Dissolved gallium in the Beaufort Sea: a promising conservative water mass tracer

Mc Allister and Orians (2015, see reference below) present the first dissolved Ga (DGa) data ever reported in the Arctic. DGa behaves very conservatively, helping to constrain the mixing of water masses of Pacific and Atlantic origins. Its conservative behaviour helps distinguishing seasonal processes that are influencing temperature and Nitrate:Phosphate of Pacific Water entering the Arctic; it also supports the interpretation that nitrogen fixation rates are associated with Pacific source waters and not to freshwater sources (i.e. Mackenzie River or sea ice melt). Comparing DGa and dissolved aluminium (DAl) profiles reveals that differential scavenging rates are affecting the two tracers.

15 McAlister

Figure: a. Dissolved gallium (Ga) was measured in the Beaufort Sea of the Western Arctic Ocean, b. the transect comprising stations L1 – L3 represent waters of the Canadian Basin, S stations represent the shelf and are discussed further in the manuscript, c) concentrations of dissolved Ga in the Canadian Basin are shown to provide a conservative tracer of Pacific and Atlantic source waters. Low concentrations of dissolved Ga associated with Pacific waters increase smoothly through the thermocline to comparatively high concentrations of Atlantic source waters. Note log depth scale to assist visualization of shallow depths.

 

Reference:

McAlister, J. A., & Orians, K. J. (2015). Dissolved gallium in the Beaufort Sea of the Western Arctic Ocean: A GEOTRACES cruise in the International Polar Year. Marine Chemistry. doi:10.1016/j.marchem.2015.05.007 Click here to download the paper.

Latest highlights

Science Highlights

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?

18.10.2021

Science Highlights

Microbial trace metal trafficking on marine particles

This study provides evidence for the processing of nine particulate trace metals in multiple manners by diverse microbial communities.

28.09.2021

Science Highlights

Volcanic emissions in the Southern Ocean: an efficient and unexpected source of iron for this remote area

This study suggests that volcanic emission can represent a significant source of bioavailable Fe to open ocean anaemic ecosystems.

20.09.2021

Science Highlights

Surprisingly heavy silicon isotopes in the surface and deep Arctic Ocean

Brzezinski and his colleagues report on a comprehensive study of the Arctic Ocean silicic acid concentrations and silicon isotopic composition…

14.09.2021

Rechercher