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Marine aerosol properties in the Mediterranean : a mesocosm study. Allison Schwier , Clémence Rose, Eija Asmi *, Karine Sellegri Laboratoire de Météorologie Physique * Finnish Meteorological Institute Frederic Gazeau , Cécile Guieu
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Marine aerosolproperties in the Mediterranean: a mesocosmstudy Allison Schwier, Clémence Rose, EijaAsmi*, Karine Sellegri Laboratoire de Météorologie Physique *FinnishMeteorological Institute FredericGazeau, Cécile Guieu Laboratoire d'Oceanographie de Villefranche-sur-mer
MediterraneanSea What are the properties of primary marine aerosolfrom the Mediterranean? • Oligotrophicenvironment • yetthere are seasonal blooms D’Ortenzio & Ribera d’AlcalàBiogeosciences 2009
STARESO, Calvi, Corsica Villefranche-sur-mer, France February – March, 2013 BLOOM conditions June – July, 2012 NON – bloom conditions 3
Experimental ProcedureBubble-bursting apparatus Cloud Condensation NucleiCounter (CCNc) Impacter Filters SMPS Sea Surface microlayer Multiple biogeochemicalmeasurements (pigments, nutrients, bacteria, etc.) sea-air aerosol flux Based on work of Fuentes et al., AMT 2010 5
Chlorophyll Concentrations NON-BLOOM BLOOM 6
Size Distributions 4 modes, includes enriched samples and different supersaturations 39 nm (0.29) 18 nm (0.32) 92 nm (0.28) 260 nm (0.11) 37 nm (0.48) 20 nm (0.19) 92 nm (0.24) 260 nm (0.9) Fuentes et al., 2010 saw with artificial sea water: 14nm (0.38), 48nm (0.32), 124nm (0.17), 334nm (0.13) 7
Number Mode Distributions During bloom conditions, large fractional increase of the 2nd mode, Aitken mode 8
Organic Fraction Organic Fractionaverage = 0.24±0.14 Organic Fractionaverage = 0.64±0.11 κ = κorgεorg + κinorgεinorg κ = hygroscopicity parameter (Petters and Kreidenweis ACP 2007) κinorg=1.25 (Collins et al., JGR 2013; Prathers et al., PNAS 2013) 9
CorrelationwithChlorophyll a Many groups have found linear correlations with chlorophyll Also exponential fitting (Gantt et al., 2011) Langmuir functional relationship (Long et al., 2011) 10
Heterotrophes, Virus-LikeParticles and TEP (transparent exopolymerparticles) Agrees with Prather et al., 2013 12
Organic Fraction Organic Fractionaverage = 0.24±0.14 Organic Fractionaverage = 0.64±0.11 No enhancement from enriched microlayer 14
Summary • Size distributions show a large increase in mode 2 (Aitken mode) during bloom period • This could be linked to increasing organic fraction • Sigmoidal correlation with chlorophyll a and other pigments • Additional weaker correlations with virus, heterotrophs and TEPs What does this tell us about marine aerosol? Aerosol size, and thus CCN, seems to be linked more strongly to physical properties than chemical 15
Acknowledgements: LaMP: Clémence Rose, EijaAsmi, KarineSellegri Villefranche-sur-mer (LOV): Frederic Gazeau, CécileGuieu Microlayer data: AlinaEbeling, William Landing (Florida State University) Pigment data: Hervé Claustre, Joséphine Ras, Mustapha Ouhssain (LOV) TEPs: Maria-LuizaPedrotti (LOV), Francesca Iuculano and Susana Agusti (Instituto Mediterráneo de Estudios Avanzados (IMEDEA), Mallorca, Spain) Bacteria, Viruses: Anastasia Tsiola (Hellenic Centre for Marine Research (HCMR), Crete, Greece) 16