Dissolved cobalt enrichments over the Kerguelen plateau confirm that most of the natural fertilization is due to partial dissolution of local basalts

Exceptionally high dissolved cobalt (Co) concentrations have been measured in the surface waters above the Kerguelen Plateau (KEOPS), and in intermediate and deep waters above its eastern slope. Lateral advection and dissolution of Co contained in basalt sediments around Heard Island were shown to imprint the process of surface enrichment over the plateau. Dissolved Co enrichment was strongest at the intercept of the eastern slope with intermediate and deep waters, probably due to more efficient mobilisation of the sediments in the slope current.

Estimate of the fertilization flux of iron inferred by using dissolved Co as a tracer of basalt sources is consistent with preceding ones (Zhang et al., DSR II, 55, 638-652, 2008; Chever et al., Biogeosciences, 7, 455-468, 2010), and the calculated iron supply matches with the phytoplankton demand (Sarthou et al., DSRII, 55, 734-751, 2008).

DCo_vertical_distribution_KEOPS

Reference:

Bown, J., Boye, M., Laan, P., Bowie, A. R., Park, Y.-H., Jeandel, C., and Nelson, D. M.: Imprint of a dissolved cobalt basaltic source on the Kerguelen Plateau, Biogeosciences, 9, 5279-5290, doi:10.5194/bg-9-5279-2012, 2012. Paper.

Latest highlights

North-South section of bioactive cadmium, nickel, zinc, copper and iron along GEOTRACES transect GP19 in the Pacific Ocean

Zheng and his colleagues propose the first full sections of the simultaneous dissolved distributions of five nutrient-type trace metals in the western South Pacific Ocean.

MOTES: a new facility designed for trace element sampling in seawater

Zhang and a group of engineers and researchers from Shanghai and Qingdao are presenting a modular trace element sampling facility.

A thorough estimate of the hydrothermal plumes on neodymium concentration and isotope oceanic cycles

Basak and co-workers investigated the influence of particulate matter on neodymium distributions in the Southern East Pacific Rise Hydrothermal Plume.

What are the drivers of the distributions of cadmium, nickel, zinc, copper and cobalt, manganese and aluminium in the Atlantic Ocean? Two papers are tackling this issue

Chen and co-authors reveal that the distributions of dissolved tracers at depth in the South Atlantic are predominantly controlled by the mixing of North Atlantic Deep Water and waters of Antarctic origin…

Rechercher