Surface South Pacific ecosystems reflect the availability of the nutrients iron, nitrate and phosphate

Thanks to a high resolution section across the South Pacific (150°E-150°W, GEOTRACES GP13 cruise), Ellwood and co-workers (2018, see reference below) identify that the gradient of sources and fates of the 3 nutrients iron (Fe), nitrogen (N) and phosphorus (P) is explaining the observed ecosystem west-east gradient. In the west, phytoplankton able to fix atmospheric nitrogen (diazotroph species) is abundant while it is the opposite in the eastern end of the section. As shown in the figure, such drop of the diazotroph species is due to the low abundance of Fe in the most remote part of the section.

18 Ellwood figure

Figure: Cartoon showing the input fluxes for iron (Fe), nitrogen (N) and phosphorus (P) into surface ocean across the GP13 zonal section. In the west, diazotrophs are abundant while it is the opposite in the eastern end of the section due to the low abundance of Fe, in the most remote part of the section. Click here to view the figure larger.

Reference:

Ellwood, M. J., Bowie, A. R., Baker, A., Gault-Ringold, M., Hassler, C., Law, C. S., Maher, W. A., Marriner, A., Nodder, S., Sander, S., Stevens, C., Townsend, A., van der Merwe, P., Woodward, E. M. S., Wuttig, K., Boyd, P. W. (2018). Insights Into the Biogeochemical Cycling of Iron, Nitrate, and Phosphate Across a 5,300 km South Pacific Zonal Section (153°E-150°W). Global Biogeochemical Cycles, 32(2), 187–207. http://doi.org/10.1002/2017GB005736

Latest highlights

Science Highlights

Transient tracers, water mass ages and mixing time scales in the Arctic Ocean

Smith and colleagues determined iodine-129, chlorofluorocarbons and sulfur hexafluoride during three GEOTRACES cruises in the Arctic Ocean.

07.02.2023

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

Rechercher