When atmospheric dynamic controls the nutrient distributions in the ocean

Science Highlights

2 April 2014

Rainfall detection with satellites together with high-resolution data (~0.3°) for dissolved iron (DFe), aluminium (DAl), and inorganic phosphorus (DIP), confirm the existence of a sharp north–south biogeochemical boundary in the surface nutrient concentrations of the (sub)tropical Atlantic Ocean.

Wet deposition in the region of the intertropical convergence zone (ITCZ) acts as the major dissolved iron (DFe) source to surface waters. These variations of higher Fe inputs tied to the ITCZ movements drive a shift in the latitudinal distribution of N2 fixation and subsequent phosphate depletion in surface waters.

Thus, atmospheric dynamic is driving surface nutrient concentrations and microbial (diazotrophic) activity, which divide the (sub)tropical Atlantic into a high-phosphate, low-iron system in the south, and a low-phosphate, high-iron system in the north.

14 Schlosser

Figure: From the top to the bottom: Data from the AMT-17 (red) and D361 (green) cruises for satellite derived rainfall, surface DFe, surface DIP, and depth integrated N2 fixation (filled circles) and Trichodesmium spp. abundance (filled stars). Click here to view the figure larger.

Reference:

Schlosser, C., Klar, J. K., Wake, B. D., Snow, J. T., Honey, D. J., Woodward, E. M. S., Lohan, M. C., Achterberg, E.D., Moore, C. M. (2014). Seasonal ITCZ migration dynamically controls the location of the (sub)tropical Atlantic biogeochemical divide. Proceedings of the National Academy of Sciences of the United States of America, 111(4), 1438–42. doi:10.1073/pnas.1318670111.

Latest highlights

Aerosol dissolution and iron isotope fractionation during atmospheric transport

Camin and co-authors present the iron concentrations and isotopic compositions of aerosols in previously undocumented areas of the Pacific Ocean.

Paradoxical influence of hydrothermal methylmercury on local ecosystems

Torres Rodríguez and her colleagues investigate hydrothermal mercury inputs at the Tonga volcanic arc and their impact on local surface ocean ecosystems.

Rare Earth and neodymium isotope cycles in the abyssal Pacific Ocean are shaking up the paradigm established for particle reactive tracers

Du and colleagues demonstrate the importance of the abyssal sediment source in the control of the trace element and isotopes marine distribution.

Anthropogenic iron impact on the surface productivity in the Pacific Transition Zone

Hawco and colleagues investigated the influence of industrial emissions on oceanic iron supply and its ecological consequences in the North Pacific.

Rechercher