Icebergs as sources of trace metals to the ocean: which impact?

Earth’s Ice Sheets are known to release significant quantities of lithogenic particles into the ocean every year, but how does this material affect trace metal availability in the ocean? Combining results from GEOTRACES cruise GN05 at the ‘79° N Glacier’ with inshore work in Greenland and the Western Antarctic Peninsula, Krause et colleagues (2021, see reference below), present trends in dissolved iron, cobalt, nickel and copper across the glacier-to-ocean salinity gradient. Elevated signals of all metals are associated with glacier runoff, although ~98% of dissolved iron supplied from freshwater is rapidly returned to particulate phases. Curiously, dissolved iron concentrations in particular appeared to be strongly buffered in inshore waters throughout spring and summer, which means lateral fluxes from fjord over-turning may be a key driver of lateral trace element export year-round.

Figure: Field locations and sample collection points: Trace metal concentrations across the salinity gradient were sampled at 8 sites spanning Greenland and the Western Antarctic Peninsula.

Reference:

Krause, J., Hopwood, M. J., Höfer, J., Krisch, S., Achterberg, E. P., Alarcón, E., Carroll, D., González, H. E., Juul-Pedersen, T., Liu, T., Lodeiro, P., Meire, L., Rosing, M. T. (2021). Trace Element (Fe, Co, Ni and Cu) Dynamics Across the Salinity Gradient in Arctic and Antarctic Glacier Fjords. Frontiers in Earth Science, 9, 878. https://doi.org/10.3389/feart.2021.725279

Latest highlights

Science Highlights

Anthropogenic aerosol has become a dominant source of zinc in the deep water of the Northern South China Sea

Liao and colleagues determined zinc concentrations and isotope compositions in sinking particles collected in the Northern South China Sea…

24.11.2021

Science Highlights

An updated global ocean chromium biogeochemical cycle

Janssen and co-authors present an exhaustive compilation of ocean chromium data…

Science Highlights

Mercury stable isotopes constrain atmospheric pathways to the ocean

The study’s results hold promise that the implementation of anti-pollution measures under the Minamata Convention will likely result in a faster decrease of oceanic mercury levels than previously thought.

18.11.2021

Science Highlights

New impetus to the debate on the sources of dissolved aluminium to the ocean

This study challenges the paradigm that dissolved aluminium in the bottom waters of the Arctic basins could result from a top-down process.

10.11.2021

Rechercher