Inferring episodic atmospheric iron fluxes in the Western South Atlantic

Evangelista, Heitor; Maldonado, Juan Gabriel García; Santos, Elaine Alves dos; Godoi, Ricardo H. M.; Garcia, Carlos Alberto Eiras; Tavano, Virgínia Maria; Jonhson, Erling; Cunha, K. Dias da; Leite, Carlos Barros; Grieken, R. Van; Meel, K. Van; Makarovska, Yaroslava; Gaiero, Diego M.

doi:10.1016/j.atmosenv.2009.11.018

Cited by 8 publications

(8 citation statements)

References 35 publications

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“…In the northern gyre provinces (NATR and NAST), where deposition and dissolution of atmospheric aerosols is the dominant source of Fe (e.g. Duce and Tindale, 1991;Duce et al 1991;Sarthou et al, 2003;Jickells et al, 2005;Baker et al, 2006;Buck et al, 2010;Evangelista et al, 2010;Ussher et al, 2013), the extremely low concentrations of dCo contrast strongly with the relatively high concentrations of dFe. A number of studies have alluded to an atmospheric source of Co which could influence surface dCo concentrations in regions of high atmospheric deposition (Bowie et al 2002;Dulaquais et al, 2014a;Knauer et al, 1982;Thuroczy et al, 2010;Wong et al 1995).…”

Section: Discussionmentioning

confidence: 99%

“…A major vector of trace elements (TEs) to Atlantic surface waters is atmospheric deposition (Jickells et al, 2005;Baker et al, 2006;Sarthou et al, 2007;Buck et al, 2010;Evangelista et al, 2010;Ussher et al, 2013;Shelley et al, 2015), much of which originates from Northwest Africa (Prospero and Carlton, 1972). An estimated 240 ± 80 Tg of dust is transported westwards annually (Kaufman et al, 2005), primarily during the summer months.…”

Section: Introductionmentioning

confidence: 99%

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A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

Shelley

Wyatt

Tarran

et al. 2017

Progress in Oceanography

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00000International audienceCobalt (Co) and iron (Fe) are essential for phytoplankton nutrition, and as such constitute a vital link in the marine biological carbon pump. Atmospheric deposition is an important, and in some places the dominant, source of trace elements (TEs) to the global ocean. Dissolved cobalt (dCo) and iron (dFe) were determined along an Atlantic Meridional Transect (AMT-19; Oct/Nov 2009) between 50°N and 40°S in the upper 150 m in order to investigate the behaviour and distribution of these two essential, bioactive TEs. During AMT-19, large differences in the distributions of dCo and dFe were observed. In the North Atlantic gyre provinces, extremely low mixed layer dCo concentrations (23 ± 9 pM) were observed, which contrasts with the relatively high mixed layer dFe concentrations (up to 1.0 nM) coincident with the band of highest atmospheric deposition (∼5–30°N). In the South Atlantic gyre, the opposite trend was observed, with relatively high dCo (55 ± 18 pM) observed throughout the water column, but low dFe concentrations (0.29 ± 0.08 nM). Given that annual dust supply is an order of magnitude greater in the North than the South Atlantic, the dCo distribution was somewhat unexpected. However, the distribution of dCo shows similarities with the distribution of phosphate (PO43−) in the euphotic zone of the Atlantic Ocean, where the North Atlantic gyre is characterised by chronically low PO4, and higher concentrations are observed in the South Atlantic gyre (Mather et al., 2008), suggesting the potential for a similar biological control of dCo distributions. Inverse correlations between dCo and Prochlorococcus abundance in the North Atlantic gyre provinces, combined with extremely low dCo where nitrogen fixation rates were highest (∼20–28°N), suggests the dominance of biological controls on dCo distributions. The contrasting dCo and dFe distributions in the North and South Atlantic gyres provides insights into the differences between the dominant controls on the distribution of these two bioactive trace metals in the central Atlantic Ocean

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

Shelley

Wyatt

Tarran

et al. 2017

Progress in Oceanography

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“…The low aerosol flux to the equatorial South Atlantic leads to both lower rates of N 2 fixation [ Moore et al ., ] and lower abundances of the N 2 ‐fixing, colonial cyanobacterium Trichodesmium [ Tyrrell et al ., ] in the South Atlantic than in the iron rich North Atlantic. Patagonian dust may also be an important source of Fe to the South Atlantic and Atlantic sector of the Southern Ocean [ Evangelista et al ., ; Johnson et al ., ]. However along the continental shelf of South America, iron is supplied in roughly equivalent amounts from the atmosphere and coastal erosion, with a minor riverine component [ Gaiero et al ., ; Gaiero et al ., ].…”

Section: Atlantic Meridional Transect–dust Impacts On Biologymentioning

confidence: 97%

Basin scale survey of marine humic fluorescence in the Atlantic: Relationship to iron solubility and H₂O₂

Heller

Gaiero

Croot

2013

Global Biogeochemical Cycles

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.[1] Iron (Fe) is a limiting nutrient for phytoplankton productivity in many different oceanic regions. A critical aspect underlying iron limitation is its low solubility in seawater as this controls the distribution and transport of iron through the ocean. Processes which enhance the solubility of iron in seawater, either through redox reactions or organic complexation, are central to understanding the biogeochemical cycling of iron. In this work we combined iron solubility measurements with parallel factor (PARAFAC) data analysis of Coloured Dissolved Organic Matter (CDOM) fluorescence along a meridional transect through the Atlantic (PS ANT XXVI-4) to examine the hypothesis that marine humic fluorescence is a potential proxy for iron solubility in the surface ocean. PARAFAC analysis revealed 4 components (C1-4), two humic like substances (C2&4) and two protein-like (C1&3). Overall none of the 4 components were significantly correlated with iron solubility, though humic-like components were weakly correlated with iron solubility in iron replete waters. Our analysis suggests that the ligands responsible for maintaining iron in solution in the euphotic zone are sourced from both remineralisation processes and specific ligands produced in response to iron stress and are not easily related to bulk CDOM properties. The humic fluorescence signal was sharply attenuated in surface waters presumably most likely due to photo bleaching, though there was only a weak correlation with the transient photo product H 2 O 2 , suggesting longer lifetimes in the photic zone for the fluorescent components identified here.

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“…Our interpretations were based on the averaged monthly ANC data, which covered a period long enough to include secondary processes from chl a blooming to aerosol formation. A contribution of dust micro-particles eroded from the Argentine Patagonian semi-desert to the ANC, although not discarded, is probably of lesser importance to the annual variability, since the flux of dust into the southern latitudes is episodic (Evangelista et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Potential source regions of biogenic aerosol number concentration apportioning at King George Island, Antarctic Peninsula

Alencar

Evangelista²,

Santos³

et al. 2010

Antarctic Science

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Abstract:Nowadays it is well accepted that background aerosols in the boundary layer over remote oceans are of marine origin and not aged continental. Particularly in the Atlantic sector of the Southern Ocean at least four main important regions exhibit significant ocean primary productivity. They are the Bellingshausen-Amundsen Sea, the Weddell Sea, the southern Argentinean shelf and the southern Chilean coast. In this work, we have combined ground-based continuous atmospheric sampling of aerosol number concentration (ANC), over-sea dimethyl sulphide (DMS) measurements, chlorophyll a (chl a) concentration provided by Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite images, in situ meteorological data and monthly regional NCEP-NCAR re-analysis wind fields in order to investigate the relative contribution of each of the above regions to the apportionment of the ANC at King George Island (KGI), South Shetland Islands. Our results suggest that, at least during the period from September 1998-December 1999, the southern Argentinean shelf acted as the main contributor to the ANC measured in KGI.

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Inferring episodic atmospheric iron fluxes in the Western South Atlantic

Cited by 8 publications

References 35 publications

A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

Basin scale survey of marine humic fluorescence in the Atlantic: Relationship to iron solubility and H₂O₂

Potential source regions of biogenic aerosol number concentration apportioning at King George Island, Antarctic Peninsula

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Inferring episodic atmospheric iron fluxes in the Western South Atlantic

Cited by 8 publications

References 35 publications

A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

Basin scale survey of marine humic fluorescence in the Atlantic: Relationship to iron solubility and H2O2

Potential source regions of biogenic aerosol number concentration apportioning at King George Island, Antarctic Peninsula

Contact Info

Product

Resources

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Basin scale survey of marine humic fluorescence in the Atlantic: Relationship to iron solubility and H₂O₂