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

Science Highlights

Terrestrial iron inputs and reverse weathering in the Amazon mouth

Understanding the key processes that condition the net input of chemical species to the ocean is an important challenge…

01.02.2023

Science Highlights

Tracing dust deposition with aluminium and silicate at a resolution never reached before

Benaltabet and his colleagues propose a study of the dissolved aluminium and silicate fate in the Gulf of Aqaba (Red Sea).

24.01.2023

Science Highlights

Actinium-227 distribution traces at least three processes in the North Atlantic Ocean

Le Roy and colleagues report an oceanic section of Actinium-227 in the North Atlantic Ocean.

23.01.2023

Science Highlights

Do you want to know more about iron and its isotopes? This review is for you!

Authors present a comprehensive review of iron and iron isotope sources, internal cycling, and sinks in the ocean.

17.01.2023

Rechercher