Embed Size (px)
Citation preview
1
2013 NETCARE WORKSHOPToronto, November 18-19, 2013
Activity IIIOcean-Atmosphere Interactions
LeadersM Levasseur, N Steiner, L Miller,
Co-applicantsJ Abbatt, A Bertram, M Gosselin, J. Murphy, A-L Norman
CollaboratorsY Gratton, R Kiene, R Leaitch, J. Liggio, T Papakyriakou, M Scarratt, S Sharma,
K Prather, Staelbler, J-É Tremblay, S Vagle
2
To address key uncertainties regarding the marine sources of primary and secondary aerosols in the Arctic and how these emissions may be affected
by the decline of summer sea ice.
Aim of Activity III
3
The CLAW hypothesis
Charlson et al. 1987
4Quinn and Bates 2011
Recognising the variety of oceanic sources of aerosols for the atmosphere
5Quinn and Bates 2011
... and how the presence of sea ice affect the strength of these sources?
sea ice
6
1. What are the sources of DMS at the ice edge in spring/summer and what is controlling the strength of these sources ?
2. Can DMS escape directly through the ice and if so what is the importance of this source for the Arctic atmosphere?
3. Is the sea-surface microlayer a source of primary organic atmospheric aerosol, and what are the cloud nucleating properties of these particles?
4. What oceanic and atmospheric conditions favour particle nucleation and growth arising from oceanic emissions?
5. What is the vertical extent of new particle formation and growth events and do such events occur primarily in the atmospheric boundary layer, or do ventilated emissions above the boundary layer promote nucleation more efficiently ?
6. How might warming-induced changes in the ice cover, and the resulting increased extent of seasonal ice and ice edge, affect the production and emission of oceanic aerosols and their precursors?
Activity III Key questions
7
What are the sources of DMS at the ice edge in spring/summer and what is controlling the strength of these sources?
Contacts: Levasseur and Gosselin
Key question 1
The different sources of DMS in the Arctic in spring & summer
8
a b
e f
c
d
Martin Fortier/ArcticNet
Martin Fortier/ArcticNet
Martin Fortier/ArcticNetMartin Fortier/ArcticNet
Christian Fritsen Virginie Galindo
Levasseur 2013
10
Levasseur Nature Geoscience 2013
Potential sources of DMS in sea-ice and at the ice edge
Ubiquitous?
New and still debatedCould experience light shock!
More frequent?
11
DMSPp
air
water
(algae)
What we know about ocean DMS production
12
DMSPp
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
13
DMSPp DMS
Algal DMSP-lyases
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
14
DMSPp DMSDMSPdExudationGrazingCell lysis
Algal DMSP-lyases
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
15
DMSPp DMSDMSPdExudationGrazingCell lysis
Algal DMSP-lyases
Algal uptake
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
16
DMSPp DMSDMSPdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Algal DMSP-lyases
FreeDMSP-lyases
Algal uptake
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
17
DMSPp DMSDMSPdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Bacterial demethylation/demethiolation
Algal DMSP-lyases
FreeDMSP-lyases
Algal uptake
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
18
DMSPp DMSDMSPdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Bacterial demethylation/demethiolation
Algal DMSP-lyases
FreeDMSP-lyases
Bacterialconsumption
Algal uptake
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
19
DMSPp DMSDMSPd DMSOdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Bacterial demethylation/demethiolation
Algal DMSP-lyases
FreeDMSP-lyases
Photochemical and biological oxydation
Bacterialconsumption
Algal uptake
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
20
DMSPp DMSDMSPd DMSOdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Bacterial demethylation/demethiolation
Algal DMSP-lyases
FreeDMSP-lyases
Photochemical and biological oxydation
Bacterialconsumption
Algal uptake
air
water
(algae)
What we know about ocean DMS production
Sinking of cells or feaces
(algae)
DMSOp(algae)
21
DMSPp DMSDMSPd DMSOdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Bacterial demethylation/demethiolation
Algal DMSP-lyases
FreeDMSP-lyases
Reduction
Photochemical and biological oxydation
Bacterialconsumption
Algal uptake
air
water
(algae)
Sinking of cells or feaces
(algae)
DMSOp(algae)
What we know about ocean DMS production
22
DMSPp DMSDMSPd DMSOdExudationGrazingCell lysis
BacterialDMS-producing enzymes
Bacterial demethylation/demethiolation
Algal DMSP-lyases
FreeDMSP-lyases
Reduction
Photochemical and biological oxydation
Bacterialconsumption
Ventilation
Algal uptake
air
water
(algae)
Sinking of cells or feaces
(algae)
DMSOp(algae)
What we know about ocean DMS production
23
Concepts and short-cuts...
1. The DMS summer paradox: At low and mid-latitudes, algal biomass and DMS are not correlated.
At those latitudes, DMS production is generally correlated with the radiation dose.
2. The ‘anti-oxydant cascade’.
At higher latitudes and in biological productive waters, DMS is correlated with algal biomass.
So, there is apparently two regimes:Bloom dominated regimeStress-forced regime
What will be the dominant regime in an ice free Arctic?
24
Levasseur 2013
Sources of DMS to be investigated during the NETCARE cruises
25
Measurements
The physical structure of the water column will be characterized through repeated Conductivity-Temperature-Depth (CTD) profiles conducted in and out the ice pack.
Fluorescence measurements made during the same profiles will provide information on the vertical distribution of the phytoplankton biomass and development of the bloom, and water will be collected at different depths in and below the photic zone .
Chlorophyll a, POC, DOC , TEPs, nutrient, algal abundance and taxonomy, pigment signatures, bacterial abundance, DMSP, DMS and DMSO.
Rates measurements: photosynthesis, bacterial production, DMSP microbial uptake and DMS production.
26
Can DMS escape directly through the ice and if so what is the importance of this source for the Arctic atmosphere?
Contacts: Papakyriakou, Miller, Levasseur
Key question 2
Why should we care about these DMS fluxes?
27
1 10 100
1000
1000
0
0
20
40
60
80
100
120
Concentration (nmol/l)
De
pth
(c
m)
DMS(P) concentrations can be extremely high in sea ice in spring
Margaux Gourdal, pers. com.
2 orders of magnitude higher than in sea water
What is the fate of this DMS? DMSP?
28
What is the fate of this DMSP and DMS?(Observations from Allen Bay , 2011)
Galindo et al. submitted
Under-ice bloom
ice
29
Question 2 will be addressed mostly during the ArcticICE program in Cambridge Bay
Project leader: CJ MundyYears: 2014, 2015, 2016
T PapakyriakouM Gosselin
Allen Bay
30
Measurements
Excursions onto sea ice floes of varying size and melt state will allow us to sample the microbiological sea ice and melt pond communities and quantify DMS concentrations within and emissions from the ice.
The melt ponds will be sampled with a bucket or a peristaltic pump for gas samples.
The water and ice samples will be transported to the ship where they will be processed by standard methods.We will sample a minimum of 25 ponds and ice cores during each cruise to constrain their heterogeneity (depth, size, salinity, etc.).
Similar activities will be conducted over landfast sea ice (sea ice attached to the coast) within the Archipelago as part of the ArcticICE program (U of Manitoba). The participation of Papakyriakou, Levasseur, Gosselin in ice camps in 2014 and 2016 will allow us to quantify locally integrated DMS emission characteristics from the landfast sea ice complex (sea ice, snow, melt ponds, leads) using the relaxed eddy accumulation technique [Zemmelink et al., 2008], an approach which cannot be used during short ice deployments, as planned from the ship.
31
Is the sea-surface microlayer a source of primary organic atmospheric aerosol, and what are the cloud nucleating properties of these particles?
Key question 3
Contacts: Miller, Bertram and Abbatt
Shematic representation by M Cunliffe and J Colin Murrell
32
Quinn and Bates 2011
Organics primary aerosols
33
Sub-questionShould we used a less sophisticated method to sample the microlayer during the cruises? Ice-free water and melt pounds.
Preliminary results from experiments conducted in Ucluelet in 2013 suggest that the microlayer can be a more important source of IN than the water column.
This question will be addressed with samples from Saanish Inlet, BC, in spring of 2014, and continued analysis of Ucluelet data.
34
Measurements
The sea-surface microlayer will be sampled in open water, at the ice edge and in melt ponds using a traditional dipping-glass-plate sampler and an innovative, high-volume autonomous microlayer skimmer developed at the Institute of Ocean Sciences/DFO.
Depending on the method used, samples from 0.1 to several liters will be collected and analyzed for DMS and its precursor DMSP, organic exopolymers, and other aerosol precursors, as well as microbiological community composition. Large sample volumes collected with the skimmer will permit experiments on DMS and aerosol production mechanisms (see below).
35
What oceanic and atmospheric conditions favour particle nucleation and growth arising from oceanic emissions? Contacts: Abbatt, Bertram, Leaitch, Levasseur, Liggio, Murphy, Norman
Key question 4
This question will be addressed during the Amundsen cruises.
Instrumentation:
Particle sizes and numbers: SMPS, APS, CPC
Particle Hygroscopicity: CCNc, filters for subsequent IN analysis, microlayer samples forsubsequent analysis
Particle composition: AIM-IC (soluble ions, PM2.5), MOUDI for S isotopes
Gas phase composition: CIMS (H3O+ and ?acetate), AIM-IC, CO2, GC for off-line samples
Note: We have decided to not do on-board aerosol generation experiments, but we will collect SML samples and do seawater bubbling experiments.
Motivation for Summertime Measurements
2008 Observations
38
Questions
1. What conditions drive new particle formation and growth events in the summertime Arctic?
2. Can we examine local heterogeneity in aerosol numbers or size distributions by deploying particle counting instruments out on the ice or near melt ponds?
3. Can we measure DMS in these ice or melt pond environments, by collection on cartridges and off-line GC analysis?
4. What is the aerosol composition, what is its degree of acidity neutralization, and can we derive its sources, in particular the biogenic vs fossil fuel fraction of the sulfur component?
5. How well do we understand the partitioning of sulfur species between the different components in this Arctic environment, e.g. DMS, DMSO, SO2, MSA, sulfate.
6. What is the aerosol CCN hygroscopicity? 7. What can we infer about sources and sinks of gases with respect to the ocean, e.g.
acetone, DMS, methanol, ? NH3. 8. What are the immersion IN levels in the ambient central Arctic? Does the sea-surface
microlayer harbour IN? 9. Is there evidence of organic gas phase chemistry occurring driven by oceanic emissions?
Measurements of isoprene, terpenes, organic acids, MVK/MACR. (CIMS)
39
What is the vertical extent of new particle formation and growth events and do such events occur primarily in the atmospheric boundary layer, or do ventilated emissions above the boundary layer promote nucleation more efficiently ?
Contacts: Leaitch and Abbatt
Key questions 5
Measurements taken from the POLAR 6 in 2014 and 2015.
40
How might warming-induced changes in the ice cover, and the resulting increased extent of seasonal ice and ice edge, affect the production and emission of oceanic aerosols and their precursors?
Key questions 6
Contact: Steiner and Levasseur
Atmosphere
Ocean
Fluxes
SST
Steiner & Denman 2008
Modelling marine aerosol sources
Includes:Ecosystem model: N
2P
2Z
2D,
Inorganic Carbon cycle: DIC,Alk,O2,N2, Si cycles
Marine DMS cycle
Additions for NETCARE:Sea ice٭, Sea-ice algae
ecosystem with DMS Other organic aerosol sources
(surface films, bubble bursting)
1-D model
Arctic regional model
U Alberta NAA model ocean- ice
?
DMSPd
Ni
Na
Z2(t)
DMSO+Sp
DMS
D
Z1
DMSPp
Ps
Sinking
AggregatesDetritusEntrainment
+Mixing
Photolysis
Bact. cons.
enzym. cleavage
Air-Sea/Air-Iceexchange
Pl Spl
Si
PSi
cleavage
Bact. cons.
PaDMSPpDMS
?
grazing
mortality
Photolysis, bact. conversion
Biol. conv.Sea Ice
Pelagic ecosystem
DMSPp
Fecal Pellets
2013 NETCARE WORKSHOPToronto, November 18-19, 2013
OPEN DISCUSSION
43
