Particle Fluxes

Arctic mercury export flux with marine particles higher than anticipated

In the ocean, the residence time of mercury (Hg), is largely driven by two removal mechanisms: evasion to the atmosphere and downward export flux with settling particles. The later was particularly poorly constrained in the Arctic Ocean, as was the Hg burial rate into the sediment. Using samples collected during the German GEOTRACES TransArcII (GN04) […]

May / 06 / 2020

Particulate fluxes and circulation in a changing Arctic Ocean: tracer data and modeling

A complete review of published and new water column profiles of thorium-230 (230Th) and protactinium-231 (231Pa) concentrations and neodymium (Nd) isotopic compositions collected in the Amerasian Basin of the Arctic Ocean between 1983 and 2015 was performed by Grenier and co-workers (2019, see reference below). This review allowed them to identify regional and temporal variability […]

Mar / 27 / 2020

South Pacific particulate organic carbon fate challenges Martin’s Law

Joint Science Highlight with US-Ocean Carbon & Biogeochemistry (OCB). Carbon storage in the ocean is sensitive to the depths at which particulate organic carbon (POC) is respired back to CO2 within the twilight zone (100-1000m). For decades, it has been an oceanographic priority to determine the depth scale of this regeneration process. To investigate this, […]

May / 16 / 2019

Arctic rivers are discharging organic matter enriched in mercury to the Labrador Sea

In the framework of GEOVIDE-GEOTRACES GA01 cruise (spring 2014), Cossa and co-workers (see reference below) measured the first high-resolution mercury (Hg) distribution pattern along a transect from Greenland to Labrador coasts. An interesting feature is the observation of Hg enrichment originating from fluvial sources in the Canadian Arctic Archipelago waters. This excess Hg is transferred […]

Apr / 09 / 2018