Lead isotopes tracks leakage of Indian Ocean seawater into the Atlantic Ocean

Stable lead isotopes have been measured by Maxence Paul and co-workers along 40°S during the first and second legs of the UK GEOTRACES cruise (GA10) in the Atlantic Ocean. They clearly help to identify three different end-members and mixing between them: open ocean South Atlantic seawater, Indian Ocean seawater, and coastal inputs from South Africa. Lead isotopes and concentrations are excellent fingerprints of the occurrence of Agulhas rings, as confirmed by satellite observations and in situ hydrographic data. This study reveals that the Agulhas Leakage is not only a key pathway for heat but also impacts biogeochemical cycles…

16 Paul l
Figure: Maps showing the location of surface seawater samples collected during Leg A (left) and Leg B (right) of UK GEOTRACES GA10 cruise D357. Shaded areas highlight the position of Agulhas rings on 19 October 2010 (left) and 17 November 2010 (right), as suggested by sea surface height (SSH) anomalies obtained from satellite data (AVISO). Middle panels: Variations of Pb isotope compositions (colored circles) and Pb concentrations (grey circles) reflect the different sources present in the Cape Basin. Sample denoted as coastal, Agulhas, transitional, and open ocean are represented in blue, red, yellow and green, respectively. The Agulhas samples are marked by low 206Pb/207Pb and and their locations are in accord with the position of the Agulhas rings, as identified by satellite observations and salinity anomalies (bottom panels). Click here to view the figure larger.

Reference:

Paul, M., van de Flierdt, T., Rehkämper, M., Khondoker, R., Weiss, D., Lohan, M. C., & Homoky, W. B. (2015). Tracing the Agulhas leakage with lead isotopes. Geophysical Research Letters, 42(20), 8515–8521. doi:10.1002/2015GL065625

Latest highlights

Science Highlights

Trace metal quotas in small flagellates: diatoms are challenged!

Sofen and colleagues found that in natural plankton assemblages and in culture, small flagellates operated at the lower range of iron quotas.

14.09.2022

Science Highlights

A vivid picture of particle distribution and sources in the Arctic Ocean

Extensive description of particle concentrations and chlorophyll-a fluorescence distribution along Arctic GEOTRACES sections.

08.09.2022

Science Highlights

The Tonga arc, an iron boundary in the South West Pacific Ocean

As part of the TONGA GEOTRACES process study, Tilliette and colleagues identified high dissolved iron concentrations in the west of the Tonga arc.

31.08.2022

Science Highlights

Dominance of the benthic flux of rare earth elements on continental shelves

Deng and his colleagues focus on one of the largest land–ocean interfaces in Asia, the Changjiang River–East China Sea system.

30.08.2022

Rechercher