Dissolved organic matter in sea spray: a transfer study from marine surface water to aerosols

Abstract

Abstract. Atmospheric aerosols impose direct and indirect effects on the climate system, for example, by absorption of radiation in relation to cloud droplets size, on chemical and organic composition and cloud dynamics. The first step in the formation of Organic primary aerosols, i.e. the transfer of dissolved organic matter from the marine surface into the atmosphere, was studied. We present a molecular level description of this phenomenon using the high resolution analytical tools of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR). Our experiments confirm the chemoselective transfer of natural organic molecules, especially of aliphatic compounds from the surface water into the atmosphere via bubble bursting processes. Transfer from marine surface water to the atmosphere involves a chemical gradient governed by the physicochemical properties of the involved molecules when comparing elemental compositions and differentiating CHO, CHNO, CHOS and CHNOS bearing compounds. Typical chemical fingerprints of compounds enriched in the aerosol phase were CHO and CHOS molecular series, smaller molecules of higher aliphaticity and lower oxygen content, and typical surfactants. A nontargeted metabolomics analysis demonstrated that many of these molecules corresponded to homologous series of oxo-, hydroxy-, methoxy-, branched fatty acids and mono-, diand tricarboxylic acids as well as monoterpenes and sugars. These surface active biomolecules were preferentially transferred from surface water into the atmosphere via bubble bursting processes to form a significant fraction of primary organic aerosols. This way of sea spray production leaves a selective biological signature of the surface water in the corresponding aerosol that may be transported into higher altitudes up to the lower atmosphere, thus contributing to the formation of secondary organic aerosol on a global scale or transported laterally with possible deposition in the context of global biogeocycling.

Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

“…Sucrose, fructose and glucose originate from plant materials such as pollen, fruits, and their fragments (Speranza et al, 1997;Baker et al, 1998;Pacini, 2000). It should be noted that surface seawater also contains a large amount of organics, ranging from small organic acids, sugars to large molecular weight proteins, which can be emitted into the MBL through bubble bursting processes in remote oceans (Leck and Bigg, 2005;Facchini et al, 2008;Sempéré et al, 2008;Hawkins and Russell, 2010;Schmitt-Kopplin et al, 2012). However, the Beaufort Sea was oligotrophic in summer with low levels of biological activities during the MALINA cruise, which was characterized with low levels of Chl a (Table 1).…”

New particle formation above a simulated salt lake in aerosol chamber experiments

“…Therefore, the samples were desalted before analysis by extracting the filters with water and enriching the organic matter by solid phase extraction (SPE) using using BAKERBOND spe Octadecyl (C18) Disposable Extraction Columns (Avantor, Center Valley, PA, USA). [38] A blank SPE extract of a non-loaded filter was also analysed by FT-ICR/MS and did not show significant contamination from the filter material.…”

Molecular characteristics of the water soluble organic matter in size-fractionated aerosols collected over the North Atlantic Ocean

“…Recently, electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR-MS) has been used to successfully characterize a large fraction of complex water soluble organic matter (WSOM) in aerosols at the molecular level (e.g., Duarte and Duarte, 2011;Reemtsma et al, 2006;Schmitt-Kopplin et al, 2012;Wozniak et al, 2008Wozniak et al, , 2014, but to our knowledge, none have examined size-fractionated marine aerosol samples. Considering the fact that significant chemical differences, which show distinct impacts in the atmosphere, have been noted previously for size-fractionated aerosol OM, it is clear that the application of ESI FTICR-MS for aerosol OM characterization of size-fractionated aerosols will advance our understanding of aerosol OM environmental impacts.…”