A Mineralogy‐Based Anthropogenic Combustion‐Iron Emission Inventory. Issue 17 (24th August 2020)

• Record Type: Journal Article
• Authors: Rathod, S. D.; Hamilton, D. S.; Mahowald, N. M.; Klimont, Z.; Corbett, J. J.; Bond, T. C.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 17(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-24
• Subjects: anthropogenic -- iron -- biogeochemistry -- mineralogy -- solubility -- emissions; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2019JD032114
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Atmospheric supply of iron can modulate ocean biogeochemistry, due to its key role in global nitrogen and carbon cycles. Current estimates predict up to 20% of global ocean net primary productivity depends on an atmospheric iron source. Using a technology‐based methodology, we revise total and soluble anthropogenic iron emissions and resolve iron into its mineral components, which allows modeling mineral‐specific atmospheric reactions. We compare different methodologies for representing anthropogenic iron solubility: measured in mild and strong leaches and estimated using a mineralogy basis and identify the emissions that are most affected by such assumptions. The inclusion of metal smelting as an iron source increases iron emissions by up to 10 times higher in the fine aerosol fraction (smaller than 1 μm) than most previous inventories. Different solubility assumptions alter anthropogenic soluble iron emissions and deposition by a factor of 20 and 10, respectively. Using solubilities measured in mild leaches and calculated by mineralogy give 20–30 Gg/yr anthropogenic emissions and 40–50 Gg/yr deposition, while those measured in strong leaches give 80–440 Gg/yr emissions and 200–450 Gg/yr deposition. This range of anthropogenic soluble iron deposition leads to global soluble iron deposition of 1, 900–2, 300 Gg/yr when dust, wildfires, and atmospheric processing are included, indicating such assumptions can affect global soluble iron supply by about 30%. In regions where marine primary productivity is iron limited, anthropogenic combustion‐iron contributes up to half of the atmospheric soluble iron flux to the North Pacific Ocean but supplies less than 5% to the Southern Ocean. Key Points: Mineralogy‐resolved anthropogenic combustion‐iron emission inventory predicts 1.1 (0.1–4) Tg Fe/yr in the fine (smaller than 1 μm) aerosol fraction—about 10 times higher than previous estimates Different assumptions in anthropogenic iron solubility alone alter global soluble iron deposition by 30% Anthropogenic emissions even without wildfires yield 20–50% of Northern Pacific soluble iron deposition but under 5% in the Southern Ocean