Organics in environmental ices: sources, chemistry, and impacts

McNeill, V. Faye; Grannas, A. M.; Abbatt, Jonathan P. D.; Ammann, Markus; Ariya, Parisa A.; Bartels-Rausch, Thorsten; Dominé, Florent; Donaldson, D. J.; Guzmán, Marcelo I.; Heger, Dominik; Kahan, Tara F.; Klán, Petr; Masclin, S.; Toubin, Céline; Voisin, Didier

doi:10.5194/acpd-12-8857-2012

Cited by 13 publications

(26 citation statements)

References 232 publications

(180 reference statements)

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“…Water in the form of ice is also a predominant material in some parts of the Earth, as snowpack or sea-ice, and in the atmosphere, in the form of ice particles. Chemical reactions at air-ice interfaces of snow or sea-ice, where the exchange of major and trace gases occurs, drive large-scale environmental effects such as ozone depletion events in Polar areas, and modify the cycling of halogen gases, and of nitrogen oxides on a global scale [17][18][19][20][21][22][23]. These examples show how heterogeneous chemistry affects the oxidative capacity of the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach

et al. 2016

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Recent years have witnessed fast advancements in near ambient pressure X-ray photoelectron (NAPP) spectroscopy, which is emerging as a powerful tool for the investigation of surfaces in presence of vapors and liquids. In this paper we present a new chamber for the investigation of solid/vapor interfaces relevant to environmental and atmospheric chemistry that fits to the NAPP endstation at the Swiss Light Source. The new chamber allows for performing X-ray photoelectron spectroscopy (XPS) and electron yield near-edge X-ray absorption fine structure spectroscopy (NEXAFS) using soft, tender and hard X-ray in vacuum and in near-ambient pressures up to 20 mbar at environmentally relevant conditions of temperature and relative humidity. In addition, the flow tube design of the chamber enables the dosing of sticky reactive gases with short pressure equilibration time. The accessible photoelectron kinetic energy ranges from 2 to 7000 eV. This range allows the determination of surface and bulk electronic properties of ice and other environmental materials, such as metal oxides and frozen solutions, which are relevant to understanding atmospheric chemistry. The design of this instrument and first results on systems of great interest to the environmental and atmospheric chemistry community are presented. In particular, nearambient pressure XPS and NEXAFS, coupled to a UV-laser setup, were used to study the adsorption of water on a TiO 2 powder sample. The results are in line with previously proposed adsorption models of water on TiO 2 , and, furthermore, indicate that the concentration of water molecules tends to increase upon UV irradiation. In a second example we illustrate how NEXAFS spectroscopy measurements at the chlorine K-edge can provide new insight on the structures of eutectic and sub-eutectic frozen NaCl solutions at high and low relative humidity, respectively, indicating the formation of solution and solid NaCl phases, respectively. Finally, we demonstrate the assets of this new chamber for the dosing of sticky acidic gases and, in particular, for the investigation of formic acid uptake on ice surfaces.Keywords Metal oxides Á Ice Á Halogens Á X-ray photoelectron spectroscopy (XPS) Á Near-edge X-ray absorption fine structure (NEXAFS) Á Near ambient pressure photoemission (NAPP)

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Section: Introductionmentioning

confidence: 99%

The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach

et al. 2016

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“…Chemical reactions taking place in ice can be very different from the aqueous counterparts (Takenaka et al, 1992(Takenaka et al, , 1996Kuo et al, 2011;Kim and Choi, 2011;McNeill et al, 2012;Guzman et al, 2006Guzman et al, , 2007Boxe and Saiz-Lopez, 2008;Cheng et al, 2010). The differences in reaction are mainly ascribed to the "freeze concentration effect", which refers to the phenomenon that organic/inorganic solutes, protons, and dissolved gases are excluded from the ice crystals and subsequently concentrated in the liquid-like grain boundary region (Takenaka et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Accelerated dissolution of iron oxides in ice

2012

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Abstract. Iron dissolution from mineral dusts and soil particles is vital as a source of bioavailable iron in various environmental media. In this work, the dissolution of iron oxide particles trapped in ice was investigated as a new pathway of iron supply. The dissolution experiments were carried out in the absence and presence of various organic complexing ligands under dark condition. In acidic pH conditions (pH 2, 3, and 4), the dissolution of iron oxides was greatly enhanced in the ice phase compared to that in water. The dissolved iron was mainly in the ferric form, which indicates that the dissolution is not a reductive process. The extent of dissolved iron was greatly affected by the kind of organic complexing ligands and the surface area of iron oxides. The iron dissolution was most pronounced with high surface area iron oxides and in the presence of strong iron binding ligands. The enhanced dissolution of iron oxides in ice is mainly ascribed to the "freeze concentration effect", which concentrates iron oxide particles, organic ligands, and protons in the liquid like ice grain boundary region and accelerates the dissolution of iron oxides. The ice-enhanced dissolution effect gradually decreased when decreasing the freezing temperature from −10 to −196 • C, which implies that the presence and formation of the liquid-like ice grain boundary region play a critical role. The proposed phenomenon of enhanced dissolution of iron oxides in ice may provide a new pathway of bioavailable iron production. The frozen atmospheric ice with iron-containing dust particles in the upper atmosphere thaws upon descending and may provide bioavailable iron upon deposition onto the ocean surface.

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“…Light appropriation by infiltrating organisms has not been obvious in our boreal simulations, but may turn out to be the rule across the austral ice domain, where melting layers are often deeply colored [40,53,83,100]. Iron binding has been attributed to several subclasses of the biopolymers discussed here [35,[98][99] and some adsorb tightly to ice interfaces [3][4][5][6][7]84]. Organometallic chemistry will therefore constitute a theme for upcoming global simulations.…”

Section: Discussion: Influence On Structure and Future Directionsmentioning

confidence: 99%

“…High molecular weight material implies interfacial activity for a subset of surfactants, adhesion for some (and this is potentially irreversible), colloid formation, and much more [5][6][7]. Our mechanism deals only with first order, homogenous solid and brine.…”

Section: Discussion: Influence On Structure and Future Directionsmentioning

confidence: 99%

“…For example, chlorophyll absorption at the edge of the ice domain can amplify global warming [1] while loss of reflective coverage dramatically alters planetary albedo [2]. Organic chemistry determines key physical features of sea ice, and is now being considered dynamically in the context of global change [3][4][5][6]. Brine drainage, thermodynamics, habitat volume and nutrient retention are all controlled in part by the macromolecular content of the internal channel network [7][8].…”

Section: Introductionmentioning

confidence: 99%

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Strategies for the Simulation of Sea Ice Organic Chemistry: Arctic Tests and Development

Elliott¹,

Jeffery²,

Hunke³

et al. 2017

Preprint

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Abstract:A numerical mechanism connecting ice algal ecodynamics with the buildup of organic macromolecules is tested within modeled pan-Arctic brine channels. The simulations take place offline in a reduced representation of sea ice geochemistry. Physical driver quantities derive from the global sea ice code CICE, including snow cover, thickness and internal temperature. The framework is averaged over ten boreal biogeographic zones. Computed nutrient-light-salt limited algal growth supports grazing, mortality and carbon flow. Vertical transport is diffusive but responds to pore structure. Simulated bottom layer chlorophyll maxima are reasonable, though delayed by about a month relative to observations due to uncertainties in snow variability. Upper level biota arise intermittently during flooding events. Macromolecular concentrations are tracked as proxy proteins, polysaccharides, lipids and refractory humics. The fresh biopolymers undergo succession and removal by bacteria. Baseline organics enter solely through cell disruption, so that the internal carbon content is initially biased low. By including exudation, agreement with dissolved organic or individual biopolymer data is achieved given strong release coupled to light intensity. Detrital carbon then reaches hundreds of micromolar, sufficient to support structural changes to the ice matrix.

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Organics in environmental ices: sources, chemistry, and impacts

Cited by 13 publications

References 232 publications

The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach

The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach

Accelerated dissolution of iron oxides in ice

Strategies for the Simulation of Sea Ice Organic Chemistry: Arctic Tests and Development

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