRACES GA01), providing the most detailed snapshot of the PREE distribution in the North Atlantic so far. Concentrations of particulate cerium (PCe) varied between 0.2 and 16 pmol L−1, while particulate neodymium (PNd) concentrations ranged between 0.1 and 6.1 pmol L−1. Particulate ytterbium (PYb) concentrations ranged between 0.01 and 0.50 pmol L−1. In addition, this study showed that PREE distributions were also controlled by the biological production in the upper sunlit ocean and by remineralization processes in the mesopelagic area. Low surface concentrations combined with normalized PREE patterns displaying a negative Ce anomaly and HREE enrichments pointed to freshly formed biogenic particles imprinting the seawater signature. A significant relationship between biogenic silica (BSi) and PHREE was also observed in the Labrador and Irminger seas, due to the occurrence of strong diatom blooms at the sampling time. In order to identify dissolved-particulate processes independent of the ionic radius, we used PHo∕PY ratios and showed that absorption processes were predominant in the upper ocean, while adsorption processes dominated at deeper depths. This study highlighted different lithogenic fractions of PREE and dispersion depending on the shelf: off the Iberian margin, up to 100 % of the PREE were determined to have a lithogenic origin. This lithogenic input spread westward along an intermediate nepheloid layer (INL), following isopycnals up to 1700 km away from the margin. In contrast, along the Greenland and Newfoundland margins, the circulation maintained lithogenic inputs of PREE along the coasts.

Particulate concentrations of the fourteen Rare Earth Elements (PREE), yttrium and 232-thorium have been 10 measured in two hundred samples collected in the epipelagic (ca 0-200 m) and the mesopelagic (ca 200-1000 m) zones of the North Atlantic, during the GEOVIDE cruise (May/June 2014, R/V Pourquoi Pas ?, GEOTRACES GA01). Particulate cerium (PCe) concentrations vary from 0.2 pmol.L -1 to 16 pmol.L -1 , particulate neodymium (PNd) ones from 0.09 pmol.L -1 to 6.1 pmol.L-1 and particulate ytterbium (PYb) ones from 0.01 pmol.L -1 to 0.5 pmol.L -1 . PREE concentrations are higher close to the Iberian margin and on the Greenland shelf, where PREE concentrations normalized to Post Archean Australian Shale 15 (PAAS) display a positive Ce anomaly between 0.3 and 3, and a light REE (LREE) enrichment compared to heavy REE (HREE) illustrated by high PNdN/PYbN ratios (normalized to PAAS). The lithogenic fraction of the particulate REE concentration is closely related to the margin morphology and the hydrodynamic context: off the Iberian margin, up to 100% of the PREEs are lithogenic and this lithogenic input spreads westward along isopycnals as intermediate nepheloid layers (INL)up to 1700 km away. Lithogenic inputs are also observed along the Greenland and Newfoundland margins, although the 20 circulation stacks them along the coasts. PREE distributions are also controlled by the biological uptake in the surface layers and remineralization processes deeper. Low surface concentrations and some normalized REE patterns displaying a negative Ce anomaly and HREE enrichment indicate freshly formed biogenic particles. A significant relationship between biogenic silica (BSi) and PHREE is also observed in the diatom blooms occurring in the Labrador and Irminger seas. PHo/PY ratio was calculated in order to identify processes independent of the ionic radius. However, we could not firmly assess the role of the 25 iron hydroxides in the scavenging prates of these elements.

Few sites of high bottom tidal velocity along the Iberian continental slope are highlighted with a semi-realistic internal tides modeling.• The sediment resuspension is confirmed on five sites based on previous sediment surveys and Shields criterion threshold.• Geochemical tracers particle measurements are explained by proposed trajectories from resuspension sites based on circulation modeling.