Anthropogenic Asian aerosols provide Fe to the North Pacific Ocean

Pinedo‐González, Paulina; Hawco, Nicholas J.; Bundy, Randelle M.; Armbrust, E. Virginia; Follows, Michael J.; Cael, B. B.; White, Angelicque E.; Ferrón, Sara; Karl, David M.; John, Seth G.

doi:10.1073/pnas.2010315117

Cited by 72 publications

(65 citation statements)

References 59 publications

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“…The regions observed in their isotope-informed simulation for anthropogenic soluble Fe deposition largely coincided with the same regions over the northern Pacific and equatorial Atlantic where we observed significant contributions of anthropogenic FeO x -like aerosols. Recent isotopic measurements of iron in seawater indicated significant anthropogenic sources from East Asia, with 21-59% of the dissolved Fe measured in seawater in the N. Pacific (35°N-40°N) attributed to anthropogenic Fe and hence broadly consistent with our observations in this region 13 .…”

Section: Discussionsupporting

confidence: 90%

“…If global emissions of FeO x aerosols from anthropogenic sources have a similar ratio to BC emissions as reported in East Asia 2 , these aerosols would provide 52% higher particulate iron deposition to the Southern Oceans than previously estimated 5 . Low isotope ratios in Fe-containing aerosols associated with anthropogenic combustion 11 and in North Atlantic and Pacific marine aerosol samples 12,13 have provided additional evidence that anthropogenic aerosols contribute bioavailable iron to the oceans [14][15][16] . These results could have important consequences for the uptake of CO 2 emissions by the oceans, and they suggest anthropogenic combustion iron aerosol emissions play a more significant role in climate than previously believed.…”

Section: Introductionmentioning

confidence: 99%

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Global-scale constraints on light-absorbing anthropogenic iron oxide aerosols

et al. 2021

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Anthropogenic iron oxide aerosols (FeOx) have been identified as a climatically significant atmospheric light absorber, and as a contributor of free iron to the oceans. Here we provide global-scale constraints on their atmospheric abundance with measurements over the remote Pacific and Atlantic Oceans from aircraft campaigns spanning 10 years. We find FeOx-like aerosols are transported far from source regions with similar efficiency as black carbon particles. Strong contrast in concentrations was observed between the Northern and Southern Hemisphere Pacific. We provide observational constraints in remote regions on the ambient ratios of FeOx relative to BC from fossil fuel burning. Comparison with a global aerosol model tuned to recent observations in East-Asian source regions confirm an upward revision of emissions based on model/observation comparison over the Pacific receptor region. We find that anthropogenic FeOx-like particles generate global-scale shortwave atmospheric heating 0.3–26% of that of black carbon in remote regions where concentrations of both aerosols are very low.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Global-scale constraints on light-absorbing anthropogenic iron oxide aerosols

et al. 2021

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“…Kurisu et al (2016) reported that very low isotope ratio in fine aerosol particles, which probably signifies evaporation of Fe at high temperatures, indicating the contribution of anthropogenic Fe to the surface of the North Pacific. Therefore, Fe isotope measurements with other trace metal isotopes will be very important for quantitative understanding of the relative importance of different sources of Fe to the ocean John 2014, 2015;Kurisu et al 2016;Pinedo-González et al 2020). Future research is needed to understand the atmospheric Fe supply.…”

Section: Impact On the Phytoplankton Ecosystemmentioning

confidence: 99%

A review: iron and nutrient supply in the subarctic Pacific and its impact on phytoplankton production

et al. 2021

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One of the most important breakthroughs in oceanography in the last 30 years was the discovery that iron (Fe) controls biological production as a micronutrient, and our understanding of Fe and nutrient biogeochemical dynamics in the ocean has significantly advanced. In this review, we looked back both previous and updated knowledge of the natural Fe supply processes and nutrient dynamics in the subarctic Pacific and its impact on biological production. Although atmospheric dust has been considered to be the most important source of Fe affecting biological production in the subarctic Pacific, other oceanic sources of Fe have been discovered. We propose a coherent explanation for the biological response in subarctic Pacific high nutrient low chlorophyll (HNLC) waters that incorporates knowledge of both the atmospheric Fe supplies and the oceanic Fe supplies. Finally, we extract future directions for Fe oceanographic research in the subarctic Pacific and summarize the uncertain issues identified thus far.

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“…Iron concentrations were determined by inductively coupled plasma mass spectrometry using isotope dilution (Pinedo-González et al 2020). Particulate Fe concentrations from the 2017 cruise (Table S1) were filtered onto a 0.2 μm Supor® membrane (MilliporeSigma, Burlington, MA, USA) and digested at high temperature in 50% nitric acid, as described by Hawco et al (2020a).…”

Section: Eddy Identification and Characterization On Three Npsg Cruisesmentioning

confidence: 99%

Nitrogen fixation in mesoscale eddies of the North Pacific Subtropical Gyre: patterns and mechanisms

Dugenne

et al. 2021

Preprint

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Recent studies suggest that mesoscale eddies may support elevated dinitrogen (N2) fixation rates (NFRs) and abundances of N2-fixing microorganisms (diazotrophs), yet the strength and mechanistic underpinnings of this trend are not fully understood. We explored the relationships among NFRs, cyanobacterial diazotroph abundances, and environmental conditions of mesoscale eddies by sampling three pairs of eddies of opposite polarity in the North Pacific Subtropical Gyre. Using the Hawaii Ocean Time-series for historical context, we found that NFRs were anomalously high (up to 18.6 nmol N L-1 d-1) in the centers of two anticyclones. The highest NFR was linked to a positive anomaly in Crocosphaera abundance. To unravel the main processes and players, we used high-resolution abundance data, metatranscriptomes, deck-board incubations, and population models to evaluate three mechanisms for each diazotroph population: bottom-up control, top-down control, and physical control. Based on cell division and grazing rate estimates, Crocosphaera anomalies appeared to be partially driven by both bottom-up control (due to elevated surface phosphate concentration promoting high growth rates) and top-down control (reduced grazing pressure from putative predators). In contrast, although large, buoyant Trichodesmium and symbionts of diatoms (Richelia ) appeared to have accumulated at the fronts between cyclonic and anticyclonic eddies, they had lower growth rates and contributed less to bulk NFRs. Together, the interplay of these three complex mechanisms may explain reports of elevated diazotroph abundances and NFRs associated with anticyclones and eddy fronts.

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Anthropogenic Asian aerosols provide Fe to the North Pacific Ocean

Cited by 72 publications

References 59 publications

Global-scale constraints on light-absorbing anthropogenic iron oxide aerosols

Global-scale constraints on light-absorbing anthropogenic iron oxide aerosols

A review: iron and nutrient supply in the subarctic Pacific and its impact on phytoplankton production

Nitrogen fixation in mesoscale eddies of the North Pacific Subtropical Gyre: patterns and mechanisms

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