Post on 16-Apr-2017
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
40
50
60
70
80
90
100
mass(
g/m
3)
1
2
3
4
5
6
7
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
2
3
4
5
6
7
8
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 .