The biogeochemical ventures of dissolved iron and manganese across the Arctic Ocean

Science Highlights

15 May 2020

The spatial distributions and biogeochemical cycling of dissolved Fe (dFe) and dissolved manganese (dMn) across the Arctic Ocean were established during summer and fall 2015. The Canadian GEOTRACES transect extended from the Canada Basin (CB) to the Labrador Sea (LS) via the Canadian Arctic Archipelago (CAA).

The surface, subsurface and deep water distributions for both metals are controlled by i) a large variety of processes and ii) a complex balance between sources and sink (river inputs in surface, advective transports and particle remineralization at depth). For example, the highest concentrations are measured in surface waters of the CAA and the CB because these regions are strongly influenced by river inputs. Contrastingly, in the highly productive Baffin Bay and Labrador Sea, the surface waters are markedly depleted in dFe and dMn while organic matter remineralization likely acts as a notable source of these elements to deep waters.

The figure below summarizes the complexity of the processes governing the fate of these elements in the Canadian Arctic Ocean.

Figure: a) Sampled stations for Fe and Mn during the Canadian Arctic GEOTRACES cruises, bathymetry and schematic of water circulation. b) Conceptual scheme displaying the concentrations and key processes (e.g. freshwater and sedimentary inputs, remineralization and scavenging removal) controlling the distributions of dissolved Fe and Mn in the Canadian Arctic Ocean.

Reference:

Colombo, M., Jackson, S. L., Cullen, J. T., & Orians, K. J. (2020). Dissolved iron and manganese in the Canadian Arctic Ocean: On the biogeochemical processes controlling their distributions. Geochimica et Cosmochimica Acta, 277, 150–174. DOI : https://doi.org/10.1016/j.gca.2020.03.012

Latest highlights

Regional zinc cycling in the Indian Ocean

Chinni and his colleagues present dissolved zinc distributions across the Arabian Sea, Bay of Bengal and southern tropical Indian Ocean…

Contrasting organic carbon  remineralisation rates revealed by particulate excess barium in the North Pacific and South China Sea

Yuan and co-workers quantify organic carbon remineralisation in the twilight zone of the China Sea using particulate excess barium as a proxy…

Sedimentary controls on seawater nickel distributions and nickel isotope compositions: a two steps study

Nickel isotopic mass balance in the ocean stands among the less understood so far…

23 million years of productivity reconstructed in the Central Pacific Ocean using past and modern proxies

Using diverse geochemical proxies, Chu and colleagues analysed an iron–manganese crust to reconstruct central Pacific productivity over the past 23 million years.

Rechercher