Oceanic biotic components, production

mechanism of organic aerosol in MBL

and cloud-climate system

Maria Cristina Facchini, Colin O'Dowd, Roberto

Danovaro

Institute of Atmospheric Sciences and Climate (ISAC)

National Research Council (CNR), Bologna, Italy.

School of Physics & Centre for Climate and Air Pollution Studies, National University of Ireland Galway, Ireland.

Department of Life and Environmental Sciences , Polytechnic University of Marche, Ancona, Italy.

Phytoplankton

DMS

H2SO4 SO4=

Marine aggregates DOM

Organics

SO4=

Sea salt

Entrainment

rate

Wind speed

Bubble bursting

Biological activity

Wind speed

Bubble bursting

Particle growth – condensation,

coagulation, cloud processing, secondary

organic aerosol formation

Biological activity

Wind speed

DMS Sea salt

Long range transport of continental

emissions in the free troposphere

Cloud Condensation Nuclei

SO2

Ocean Surface Layer Macromolecules Colloids Macrogels Microgels Phytoplankton Fragments of Organisms

Exopolymer

Gels

Aggregates, Particulates,

Macromolecules bound by

Exopolymer Gels

Phytoplankton Primary source of organic matter in the ocean

• Growth

• Grazing

• Viral lysis

“Dissolved”

Organic Matter All major classes of

carbohydrates

Consumption

by

Heterotrophic

Bacteria

Aggregation

Viruses Fragments of Organisms Organic Detritus

Ocean Photic Zone

Atmosphere Wind-driven emission from the ocean surface

Degradation by UV light or acidification

CCN

Verdugo et al, Anu. Rev. Marine Sci. 2012

Oceanic gels: a continuum between dissolved, colloidal and

particulate organic carbon

Verdugo & Santschi, Deep-Sea Research II, 2010

Hydrophilic

Hydrophobic

Brine

channels

! "#$ $ "

bacterium!

microgel!

nanogel

! "# $

gels

NaCl(s)

gels

gels

Chemistry and surface tension: WIOM,

lipo-polysaccharides and surfactants

• H-NMR analysis of FRESH GENERATED OM during bloom shows that is

mainly water insoluble and it is constituted by surface active lipopolysaccharides,

phytoplankton exudates, occurring as fine POC particles, or large colloids

(Facchini et al., 2008). Schmitt-Kopplin et al., 2013 showed that the DOM

transferred to sea spray is quite fresh (low-O) and surface active material very

different from the refractory DOM (dominated by fulvic acids)

• The surface active dynamic properties of the OM was coherent with chemistry

indicating the the presence of mostly insoluble –lipid like surfactants, very

different from marine fulvic fraction

R-DOM BB_ aerosol

Bubble bursting

experiment data

confirm transfer of

viruses and other

biogenic material,

particularly in fine

sea spray aerosol.

Role of marine virus ?

P

A

A A

A

P

P

V V

S

V

D

D

D E

E E

D

D

E

V

E

D-E

D-E

D

D-E

S

a) b)

c) d)

e)

g)

f)

h)

SEM images of sea spray

generated by bubble

bursting in the experiments

of culture tanks of filtered

seawater, inoculated with

Emiliania huxleyi and its

specific virus EhV86,

showing the effects of

interactions between algae,

prokaryotes and viruses

mass f

racti

on

(%)

10

20

30

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50

60

70

80

90

100

mass(

g/m

3)

1

2

3

4

5

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8

9

10

sea-salt NH4 nss-SO4 NO3 WSOC WIOC BC

no

t d

ete

cta

ble

SUMMER

D(m)

0.06 0.125 0.25 0.5 1 2 4 8

mass f

racti

on

(%)

0

10

20

30

40

50

60

70

80

90

100

mass(

g/m

3)

0

1

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9

10

(a) LBA period

(b) HBA period

(Sciare et al., JGR, 2009)

(O’Dowd , Facchini et al., Nature 2004)\

• Contrasting results about the relative

abundance of OM fraction in sub-micron sea

spray aerosol are present in literature:

• some ambient measurements demonstrated high

fractional OM contribution (~ 80%) (Keene et al.,

2007; Facchini et al., 2008, Ovadnevaite et al.,

2011, Sciare et al., 2007)

• while studies in different areas and in the lab

(Prather et al., 2013, Fuentes et al., 2010; 2011;

Modini et al., 2011, Quinn et al., 2014, revealed

much lower concentrations (~ 5-10%).

• Controversial is also the relationship between

the organic content of sea spray and oceanic

productivity (estimated based on Chl-a):

• Significant correlation over large space and time

scales (O’Dowd et al., 2008; Rinaldi et al., 2013)

• No correlation in-situ ambient and in laboratory

experiments (Prather et al., 2013; Quinn et al.,

2014).

• Good correlation in laboratory experiment (Prather

et al., 2015)

Large space and time scale (Rinaldi et al., 2013):

Satellite Chl-a over a wide region facing Mace Head, multi-year dataset of ambient aerosol (*)

Punctual scale (Quinn et al., 2014)

In situ measurements of Chl-a and sea spray

production(*)

*Quinn et al., 2014 concluded that OM enrichment in

sea spray is driven by more refractory DOM,

accounting for a constant 5-10% worldwide

(*) 8-days time delay between peak Chl-a and

peak OM enrichment: biochemical processing?

Significant correlation over large space and time scales

No correlation on Punctual scale

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Lag [days]

R

Chl-a

CDM

POC

Chl-a CDM POC

Om vs Cl-a : correlation Analysis

Correlation coefficient at

50-60 N and 10-20 W

as a function of the time

lag

Max correlation at:

• 8 days for Chl-a

• 10 days for CDM

• 8 days for POC

Correlation maps were obtained for each satellite product with OMSS and for each time lag

Rinaldi et al., 2013

The monthly timescale

corresponds approximately to

the 26-day bloom cycle

(induced by virus) as recently

illustrated by Lehahn et al.

(2014)

Magnitude and variation of OM

enrichment in sea spray is

clearly observed in the 3-years

AMS dataset.

Correlation with biomass

indicators is a function of the

time scale The production of OM appears to be more linked to the bloom’s decay and

cell lysis rather that life cycle. The bloom demise forms an essential

component of the climate-mediated “plankton dance” and plays an

essential role in the organic carbon cycle. This is in agreement with the

Virus infection hypothesys

O’Dowd et al., Scientific Report ,

20015 in press

Sea Spray Hygroscopicity and CCN

activation

Ovadnevaite, J.et al., (2011), Primary marine organic aerosol: A dichotomy of low hygroscopicity and high CCN activity,

Geophys. Res. Lett., 38, L21806, doi:10.1029/2011GL048869.

Sea Spray Impact on Clouds

The sea-spray has low hygroscopicity at RH<100% but are super efficient CCN, more

than sea salt or sulphates, leading to large increases in cloud droplet concentrations.

More that 400 cm-3!!!!

Ovadnevaite, et al., Primary marine organic aerosol: A dichotomy of low hygroscopicity and high CCN activity, Geophys.

Res. Lett., 38, L21806, doi:10.1029/2011GL048869.

Conclusions

• The increased correlation between OM enrichment and biological

activity indicators, as the timescale is increased, supports the concept

that the production of OM, and its enrichment in spray is strongly

correlated to the degree of surface water biological activity;

• The production of OM appears to be more linked to the bloom’s decay

and cell lysis rather that life cycle.

• OurHNMR and surface tension studies confirm that the chemical

fingerprint of OM transferred in sea spray is dominated by more fresh

and less Ox material as respect to background DOM (dominated by

fulvic acids).

• Further studies on the virus-phytoplankton-prokaryotes interactions

could contribute to explain why the phytoplankton biomass in surface

waters is a pre-requisite for the release of OM-enriched sub-micron sea

spray particles.

• The sea spray highly enriched of OC can produce highly CCN efficient

particles, strongly influencing the cloud properties

thank you….

AIR-SEA LAB PROJECT

Climate air pollution interaction in

coastal environment

Lipopolisaccharides from exudates

of Skeletonema Costatum (Kovac et

al., 2002)

Sea spray organic fraction:

HNMR characterization

•FRESH GENERATED WIOM is mainly constituted by surface active lipopolysaccharides, phytoplankton exudates, occurring as fine POC particles or large colloids .