Labile particulate iron isotopic signatures trace hydrothermal and margin inputs down to the benthic layers in the Eastern Pacific Ocean

For the first time, labile and total particulate iron (pFe) isotopic signatures were measured along a full depth oceanographic section (more than 200 0.8-51 µm-sized particles) in the Eastern Pacific Ocean (GP16 East Pacific Zonal Transect cruise). Marsay and co-authors revealed that: a hydrothermal plume emanating from the South East Pacific Rise was identified as […]

Jun / 06 / 2018

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

Particle distribution in repeated ocean sections and sediment resuspension

This is the first compilation of an expansive data base of transmissometer data on a decadal period of time. More than 7376 stations have been analyzed for “cp” value, a proxy for particle concentrations, by Gardner and co-workers (2018, see reference below). Full water-column sections confirm that particle concentrations are higher in surface waters, decrease […]

Jan / 25 / 2018

What controls hydrothermal plume transport of iron over 4000 km in the deep Pacific Ocean?

The striking extension of the dissolved iron and manganese plumes over more than 4000 km from their hydrothermal sources along the US GEOTRACES East Pacific Zonal Transect (EPZT) cruise (GP16) has challenged our understanding of these element cycles (Resing et al., 2015 see GEOTRACES science highlight). Fitzsimmons and co-workers (2017, see reference below) analysed the particulate […]

Mar / 23 / 2017

Changing the paradigm on the oceanic iron cycle

Tagliabue and co-workers (2017, see reference below) discuss an extensive review on the recent findings on iron (Fe) cycle in the ocean. They figure out clearly that: Fe is a nutrient as essential as nitrogen (N) or phosphorus (P) for the phytoplankton. In other words, the full understanding of any marine ecosystem cannot neglect the […]

Mar / 17 / 2017

Solute-particle interactions and the enhanced dissolved barium flux from the Ganga River estuary

Dissolved and particulate barium (Ba) were investigated in samples that were collected in six periods of contrasting water discharge over two years (2012 and 2013) by Saumik and Dalai (2016, see reference below) in the Ganga (Hooghly) River estuary. The authors thoroughly documented anthropogenic sources and submarine groundwater discharges, which account for less than 2% […]

Nov / 16 / 2016

Inference about rates of thorium and particle cycling in the ocean water column

Insoluble thorium (Th) isotopes are particle reactive while their radioactive parents are fairly soluble. This difference of behaviour has allowed chemical oceanographers to use Th isotopes to develop understanding about the scavenging of particle reactive elements and the cycling of particles in the water column. However, many prior models rely on numerous assumptions. Among these […]

Aug / 30 / 2016

Changing the cadmium : phosphorus paradigm?

The well-established strong linear relationship linking dissolved cadmium (Cd) and phosphorus (P) concentrations in seawater is at the origin of the attraction of Cd as a proxy for PO4 in the paleocean. However, exploring the dissolved Cd and PO4 distributions in the ocean, Quay and co-workers (2015, see reference below) show that the Cd/P of […]

Sep / 21 / 2015

Insights into Particle Cycling from Thorium and Particle Data

Phoebe Lam and Olivier Marchal (2015, see reference below) propose to describe, with the same model, the dynamics of particles in the oceanic water column and its effects –on four different tracers characterized by very distinct sources and sinks. The considered tracers are: Particulate Organic Carbon (POC) (a biogenic compound), barium (Ba) (an authigenic mineral), […]

May / 21 / 2015