Single-particle insights into the influence of biological activity on

sea spray aerosol mixing-state

Dr. Cassandra J. GastonMarch 18, 2014

Aerosol Time-of-Flight Mass Spectrometer (ATOFMS)

ParticleInlet

ParticleSizing

ParticleComposition

PMT

Scattering Lasers(532 nm)

EllipsoidalMirrors

Nd:YAGLaser (266 nm)Detectors

Reflectron

+ ions - ions

Gard, E. et al. (1997) Anal. Chem, 69, 4083-4091.

Inlet

Size and Chemistry of Single Particles in real-time

Chemical Fingerprints of Particle Sources and Age

Fresh SS HNO3, N2O5 Reacted SS

HCl, ClNO2

Atmospheric processing of particles from different sources in real-time

Marine Organic Material and Sea Spray Aerosol

Bigg, E.K. (2007) Environ. Chem., 4 (3), 155-161Facchini, M.C. et al. (2008) Geophys. Res. Lett., 35, L17814, doi:10.1029/2008GL034210Hawkins, L.N. & Russell, L.M. (2010) Advances in Meteorology, doi:10.1155/2010/612132Meskhidze , N. & Nenes, A. (2006) Science, 314 (5804), 1419-1423O’Dowd, C.D. et al. (2004) Nature, 431 (7009), 676-680

Low Biological Activity High Biological Activity

Sea Salt (NaCl)

Sea Salt + Organic Material

Sea Salt

Organic MaterialMicroorganismsOrganic enrichment in ejected aerosol compared to seawater due to

biological activityHow are organics mixed in sea spray?

How will this affect water uptake and cloud formation?

Observations of Unique Ocean-Derived Particles

Gaston, C.J. et al. (2011) J. Geophys. Res., 116, D18310, doi:10.1029/2010JD015289

•Shipboard measurements: INDOEX (Indian Ocean) and ACE-Asia (Pacific Ocean)•Coastal measurements: CIFEX (N. California Coast)

Evidence for a Biological Source for Mg-type Particles

Gaston, C.J. et al. (2011) J. Geophys. Res., 116, D18310, doi:10.1029/2010JD015289

Mg-type particles associated with proxies for marine biological activity

Potential Sources for Mg-type Particles

Casillas-Ituarte, N.N. (2010) PNAS, 107, 6616-6621Leck, C. & Bigg, E.K. (2005) Tellus, 57, 305-316Orellana, M.V. et al. (2011) PNAS, 103, 13612-13617Wells, M.L. (1998) Nature, 391, 530-531

MgMg

MgMg

MgMg

Sea Salt (NaCl)

Mg2+

Mg2+

Mg2+

Mg2+

Mg2+Mg2+

Mg2+

Mg2+

• Potential role of exopolymeric material on atmospheric chemistry

• Mg enrichment on particle surface could affect trace gas uptake and cloud formation

Conclusions: How Does Biological Activity Impact Sea Spray Aerosol Chemistry?

• Ambient data shows sea spray particles enriched in organic and inorganic compounds (Mg-type particles)

• Mg-type particles provide insight into single-particle diversity of sea spray aerosol influenced by biological activity– Implications for parameterizing sea spray aerosol in

climate models

Acknowledgments• Joel Thornton Funding• Kim Prather -NSF• Thornton Group -California Air• Prather Group Resources Board• NOAA/PMEL– Tim Bates– Trish Quinn

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