Unique ocean-derived particles serve as a proxy for changes in ocean chemistry

Abstract

[1] Oceans represent a significant natural source of gases and particles to the atmosphere. Relative to gas phase compounds, less is known regarding the influence of changes in biological activity in the ocean on the chemistry of sea spray aerosols produced in marine environments. To gain insight into the influence of ocean biology and chemistry on atmospheric aerosol chemistry, simultaneous real-time measurements were made of atmospheric aerosol size and chemical mixing-state, gas phase dimethyl sulfide (DMS), as well as seawater DMS and chlorophyll a. In three different marine environments with elevated chlorophyll a and DMS, unique Mg particles were detected containing Mg 2+ , Ca 2+ , K + , and organic carbon. These particles were segregated from sea salt particles highlighting that two subpopulations within the sea spray were being ejected from the ocean. Strong temporal correlations were observed between these unique ocean-derived particles and freshly emitted sea salt particles (R 2 = 0.86), particularly as wind speed increased to at least 10 m/s, and atmospheric DMS (R 2 = 0.76). Time series correlations between ocean measurements and atmospheric aerosol chemistry suggest that chlorophyll a and DMS serve as indicators of changes in the chemistry of the ocean, most likely an increase in organic material, which is directly reflected in the single particle mixing-state. This is the first time such real-time correlations are shown between ocean chemistry and atmospheric aerosol mixing-state. The reasons behind these observed changes in aerosol chemistry are critical for understanding the heterogeneous reactivity, water uptake, and cloud forming potential of sea spray aerosols.

Characteristics of individual particles in the atmosphere of Guangzhou by single particle mass spectrometry

“…Mass spectra of LC-EC type are dominated by the distinct carbon ion clusters ranged from m/z −120 to m/z 180, with minor ion intensities from other species. Differently, NaK-EC type shows the carbon ion clusters mainly in the negative mass spectra, combined with dominant peaks from 23 [Na] ) are present in mass spectra of Na-rich, indicating transport and evolution of sea salt particles (Gaston et al, 2011. The presence of nitrate in Na-rich particles implies the replacement of chloride by nitrate during long-range transport (Gard et al, 1998;Zhao and Gao, 2008).…”

Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

“…Since it is well known that SSA is produced by the bursting of air bubbles at the sea surface (e.g., Blanchard and Woodcock, 1957;Lewis and Schwartz, 2004;de Leeuw et al, 2011), the differences between generation methods for SSA in the laboratory differ primarily by the method of bubble production. Recent reports indicate that pneumatic atomization does not produce particles of similar physical or chemical properties to those generated by bubble bursting (Fuentes et al, 2010b;Gaston et al, 2011). Until recently, two different bubble production techniques have been utilized for laboratory studies of aerosol composition: (1) air (or N 2 ) forced through sintered glass filters ("frits") (Cloke et al, 1991;Keene et al, 2007;Wise et al, 2009;Fuentes et al, 2010b;Modini et al, 2010;Park et al, 2014), and (2) impinging water jets (Facchini et al, 2008;Fuentes et al, 2010b;Hultin et al, 2010).…”

“…Divalent cations, such as Mg 2+ or Ca 2+ , have the ability to stabilize organic supramolecular structures (Verdugo, 2012) and coordinate surface-active organic ligands at interfaces (Casillas-Ituarte et al, 2010). Magnesium has been shown to be a good tracer for SSA produced from bacteria-rich seawater and has been observed in aerosol over the ocean in association with biological activity (Gaston et al, 2011). Hence, the enrichment of Ca, Mg, and K in the 1-1.5 µm size range in the CC-SEM/EDX analysis is in good agreement with the ATOFMS results, which show an increased fraction of OC and biological particles from the sintered glass filter-generated SSA in this same size range, relative to wave production.…”

Latitudinal and Size Segregated Compositional Variability of Aerosols over the Indian and Southern Ocean during 2010 Austral Summer

“…The high loading of MSA (0.8) indicates an organic source as MSA is specifically of biogenic origin in the marine environment. Although Mg 2+ is largely of marine or continental origin, few studies suggested that small fraction of Mg 2+ in the marine environment could also be originated from biogenic sources due to their temporal correlation with DMS and Chl a (Gaston et al, 2011). This factor reflected a comparatively similar contribution over the study region ranging from 27% to 32% from SO to NIO (Fig.…”