Themes of major importance
for SOLAS research over the next decade
Early white paper draft versions- October 2013
This preliminary draft is intended as a consultation document.
Comments/edits welcome. Please do not use or cite.
Table of Contents
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Theme 1: Greenhouse gases and the oceans ...................................................................................................3
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Theme 2: The air-sea interface and fluxes of mass, energy ..............................................................................8
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Theme 3: Atmospheric nutrient and particles supply to the surface ocean .................................................... 12
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Theme 4: Interconnections between aerosols, clouds, and ecosystems ........................................................ 18
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Theme 5: Ocean emissions and tropospheric oxidizing capacity ................................................................... 23
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Theme 6: Interconnections between ocean biogeochemistry and stratospheric chemistry ............................ 26
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Theme 7: Multiple stressors and ocean ecosystems ...................................................................................... 28
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Theme 8: High Sensitivity Systems- HS2 ........................................................................................................ 32
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Theme 1: Greenhouse gases and the oceans
Author: Christoph Heinze
1. Brief statement defining the theme:
The major driving forces for on-going climatic change are large additions of greenhouse gas to the Earth system
resulting from human activities. The natural cycles of these greenhouse gases in the oceans and troposphere
interact with these unprecedented direct inputs and lead to climatic feedbacks as well as environmental impacts,
which need to be identified, quantified, and predicted on local to global scale and on a variety of different time
scales.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
Scientific basis: For the present increase in greenhouse gases - notably CO2, N2O, and CH4 - no adequate
paleo-analogue exists. While for the inorganic carbon cycling a well-developed fundamental research framework
has been established, still oceanic and atmospheric measurements are lacking in specific key regions - and
especially the Southern Ocean. For the modulation of the carbon cycle through biologically induced changes our
process-based knowledge is very poor. This applies as well for the increasing ocean acidification and associated
impacts/feedbacks. The N2O and CH4 cycles are still less well understood than the carbon cycle, especially in
view of changing physical as well as chemical boundary conditions. Global databases for N2O and CH4 are only
slowly emerging. The potential vulnerabilities of ocean carbon uptake as well as potentially further strongly
increasing ocean based greenhouse gas sources must be identified and taken into account in estimating future
greenhouse gas budgets for the Earth system. Societal basis: A firm understanding and quantification (past,
present, future) of greenhouse gas sources and sinks is key to predict climatic change and environmental
change appropriately within the on-going Anthropocene. Energy production, food production, redistribution of
goods, access to natural resources and local societal infrastructures are dependent on a best possible
understanding and governance of related biogeochemical cycles. Why is it critical and why does it need to be
done now? We are currently at the beginning of an accelerating climatic and environmental change due to
increasing population and emergent greenhouse gas emissions on the pessimistic/high side of potential
alternatives. There are two major reasons why research on ocean-atmosphere interaction of greenhouse gases
is essential: 1. We need to provide a description of the present state of greenhouse gas budgets and related
Earth system variables now, in order to have a reference point for calibrating predictive models better once
climatic/environmental change will have progressed more strongly in the coming decades. 2. We need to set up
a complete as possible spectrum of processes and greenhouse gas interactions to determine whether
postulated and emergent feedbacks, impacts, as well as vulnerabilities are occurring as predicted or whether
new surprises become evident. What is the end goal? The end goal of the theme is to provide integrated
predictive capabilities of the distribution of key greenhouse gases - primarily CO2, N2O, and CH4 – in the oceanatmosphere system including impacts, feedbacks, and vulnerabilities for optimal design of mitigation/adaptation
measures concerning management of the carbon and nutrient cycles worldwide. Why is international
coordination required? Observations on greenhouse gases - data collection (ships, aircraft, satellites, automated
devices) as well as in-situ, laboratory, and mesocosm experiments - and Earth system modelling including
dynamical interactive greenhouse gas cycles are expensive undertakings and cannot be carried out in national
isolation. Data sets on measurements and modelling have to be merged from different originators in a sound
way in order to achieve calibrated, homogeneous, and quality checked data synthesis products. Earth system
models need to be developed within the context of international discussion, as hardly at every modelling centre
key expertise on all critical aspects is present.
3. Background – major scientific concepts, key prior work defining the issues:
Coupled cycles: CO2 is still the major anthropogenic greenhouse gas directly emitted into the atmosphere and
then partially taken up by the ocean and land. In recent years, increasing focus has emerged also on other
important greenhouse gases whose cycle is influenced by human behaviour and climate/environmental change.
After all, the cycles of CO2, CH4, and N2O are interlinked, e.g. after release of CH4 from gas hydrates it becomes
relatively quickly oxidised to CO2, N2O production is highest near production of biogenic organic matter (N 2
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fixation) or its degradation at low oxygen levels (denitrification). Though considerable knowledge gaps
concerning the CO2 related carbon cycle still exist, uncertainties with respect to CH4 and N2O are presumably
even higher. The cycling of CH4 is critically linked to warming (destabilisation threshold) and tectonics, the N 2O
cycle is linked to a multitude of other factors influenced by human beings (de-oxygenation, nutrient inputs from
continents and artificial fertiliser production/use, increased water column stratification and slowing ocean
circulation as consequence of warming). Vulnerable greenhouse gas sources/sinks: Oceanic cycling of
greenhouse gases may undergo potential critical changes for the different long-lived gases CO2, N2O, and CH4.
For CO2 buffering it is critical that water saturated already with respect to CO 2 is mixed downward in the water
column and replaced by water masses carrying still lower CO2 loads. In the recent past, transient decreases in
CO2 sink strengths have occurred in regions, which so far are hot spots of anthropogenic carbon storage
(northern North Atlantic, Southern Ocean; Watson et al., 2009; Le Quéré et al., 2007). On the other hand until
the end of this century, the Southern Ocean is projected to become one of the strongest sink regions for
anthropogenic carbon. Do these predictions hold? Will evidence from observations support this? For modulation
of anthropogenic CO2 uptake rates through the biological pump, a change in size spectra of marine particle flux
under warming/increased stratification and less CaCO 3 ballasting could lead to shallowing of the organic carbon
remineralisation depth interval with a corresponding increase in outgassing (e.g., Laws et al., 2000; Klaas and
Archer, 2002). On the other hand, carbon overconsumption in response to ocean acidification has been
suggested as a potential negative feedback (Riebesell et al., 2007). O2/N2 measurements in the atmosphere so
far do not directly indicate such changes but do not exclude them for the future as yet. For N 2O, decreased
upwelling and de-oxygenation in conjunction with eutrophication and slowing overturning increase production,
especially close to continents (Naqvi et al., 2010). Further increases in marine levels N 2O could occur through a
potential stimulation of N2 fixation if dust deposition and additional iron supply would happen, though the change
of atmospheric dust mobilisation, transport, and deposition is not yet conclusively quantified (Mahowald and Luo,
2003). For the open ocean, N2 fixation has been proposed to be the key source of N2O (Freing et al, 2012).
Potential marine CH4 sources could occur due to accelerating deoxygenation and respective methanogenesis in
very low oxygen regimes (water column, sediment) especially in shallow seas and at the continental margins, but
also especially due to large scale destabilisation of methane gas hydrates once the stabilisation point
(temperature, pressure) has been reached under global warming. Arctic Ocean shallow shelves (sub-sea
permafrost areas) and continental margin areas may be susceptible (Biastoch et al., 2011), as they are areas of
higher tectonic activity. Critical oceanic GHG domains are marked in Figure 1. Observational systems and
related data sets: A suite of recent data syntheses and data collections concerning the marine carbon and
nitrogen cycles has emerged (GLODAP, CARINA, PACIFICA, SOCAT, MEMENTO). Still some oceanic areas
are highly under sampled in space and time. Modelling efforts, MIPs and related data sets: For climate
projections on timescales of several centuries, coupled Earth system models (ESMs) have been developed
which include detailed chemical and biogeochemical interactions as far as relevant process knowledge is
available. Output data sets are available through large international model intercomparison projects (MIPs) such
as CMIP5. Combining observations and models: Data assimilation of biogeochemical ocean models is still in its
infancy but progress has been made in implementing sequential as well as variational methods for ocean
biogeochemical models. The emergent constraint approach (e.g. Cox et al., 2013) can provide a short cut for
identifying the potentially most reliable models for future projections.
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Figure 1: Overview on critical areas for modifications of atmospheric greenhouse gases through the ocean.
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
APPROACHES:
Dynamical process formulations and firmer knowledge about impacts: The various drivers for modifications of
greenhouse gas fluxes such as changes in ice cover, reactive nitrogen input into the ocean, warming, ocean
acidification, and increasing stratification need to be linked in a dynamical way to the respective impacts and
feedbacks. This can be achieved to some degree by laboratory and mesocosm experiments. In addition, a
biogeographical approach is needed, where case studies in selected key regions along physical and
biogeochemical gradients are carried out in order to ground truth findings from artificially forced experiments.
Bridging the spatial scales: In order to quantify and predict oceanic greenhouse gas budgets and related air-sea
fluxes correctly, the highly heterogeneous continental margins have to be included in global budgets (as well as
for national greenhouse gas budgets to close budgets across national borders). This is a particular challenge as
outlined by Regnier et al. (2013). Respective higher resolution coupled ocean-atmosphere models including
biogeochemical cycles need to be developed, which allow for a proper representation of continental margins and
shallow seas in greenhouse gas budgets. This is of particular importance to upwelling systems and areas of
large N2O production. Better observational coverage in space and time through automated systems: In order to
assess variations in greenhouse gas fluxes within the ocean and across the air-sea interface still a far denser
observing system is needed. Automated systems need not only be installed on ships, but also on floats. Some
progress has been made to install O2 sensors on ARGO floats. Calibration problems still need resolving. With
high priority also pH sensors and highest-accuracy alkalinity sensors are needed in order to monitor changes in
ocean acidification and their impacts. Remotely sensed atmospheric greenhouse gas concentrations need to be
linked to oceanic measurements. Combining models and observations: The combination of observations and
models through systematic performance assessment and data assimilation will improve the models through
optimisation of free parameters in process descriptions and also elucidate the reason for regional variations in
marine greenhouse gas sources and sinks. Both sequential and variational methods are being implemented
currently and may come to full operational state within the next pentad.
ACHIEVEMENTS:
● Combined Observing-modelling capabilities will be created in order to monitor expected and potentially unexpected changes in GHG budgets and allow a better check on emission reductions.
● Transformations of biogeochemical cycles and ecosystems under multiple stressor forcing will be assessed
and predicted including the effects of ocean acidification, de-oxygenation, and reactive nitrogen deposition to the
ocean.
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● Internationally coordinated data syntheses actions will provide legacy data sets as reference for future
generations when climate as well as environmental change will have progressed more severely than now. This
includes also high accuracy CaCO3 and BSi (biogenic silica hard parts) production maps for the world ocean.
● An improved estimate of the varying land carbon sink through better ocean/atmosphere assessment including
O2 budgets will be achieved. This is important especially in view of the current discussion about nutrient
limitation of the terrestrial carbon fertilisation effect.
● Standardised procedures, formats, models, observations will be made open access to a wide user community
working on climate mitigation/adaptation.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
Community readiness – is there an existing community engaged on this issue? Worldwide projects such as
SOLAS, IMBER, IOCCP, and GCP have essentially contributed to recent achievements in quantifying marine
greenhouse gas fluxes. The recently established international ocean acidification coordination centre (OA-ICC)
is underpinning this collaboration. Continent-/basin-wide projects have provided actual resources to carry out
respective research work such as OCB (US), the EU framework programmes 6 and 7 (with CARBOOCEAN,
CARBOCHANGE, EPOCA, and more), PICES and others. Linking the South American and in particular African
communities needs still a lot of improvement though progress could be made (e.g. cooperation with CSIR South
Africa, and Morocco). Ocean carbon cycle research is also supported through CLIVAR (repeat hydrography
programme). The community is linked to GEO and GOOS/FOO through a number of projects. Are there
institutional or other barriers to progress? An increasing number of joint projects between the terrestrial,
atmospheric, and oceanic greenhouse gas communities have emerged over the past decade, but still the
disciplinary groups work quite separately. Specifically targeted projects and collaboration networks may help to
enhance the communication and joint research work between these communities further. A better link to LOICZ
for incorporating the coastal oceans in worldwide greenhouse gas budgets would be welcomed. With respect to
oceanic greenhouse gas cycling, the spatial discrimination between SOLAS (upper ocean) and IMBER (deep
ocean) is somewhat artificial from an oceanographic point of view. Therefore, the SOLAS-IMBER carbon groups
(SIC, WG1-3) have been implemented. Concerning the coordination of international research, IOCCP and OAICC are encouraged to collaborate closely with each other in order to avoid fragmentation of the research
coordination worldwide. Is infrastructure or human capacity building required in order to achieve the goals?
Ocean observations as well as Earth system modelling are both expensive undertakings. Optimal international
coordination and use of research vessels as well as supercomputers is essential for greenhouse gas research.
Tracer measurements should be done as multi-tracer data sets in order to correlate as many as possible
different variables from the same casts. A particular problem is the storage of large model data sets as computer
power progresses faster than storage technology. Transdisciplinary collaboration is needed to take into account
for and implement dynamics of human behaviour (economics, energy, matter flow/waste handling, etc.) also in
the Earth system models through interactive modules. Personnel for professional data management have to be
trained and sustained, in particular also to facilitate data extraction from the substantial data archives.
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
As outlined in section 5, the ocean greenhouse gas communities are already based on established projects,
which are linked through coordination mechanisms (IOCCP, OA-ICC). Therefore, a firm framework for
collaboration and communication is already in place. Concerning the collaboration between modellers and
observing scientists, one may envisage a task team – possibly as part of the already well functioning SIC groups
– on greenhouse gas data assimilation and Earth system modelling (with links to their respective programmes
and networks such as WCRP and ENES). Further the SIC groups may open up to also include research on
nitrogen cycling and N2O.
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7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
Optimal information and knowledge concerning greenhouse gas fluxes are the foundation for informed policy
decisions on measures for climate mitigation and adaptation. Integration of ocean-atmosphere greenhouse gas
cycling is therefore a condition sine qua non for any development towards sustainability (impacts of greenhouse
gases – also through ocean acidification, sources/sinks of greenhouse gases, optimal pathways for emission
reductions etc.). Because greenhouse gas emissions and greenhouse gas levels in the atmosphere and ocean
are tightly coupled to energy production, food supply, land use (including fertiliser applications), traffic, and also
health, the research topic is at the heart of FE.
References:
Biastoch, A., T. Treude, L. H. Rüpke, U. Riebesell, C. Roth, E. B. Burwicz, W. Park, M. Latif, C. W. Böning, G.
Madec, and K. Wallmann, 2011, Rising Arctic Ocean temperatures cause gas hydrate destabilization and ocean
acidification, Geophysical Research Letters, 38, L08602, doi:10.1029/2011GL047222.
Cox, P. M., D. Pearson, B. B. Booth, P. Friedlingstein, C. Huntingford, C. D. Jones, and C. M. Luke, 2013,
Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability, Nature, 494, 341-344,
doi:10.1038/nature11882.
Freing, A., D. W. R. Wallace, and H. W. Bange, 2012, Global oceanic production of nitrous oxide, Phil. Trans. R.
Soc. B, 367, 1245–1255, doi:10.1098/rstb.2011.0360.
Klaas, C., and D. E. Archer, 2002, Association of sinking organic matter with various types of mineral ballast in
the deep sea: Implications for the rain ratio, Global Biogeochemical Cycles, 16(4), 1116,
doi:10.1029/2001GB001765.
Laws, E.A., P. G. Falkowski, W. O. Smith Jr., H. Ducklow, J. J. McCarthy, 2000, Temperature effects on export
production in the open ocean, Global Biogeochemical Cycles, 14(4), 1231-1246.
Le Quéré, C. Rödenbeck, E.T. Buitenhuis, T.J. Conway, R. Langenfelds, A. Gomez, C. Labuschagne, M.
Ramonet, T. Nakazawa, N. Metzl, N. Gillett, and M. Heimann, 2007, Saturation of the Southern Ocean CO 2 sink
due to recent climate change, Science, 316(5832), 1735-1738.
Mahowald, N., and C. Luo, 2003, A less dusty future? Geophysical Research Letters, 30(17), 1903,
doi:10.1029/2003GL017880.
Naqvi, S. W A., H. W. Bange, L. Farías, P. M. S. Monteiro, M. I. Scranton, and J. Zhang, 2010, Marine
hypoxia/anoxia as a source of CH4 and N2O, Biogeosciences, 7, 2159–2190,
www.biogeosciences.net/7/2159/2010/, doi:10.5194/bg-7-2159-2010.
Regnier, P., P. Friedlingstein, P. Ciais, F. T. Mackenzie, N. Gruber, I. A. Janssens, G. G. Laruelle, R. Lauerwald,
S. Luyssaert, A. J. Andersson, S. Arndt, C. Arnosti, A. V. Borges, A. W. Dale, A. Gallego-Sala, Y. Goddéris, N.
Goossens, J. Hartmann, C. Heinze, T. Ilyina, F. Joos, D. E. LaRowe, J. Leifeld, F. J. R. Meysman, G. Munhoven,
P. A. Raymond, R. Spahni, P. Suntharalingam, and M. Thullner, 2013, Anthropogenic perturbation of the carbon
fluxes from land to ocean, Nature Geoscience, published online: 9 June 2013, 11 p., doi: 10.1038/NGEO1830.
Riebesell, U., K.G. Schulz, R.G.J. Bellerby, M. Botros, P. Fritsche, M.Meyerhöfer, C. Neill, G. Nondal, A.
Oschlies, J.Wohlers, and E. Zöllner, 2007, Enhanced biological carbon consumption in a high CO 2 ocean,
Nature, 450(7169), 545-548, doi:10.1038/nature06267.
Watson, A.J., U. Schuster, D.C.E. Bakker, N.R. Bates, A. Corbière, M. González-Dávila, T. Friedrich, J. Hauck,
C. Heinze, T. Johannessen, A. Körtzinger, N. Metzl, J. Olafsson, A. Olsen, A. Oschlies, X.A. Padin, B. Pfeil, J.
M. Santana-Casiano, T. Steinhoff, M. Telszewski, A.F. Rios, D.W.R. Wallace und R. Wanninkhof, 2009, Tracking
the variable North Atlantic sink for atmospheric CO2, Science, 326, 1391-1393.
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Theme 2: The air-sea interface and fluxes of mass, energy
Co-authors: Brian Ward and Christoph Garbe
1. Brief statement defining the theme:
The transfer of material across the air-sea interface is controlled by several processes including wind, waves,
turbulence, bubbles, sea spray, rain, and surface films. Air-sea transfer is mostly modelled by various functional
dependencies of the wind speed, but more sophisticated measurement techniques and physically based
parameterisations are required to adequately describe air-sea fluxes.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
The scientific and societal basis justifying research on this issue: Atmospheric greenhouse gas (GHG)
concentrations (CO2 and non-CO2) are about 40% higher today than they were in 1850 and surpass all levels in
the past 2M years. It is estimated that a business-as-usual scenario could cost at least 5% of annual global
gross domestic product (GDP). Reduction in GHG emissions to 80-95% of 1990 levels could limit this economic
cost to 1% of annual GDP.
Ocean-atmosphere fluxes are some of the most critical factors affecting climate. However, these fluxes remain
poorly quantified. For this reason, there is an urgent requirement to generate more scientific expertise for the
quantification of air-sea fluxes.
On regional scales, air-sea fluxes are a driving factor of air-quality and ecological communities. On these scales,
fluxes are even less well constrained than on global ones. This is mainly due to the inhomogeneous nature of
processes and their complex interactions on a wide range of scales.
There is also a strong policy requirement: nothing in the current international agreements on climate specifically
addresses the effects of GHG absorption in the oceans. But it is likely that future treaties will require accurate
quantification of the transport of GHGs across the air-sea interface. The scientific community therefore needs to
act now to develop skills required to address this.
Why is it critical and why does it need to be done now? Recent evidence from observations of air-sea fluxes has
shown that the North Atlantic efficiency in CO2 uptake is declining (Watson et al., 2009). The question as to
whether this is a trend or whether it will fluctuate remains to be answered. At the same time, regional and mesoscale numerical models have been making significant progress in these areas, but are currently limited by our
current inability to produce an accurate parameterization of fluxes.
What is the end goal? The end goal is to parameterise air-sea exchange with processes that more completely
describe the transport, and to accurately predict the transfer over the full range of conditions. This prediction will
not be limited to global scales, but also include meso- and regional scales.
Why is international coordination required? This challenge can only be addressed at the international level, as
individual countries have neither the means nor the expertise to address all the scientific issues. In order to
make progress, a strong interlink between measurement facilities and techniques as well as modelling
capabilities are required. Particularly for regional studies, expertise in the uniqueness of the region at hand is
also required.
The challenge of Future SOLAS is a global one, and meeting these challenges cannot be at the national level.
3. Background – major scientific concepts, key prior work defining the issues:
The oceans are the biggest reservoirs for heat, freshwater, and CO 2, and distribute these constituents globally.
Ocean-atmosphere fluxes are the exchanges of these quantities at the air-sea interface. Uncertainty in the
quantification of these fluxes inhibits our ability to model a changing climate. Accurate knowledge of air-sea
fluxes is essential for assessing the ocean’s role in climate variability, understanding climate dynamics, for
forcing ocean models for predictions from weather to climate timescales.
It is well recognised that the ocean and atmosphere are a coupled system which affects and is affected by
climate and environmental change. Understanding the air-sea interconnection requires that the processes that
control the transport across the interface be accurately quantified. The primary forcing factor for air-sea
exchange is wind speed, which induces near-surface turbulence, causing the molecular boundary layer to be
eroded thereby enhancing transport across the interface. Traditionally the air-sea exchange of the physical
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parameters (momentum, sensible & latent heat) are the best understood as they have been the most widely
measured, and advances in understanding the fluxes of gas and aerosols are largely based on heat fluxes. Of
the GHGs, we are primarily concerned with CO2 as this contributes to radiative forcing more than the others. The
air-sea exchange of aerosols is largely driven by wave breaking at the ocean surface. Turbulence in the ocean
surface controls the air-sea exchange of heat, GHGs, and momentum. These exchanges heavily control the
ability of the oceans to regulate climate. The ocean surface boundary layer (OSBL) also controls the subduction
of atmospheric material into the ocean interior through the boundary conditions to deep-ocean stratification and
dynamics. The surface ocean is therefore critical in determining the role of global ocean circulation on climate.
Quantitative understanding of the turbulent processes in the OSBL is likely to be the key to understanding airsea exchange and the role in affecting climate.
Figure 1: Processes controlling air-sea fluxes of heat, gas, momentum, and aerosols.
Figure 2: Simplified schematic of factors influencing air-sea CO2 fluxes.
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
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the 10 years of Future SOLAS?
Approaches what will it take to make substantive progress on the issue?
• Technology development for new observations: improved sensitivity and accuracy for sensors for direct gas
and particle fluxes; longer battery life; deployment of microstructure sensors on platforms such as autonomous
gliders and floats.
• More realistic, multidisciplinary experiments, e.g. wind/wave channel experiments with full saline water,
including biology, surface films
• Linking measurements and models through advances in coupled models, simulating gas transfer over a wide
range of Schmidt numbers.
What will be achieved in the 10 years of Future SOLAS?
Ability to accurately quantify air-sea fluxes of GHG’s and particles through new observations and to better
parameterize these fluxes for inclusion into Earth-System models. Significant progress will be made particularly
on regional and meso-scales.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
The need for progress in understanding air-sea fluxes has been widely recognized. The community is strongly
pushing forward. The questions of air-sea fluxes are major themes in national and international programs, such
as the German SOPRAN or the international CARBOOCEAN initiative. Recently, there has also been a push
from the earth observation community through ESA’s Oceanflux projects. Currently available satellite products
have been merged to refine a more physically based parameterization and improving the accuracy of flux
estimates.
Is infrastructure or human capacity building required in order to achieve the goals?
Capacity building is strongly needed, in order to gain expertise in the complex processes involved and their
influence ranging from small-scale processes all the way to ecological impact and regional effects. Even though
a strong infrastructure is in place for global assessments, this is still lacking for a wide range of very important
regional studies.
One of the fundamental goals for FE is to bring capacity building to developing countries. Future SOLAS should
consider establishing capacity building programmes in developing countries whereby SOLAS scientists and PhD
students would spend short periods training students in SOLAS science.
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
What partnerships are required in order to achieve the goals?
Strong international partnerships between observationalists (linked studies in the laboratory and in the field),
theoreticians, modellers and earth observationalists are required in order to achieve the set goals. Through the
multifaceted and highly complex processes, strong links between disciplines such as physicists, chemists,
biologist and ecologists are required. Particularly on regional scales, on which air-sea fluxes have a significant
impact on ecosystems and human activities, research of this theme needs to be put in a wider context.
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
Transport of heat and mass across the air-water interface directly impacts ecosystems and is central to a
number of different services important to achieve FE's goals of global development and transformation towards
sustainability. Regulating services such as air quality, waste treatment, climate regulation and nutrient cycles are
becoming increasingly more important, also for policy makers. Only through a better understanding of fluxes and
relevant processes at the interface can predictions be made and future impacts be assessed. This theme is
central to FE and might also be cross cutting to other projects such as IGAC, IMBER, iLEAPS, PAGES and
CLIVAR.
References:
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Watson, A. J., et al. (2009), Tracking the variable north Atlantic sink for atmospheric CO2,
Science, 326, doi:10.1126/science.1177394.
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Theme 3: Atmospheric nutrient and particles supply to the surface ocean
Co-authors: Cécile Guieu, Diego Gaiero and Huiwang Gao
1. Brief statement defining the theme:
The ocean receives a broad variety of particles, a range of key macro- and micronutrients, and toxic elements
from the atmosphere. These materials are delivered in chemical forms and amounts that are very different from
the upward supply of internally recycled nutrients from within the ocean. This atmospheric deposition affects vast
regions of the ocean, including sensitive regions far from land. It is a result of both natural processes (e.g. dust
deposition, volcanic eruptions) and, increasingly, by human activities (e.g. increased nitrogen deposition from
pollution). Indirectly, human activity is also likely altering dust emissions/deposition with unknown feedbacks on
climate and biogeochemistry. Despite significant laboratory, field and modelling work over the past decade, the
links between atmospheric deposition, nutrient availability, ocean productivity (up to high trophic levels), carbon
cycling and feedbacks to climate are still poorly understood and modelled.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
This theme focuses on the relation between atmospheric input, the carbon cycle and feedbacks to climate. The
consideration of the impacts of atmospheric input on the biogeochemistry of the ocean is quite recent (only few
decades). There is a need to better understand and parameterize the numerous processes involved at a
fundamental level. Work in this area is progressing thanks to recently developed tools (such as measurements of
nutrients and micronutrients at very low levels both in the atmosphere and in seawater and new experimental
enclosures to perform artificial seeding, etc.). Ongoing and future anthropogenic and global changes, both
increasing emissions (e.g., N) and in situ conditions (stratification, pH) may induce changes in atmospheric
deposition fluxes/turn over time in the surface mixed layer and in stoichiometry of the ‘new nutrients’ coming
from the atmosphere. In turn, these changes may result in changes in both biodiversity and microorganism
adaptive strategies for competing for nutrients. Fundamental differences in the response of the microbial
community structure to the input of new nutrients (e.g. stimulation of heterotrophy v. autotrophy) will result in
opposite effect regarding carbon budget depending on the balance between CO2 fixation and respiration. This is
critical because it has direct implications for the way we think about productivity in the ocean and therefore
atmospheric CO2 uptake and fisheries.
This theme has relevance for society as it concerns global and transnational pollution issues, health of the ocean,
and, via potential impacts on fish and higher trophic levels, it touches on issues closely related to deliberate (as
opposed to inadvertent) fertilization of the ocean.
The end goal is to assimilate all information gained from field measurements and laboratory experiments into
more realistic models of deposition and associated mechanisms, taking into account the variable stoichiometry
of atmospheric nutrients and surface ocean biota, with better representation of competitive interactions between
plankton groups. Modeling should also include prediction considering on going and future anthropogenic and
global changes, including both increasing emissions (e.g.., N) and changes in situ conditions (stratification, pH).
International coordination is required considering the vast multi-disciplinary fields involved (atmosphere/ocean
both for biology, chemistry, physic, modeling) and the large spatial variability observed in response to
atmospheric deposition. For example, international coordination is necessary to create a network of existing
time-series data to couple aerosol composition and biogeochemistry of the ocean (e.g. HOT, BATS, CVOO and
DYFAMED). Such coordination could also allow for the integration/implementation into the network of new
coupled atmosphere/ocean time-series in a number of key areas (Patagonia, Falkland/Malvinas) and also in
HNLC area under the influence of volcano plumes (NE Pacific). The end result will be a large database
integrating all the observations acquired. International coordination could also allow for conducting similar
experiments in different locations, possibly employing Lagrangian studies using tracers or drifting buoys. Trace
element clean mesocosms and tracer-labeled in situ manipulations could also be used to address wholeecosystem effects of atmospheric nutrient input, including particulate organic carbon export.
12
3. Background – major scientific concepts, key prior work defining the issues:
- Material transported in the atmosphere originates from a variety of natural and anthropogenic sources and
contains both macro- and micronutrients (N, P, C, Si, trace metals including Fe and Cu), and potentially toxic
elements (e.g. Cu, Pb) (GESAMP 1989, Duce et al. 1991, Paytan et al. 2009). Atmospheric transport and
deposition are an important source of new nutrients and particles for large regions of the open ocean (GESAMP,
1989, Duce et al., 1991) and the significance of air-sea exchange to marine nutrient budgets has been
established for nitrogen (Duce et al., 2008), iron (Mahowald et al., 2005; Jickells et al., 2005) and phosphorus
(Mahowald et al., 2008).
- Atmospheric supply of dissolved constituents to the surface ocean depends on particle concentration and size
spectrum, and the solubility of the element-bearing phases in aerosols (Trapp et al., 2010; Baker and Jickells,
2006), which is influenced by atmospheric processing during transport (Krishnamurthy et al., 2009).
- The main natural source of land-derived particles to the open ocean is wind-blown desert dust, which
constitutes the primary atmospheric source of iron (Jickells et al., 2005) and Figure 1.
- Atmospheric nitrogen is mainly derived from anthropogenic combustion or agricultural sources from densely
populated regions throughout the world (Duce et al., 2008)
- Phosphorus originates from both desert dust and anthropogenic sources (Mahowald et al., 2008)
- The extent to which dust interacts with anthropogenic acids (H 2SO4 and HNO3) during transport increases the
solubility of various elements (Desboeufs et al., 2001) resulting in enrichment of nitrogen (Geng et al., 2009),
and enhanced supply of potentially bioavailable compounds to the surface ocean.
- Post-depositional processes associated with the quantity and quality of dissolved organic matter in seawater
are very important in the bioavailability of atmospheric new (micro)nutrients (Wagener et al., 2010, Bressac and
Guieu, 2013); for example it could result in a strong scavenging of iron on dust instead of dissolution from dust
(Bressac and Guieu, 2013; Wagener et al., 2010; Wuttig et al., 2013).
- The supply of new nutrients to the ocean from external sources such as atmospheric deposition has been
extensively addressed in iron-limited High Nutrient-Low Chlorophyll regions (i.e. Boyd et al., 2007), most of
which receive low atmospheric inputs at the present time (Figure 1). However, much less attention has been
paid to the importance of atmospheric deposition to LNLC regions where it likely represent an important source
of new nutrients for the surface mixed layer (Guieu et al., 2013).
- Impact from volcanoes has been recently emphasized (see for ex. Olgun et al., 2013) with consequences up to
high trophic levels.
- Impact on biota from field and laboratory experiments in LNLC areas indicate positive responses to aerosol
addition, with bacterial production and N2 fixation showing the strongest responses (see review Guieu et al.,
2013). Increases in chlorophyll-a are seen to a lesser extent, however, differential responses among
phytoplankton groups are also apparent (i.e. Paytan et al., 2009; Giovagnetti et al., 2013). Changes in standing
stocks tend to be smaller than changes in metabolic rates (Guieu et al., 2013) (Figure 2).
- The effect of atmospheric deposition on the surface ocean may vary with the degree of oligotrophy of the
receiving waters (Marañon et al., 2010)
- The effect of atmospheric deposition on the surface ocean cannot be seen as a simple fertilization effect
(Guieu et al., 2013) as it results in fundamental differences in the response of the microbial community structure
(e.g. stimulation of heterotrophy v. autotrophy), and hence, in the vertical carbon export and nutrient cycling
(Marañon et al., 2010).
- Aggregation between atmospheric particles and dissolved organic matter can induce a strong and rapid POC
export independently of a fertilization effect (Ternon et al., 2010; Bressac and Guieu, 2013). This ‘lithogenic
carbon pump’ (Bressac and Guieu, 2013) may significantly augment the export flux resulting from increased
nutrient supply by atmospheric deposition.
- Atmospheric impacts in LNLC regions have been underestimated by models as they typically overlook large
synoptic variations in atmospheric deposition and the associated nutrient and particle inputs (Guieu et al., 2013)
13
Figure 1. Average estimation of dust deposition (g.m -2. yr-1) over the world oceans (Jickells et al., 2005)
Figure 2. Box-Whisker plots (mean ± standard error and 95% confidence limits) showing the responses of
different biological variables to aerosol additions in LNLC waters (60% of the ocean): synthesized from available
data from a total of 26 field and laboratory aerosol addition bioassay experiments, and mesocosms experiments.
The responses are % changes in the aerosol treatment relative to the control after 2-8 days, with zero indicating
no difference between the aerosol treatment and the control, and a positive response indicating an increase in
the parameter measured for the aerosol treatment relative to the control. Parameters: (BA) Bacteria Abundance,
(BR) Bacteria Respiration, (BP) Bacteria Production, (Syn.) Synechococcus abundance, (Proc.) Prochlorococcus
abundance, (pico & nano-euks) Nano- and Picoeukaryotes abundance, (nano & microphyto) nano- and microphytoplankton abundance, (Chla) Chlorophyll-a, (PP) primary production, (N2Fix) nitrogen fixation. (Guieu et al.,
2013)
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4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
Systematic measurements are required of atmospheric deposition and nutrients in the surface mixed layer in
regions where atmospheric (natural and/or anthropogenic) supply plays an important role as in Low Nutrient Low
Chlorophyll regions (Guieu et al., 2013) and also in HNLC area such as the NE Pacific. Anthropogenic nitrogen
forcing is primarily a Northern hemisphere phenomenon but, as climate and ocean acidification are global drivers,
there is a requirement for coupled atmosphere marine time-series sampling sites in both hemispheres. Although
reliable measurements of dry deposition remain technically challenging, it will be beneficial to extend wet and dry
deposition measurements and particle characterization to repeat sampling lines across regional deposition
gradients and surface water biogeochemical gradients, using research vessels and voluntary observing ships.
These transects should ideally accommodate rate measurements and nutrient manipulation experiments to gain
insight into the proximal controls of plankton composition and process rates. Linking time-series studies of
aerosol composition with oceanic time-series data (Schultz et al., 2012) is valuable for constraining the response
of the marine ecosystem to deposition events. Existing time series stations that monitor both atmosphere and
ocean properties (e.g. HOT, BATS, CVOO, DYFAMED) could become focal points for more detailed
experiments and process studies, possibly employing Lagrangian studies using tracers and/or drifting buoys.
Trace-element clean mesocosms and tracer-labeled in situ manipulations could also be used to address wholeecosystem impacts of atmospheric nutrient input, including particulate organic carbon export. If such
international effort is deployed (allowing comparative studies and data collection from time-series and data
sharing, the SOLAS community should be able, within 10 years, to provide the necessary information for their
assimilation into realistic models of deposition and associated mechanisms, taking into account the variable
stoichiometry of atmospheric nutrients and surface ocean biota, with better representation of competitive
interactions between plankton groups and aerosols/organic matter aggregation processes. Transport, deposition
and biogeochemical models require thorough testing and validation against in-situ time series datasets and
remote-sensing observations. In addition, methodological intercalibration, sample sharing, common reference
materials and standardization of techniques are all required to ensure global coherence and quality control.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
An existing research community is addressing these issues but it is not well coordinated due to the multidisciplinary nature of the research. In addition, in general, each group works in a dedicated area with no
geographical connection with other groups (e.g.,. Sargasso Sea, East tropical Atlantic, off Patagonia, Western
Pacific, Mediterranean Sea). International coordination is a difficult task because it has to be maintained over
time. Recently the existing marine time-series started to coordinate their effort (Karl et al., 2003) for the marine
biogeochemistry. Recently Schultz et al. 2012 proposed to set up a ‘Marine Atmospheric network’ for the longterm observation of the link between dust/iron and marine biogeochemistry. They recommended focusing on an
HNLC area because of the impacts of dust in such regions. The Schultz et al. (2012) work results from GESAMP
Working Group 38 ‘The Atmospheric Input of Chemicals to the ocean’. Coordinated aerosol – marine
biogeochemistry measurements could also be implemented for other atmospheric nutrients that impact LNLC
areas. In addition to encouraging international coordination in a “Marine Atmosphere time-series network”,
SOLAS could help reach the presented goals for this theme by encouraging a large group of experts to setup a
common processes studies project in a dedicated area that would be chosen by all the experts to fulfill a large
number of remaining questions. Finally, research related to this theme is evolving with time; for example the
potential fertilizing effect of volcanic ash is the subject of many new projects that produce important literature.
Multi-disciplinary meetings where people with different interests (ex. dust, volcanic ashes, pollution) can share
their experience and point of view should be encouraged.
Considering all those different tasks, a dedicated person to organize a successful international effort will be
necessary.
15
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
To setup a network and/or initiate a joint process studies project, SOLAS could organize a joint workshop with
coordinators of GESAMP working group 38, BioGEOTRACES, ISAR (International Society for Aeolian
Research*), and IMBER. Another important community is the one dedicated to understanding atmospheric
deposition fluxes to the ocean. Still models yield a wide range of estimates of the ratios of wet-to-dry deposition.
The knowledge of deposition over the ocean is based upon a few limited experimental data sets that are today
mostly discontinued (e.g., SEAREX, AEROCE). Fostered by the World Meteorological Organization (WMO), a
few monitoring stations exist that are equipped with sophisticated instrumentation (e.g., Malta and Izaña), and
some programmes in Africa and Asia (e.g. AMMA, SAMUM, ACE-ASIA) and ship measurements have provided
shorter-term information.
* (ISAR) scientists undertaking research in aeolian processes, landforms, and modeling, to stimulate scientific
research in aeolian topics and related fields and contribute largely to understand the emission process of
dust/aerosols. This community is very active in trying to improve our knowledge in subjects like the amount of
dust/aerosol emitted and its embedded nutrients and largely contribute on having reasonable information on the
geographic distribution of dust sources.
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
As detailed in section 3, the project will first tackle fundamental scientific questions on the impact of atmospheric
deposition in biogeochemistry and (end to end) ecosystem functioning. Because we consider (via experimental
approach and modelling) how ongoing anthropogenic and natural changes will modify the present functioning
and how this will impact on carbon storage- one of the most important ecosystem service that ocean is providing
to Man- this project can indeed be articulated with the objectives of FE.
References:
Baker A.R. and T.D. Jickells (2006), Mineral particle size as a control on aerosol iron solubility, Geophysical Res.
Let., VOL. 33, L17608, doi: 10.1029/2006GL026557.
Boyd, P. W., Jickells, T., Law, C. S., Blain, S., Boyle, E. A., Buesseler, K. O., Coale, K. H., Cullen, J. J., de Baar,
H. J. W., Follows, M., Harvey, M., Lancelot, C., Levasseur, M., Owens, N. P. J., Pollard, R., Rivkin, R. B.,
Sarmiento, J., Schoemann, V., Smetacek, V., Takeda, S., Tsuda, A., Turner, S., and A.J Watson (2007), A
synthesis of mesoscale iron enrichment experiments 1993–2005: key findings and implications for ocean
biogeochemistry, Science, 315, 612–617.
Bressac M., C. Guieu. Post-depositional processes: What really happens to new atmospheric iron in the ocean
surface? Global Biogeochemical Cycles, doi:10.1002/gbc.20076, in press.
Desboeufs, K. V., Losno, R. and J.L. Colin (2001), Factors influencing aerosol solubility during cloud processes.
Atmos. Environ. 35, 3529-3537.
Duce R.A, J. LaRoche, K. Altieri, K.R. Arrigo, A.R. Baker, D.G. Capone, et.al., Impacts of atmospheric
anthropogenic nitrogen on the open ocean,Science, 2008, 320(5878): doi:10.1126/science.1150369, 893-897
Duce R.A, P.S. Liss, J.T. Merill, E.L. Atlas, P. Buat-Menard, B.B. Hicks, et al., The atmospheric input of trace
species to the world ocean, Global Biogeochem. Cycles, 1991, 5, 193–259
Geng, H., Park, Y., Hwang, H., Kang, S. and Ro, C.U., 2009. Elevated nitrogen-containing particles observed in
Asian dust aerosol samples collected at the marine boundary layer of the Bohai Sea and the Yellow Sea.
Atmospheric Chemistry and Physics, 9: 6933-6947
GESAMP, The atmospheric input of trace species to the world ocean, Rep. Stud., GESAMP, 1989, 38, 111 PP
Giovagnetti V. , C. Brunet, F. Conversano, F. Tramontano, I. Obernosterer, C. Ridame, and C. Guieu , 2013,
Assessing the role of dust deposition on phytoplankton ecophysiology and succession in a low-nutrient lowchlorophyll ecosystem: a mesocosm experiment in the Mediterranean, Sea , Biogeosciences 10, 2973–2991 (SI
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Guieu C., O. Aumont, A. Paytan, L. Bopp, C.S. Law, N. Mahowald, E. P. Achterberg, E. Marañón, B. Salihoglu,
A. Crise, T. Wagener, B. Herut, K. Desboeufs, M. Kanakidou, N. Olgun, F. Peters, E. Pulido-Villena, A. TovarSanchez, C. Völker, 2013, The significance of episodicity in atmospheric deposition to Low Nutrient Low
Chlorophyll regions, Global Biogeochemical Cycles, submitted.
Jickells T.D., Z.S. An, K.K. Andersen, A.R. Baker, G. Bergametti, N. Brooks, et al., Global iron connections
between dust, ocean biogeochemistry and climate, Science , 2005, 308 5718 DOI: 10.1126/science.1105959,
67–71
Karl D.M et al., Temporal Studies of Biogeochemical Processes Determined from Ocean Time-Series
Observations During the JGOFS Era, Global Change — The IGBP Series (closed) 2003, pp 239-267
Krishnamurthy, A. J. K Moore, N Mahowald, C Luo, S C. Doney, K Lindsay and C S. Zender (2009), Impacts of
increasing anthropogenic soluble iron and nitrogen deposition on ocean biogeochemistry. Global Biogeochem.
Cycles 23, GB3016, 10.1029/2008gb003440.
Mahowald N.M, A.R Baker, G. Bergametti, N. Brooks, T.D.Jickells, R.A. Duce, et. al, The atmospheric global
dust cycle and iron inputs to the ocean, Global Biogeochemical Cycles, 2005, 19: GB4025
doi:10.1029/2004GB002402
Mahowald N.M, T.D. Jickells, A.R. Baker, P.Artaxo, C.R. Benitez-Neslon, G. Bergametti, et al., Global
distribution of atmospheric phosphorous sources, concentrations and deposition rates, and anthropogenic
impacts., Global Biogeochemical Cycles, 2008, 22 4: GB4026 DOI: 10.1029/2008GB003240
Marañón, E., Fernández, A., Mourino-Carballido, B., Martínez-García, S., Teira, E., Cermeno, P., et al. (2010),
Degree of oligotrophy controls the response of microbial plankton to Saharan dust. Limnology and
Oceanography, 55(6), 2339-2352
Olgun N, Duggen S, Langmann B, Hort M, Waythomas CF, Hoffmann L, Croot P (2013) Geochemical evidence
of oceanic iron fertilization by the Kasatochi volcanic eruption in 2008 and the potential impacts on Pacific
sockeye salmon. Mar Ecol Prog Ser 488:81-88
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Marine Phytoplankton, PNAS, 2009, 106 doi:10.1073/pnas.08114868106, 4601-4605
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dust to the ocean - Implications for research needs, Environmental Science and Technology, 2012, 46, 10, 39010.
Ternon E. , C. Guieu , M-D. Loÿe-Pilot, N. Leblond, E. Bosc, B. Gasser, J. Martin, J-C. Miquel, 2010, The impact
of Saharan dust on the particulate export in the water column of the North Western Mediterranean Sea,
Biogeosciences, 7, 809–826, 2010.
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dust measured in trade wind aerosols at Barbados and Miami. Mar. Chem. 120, 71-82Wagener T., PulidoVillena E., Guieu C., 2008, Dust iron dissolution in seawater: Results from a one-year time-series in the
Mediterranean Sea, Geophys. Res. Lett., 35, L16601, doi:10.1029/2008GL034581.
Wagener, T., Guieu C., Leblond N., 2010, Effects of dust deposition on iron cycle in the surface Mediterranean
Sea: results from a mesocosm seeding experiment., Biogeosciences, 7, 3769-3781.
Wuttig K., T. Wagener, M. Bressac, A. Dammshäuser, P. Streu, C. Guieu, and P. L. Croot, 2013, Impacts of dust
deposition on dissolved trace metal concentrations (Mn, Al and Fe) during a mesocosm experiment
Biogeosciences 10, 2583-2600 (SI DUNE)
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4
Theme 4: Interconnections between aerosols, clouds, and ecosystems
Co-authors: Trish Quinn, Ilan Koren and Rafel Simo
1. Brief statement defining the theme:
Interconnections between ocean-derived aerosols, clouds, and marine ecosystems are not well understood.
Assessing the system as a whole is required for an accurate understanding of how a change in one component
is manifested in another as well as the potentially complex web of associated feedbacks. In addition, accurate
projections of the evolution of climate and the ocean biosphere can only be achieved through a better
understanding of these potential interactions and feedbacks. The intent of this theme is to assess interactions
between key components of marine aerosols, clouds, and ecosystems and associated feedbacks.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
Although clouds play a major role in climate and account for approximately two thirds of Earth’s albedo, they are
the least understood component of the climate system and carry the largest uncertainty in global warming
projections (Forster et al., 2007). Interactions between aerosol and clouds and impacts of the biosphere on both
aerosols and clouds contribute to this uncertainty. Links between oceanic ecosystems and clouds may act as
either amplifiers or buffers of climate variability.
Changes in cloud properties may impact ecosystems, including plankton physiology and dynamics, by altering
incident radiation, precipitation, surface winds, the ocean mixed layer energy budget, and sea surface
temperature. At the same time, aerosols alter the microphysical (e.g., cloud droplet number concentration and
size distribution) and macrophysical (e.g., extent and lifetime) properties of clouds by acting as seeds for cloud
droplet and ice crystal formation, i.e., by serving as cloud condensation nuclei (CCN) and ice nuclei (IN). A large
fraction of the emission and production of ocean-derived CCN occurs in remote regions where concentrations of
continentally derived CCN are low. In these regions, clouds are particularly susceptible to small changes in
aerosol concentration.
Due to the scarcity of measurements and limited modelling capabilities, the emission, formation, transformation,
and climate effects of ocean-derived aerosols are poorly understood. Hence, this theme will focus on first order
problems including the biological, physical and chemical processes that determine the emission, production, and
composition of ocean-derived aerosols and their effects on clouds. A first step is to obtain the data necessary to
develop empirically constrained parameterizations of the emission flux and production rates of ocean-derived
sea spray aerosol (SSA) and gaseous precursors of secondary aerosol (SA) and their impacts on cloud
properties. The goal is to develop parameterizations for use in chemical transport models (CTMs), cloud
resolving models (CRMs) and global climate models (GCMs) to accurately estimate impacts of ocean-derived
aerosols on cloud properties and associated feedbacks on marine ecosystems.
A concerted effort involving shipboard measurements, remote sensing, and modelling studies is required to
achieve these goals. The research will be interdisciplinary in nature involving oceanographers and atmospheric
scientists. Current limitations in funding and ship time require that resources be pooled and that the effort be
internationally coordinated.
3. Background – major scientific concepts, key prior work defining the issues:
Primary ocean-derived SSA is produced from the entrainment of air bubbles as waves break on the ocean
surface. When injected to the atmosphere, the bubbles burst and yield SSA composed of both inorganic sea salt
and organic matter. SSA is highly enriched in organic matter relative to seawater, especially for particles less
than 500 nm in diameter (Keene et al., 2007; Facchini et al., 2008; Bates et al., 2012). The composition of the
organic fraction is not fully known but has been reported to be composed of viruses, bacteria, microalgal debris,
biogenic polymeric and gel-forming organic material (Facchini et al., 2008; Hawkings and Russell, 2010;
Orellana et al., 2011). The processes controlling the source of the organics are not well understood and the
impact of organics on the ability of SSA to act as CCN or IN and nucleate cloud droplets is very uncertain. This
uncertainty is due, in large part, to a scarcity of measurements of freshly emitted SSA. Current model estimates
of the flux and climate impact of SSA either do not take into account the organic component or parameterize the
organic component based on surface seawater chlorophyll concentrations (e.g., Rinaldi et al., 2013). Chlorophyll
18
is a measure of phytoplankton biomass but does not account for species composition, physiological status,
productivity and non-phytoplankton planktonic activity, all of which may play a role in the production of organic
matter available for incorporation into SSA.
Secondary aerosols (SA) form by nucleation of low volatility, oxidized products of trace gases and subsequent
growth by condensation of semi volatile species on the seed particles. The most studied SA production process
in the marine atmosphere is the oxidation of biogenic dimethylsulfide (DMS) into sulfuric and sulfonic acids. This
process is the basis for the CLAW hypothesis whereby emissions of DMS, a by product of phytoplankton
processes, lead to enhanced CCN concentrations and cloud albedo resulting in a biological regulation of climate
(Charlson et al., 1987). The impact of a change in cloud albedo on DMS emission relies on particle nucleation in
the boundary layer. The lack of observations of MBL nucleation over the open ocean along with evidence for
primary (wind-driven) and free tropospheric sources of MBL CCN (including DMS) has led to the realization that
sources of CCN to the MBL are much more complex than originally thought (Carslaw et al., 2010; Quinn and
Bates, 2011; Clarke et al., 2013).
Nucleation events have been observed at coastal sites (Modini et al., 2009; O’Dowd et al., 2010; Chang et al.,
2011) and sulfuric and sulfonic acids have been shown to nucleate new particles in the presence of organic
condensable species in smog chamber studies (Metzger et al. 2010; Dawson et al. 2012). How these results
apply to open ocean conditions is yet to be determined. Recent improvements in observational tools (Kulmala et
al., 2013) should reveal the actual contribution of nucleation to total CCN numbers.
The growth of primary organic aerosols by condensation of surface active and hygroscopic compounds is also
suggested as a CCN source (Andreae and Rosenfeld, 2008; Clarke et al., 2013). A very recent work suggests
that bursts of nanoparticles can occur by in-cloud downsizing of primary organic aerosols (Karl et al., 2013). All
in all, the contribution of primary and secondary sources to CCN numbers is yet to be fully assessed. The task
stands as a formidable challenge due to the reaction of freshly emitted SSA with existing atmospheric gases and
particles soon after emission resulting in a blurring of the distinction between SSA and SA.
Further complication comes from the transport of gases and aerosols that are derived in continental
atmospheres and advected into the marine atmosphere resulting in complex internal and external particle
mixtures (Andreae and Rosenfeld, 2008). Attempts to evaluate the impact of the ocean on cloud formation and
properties and the radiative budget on a global scale must be able to distinguish between ocean and continental
sources of aerosols that exist in the marine atmosphere.
The effects of marine ecosystem changes associated with global change (such as water warming and
stratification, regional oligotrophication or eutrophication, and ocean acidification) on the formation and
properties of ocean-derived aerosol and clouds remains uncertain. Equally uncertain are the feedbacks of
naturally driven or global change associated changes in clouds and aerosols on marine ecosystems.
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
 Simultaneous observations of surface seawater and freshly emitted SSA properties are required to determine
the processes controlling the organic enrichment of freshly emitted SSA.
 New approaches for determining the emission flux of SSA and SA precursors, especially at high wind speeds,
are required to reduce associated uncertainties.
 Development of techniques for the identification of the most important players among marine SA precursors
(beyond DMS, isoprene and iodine) and to determine their sources, volatility, and aerosol yields. Amines and
semi volatile hydrocarbons are suggested as target candidates.
 New techniques that allow for counting and characterizing nascent ultra-small aerosols to better assess the
frequency and mechanisms of particle nucleation in the marine boundary layer.
 Measurements able to elucidate processes that modify aerosol in the MBL including growth, aging,
photochemistry and internal mixing. Implementation of these processes in models.
 Simultaneous studies of surface ocean plankton taxonomy/ecophysiology/bloom dynamics, surface
concentrations of aerosol precursors and aerosol characteristics to constrain and model the biological and
19
environmental drivers of biogenic aerosol emission. Time-series studies (both short term –through bloom
phases- and long term –through seasons and years) and across-provinces studies will be fundamental tools.
 Development of methods to discriminate between ocean- and continentally-derived aerosols found in the
marine atmosphere to allow for the assessment of the impact of the marine biosphere on tropospheric
aerosols and clouds.
 High quality and high-resolution measurements of the physical properties of the surface ocean mixed layer
and the atmospheric MBL to decouple ocean-derived aerosol affects on marine clouds from physical effects.
 In situ and high-resolution satellite observations of aerosols, winds and cloud properties to improve process
understanding and develop parameterizations of marine – cloud interactions. Participation by the marine
aerosol community in the development of new remote sensing platforms and sensors, ensuring their
relevance to ocean-aerosol-clouds feedbacks.
 Development of high-resolution numerical models to integrate cloud microphysics into small-scale process
dynamics.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
There is a growing effort among existing oceanographic and atmospheric science communities to address this
issue, largely triggered by SOLAS during the last decade. Yet field studies with balanced contributions from both
sides of the ocean-atmosphere interface are rare and should be emphasized in the future. Development of a
common language (both concepts and terminology) to be shared by the two communities is in its infant stages
but is needed for progress in address interconnections between aerosols, clouds, and ecosystems. In addition,
the education of a new generation of scientists capable of looking across the interface will eventually be
reflected in the building of truly coupled ocean-atmosphere modules in Earth System models.
There is a clear need to maintain and reinforce a dedicated international, interdisciplinary program like SOLAS to
build frameworks that will bring the two disciplines together to facilitate the exchange of ideas and enhance the
results of future experiments.
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
Desired partnerships:
 IGAC
 Atmospheric Chemical Transport and Climate Modeling Communities
 Ocean Ecosystem Community
 ICCP (The International Commission on Clouds and Precipitation) http://www.iccp-iamas.org
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
 The production of climate-active aerosols and clouds by the oceans must be considered when accounting for
ecosystem services. The pelagic ocean provides aerosols that scatter sunlight as well as water vapor and
seeds for cloud condensation, in addition to food provision, CO 2 sequestration, O2 production, waste dumping
and recycling, transportation and recreation, and cultural reference.
 Aerosols stand as one of the largest paradoxes in global change mitigation efforts. Since the Industrial
Revolution, global dimming by anthropogenic aerosols has acted as the most powerful counterforce to
greenhouse gas derived warming (IPCC 2007). Since the decade of 1980s when the harmful effects that
aerosols have on health, visibility and cultural heritage were fully recognized, the development of cleaner and
more efficient combustion technologies has led to reductions in anthropogenic aerosol emissions, at least in
the most industrialized countries. The benefits of this reduction have (and will) come along with an
20
acceleration of warming by reduction of the atmospheric dimming. An accurate assessment of the effects of
aerosol emission policies on climate requires a solid knowledge of the current and projected roles of natural
(including marine) aerosols on the energy balance at the regional and global scales.
References:
Andreae, M.O., D. Rosenfeld, Aerosol–cloud–precipitation interactions. Part 1. The nature and sources of cloudactive aerosols, Earth-Science Rev., 89, 13–41, 2008.
Bates, T.S., P.K. Quinn, A.A. Frossard, L.M. Russell, J. Hakala, T. Petäjä, M. Kulmala, D.S. Covert, C.D. Cappa,
S.-M. Li, K.L. Hayden, I. Nuaaman, R. McLaren, P. Massoli, M.R. Canagaratna, T.B. Onasch, D. Sueper, D.R.
Worsnop, and W.C. Keene, Measurements of ocean derived aerosol off the coast of California, J. Geophys. Res.,
117(D00V15), doi:10.1029/2012JD017588, 2012.
Carslaw et al., A review of natural aerosol interactions and feedbacks within the Earth system, Atmos. Chem.
Phys., 10, 1701 – 1737, 2010.
Charlson, R.J., Lovelock, J.E., Andreae, M.O., & Warren, S.G. Oceanic phytoplankton, atmospheric sulphur,
cloud albedo, and climate, Nature, 326, 655 – 661, 1987.
Chang, R. Y.-W., S. J. Sjostedt, J. R. Pierce, T. N. Papakyriakou, M. G. Scarratt, S. Michaud, M. Levasseur, W.
R. Leaitch, and J. P. D. Abbatt, Relating atmospheric and oceanic DMS levels to particle nucleation events in the
Canadian Arctic, J. Geophys. Res., 116, D00S03, doi:10.1029/2011JD015926, 2011.
Clarke, A.D. et al., Free troposphere as a major source of CCN for the equatorial pacific boundary layer: longrange transport and teleconnections, Atm. Chem. Phys., 13, 7511-7529, 2013.
Dawson, M.L., M.E. Varner, V. Perraud, M.J. Ezell, R.B. Gerber, and B.J. Finlayson-Pitts, Simplified mechanism
for new particle formation from methanesulfonic acid, amines, and wáter via experiments and ab initio
calculations, Proc. Nat. Acad. Sci. USA, 109, 18719–18724, 2012.
Facchini, M.C., M. Rinaldi, S. Decesari, C. Carbone, E. Finessi, M. Mircea, S. Fuzzi, D. Ceburnis, R. Flanagan,
E.D. Nilsson, G. de Leeuw, M. Martino, J. Woeltjen, C.D. and O’Dowd, C.D, Primary submicron marine aerosol
dominated by insoluble organic colloids and aggregates, Geophys. Res. Lett., 35, L17814,
doi:10.1029/GL034210, 2008.
Forster, P. et al., Changes in atmospheric constituents and in radiative forcing, In Climate Change 2007: The
physical science basis, Cambridge University Press, Cambridge, UK, 129 – 234, 2007.
Hawkins, L.N. and L.M. Russell, Polysaccharides, Proteins, and Phytoplankton Fragments: Four Chemically
Distinct Types of Marine Primary Organic Aerosol Classified by Single Particle Spectromicroscopy, Advances in
Meteorology, 612132, doi10.1155/2010/612132, 2010.
Karl, M., C. Leck, E. Coz, and J. Heintzenberg, Marine nanogels as a source of atmospheric nanoparticles in the
high Arctic, Geophys. Res. Lett., 40, doi:10.1002/grl.50661, 2013.
Keene, W.C., H. Maring, J.R. Maben, D.J. Kieber, A.A.P. Pszenny, E.E. Dahl, M.A. Izaguirre, A.J. Davis, M.S.
Long, X. Zhou, L. Smoydin, and R. Sander, Chemical and physical characteristics of nascent aerosols
produced by bursting bubbles at a model air-sea interface, J. Geophys. Res., 112, D21202,
doi:10.1029/2007JD008464, 2007.
Kulmala, M. et al., Direct observations of atmospheric aerosol nucleation, Science, 339, 943-946, 2013.
Metzger, A. et al., Evidence for the role of organics in aerosol particle formation under atmospheric conditions,
Proc. Natl. Acad. Sci., 107, 6646 – 6651, 2010.
Modini, R.L., Z.D. Ristovski, G.R. Johnson, C. He, N. Surawski, L. Morawska, T. Suni, and M. Kulmala, New
particle formation and growth at a remote, sub-tropical location, Atm. Chem. Phys., 9, 7607 – 7621, 2009.
21
O’Dowd, C., C. Monahan, and M. Dall’Osto, On the occurrence of open ocean particle production and growth
rates, Geophys. Res. Lett., 37, L19805, doi:10.1029/2010GL044679, 2010.
Orellana, M.V., P.A. Matrai, C. Leck, C.D. Rauschenberg, A.M. Lee, and E. Coz, Marine microgels as a source
of cloud condensation nuclei in the high Arctic, Proc. Nat. Acad. Sci, doi/10.1073/pnas.1102457108, 2011.
Quinn, P.K. and T.S. Bates, The case against climate regulation via oceanic phytoplankton sulfur emissions,
Nature, 480, 51-56, doi:10.1038/nature10580, 2011.
Rinaldi, M., S. Fuzzi, S. Decesari, S. Marullo, R. Santoleri, A. Provenzale, J. von Hardenberg, D. Ceburnia, A.
Vaishya, C.D. O’Dowd, and M. C. Facchini, Is chlorophyll-a the best surrogate for organic matter enrichment in
submicron primary marine aerosol? J. Geophys. Res., doi:10.1002/jgrd.50417, 2013.
22
5
Theme 5: Ocean emissions and tropospheric oxidizing capacity
Co-authors: Roland von Glasow and Eric Saltzman
1. Brief statement defining the theme:
Compounds that can affect the tropospheric oxidation power are being exchanged across the air-sea interface.
This includes reactive (inorganic) halogens, sulphur-containing compounds, halocarbons with lifetimes of
minutes to weeks, halogen-containing aerosol particles, certain organic gases, nitrogen-containing gases as well
as organic aerosol.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
The oxidation capacity of the troposphere is key for the self-cleansing capability of the troposphere and is to a
large degree determined by ozone, which also acts as a greenhouse in the troposphere. Methane is a very
strong greenhouse gas, which is predominantly broken down in the marine troposphere, especially in the tropics.
These two gases are the only greenhouse gases that have relevant chemical sinks in the troposphere.
Air quality and climate change are some of the most important challenges that our societies face but despite
decades of research large uncertainties remain to quantify the response of the Earth’s climate system to natural
and anthropogenic emissions. Pollution and issues relating to the oxidation capacity of the atmosphere are
global issues due to atmospheric transport patterns and lifetimes of these compounds in the atmosphere. In
brief, these challenges are global challenges and can efficiently only be addressed in the international
framework
3. Background – major scientific concepts, key prior work defining the issues:
In the last decades the importance of natural emissions from the oceans on the composition and reactivity of the
troposphere has been established and major progress has been made. The quantification of the bidirectional
fluxes is however still very uncertain and recent discoveries of new interactions show that our knowledge about
ocean-atmosphere interactions is still limited.
The compounds exchanged at the ocean-atmosphere interface can be divided into the following groups:
 Inorganic halogens (e.g., I2, HOI)
 Organic halogens (e.g., CH3I, CH2I2, CHBr3...)
 Sulphur-containing compounds (e.g., dimethylsulphide, DMS)
 Volatile organic compounds (VOCs) and oxidized volatile organic compounds (OVOCs) (e.g., isoprene,
methanol, acetone)
 Nitrogen-containing gases (e.g., ammonia, amines, alkyl nitrates)
 Primary marine aerosol (organic and inorganic)
The marine troposphere is furthermore exposed to long-range transport from the continents, especially coastal
cities and emissions from ships.
Inorganic halogens can be directly released from the ocean surface (e.g., I2, HOI, Carpenter et al., 2013),
originate from the breakdown of organic halogens or be released by acid displacement or photochemical
reactions from sea salt aerosol. Inorganic halogens destroy ozone very efficiently but also oxidise DMS, the
greenhouse gas CH4 (only Cl atoms) and iodine oxides can lead to particle formation and growth (e.g., SaizLopez et al., 2012). Recent studies showed that reactive halogens can account for about a third of
photochemical ozone destruction in the North Atlantic (e.g., Read et al., 2008, Sommariva and von Glasow,
2012) and likely also in other ocean regions. Global model studies suggest an important role of halogens, mainly
of marine origin, for the ozone budget in the free troposphere as well (see e.g. Saiz-Lopez and von Glasow,
2012, for a recent review on tropospheric halogen chemistry).
Most of the photochemical loss of the greenhouse gas methane occurs in the marine troposphere by reaction
with the OH radical. Measurements in the North Atlantic further suggested that up to 15% of the breakdown of
methane could be due to chlorine chemistry (Lawler et al., 2011).
23
Figure: Simplified schematic depiction of the most important halogen-related processes in the troposphere.
(From Saiz-Lopez and von Glasow, 2012)
Ozone concentrations are further affected by long-range transport and ship emissions but potentially also by NO x
released from marine alkyl nitrates.
Dimethylsulphide is produced biologically in the ocean and together with volcanic emissions amounts for the
bulk of natural sulphur emissions. The resulting SO2 and is a precursor for sulphate aerosol and plays a role in
the formation and growth of aerosol particles and can lead to the formation/growth of so-called cloud
condensation nuclei (CCN). Aerosol particles (sea salt, sulphate, organic) play an important role as CCN and
can affect climate directly by scattering sunlight.
The detection of the very shortlived glyoxal (Sinreich et al., 2010) over the eastern Pacific Ocean might indicate
that large, currently unquantified sources exist. A large number of Volatile organic compounds (VOCs) and
oxidized volatile organic compounds (OVOCs) are monitored on the Cape Verde site (Carpenter et al., 2010)
and their importance for regional and global ozone production needs to be established.
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
In order to make substantive progress in this field a combination of smaller “pilot” field studies combined with
larger campaigns that are ship and / or aircraft based are required. These should be supported by model studies
to support the field campaigns but also to improve our process understanding and to upscale from the study
region to ocean basins and globally.
Many fundamental questions regarding reaction pathways especially related to multiphase reactions are still
unknown hence laboratory studies that address these issues are essential.
Measurements over the oceans always require coordination between various groups in terms of logistics but
also regarding the scientific equipment as a full characterisation of the composition of the atmosphere (gas
phase and aerosol) is usually beyond individual laboratories and often requires scientists from different
countries.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
SOLAS has made a major contribution to the establishment of an international community and the training of the
next generation of scientists through its open science meetings, focussed workshops and summer schools. This
is a great achievement but an ongoing effort is required to maintain the links in this “new” community.
24
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
The issues related to atmospheric composition have a strong connection with the International Global
Atmospheric Chemistry (IGAC) project as well as the international Commission on Air Chemistry and Global
Pollution (iCACGP).
Focussed workshops have been held for specific topics partly together with IGAC. The SOLAS/IGAC sponsored
task Halogens in the Troposphere has also played a role in this.
Coordination of these collaborations is essential to enable progress in this important field. Funding through the
Belmont Forum would facilitate international collaboration and lobbying to this end would be very helpful.
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
The oceans provide a vast amount of ecosystem services to humanity. Pollution of the atmosphere has a
detrimental effect on this. Furthermore it is likely that the processes listed above are affected by Global Change
but given the link with greenhouse gases Global Change is also affected by oxidative processes or marine gases
and particles in the troposphere.
References:
Carpenter et al., Seasonal characteristics of tropical marine boundary layer air measured at the Cape Verde
Atmospheric Observatory, J. Atmos. Chem, 2010, 67, 87 - 140
Carpenter , L. J. and S. M. MacDonald and M. D. Shaw and R. Kumar and R. W. Saunders and R. Parthipan
and J. Wilson and J. M. C. Plane, Atmospheric iodine levels influenced by sea surface emissions of inorganic
iodine, Nature Geosc., 2013, 6, 108 - 111
Lawler, M. J., R. Sander, L. J. Carpenter, J. D. Lee, R. von Glasow, R. Sommariva, and E. S. Saltzman
HOCl and Cl2 observations in marine air, Atmos. Chem. Phys., 11, 7617-7628, 2011
Read et al., Extensive halogen-mediated ozone destruction over the tropical Atlantic Ocean, Nature, 2008, 453,
1232 - 1235
Saiz-Lopez A. and R. von Glasow, 2012, Reactive halogen chemistry in the troposphere. Chem. Soc. Rev.,
2012, 41, 6448-6472, DOI:10.1039/C2CS35208G
Saiz-Lopez, A., J. M. C. Plane, A. R. Baker, L. J. Carpenter, R. von Glasow, J. C. Gomez Martin, G. McFiggans
and R. W. Saunders, Atmospheric Chemistry of Iodine, Chem. Rev., 112, 1773-1804, 2012
Sinreich, R., S. Coburn, B. Dix and R. Volkamer, Ship-based detection of glyoxal over the remote tropical Pacific
Ocean, Atmos. Chem. Phys., 2010, 10, 11359 – 11371
Sommariva, R. and R. von Glasow, Multi-phase halogen chemistry in the tropical Atlantic Ocean, Env. Sci.
Tech., 46, 10429-10437, 2012
25
6
Theme 6: Interconnections between ocean biogeochemistry and stratospheric chemistry
Co-authors: Eric Saltzman and Roland von Glasow
1. Brief statement defining the theme:
Reactive gases emitted from the sea surface are transported to the stratosphere in the tropics, where they can
influence photochemistry and chemistry and catalytically destroy ozone. The chemical composition and
spatial/temporal distributions of these emissions, and the biogeochemical factors controlling them are not well
understood. The goal of this theme is to provide a basis for understanding how the oceans impact stratospheric
chemistry and how future changes in oceanic ecosystems will influence stratospheric ozone.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
Stratospheric chemistry is of great importance to the Earth system because of its role as a protective shield
against harmful ultraviolet solar radiation and its influence on Earth’s energy budget. Over the past century,
industrial and agricultural emissions have altered stratospheric chemistry by the emission of chlorofluorocarbons
and other halogenated chemicals, methane, nitrous oxide, and sulfur dioxide. There has been progress
controlling the emissions of some of these compounds through international agreements under the international
Montreal Protocol and others are discussed under the Kyoto Protocol and other frameworks. However, the task
of returning stratospheric ozone to a natural or preindustrial state is complicated by other ongoing environmental
changes, which have the potential to alter biogeochemical emissions of stratospheric ozone-depleting chemicals.
For example, large-scale changes in oceanic ecosystems are anticipated over the coming century, driven by the
multiple stressors of climate change, ocean acidification, and anthropogenically-driven changes to nutrient
cycles. These changes may affect the emissions of ozone depleting substances from the ocean surface. As a
consequence, predicting the future evolution of stratospheric ozone during the coming century involves
understanding the oceanic emissions of ozone-depleting substances and how they will evolve.
Understanding the oceanic impact on stratospheric chemistry is a multidimensional problem, involving ocean
ecosystem dynamics, surface ocean biogeochemistry, and atmospheric chemistry and dynamics. The research
requires interaction across a wide range of disciplines – from phytoplankton physiology to photochemistry,
meteorology, oceanography, and climate. The observational requirements include coordinated observations in
the oceans and atmosphere, remote sensing, and coupled ocean/atmosphere modeling. The need for
international coordination is compelling in order to plan, and execute major field programs, involving both
oceanographic and atmospheric research platforms, and to facilitate communication between the various
communities engaged in the work. In terms of societal need, we require not only a scientific understanding of the
problem, but policies capable of responding to the factors coupling the two issues of stratospheric ozone and
climate change.
3. Background – major scientific concepts, key prior work defining the issues:
It is well established that halogen atoms (Cl, Br) released from halocarbons lead to the catalytic destruction of
stratospheric ozone. The majority of the chlorine and bromine in the stratosphere is derived from anthropogenic
emissions of long-lived compounds which are long-lived in the atmosphere, and which are controlled under the
Montreal Protocol. However, a portion of stratospheric ozone depletion can be attributed to the emissions and
transport of so-called “very short-lived substances” or VSLS. These are defined as trace gases whose chemical
lifetimes are comparable to transport times in the troposphere (<0.5 years). Hence, they are non-uniformly
distributed in the lower atmosphere and their effects on the upper atmosphere are highly sensitive to their
chemistry and transport, and the location of their emissions. VSLS include both anthropogenic and natural
compounds.
It has been shown that the tropical oceans play a role in the delivery of VSLS: 1) a wide range of volatile
halogenated and sulfur-containing compounds are produced biologically and photochemically in seawater and
are released to the marine atmosphere, and 2) some biologically productive waters occur in tropical regions with
26
strong vertical uplift, where air is entrained into the upper troposphere/lower stratosphere.
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
 Field observations of emissions, and atmospheric distributions of stratospherically active compounds and
precursors over oceanic, most importantly the Indonesian “maritime continent” and tropical western Pacific
where strong uplift occurs.
 Laboratory, mesocosm, and field studies of the mechanism of production of such gases and the processes
that control their emissions from the sea surface, and investigation of how future changes in ocean nutrients,
pH, etc. will impact these processes at the organism or ecosystem level.
 Atmospheric chemistry field, laboratory, and modeling studies of the transformations of VSL compounds after
emission.
 Modeling studies examining the impact of oceanic emissions on stratospheric chemistry and the linkages
between climate and the biogeochemistry of these compounds.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
This research requires collaborative interaction among communities which historically are trained in different
institutions, attend different scientific conferences, and utilize very different vocabularies. These include
microbiologists, biomolecular chemists, chemical oceanographers, tropospheric/stratospheric chemists and
dynamicists, and climate scientists. Progress in this area will require scientists who share a common
understanding of the complex interconnections between the ocean, stratosphere, and climate. The atmospheric
chemistry and dynamics communities are fairly well linked via joint consortia (e.g., the recent EU-funded SHIVA
consortium) and assessments, most prominently the WMO Scientific Assessment of Ozone depletion. New
efforts are needed to extend these linkages to the other communities listed above.
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
Important partnerships include the IGAC/SPARC Chemistry-Climate Model Initiative (CCMI), the SPARC
Stratospheric Sulfur and its Role in Climate (SSiRC).
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
Maintaining a healthy stratosphere is one of the most fundamental requirements of a sustainable society. The
costs of stratospheric degradation include human health risks, damage to oceanic ecosystems and food web,
potential changes in genetic mutation rates, damage to agricultural crops and livestock. In addition, there are
many interactions between stratospheric ozone and other elements of the climate system. There is a direct
societal interest in understanding the risks associated with various forms of human activity. The Montreal
Protocol was an outstanding example of how dramatic environmental change (i.e. the Antarctic ozone hole)
galvanized nations society to successfully cope with an urgent global environmental issue. The longer-term
climate/ozone interactions discussed here have the potential to change the “baseline” of ozone depleting gases
which the Montreal Protocol seeks to regulate. Furthermore, some proposed geoengineering schemes involve
changing surface oceanic biogeochemistry. It is important to have a multidisciplinary community capable of
assessing such scheme for the full range of possible environmental consequences.
27
7
Theme 7: Multiple stressors and ocean ecosystems
Co-authors: Minhan Dai and Anja Engel
1. Brief statement defining the theme:
Over the last century, the ocean ecosystems have been experiencing unprecedented changes driven by both
natural and anthropogenic stressors such as temperature rising, eutrophication, deoxygenation/hypoxia, plastic
litter and ocean acidification. Several of these stressors occur simultaneously and interact with each other, which
presents an immense challenge to identify key stressors and combined effects on ocean biogeochemistry, airsea interactions, as well as ecosystem functioning and services.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
The ocean and its ecosystems provide a variety of valuable economic services to human society. Examples
include supporting services of nutrient balance, hydrological balance, regulating services of pollutant attenuation
and climate regulation and cultural services of science and education, recreational opportunities as well as food
production. Theme 7 has thus a clear and direct relevance to the human society.
Understanding how marine ecosystems respond to individual stressors and their combinations in the past,
present and future is however scientifically challenging but essential in order to identify the associated ecological
and economic implications of environmental changes, as well as to seek effective management strategies
towards sustainability. Moreover, multiple changes in ecosystem structure, functioning and dynamics can be
expected to differ from single stressor effects, and vary by region, and over time. International coordination is
thus crucial in order to identify research priorities, evaluate and guide experimental and methodological
approaches, and intercomparison of individual research results, and to translate scientific knowledge to support
socioeconomic risk assessment and political decision making
The primary goal of theme 7 is to identify anthropogenic key stressors and to understand consequences of the
simultaneous interaction of stressors resulting in multiple transitional ecosystem states and to significantly
improve our predictive ability of the future marine ecosystem changes. In focus are the most vulnerable/hot,
ecologically and economically important regions that currently experience unprecedented change (link to theme
8) such as human impacted coastal and marginal seas, large river delta systems, upwelling systems, and the
pristine Polar Seas. The scientific challenge is to establish an ecosystem baseline, i.e. identify natural variability,
to capture changes driven by anthropogenic stressors, and ultimately to provide a holistic view of multiple
stressors interactions with respect to global and regional ecosystems. An FE related goal would be to estimate
socioeconomic consequences of multiple stressors with respect to regional and global climate change, ocean
productivity, ocean health and ecosystem services, and to transfer this knowledge to support policy and decision
making.
3. Background – major scientific concepts, key prior work defining the issues:
Human footprints have imbedded in and impacted on the ocean’s ecosystems on various ways and at different
spatial-temporal scales (Fig. 1, Doney et al., 2010). Several key stressors can be identified: The progressive
increase in atmospheric CO2 directly and indirectly affects the marine biosphere. Indirect effects are expected
through global warming related rising of sea surface temperatures, which may cause increased surface ocean
stratification and mixed layer insulation, thereby changing the dissolved oxygen content in seawater. Due to the
rapid air-sea exchange of CO2, direct, and already determined, effects of increased atmospheric CO 2
concentration are the rise of CO2 concentration in the surface ocean and a related shift in its chemical
equilibrium (Chen and Millero 1979), including an unprecedented rapid decline in surface seawater pH, referred
to as ocean acidification. Multiple effects of changes in pH, O 2 and CO2 concentration are expected for plankton
28
organisms, their physiological rates, species diversity, and population dynamics, in turn affecting the productivity
and biogeochemical cycling of marine ecosystems (Gattuso and Hansson, 2011). Yet, mechanisms and
magnitude of biological and biogeochemical responses to environmental change in a “hot”, “sour” and
“breathless” ocean are largely unknown. Another suites of stressors are primarily related to the nutrient influxes
into the ocean through land-ocean (Cai et al., 2011) or air-sea interfaces (Kim et al., 2011). Accumulative and
even excessive nutrients input into the ocean have clearly affected the coastal ecosystems, the similar signals of
which have emerged in open waters. Since the middle of the last century, increasing global production of plastic
material resulted in the accumulation of plastic litter in the ocean. Thereby, larger plastic litter mostly fragments
over time to form a pool of microplastics (< 5 mm) together with primary plastic litter of micro-size. Microplastics
can enter the food chain and affect the nutritional quality of marine products, particularly as they contain and
adsorb toxins such as persistent organic polutants (POPs) (Hidalgo-Ruz et al. 2012).
We currently fail to understand how multiple stressors impact marine ecosystems and related biogeochemical
processes, being themselves variable in time and space, primarily because we do not understand how marine
ecosystems function. The number of studies addressing the ocean’s responses to environmental change has
been vastly increasing over the past decades, yet the insight gained is relatively small. This is due to the
complexity of the problem on the one hand, but also owing to a lack of coherent scientific approaches, resulting
in the danger of global change research becoming ‘a Gordian Knot of disparate strands of data’ (Boyd, 2013)
(Fig. 2). Moreover, there is a striking disparity between sound scientific knowledge and attempts/ needs to
economically value the impact of multiple stressors on marine ecosystems.
(from Doney et al., 2010)
29
Fig. 2 from Boyd, 2013, Nature Climate Change, 3, 530-533.
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
Theme 7 will expand the SOLAS theme of atmosphere-ocean interactions by emphasizing the effect of the
human perturbation. SOLAS can improve and maximize the output of multiple stressor research by a series of
actions. The primary aims would be to:



Gain coherence by i) stimulating the dialog between disciplines to identify the quality and quantity of
observational data needed for regional and global physical-ecosystem coupled models and ii) set-up a frame for
future scenarios being tested (i.e. IPCC), iii) identify key regions
Improve quality by i) enforcing experimental and methodological standardization, ii) fostering intercomparison
exercises on disparate studies, iii) supporting capacity building
Enhance outreach of scientific results by i) promoting the assimilation of empirical and observational-based
knowledge in Earth System Models, economic models, impact assessments, and policy frameworks, ii) foster
information exchange with FE, policy makers, stakeholders etc…
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals? 6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
There is quite consensus in the scientific community that the ocean ecosystem is changing under multiple
stressors. Such a consensus is at least partially attributable to the fast growing community in ocean acidification
research. As a result, the Ocean Acidification Working Group jointly sponsored by SOLAS and IMBER has
fostered a new initiative, the Ocean Acidification International Coordination Centre (OA-ICC) presently operated
by the IAEA Environment Laboratories in Monaco. Given the magnitude of the problems and the complexity of
the largely unknown future changes that the ocean ecosystem is facing requires international coordination more
30
than the researches of ocean acidification. Partner coordination with OA-ICC would however be very beneficial
in progressing the present multiple stressor theme.
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
The ocean ecosystem and multiple stressors is clearly a direct and complex issue of sustainability, which shall
be an obvious goal of the FE.
References:
Boyd, Philip W. "Framing biological responses to a changing ocean." Nature Climate Change 3.6 (2013): 530533.
Cai, W.-J., X. Hu, W.-J. Huang, M.C. Murrell, J.C. Lehrter, S.E. Lohrenz, W.-C. Chou, W. Zhai, J.T. Hollibaugh,
Y. Wang, P. Zhao, X. Guo, K. Gundersen, M. H. Dai, and G.-C. Gong (2011), Acidification of subsurface coastal
waters enhanced by eutrophication, Nature Geoscience, 4 (11), 766-770.
Chen, G.-T. and Millero, F.J. (1979). Gradual increase of oceanic CO 2. Nature 277, 205-206.
Doney, Scott C. "The growing human footprint on coastal and open-ocean biogeochemistry." Science 328.5985
(2010): 1512-1516.
Gattuso J.-P. & Hansson L. (Eds.), 2011. Ocean acidification, 326 p. Oxford: Oxford University Press.
Hidalgo-Ruz, Valeria, et al. "Microplastics in the marine environment: a review of the methods used for
identification and quantification." Environmental science & technology 46.6 (2012): 3060-3075
Kim, Tae-Wook, et al. "Increasing N abundance in the northwestern Pacific Ocean due to atmospheric nitrogen
deposition." Science 334.6055 (2011): 505-509.
31
8
Theme 8: High Sensitivity Systems- HS2
Co-authors: Michelle Graco, Anja Engel, Lisa Miller, Véronique Garçon and Jacqueline Stefels
1. Brief statement defining the theme:
In the global context Eastern Boundary Upwelling Systems (EBUSs) and Polar systems have been identified as
hot spots for air-sea exchange research, because of their significant role in the ocean ecosystems and global
biogeochemical cycles. They are also identified as High Sensitivity Systems (HS2) to the global change impacts.
Hence, research on the potential consequences and feedbacks of global change needs to include focused
studies of such specific HS2.
2. The scientific and societal basis justifying research on this issue. Why is it critical and why does it
need to be done now? What is the end goal? Why is international coordination required?
The Equatorial Boundary Upwelling Ecosystems (EBUSs) and Sea-Ice ecosystems are particularly relevant to
the SOLAS goal ”To achieve quantitative understanding of the key biogeochemical-physical interactions and
feedbacks between the ocean and the atmosphere”. These environments are included in the SOLAS Mid-term
Strategies (Law et al., 2013). However the existing knowledge is still insufficient and because of their
implications and complexity it is necessary to reinforce multidisciplinary studies in the coming years in these
systems and also other HS2.
The EBUSs are among the most productive areas in the world ocean and support important fisheries.
Their high productivity feeds one of the world’s largest and most intense Oxygen Minimum Zones (OMZs), which
are associated with new paradigms in the nutrient cycling and significant releases of greenhouse gases. We
know that these areas influence the cloud properties and the climate and any change in the upwelling and OMZ
conditions, such as change in circulation patterns, deoxygenation, is expected to result in changes in
productivity, biogeochemical processes and trace gases production. In turn, the dynamics and consequence of
the changes in Sea-Ice characteristics and distribution in the polar oceans are critical to understand and model
feedback effects and future scenarios of climate change. We understand that sea ice is an active player in the
climate, through air-sea gas exchange and aerosol production, as well as carbon dioxide export.
However, in EBUSs and Sea-Ice systems existing knowledge is yet insufficient to a) assess the direction
and extent of future changes in biogeochemical cycles resulting from warming, deoxygenation and changing
sea-ice distributions, b) determine critical thresholds and resilience capacity of these systems, and c) improve
management strategies for human interactions with high sensitive systems (HS 2) and apply an ecosystemic
approach based management including other aspects as resource extraction, tourism, transportation and
pollutant cycling.
The challenge of this “hot-spot” research of complex systems in unique environments is to develop
multidisciplinary collaborations with highly qualified scientists, and to combine research and capacity building,
with new techniques and innovative technologies for observational and modeling approaches. In such contexts
national efforts are insufficient and international coordination is required.
3. Background – major scientific concepts, key prior work defining the issues:
EBUSs, as the California, Humboldt, Benguela and Canary Currents, are characterized by high
productivity and support the largest fisheries of the world (e.g. Chavez et al., 2009). The high productivity is
associated with shallow and intense Oxygen Minimum Zones (OMZs) with high CO 2 contents, low pH values and
a shallow aragonite saturation horizons that can impinge on the euphotic zone, impacting the surface ecosystem
and releasing CO2 and N2O, strong greenhouse gases, to the atmosphere (e.g. Bange et al., 2006, Farías et al.,
2007, Friederich et al., 2008, Paulmier et al., 2008; Paulmier and Ruiz-Pino, 2009). EBUSs and OMZs are
characterized also by an intense microbial recycling associated with the nitrogen and sulphur cycling that deeply
impact in the environmental conditions, the communities and the greenhouse sink-source of the coastal waters
(e.g. Lam et al, 2010, Schunk et al., 2013, Ulloa et al., 2012). Ultimately, these biogeochemical processes
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determine the productivity of these systems and their role as sinks or sources of climate-active gases needs to
be adequately addressed in order to understand the interactions with the climate system (Law et al., 2013).
Until now, sea ice was assumed to block air-sea gas and material exchange, momentum and heat were
thought to be the only parameters that effectively passed through the ice. However, over the last 10 years and
thanks to a massive research effort, much of which has been conducted by SOLAS scientists, we now
understand that sea ice is not a passive barrier to air-sea exchange, but is an active participant in the
biogeochemical cycles of many elements, producing climatically-active atmospheric aerosols (Leck and Bigg,
2010), modulating the surface ocean ecosystem (e.g., Arrigo et al., 2010), contributing to substantial seasonal
CO2 fluxes, and possibly facilitating long-term export and CO2 sequestration in deep waters (e.g., Loose et al.,
2011). Dramatic changes in air-sea gas exchange rates co-vary with the open-water fraction (Loose et al., 2009;
Else et al., 2011). Therefore, the polar oceans are a true, year-round hot spot for air-sea interactions. The
researches over the last decade conclude that sea ice is a very rich and complex system in which biotic and
abiotic processes interact in changing ways throughout the lifetime. The freeze melt of sea ice strongly impacts
on the physical characteristics of surrounding surface waters (Thomas and Dieckmann, 2010). This newly
identified complexity in the sea-ice system is confounding efforts to predict how changes in ice cover will
propagate throughout polar ecosystems and feed back onto the global climate system.
Sea ice and the EBUSs are only two examples of complex regional systems undergoing dramatic
changes that are not only intimately linked with climate, but that also impact human communities. Nonetheless,
the interdisciplinary and international framework SOLAS provides to tackle these problems will also serve
research in other high sensitivity systems, as their importance becomes evident.
Sea- ice Ecosystems
Habitat, source, sink and barrier for gas
exchange:
-Trace Gas emissions/ Photochemistry
-DMS and Climate
-CO2 Cycling and climate
Coastal Upwelling Ecosystems /OMZs
Habitat, source, sink for gas exchange:
-Trace gas Emissions/ Photochemistry
-Atmospheric Nitrogen Cycling, N2O and
Climate
-CO2 Cycling, acidification, deoxygenation and
Climate
From Law et al., 2013
4. Approaches – what will it take to make substantive progress on the issue? What will be achieved in
the 10 years of Future SOLAS?
“Holistic” multidisciplinary approaches are required to address ocean-atmosphere exchange, processes and
feedbacks in high sensitivity systems if we are to improve our capacity to predict climate change impacts and
identified effective mitigation and/or adaption strategies.
The Future SOLAS has a key role in coordinating national efforts and to implement the multidisciplinary
research projects required to address climate-change impacts by the High Sensitivity Systems- HS2 .
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For the next 10 years, Future SOLAS will support research in High Sensitive Systems (HS2) through:
-GAS EXCHANGE MONITORING AND PROCESS STUDIES. Continue and reinforce the biological, chemical
and physical controls of greenhouse and reactive trace gas cycling in EBUSs and at the sea-ice interfaces.
-HS2 AND MULTIPLE STRESSORS. To explore the regional dynamics of relevant stressors and their
synergistically effect in EBUSs and Sea Ice systems.
-REGIONAL MODELS. Improve representations of biogeochemistry in regional models of sea ice and EBUSS,
with better descriptions of biogeochemical processes coupled with higher temporal and spatial resolution of
observational data. Develop high-resolution coupled atmosphere-physical and biogeochemical models nested in
larger resolution models.
-EARTH SYSTEM MODELS. Identify the elements of HS2 systems that are key parameters to global change
and incorporate them into Earth System Models to address impacts and feedbacks in future global change
scenarios.
-OBSERVATIONAL PLATFORMS. Articulate and reinforce observation platforms (local and regional ship-based
cruises, moorings, floats, autonomous vehicles, satellites) in order to obtain time series with good resolution on
spatial and temporal scales of different climatic variables (e.g. temperature, salinity, trace and greenhouses
gases, nutrients, oxygen, carbonate system).
- HS2 DATABASES AND INTERCOMPARISONS. Organize linked databases at LOCAL AND GLOBAL LEVEL,
facilitating decision making for local countries, while also feeding global climate models to determine vulnerability
and risk and to predict future social-economics impacts of climate change. Evaluation and standardization of
methodology and protocols for comparable measurements.
-OTHER HS2 REGIONS. Develop flexible and innovative strategies for initiating air-sea exchange research in
other climatically important hot spots.
5. Community readiness – is there an existing community engaged on this issue? Are there institutional
or other barriers to progress? Is infrastructure or human capacity building required in order to achieve
the goals?
In 2008, five research topics and issues that require international coordination to make progress have been
identified. Air-sea gas fluxes at Eastern boundary upwelling and Oxygen Minimum Zone (OMZ) systems (PI: V.
Garcon) and Sea-ice biogeochemistry and interactions with the atmosphere (PI: J. Stefels) compose the socalled SOLAS Mid-Term Strategy. Following initiatives within SOLAS’ Mid-Term Strategy other programs as
CLIVAR-IMBER and SCOR Working Group (WG 140) examining these systems but in complementary aspects,
e.g. to develop strategies and initiate a number of important activities, including methodological intercomparison
and standardizations, database development, and regional and earth system model advancements. These
working groups will directly benefit from continuing SOLAS support.
6. External connections – what partnerships are required in order to achieve the goals? What
mechanisms will be used to accomplish the interactions?
The Global Ocean Observing System (GOOS) Through their focus on autonomous observation platforms and
remote sensing, GOOS is facilitating the high temporal and spatial resolution monitoring necessary to resolve
many of the complex processes in HS2 and to improve the success rate and usefulness of in situ biogeochemical
sensor deployments. The GOOS subsidiaries AOOS and SOOS (in the Arctic and Southern Oceans,
respectively) are also enhancing our capacity to understand sea-ice and ocean dynamics in these regions where
ship-based work is difficult and sparse.
The SFB 754 at GEOMAR "Climate-Biogeochemistry Interactions in the Tropical Ocean. Collaborative
Research Center addresses the relatively newly recognized threat of ocean deoxygenation, its possible impact
on tropical oxygen minimum zones and implications for the global climate-biogeochemistry system. The overall
goal of the SFB 754 is to improve understanding of the coupling of tropical climate variability and circulation with
the ocean's oxygen and nutrient balance, to quantitatively evaluate the nature of oxygen-sensitive tipping points,
as well as to assess consequences for the Ocean's future. (https://www.sfb754.de/de).
The French AMOP project (Activités de recherche dédiées au Minimum d’Oxygène du Pacifique-est:
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http://www.legos.obs-mip.fr/recherches/projets-en-cours/amop/scientific-objective), with collaborations with
Germany, Denmark, Mexico and Peru, to cite a few, is focused on the Eastern South Pacific and its overarching
goal is to understand the oxygen dvnamics in this OMZ by providing a comprehensive budget for oxygen based
on oceanographic cruise efforts, time series acquisition from a mooring deployed off Peru, and a high resolution
coupled atmosphere-physical and biogeochemical modeling platform.
International collaboration and cooperation will also be sought within the networks of SCOR, SCAR,
PICES, and AOSB in order to involve key scientific groups, to interact with stakeholders and communicate the
progress of our knowledge.
7. Sustainability – articulate relationship (if any) between this project and the FE goals of Global
Development and Transformation Towards Sustainability.
At present, many key ecosystems are threatened by climate change and other stressors associated with human
exploitation, and those threats are feeding back into strains on the communities that depend on those
ecosystems. Every country must rise to the challenge of protecting Biodiversity and Ecosystem Services, but it
must also be done through international collaboration. Present and future changes are particularly critical at HS 2,
and impacts need to be addressed at different levels, local, national, regional, and global. In this context it is
important to sensibly mobilize all the stakeholders to focus on national and international research efforts and
capacity building for sustainable development.
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