Linking variations in sea spray aerosol particle hygroscopicity to
composition during two microcosm experiments

Abstract. The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 %) measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer) and single particle (using an aerosol time-of-flight mass spectrometer) measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 %) values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 %) depression and the peak chlorophyll a (Chl a) concentrations by either 1 (indoor MART) or 3-to-6 (outdoor MART) days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 %) values (relative to pure sea salt) is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM) comprising the SSA. The GF(85 %) values exhibited a reasonable negative correlation with the SSA NR-OM volume fractions after the peak of the blooms (i.e., Chl a maxima); i.e., the GF(85 %) values generally decreased when the NR-OM volume fractions increased. The GF(85 %) vs. NR-OM volume fraction relationship was interpreted using the Zdanovskii–Stokes–Robinson (ZSR) mixing rule and used to estimate the GF(85 %) of the organic matter in the nascent SSA. The estimated pure NR-OM GF(85 %) values were 1.16 ± 0.09 and 1.23 ± 0.10 for the indoor and outdoor MARTS, respectively. These measurements demonstrate a clear relationship between SSA particle composition and the sensitivity of light scattering to variations in relative humidity. The implications of these observations to the direct climate effects of SSA particles are discussed.

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Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

10.5194/acp-2016-36 ◽

2016 ◽

Author(s):

Sara D. Forestieri ◽

Gavin C. Cornwell ◽

Taylor M. Helgestad ◽

Kathryn A. Moore ◽

Christopher Lee ◽

...

Keyword(s):

Light Scattering ◽

Relative Humidity ◽

Salt Content ◽

Sea Salt ◽

Sea Spray ◽

Hygroscopic Growth ◽

Phytoplankton Blooms ◽

Aerosol Composition ◽

Sea Spray Aerosol ◽

Indoor And Outdoor

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A Dynamic Link between Ice Nucleating Particles Released in Nascent Sea Spray Aerosol and Oceanic Biological Activity during Two Mesocosm Experiments

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-16-0087.1 ◽

2017 ◽

Vol 74 (1) ◽

pp. 151-166 ◽

Cited By ~ 46

Author(s):

Christina S. McCluskey ◽

Thomas C. J. Hill ◽

Francesca Malfatti ◽

Camille M. Sultana ◽

Christopher Lee ◽

...

Keyword(s):

Biological Activity ◽

Heterotrophic Bacteria ◽

Phytoplankton Bloom ◽

Sea Spray ◽

Emission Rates ◽

Phytoplankton Blooms ◽

Aerosol Composition ◽

Chl A ◽

Mesocosm Experiments ◽

Sea Spray Aerosol

Abstract Emission rates and properties of ice nucleating particles (INPs) are required for proper representation of aerosol–cloud interactions in atmospheric models. Few investigations have quantified marine INP emissions, a potentially important INP source for remote oceanic regions. Previous studies have suggested INPs in sea spray aerosol (SSA) are linked to oceanic biological activity. This proposed link was explored in this study by measuring INP emissions from nascent SSA during phytoplankton blooms during two mesocosm experiments. In a Marine Aerosol Reference Tank (MART) experiment, a phytoplankton bloom was produced with chlorophyll-a (Chl a) concentrations reaching 39 μg L−1, while Chl a concentrations more representative of natural ocean conditions were obtained during the Investigation into Marine Particle Chemistry and Transfer Science (IMPACTS; peak Chl a of 5 μg L−1) campaign, conducted in the University of California, San Diego, wave flume. Dynamic trends in INP emissions occurred for INPs active at temperatures > −30°C. Increases in INPs active between −25° and −15°C lagged the peak in Chl a in both studies, suggesting a consistent population of INPs associated with the collapse of phytoplankton blooms. Trends in INP emissions were also compared to aerosol composition, abundances of microbes, and enzyme activity. In general, increases in INP concentrations corresponded to increases in organic species in SSA and the emissions of heterotrophic bacteria, suggesting that both microbes and biomolecules contribute to marine INP populations. INP trends were not directly correlated with a single biological marker in either study. Direct measurements of INP chemistry are needed to accurately identify particles types contributing to marine INP populations.

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Phytoplankton blooms weakly influence the cloud forming ability of sea spray aerosol

Geophysical Research Letters ◽

10.1002/2016gl069922 ◽

2016 ◽

Vol 43 (18) ◽

pp. 9975-9983 ◽

Cited By ~ 29

Author(s):

Douglas B. Collins ◽

Timothy H. Bertram ◽

Camille M. Sultana ◽

Christopher Lee ◽

Jessica L. Axson ◽

...

Keyword(s):

Sea Spray ◽

Phytoplankton Blooms ◽

Sea Spray Aerosol

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Effect of primary organic sea spray emissions on cloud condensation nuclei concentrations

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-89-2012 ◽

2012 ◽

Vol 12 (1) ◽

pp. 89-101 ◽

Cited By ~ 46

Author(s):

D. M. Westervelt ◽

R. H. Moore ◽

A. Nenes ◽

P. J. Adams

Keyword(s):

Surface Tension ◽

Southern Ocean ◽

Source Function ◽

Cloud Condensation Nuclei ◽

Organic Aerosol ◽

Sea Salt ◽

Sea Spray ◽

Aerosol Emission ◽

Sea Spray Aerosol ◽

Surfactant Effects

Abstract. This work estimates the primary marine organic aerosol global emission source and its impact on cloud condensation nuclei (CCN) concentrations by implementing an organic sea spray source function into a series of global aerosol simulations. The source function assumes that a fraction of the sea spray emissions, depending on the local chlorophyll concentration, is organic matter in place of sea salt. Effect on CCN concentrations (at 0.2% supersaturation) is modeled using the Two-Moment Aerosol Sectional (TOMAS) microphysics algorithm coupled to the GISS II-prime general circulation model. The presence of organics affects CCN activity in competing ways: by reducing the amount of solute available in the particle and decreasing surface tension of CCN. To model surfactant effects, surface tension depression data from seawater samples taken near the Georgia coast were applied as a function of carbon concentrations. A global marine organic aerosol emission rate of 17.7 Tg C yr−1 is estimated from the simulations. Marine organics exert a localized influence on CCN(0.2%) concentrations, decreasing regional concentrations by no more than 5% and by less than 0.5% over most of the globe, assuming direct replacement of sea salt aerosol with organic aerosol. The decrease in CCN concentrations results from the fact that the decrease in particle solute concentration outweighs the organic surfactant effects. The low sensitivity of CCN(0.2%) to the marine organic emissions is likely due to the small compositional changes: the mass fraction of OA in accumulation mode aerosol increases by only ~15% in a biologically active region of the Southern Ocean. To test the sensitivity to uncertainty in the sea spray emissions process, we relax the assumption that sea spray aerosol number and mass remain fixed and instead can add to sea spray emissions rather than replace existing sea salt. In these simulations, we find that marine organic aerosol can increase CCN by up to 50% in the Southern Ocean and 3.7% globally during the austral summer. This vast difference in CCN impact highlights the need for further observational exploration of the sea spray aerosol emission process as well as evaluation and development of model parameterizations.

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Wind speed dependent size-resolved parameterization for the organic mass fraction of sea spray aerosol

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-8777-2011 ◽

2011 ◽

Vol 11 (16) ◽

pp. 8777-8790 ◽

Cited By ~ 100

Author(s):

B. Gantt ◽

N. Meskhidze ◽

M. C. Facchini ◽

M. Rinaldi ◽

D. Ceburnis ◽

...

Keyword(s):

Chemical Composition ◽

Wind Speed ◽

Organic Carbon ◽

Mass Fraction ◽

Surface Wind ◽

Surface Wind Speed ◽

Sea Spray ◽

Organic Mass ◽

Chl A ◽

Sea Spray Aerosol

Abstract. For oceans to be a significant source of primary organic aerosol (POA), sea spray aerosol (SSA) must be highly enriched with organics relative to the bulk seawater. We propose that organic enrichment at the air-sea interface, chemical composition of seawater, and the aerosol size are three main parameters controlling the organic mass fraction of sea spray aerosol (OMSSA). To test this hypothesis, we developed a new marine POA emission function based on a conceptual relationship between the organic enrichment at the air-sea interface and surface wind speed. The resulting parameterization is explored using aerosol chemical composition and surface wind speed from Atlantic and Pacific coastal stations, and satellite-derived ocean concentrations of chlorophyll-a, dissolved organic carbon, and particulate organic carbon. Of all the parameters examined, a multi-variable logistic regression revealed that the combination of 10 m wind speed and surface chlorophyll-a concentration ([Chl-a]) are the most consistent predictors of OMSSA. This relationship, combined with the published aerosol size dependence of OMSSA, resulted in a new parameterization for the organic mass fraction of SSA. Global emissions of marine POA are investigated here by applying this newly-developed relationship to existing sea spray emission functions, satellite-derived [Chl-a], and modeled 10 m winds. Analysis of model simulations shows that global annual submicron marine organic emission associated with sea spray is estimated to be from 2.8 to 5.6 Tg C yr−1. This study provides additional evidence that marine primary organic aerosols are a globally significant source of organics in the atmosphere.

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Global scale emission and distribution of sea-spray aerosol: Sea-salt and organic enrichment

Atmospheric Environment ◽

10.1016/j.atmosenv.2009.11.013 ◽

2010 ◽

Vol 44 (5) ◽

pp. 670-677 ◽

Cited By ~ 148

Author(s):

E. Vignati ◽

M.C. Facchini ◽

M. Rinaldi ◽

C. Scannell ◽

D. Ceburnis ◽

...

Keyword(s):

Global Scale ◽

Sea Salt ◽

Organic Enrichment ◽

Sea Spray ◽

Sea Spray Aerosol

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The Impact of Divalent Cations on the Enrichment of Soluble Saccharides in Primary Sea Spray Aerosol

Atmosphere ◽

10.3390/atmos9120476 ◽

2018 ◽

Vol 9 (12) ◽

pp. 476 ◽

Cited By ~ 6

Author(s):

Steven Schill ◽

Susannah Burrows ◽

Elias Hasenecz ◽

Elizabeth Stone ◽

Timothy Bertram

Keyword(s):

Divalent Cation ◽

Organic Material ◽

Large Fraction ◽

Co Adsorption ◽

Sea Spray ◽

Surface Microlayer ◽

Volume Fractions ◽

Sea Surface Microlayer ◽

Sea Spray Aerosol ◽

The Impact

Field measurements have shown that sub-micrometer sea spray aerosol (SSA) is significantly enriched in organic material, of which a large fraction has been attributed to soluble saccharides. Existing mechanistic models of SSA production struggle to replicate the observed enhancement of soluble organic material. Here, we assess the role for divalent cation mediated co-adsorption of charged surfactants and saccharides in the enrichment of soluble organic material in SSA. Using measurements of particle supersaturated hygroscopicity, we calculate organic volume fractions for molecular mimics of SSA generated from a Marine Aerosol Reference Tank. Large enhancements in SSA organic volume fractions (Xorg > 0.2) were observed for 50 nm dry diameter (dp) particles in experiments where cooperative ionic interactions were favorable (e.g., palmitic acid, Mg2+, and glucuronic acid) at seawater total organic carbon concentrations (<1.15 mM C) and ocean pH. Significantly smaller SSA organic volume fractions (Xorg < 1.5 × 10−3) were derived from direct measurements of soluble saccharide concentrations in collected SSA with dry diameters <250 nm, suggesting that organic enrichment is strongly size dependent. The results presented here indicate that divalent cation mediated co-adsorption of soluble organics to insoluble surfactants at the ocean surface may contribute to the enrichment of soluble saccharides in SSA. The extent to which this mechanism explains the observed enhancement of saccharides in nascent SSA depends strongly on the concentration, speciation, and charge of surfactants and saccharides in the sea surface microlayer.

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Model evaluation of marine primary organic aerosol emission schemes

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-8553-2012 ◽

2012 ◽

Vol 12 (18) ◽

pp. 8553-8566 ◽

Cited By ~ 24

Author(s):

B. Gantt ◽

M. S. Johnson ◽

N. Meskhidze ◽

J. Sciare ◽

J. Ovadnevaite ◽

...

Keyword(s):

Model Comparison ◽

Transport Model ◽

Organic Aerosol ◽

Sea Spray ◽

Mean Values ◽

Chl A ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Aerosol Emission ◽

Sea Spray Aerosol

Abstract. In this study, several marine primary organic aerosol (POA) emission schemes have been evaluated using the GEOS-Chem chemical transport model in order to provide guidance for their implementation in air quality and climate models. These emission schemes, based on varying dependencies of chlorophyll a concentration ([chl a]) and 10 m wind speed (U10), have large differences in their magnitude, spatial distribution, and seasonality. Model comparison with weekly and monthly mean values of the organic aerosol mass concentration at two coastal sites shows that the source function exclusively related to [chl a] does a better job replicating surface observations. Sensitivity simulations in which the negative U10 and positive [chl a] dependence of the organic mass fraction of sea spray aerosol are enhanced show improved prediction of the seasonality of the marine POA concentrations. A top-down estimate of submicron marine POA emissions based on the parameterization that compares best to the observed weekly and monthly mean values of marine organic aerosol surface concentrations has a global average emission rate of 6.3 Tg yr−1. Evaluation of existing marine POA source functions against a case study during which marine POA contributed the major fraction of submicron aerosol mass shows that none of the existing parameterizations are able to reproduce the hourly-averaged observations. Our calculations suggest that in order to capture episodic events and short-term variability in submicron marine POA concentration over the ocean, new source functions need to be developed that are grounded in the physical processes unique to the organic fraction of sea spray aerosol.

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The impact of atmospheric oxidation on hygroscopicity and cloud droplet activation of inorganic sea spray aerosol

Scientific Reports ◽

10.1038/s41598-021-89346-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Bernadette Rosati ◽

Sigurd Christiansen ◽

Anders Dinesen ◽

Pontus Roldin ◽

Andreas Massling ◽

...

Keyword(s):

Growth Factor ◽

Uv Light ◽

Cloud Droplet ◽

Sea Salt ◽

Sea Spray ◽

Hygroscopic Growth ◽

Activation Potential ◽

Sea Spray Aerosol ◽

Cloud Activation ◽

The Impact

AbstractSea spray aerosol (SSA) contributes significantly to natural aerosol particle concentrations globally, in marine areas even dominantly. The potential changes of the omnipresent inorganic fraction of SSA due to atmospheric ageing is largely unexplored. In the atmosphere, SSA may exist as aqueous phase solution droplets or as dried solid or amorphous particles. We demonstrate that ageing of liquid NaCl and artificial sea salt aerosol by exposure to ozone and UV light leads to a substantial decrease in hygroscopicity and cloud activation potential of the dried particles of the same size. The results point towards surface reactions on the liquid aerosols that are more crucial for small particles and the formation of salt structures with water bound within the dried aerosols, termed hydrates. Our findings suggest an increased formation of hydrate forming salts during ageing and the presence of hydrates in dried SSA. Field observations indicate a reduced hygroscopic growth factor of sub-micrometre SSA in the marine atmosphere compared to fresh laboratory generated NaCl or sea salt of the same dry size, which is typically attributed to organic matter or sulphates. Aged inorganic sea salt offers an additional explanation for such a measured reduced hygroscopic growth factor and cloud activation potential.

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Atmospheric Ageing of Inorganic Sea Spray Aerosol: Implications for Hygroscopicity and Cloud Activation Potential

10.21203/rs.3.rs-127699/v1 ◽

2020 ◽

Author(s):

Bernadette Rosati ◽

Sigurd Christiansen ◽

Anders Dinesen ◽

Pontus Roldin ◽

Andreas Massling ◽

...

Keyword(s):

Uv Light ◽

Sea Salt ◽

Sea Spray ◽

Hygroscopic Growth ◽

Sea Salt Aerosol ◽

Activation Potential ◽

Sea Spray Aerosol ◽

Marine Areas ◽

Cloud Activation ◽

Additional Explanation

Abstract Sea spray aerosol (SSA) contributes significantly to natural aerosol particle concentrations globally, in marine areas even dominantly. The potential changes of the omnipresent inorganic fraction of SSA due to atmospheric ageing is largely unexplored. We demonstrate that ageing of liquid NaCl and artificial sea salt aerosol by exposure to ozone and UV light leads to a substantial decrease in hygroscopicity and cloud activation potential. The results point towards surface reactions that are more crucial for small particles and the formation of salt structures with water bound within the aerosols, termed hydrates. Our findings suggest an increased formation of hydrate forming salts during ageing and the presence of hydrates in dried SSA. Field observations indicate a reduced hygroscopic growth of sub-micrometre SSA in the marine atmosphere compared to pure NaCl which is typically attributed to organic matter or sulphates. Aged inorganic sea salt offers an additional explanation for reduced hygroscopicity and cloud activation potential.

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