Informative zinc isotopic fractionation in the Southern Ocean

Ellwood and co-workers (2020, see reference below) established the distribution of dissolved and particulate zinc (dZn and pZn respectively) and its isotopes in the Subantarctic Zone South of Tasmania.

Concentration profiles show that zinc has a longer regeneration length scale than phosphorus and of cadmium, but shorter than copper. Modelling of the particulate profiles produced variable vertical attenuation factors of 0.82, 2.04, 2.41 and 0.28 for zinc, phosphorus, cadmium and copper respectively.

Interestingly, concentrations and isotopic Zn distributions were established inside cold-core eddy (CCE) and compared to the same parameter distributions outside the eddy.

The isotope composition of surface dZn (δ66Zndissolved) from the CCE station is ~ twice its deep water value. This is likely due to the isolated nature of the cold-core, which retains the signals of isotope fractionation, while they are likely lost by mixing outside the core.

The authors then apply a 1D-simulation to their data and show that the isotopic structure of the dissolved and particulate zinc from this specific station are determined by the interplay of processes like uptake by phytoplankton, complexation of zinc with natural organic ligands and the regeneration of zinc from particulate matter.

Reference:

Ellwood, M. J., Strzepek, R., Chen, X., Trull, T. W., & Boyd, P. W. (2020). Some observations on the biogeochemical cycling of zinc in the Australian sector of the Southern Ocean: a dedication to Keith Hunter. Marine and Freshwater Research, 71(3), 355. Access the paper: https://doi.org/10.1071/MF19200

Latest highlights

Science Highlights

Controls of cadmium-phosphate systematic unraveled by Neural Networks and Ocean Circulation Inverse Model

Roshan and DeVries explore the similarities and contrasts between oceanic cadmium and phosphate cycles using an Artificial Neural Network mapping technique and Ocean Circulation Inverse Model.

23.06.2021

Science Highlights

Retreat of large marine-terminating glaciers may increase iron supply to surface waters

The findings demonstrate that glacial retreat and loss of ice-shelves may potentially result in increases in dissolved Fe supply to surface waters downstream of large marine terminating glaciers in future.

31.05.2021

Science Highlights

A new and more quantitative atlas of the deep-sea burial fluxes of major and trace elements

Among other findings, authors find that the new opal flux is roughly a factor of two increase over previous estimates having important implications for the global silicon cycle.

21.05.2021

Science Highlights

Updated compilation of the global continental and marine lithogenic neodymium isotopic measurements

This new compilation and gridded datasets offer a concrete way forward to improve the application of neodymium isotopes as a useful tracer of ocean circulation.

05.05.2021

Rechercher