A unique insight into the properties of iron aerosols in the Arctic Ocean

Gao and co-workers (2019, see reference below) collected size-segregated aerosols over 8 segments of the 2015 US GEOTRACES cruise (GN01) across the Arctic Ocean. They show that:

  • aerosol iron (Fe) had a single-mode size distribution, peaking at 4.4 μm in diameter, suggesting regional dust sources of Fe around the Arctic Ocean,
  • Fe in the coarse-mode particles accounted for ~68% of the aerosol Fe from all samples and 59% if sample M7 is excluded,
  • the low Fe/Ti ratio indicate that Fe was not enriched relative to average upper continental crust,
  • although the less abundant fraction, the fine dusts (<1µm) contain the most dissolvable fraction of iron but abundant organic ligands are also suspected to increase the Fe solubility and,
  • dry deposition rates of aerosol Fe decreased from 6.1 μmol m−2 yr−1 in the areas of ~56°N–80°N to 0.73 μmol m−2 yr−1 in the areas north of 80°N.

2020 GaoFigure: (a) Cruise tracks showing the coverage of eight sets (M1 – M8) of aerosol samples collected in the Arctic Ocean aboard the US Coast Guard Ice Breaker Healy during the period from 9th August 2015 to 12th October 2015. (b) Spatial variation of atmospheric concentrations of aerosol Fe in fine- and coarse-mode particles and total (coarse + fine) particles. Higher concentrations of aerosol Fe in samples M2 and M7 likely resulted from dust materials transported from nearby continental areas. (c) Atmospheric concentrations of total dissolvable Fe in fine aerosols were higher than those in coarse aerosols. One explanation is that smaller aerosols may provide larger surface areas relative to their volume for chemical reactions with other substances that promote Fe dissolution from dust. Click on the figure to view it larger.

Reference:

Gao, Y., Marsay, C. M., Yu, S., Fan, S., Mukherjee, P., Buck, C. S., & Landing, W. M. (2019). Particle-Size Variability of Aerosol Iron and Impact on Iron Solubility and Dry Deposition Fluxes to the Arctic Ocean. Scientific Reports, 9(1), 16653. https://doi.org/10.1038/s41598-019-52468-z

Latest highlights

Science Highlights

New trace metal data in the Seas of Japan and Okhotsk

Nakaguchi and colleagues realized full-depth and section distributions of traces metals collected from the Seas of Japan and Okhotsk.

24.05.2022

Science Highlights

The Arctic Ocean is a net source of micronutrients toward the North Atlantic through the gateway of Fram Strait

Krisch and colleagues present a flux budget for micronutrient exchange between the Arctic and the North Atlantic Ocean.

18.05.2022

Science Highlights

Confrontation of two models to constrain the hydrothermal iron contribution to the Southern Ocean export production

Tagliabue and his co-workers compare the hydrothermal dissolved iron simulated by both models.

11.05.2022

Science Highlights

A better insight into parameters that control particle flux in the ocean

Xiang and coworkers compiled full ocean-depth size-fractionated particle data from 3 recent U.S. GEOTRACES cruises.

10.05.2022

Rechercher