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

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

Science Highlights

Deep sea lithogenic weathering a source of iron colloids for the ocean

Homoky and co-workers determined the isotope composition of dissolved iron profiles in shallow surface sediments of the South Atlantic Uruguayan margin…

28.03.2021

Science Highlights

Adding external sources allow a better simulation of the oceanic rare earth elements cycles

Oka and colleagues demonstrate that the global distribution of REE can be reproduced by considering the internal cycle associated with reversible scavenging and external REEs inputs around continental regions.

26.03.2021

Science Highlights

First direct measurements of luxury iron uptake in natural phytoplankton communities: surprising results!

This study demonstrates the importance of biology and ecology to understanding iron biogeochemistry.

19.03.2021

Science Highlights

Air-sea gas disequilibrium drove deoxygenation of the deep ice-age ocean

This study provides one of the first mechanistic explanations for Last Glacial Maximum deep ocean deoxygenation.

18.03.2021

Rechercher