Land-ocean Inputs

Oceanic Margins as sources of lithogenic particulate and dissolved iron in the North Pacific Ocean

Three GEOTRACES Japanese cruises on board the R/V Hakuho Maru allowed establishing basin-scale and full-depth sectional distributions of total dissolvable iron (tdFe), dissolved iron (dFe), and labile particulate iron (lpFe=tdFe – dFe) in the North Pacific Ocean. Zheng and Sohrin (2019, see reference below) also discuss aluminum (Al) and manganese (Mn) data in this work. […]

Mar / 10 / 2020

Unprecedented iron delivery from the Congo River margin to the South Atlantic Gyre

The Congo River is the world’s second largest river by discharge volume and the only major river discharging into an eastern boundary region. Despite of its size, the Congo River plume and its influence on trace element cycles and ocean primary productivity is poorly constrained. During GEOTRACES cruise GA08, Vieira and co-workers (2020, see reference […]

Jan / 30 / 2020

Tracing water mass mixing in the Cape Basin and the restricted Angola Basin with radiogenic neodymium isotopes

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 […]

Dec / 16 / 2019

Rare Earth distribution and pattern anomalies in the Solomon Sea

The Solomon Sea is surrounded by high and intensively weathered islands. Its complex topography and hydrography make this area a potential source of trace elements to the waters flowing through it. Dissolved rare earth elements (DREE) analysis of more than 150 samples collected in the framework of the PANDORA cruise (along GEOTRACES GP12 section) showed that […]

The Scottish shelf break is not a significant source of iron to North Atlantic surface waters

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

Rare Earth Elements are less and less natural tracers in the ocean

This verdict is well illustrated by the recent study of Rodrigo Pedreira (2018, see reference below) off the North East Brazilian coast. His Rare Earth Elements (REE) data reveal marked positive Gadolinium (Gd) anomaly which reflects the release of Gd in hospital and domestic effluents. Indeed, this element is used as contrasting agent in magnetic resonance […]

Sep / 19 / 2018

Revelations from the dissolved 226Ra-228Ra pair distribution in the South East Pacific Ocean

While it is confirmed that radium-226 (226Ra) is an interesting tracer of the water masses encountered along the GP16 US East Pacific Zonal Transect (EPZT) section cruise, 228Ra data coupled to the dissolved iron (Fe), cobalt (Co) and manganese (Mn) ones provide evidence that lateral transport of sediments from continental margins, including shelves and slopes, […]

Jun / 05 / 2018

Astonishing protactinium and thorium profiles in the Mediterranean Sea

In the framework of the GEOTRACES cruise along the GA04 section in the Meditterranean Sea, Gdaniec et al. (2018, see reference below) measured thorium (Th) and protactinium (Pa) isotope distributions on 8 profiles across the Mediterranean Sea. Contrasting with what is observed in the open ocean: Depth profiles of these tracers are non linear, indicating […]

Mar / 29 / 2018