Chemical characterisation of marine aerosol at Amsterdam Island during the austral summer of 2006–2007
Introduction
A chemical characterisation was carried out of marine aerosols that were collected at Amsterdam Island in the southern Indian Ocean during a period of high biogenic activity. The aim of the study was to examine whether the remote ocean is an important source of secondary organic aerosol (SOA) from biogenic origin that could serve as cloud condensation nuclei (CCN). It is well-known that oceanic areas of high primary productivity emit dimethylsulphide (DMS) (Kettle & Andreae, 2000), which is converted into submicrometer-sized sulphate and methanesulphonate aerosols within the atmosphere, and that these aerosols can affect cloud albedo and climate (Charlson, Lovelock, Andreae, & Warren, 1987). In addition, a comparison of satellite-derived cloud properties and radiation over and near phytoplankton blooms in the Southern Ocean (Meskhidze & Nenes, 2006) found a doubling of cloud droplet concentration over the blooms and a decrease of 15 W m−2 in short-wave radiation flux at the top of the atmosphere, suggesting that CCN production in bloom regions was greatly enhanced. This illustrates the importance of defining precisely the origin of marine CCN.
Several experimental studies have indicated the presence of significant concentrations of organic matter in marine aerosol (Cavalli et al., 2004; Facchini, Rinaldi et al., 2008; Kleefeld, Hoffer, Krivacsy, & Jennings, 2002; Middlebrook, Murphy, & Thompson, 1998; Novakov et al., 1997; O’Dowd et al., 2004). However, little is known about the chemical composition of the marine carbonaceous aerosol (Facchini, Decesari et al., 2008; Gogou, Apostolaki, & Stephanou, 1998; Kawamura & Gagosian, 1990). Primary aerosols are produced by sea spray involving a bubble bursting mechanism, while the mechanisms leading to secondary aerosols are only partially understood to date. With regard to primary components, it has been well documented by electron microscopic studies that marine aerosol particles have a complex composition and contain bacteria, virus-like particles, fragments of marine organisms, and amorphous gel-like material similar to exopolymer secretions of algae and bacteria (Leck & Bigg (2005a), Leck & Bigg (2005b)). Identified SOA components include methanesulphonate (MSA) (e.g., Ayers, Ivey, & Gillett, 1991; Saltzman, Savoie, Zika, & Prospero, 1983), dicarboxylic acids (Gogou et al., 1998; Wang, Kawamura, & Yamazaki, 2006), and dimethyl- and diethylalkylammonium salts (Facchini, Decesari et al., 2008). SOA from the photo-oxidation of isoprene produced by phytoplankton blooms has also been proposed as a potentially important marine SOA source (Meskhidze & Nenes, 2006).
Recent experimental studies on aerosol from forested areas have indicated substantial concentrations of organosulphates formed by sulphation of SOA components from the photo-oxidation of isoprene, monoterpenes and unsaturated fatty acids that contain hydroxyl or keto/aldehyde groups (Gómez-González et al., 2008; Iinuma et al., 2007; Surratt et al. (2007), Surratt et al. (2008)). These studies prompted us to evaluate whether isoprene SOA-related organosulphates, i.e., 2-methyltetrol sulphates, are present in fine marine aerosol from Amsterdam Island. Our rationale for considering the 2-methyltetrol sulphates was that the 2-methyltetrols are markers for the photo-oxidation of isoprene under low-NOx conditions (Surratt et al., 2006), such as found in a pristine marine environment, and that, if formed, they would be converted to sulphates given that fine marine aerosols contain a substantial amount of sulphate. Using liquid chromatography/mass spectrometry techniques based on negative ion electrospray ionisation [LC/(–)ESI-MS] for the sensitive detection of organosulphates, we also aimed at detecting and identifying additional polar marker compounds that are specific to the marine environment and thus to elucidate a larger fraction of the organic aerosol. It is noted in this respect that organic mass spectrometry speciation studies on marine aerosol have so far mainly been performed by resorting to gas chromatography/mass spectrometry with prior derivatisation (e.g., Gogou et al., 1998; Kawamura & Gagosian, 1990; Wang et al., 2006). With this methodology several polar and acid-sensitive analytes such as organosulphates escape detection.
Section snippets
Aerosol sampling and chemical analyses
The aerosol samples were collected at Amsterdam Island (37.48°S, 77.34°E), which is located in the southern Indian Ocean about half-way between the southern edge of Africa and the southern edge of Australia. An open-faced high-volume dichotomous sampler (HVDS) was used to collect samples in two size fractions, fine or PM2.5 [<2.5 μm aerodynamic diameter (AD)] and coarse (>2.5 μm AD) (Solomon, Moyers, & Fletcher, 1983). Double Pallflex quartz fibre filters of 102 mm diameter (pre-fired for 24 h at
Atmospheric concentrations
The idea of the double filters for each size fraction was to assess sampling artifacts for the carbonaceous and organic species (e.g., Turpin, Saxena, & Andrews, 2000). However, the back/front filter ratios were unusually large (means of typically around 0.8) for the sea salt ions, WSOC, MSA, and the dicarboxylic acids (for OC the mean back/front filter ratio was 0.4). It is likely that the aerosol contained a lot of water, that the filters became somewhat wet during the sampling, and that the
Conclusions
Our results indicate that organic aerosol for samples collected at Amsterdam Island during the austral summer of 2006–2007, a period of high biological activity, makes up less than 10% of the mass in both the fine and the coarse size fractions. Our percentage in the fine size fraction is much less than the 65% of OC (sum of WIOC+WSOC) found for submicrometer-sized aerosol during a high biological activity period at the Atlantic Ocean site of Mace Head (O’Dowd et al., 2004). On a mass basis, sea
Acknowledgements
This research was funded by the European Commission (OOMPH project), the Belgian Federal Science Policy Office (BIOSOL project), the Fund for Scientific Research—Flanders (FWO), and the French Polar Institute (AEROTRACE). The Waters UPLC-LCT Premier XT time-of-flight mass spectrometer used for accurate mass measurements was purchased in 2006 with a grant from the US National Science Foundation.
References (38)
- et al.
Chemical fingerprinting of algeanan using RuO4 oxidation
Organic Geochemistry
(2006) - et al.
Determination of organic molecular markers in marine aerosols and sediments: One-step flash chromatography compound classification and capillary gas chromatographic analysis
Journal of Chromatography A
(1998) - et al.
Importance of organic and black carbon in atmospheric aerosols at Mace Head, on the west coast of Ireland
Atmospheric Environment
(2002) - et al.
Hydroxy acids in Antarctic lake sediments and their geochemical significance
Organic Geochemistry
(1988) - et al.
Measuring and simulating particulate organics in the atmosphere: Problems and prospects
Atmospheric Environment
(2000) - et al.
Organic and elemental carbon concentrations in carbonaceous aerosols during summer and winter sampling campaigns in Barcelona, Spain
Atmospheric Environment
(2006) - et al.
Evaluation of the global oceanic isoprene source and its impacts on marine organic carbon aerosol
Atmospheric Chemistry and Physics
(2009) - et al.
Collisionally-induced dissociation mass spectra of organic sulfate anions
Journal of the Chemical Society, Perkin Transactions
(2001) - et al.
Coherence between seasonal cycles of dimethyl sulfide, methanesulfonate and sulfate in marine air
Nature
(1991) - et al.
Elemental carbon-based method for monitoring occupational exposures to particulate diesel exhaust
Aerosol Science and Technology
(1996)
Advances in identification of organic matter in marine aerosol
Journal of Geophysical Research
Oceanic phytoplankton, atmospheric sulfur, cloud albedo and climate
Nature
Size distribution of mineral aerosols at Amsterdam Island and dry deposition rates in the southern Indian Ocean
Comptes Rendus de l’Academie des Sciences, Serie II
Important source of marine secondary organic aerosol from biogenic amines
Environmental Science and Technology
Primary submicron marine aerosol dominated by insoluble organic colloids and aggregates
Geophysical Research Letters
Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/(–)electrospray ionization mass spectrometry
Journal of Mass Spectrometry
Comparison of modeled versus measured MSA:nss SO42- ratios: A global analysis
Global Biogeochemical Cycles
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