K. Kunde and colleagues (2019, reference below) show that a highly dynamic colloidal iron phase in the upper ocean and at the seafloor boundary controls the distribution of dissolved iron at key sources and sinks across the subtropical North Atlantic Ocean, while the ocean interior is marked by an equilibrium partitioning between the soluble and […]
Feb / 07 / 2020
Icebergs have been speculated to constitute one of the largest fluxes of iron (Fe) into the polar oceans since the 1930s and thus recent increases in ice discharge around the world could potentially change Fe availability in the ocean. But how much Fe is in an iceberg? As part of an international collaboration involving several […]
Dec / 16 / 2019
In the frame of GEOTRACES cruise GA08, Rahlf et al. (2020, see reference below) determined seawater profiles of dissolved radiogenic neodymium isotope signatures (εNd) and neodymium concentrations across the restricted western Angola Basin and along the northern Cape Basin to investigate mixing and provenance of water masses. Nd isotope compositions of deep water masses in both […]
Conway and co-authors (2019, see reference below) present the first evidence that anthropogenic iron (Fe) from combustion sources is visible at the basin scale, using iron isotopic composition (δ56Fe) analysis of the soluble aerosol phases collected during GEOTRACES cruise GA03 in the North Atlantic Ocean. Off Sahara, soluble aerosol samples have near-crustal δ56Fe whereas those from near […]
Oct / 08 / 2019
Dissolved chromium (Cr) in the ocean is present under two oxidation states: The oxidized and soluble Cr (VI) and the reduced more reactive Cr (III). Reduction of Cr (VI) to Cr (III) is favored by the occurrence of biological particles, reducing conditions in the sediments or the water column (at least in the Pacific Oxygen […]
Mar / 19 / 2019
A high resolution survey of the distribution of dissolved iron (dFe) over the Hebridean (Scottish) shelf break was conducted as part of the U.K. Shelf Sea Biogeochemistry programme, a GEOTRACES process study (GApr04). Despite the close proximity to shelf sediments, which are known to supply large quantities of dFe to overlying water column, the results […]
Feb / 18 / 2019
Three articles from three cruises highlighted here! Atlantic waters have been recently recognized to play an increasing role in reducing sea-ice extent in the Arctic Ocean at a rate now comparable to losses from atmospheric thermodynamic forcing. Beyond the Arctic Ocean, the water mass transport and transformation processes in the North Atlantic Ocean substantially contribute […]
Jan / 30 / 2019
The linear relationship between the seawater cadmium and phosphate dissolved concentrations lead to use the cadmium/calcium (Cd/Ca) imprinted in calcareous archives to reconstruct the past phosphate (PO4) distributions. However, variations in the Cd/PO4 ratio between different water masses and within vertical oceanic profiles were recently identified. Among the processes that could explain these variations, sequestration […]
Jan / 07 / 2019
Based on the thorium-234 (234Th) isotopes and the Particulate Organic Carbon/Thorium (POC/Th) ratios measured in small and large particles collected at 11 stations along the GEOVIDE section (GA01) using in situ pumps, exported POC flux relative the surface primary production were determined by Lemaitre and colleagues (2018, see reference below). While a factor of 9 […]
Dec / 12 / 2018