GESAMP Working Group 38
The Atmospheric Input of Chemicals to the Ocean
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Recall the Issue
Recognition continues to grow concerning the impact of
the atmospheric input of both natural and anthropogenic
substances on ocean chemistry, biology, and
biogeochemistry as well as climate. In the 1980s, GESAMP
formed a working group sponsored by WMO,
UNESCO/IOC, and UNEP that developed a comprehensive
review of the input of atmospheric trace species to the
global ocean (GESAMP, 1989). That benchmark effort led to
a scientific publication in Global Biogeochemical Cycles
that for ~15 years was the state-of-the-art reference in this
area, leading to over 700 citations in the literature. That
paper is now more than 20 years old, and a new overall
look at this issue was needed.
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For this reason Working Group 38 was formed during 2008
and it held its first meeting at the University of Arizona,
Tucson, AZ, in 2008. Subsequent meetings were held at
IMO in London in 2010 and Malta in 2011.
Sponsors of previous WG 38 efforts have included WMO,
IMO, SCOR, SIDA, the European Commission Joint
Research Centre, the University of Arizona, and the
International Environment Institute at the University of
Malta. The new work that will be described later is
supported by WMO, IMO, the US National Science
Foundation, and SCOR.
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The membership of WG 38 has been as follows
Co-Chairs: Robert Duce, USA and Peter Liss, United Kingdom
Members of the Working Group:
Alex Baker - United Kingdom
Frank Dentener - Italy
Keith Hunter - New Zealand
Maria Kanakidou - Greece
Nilgun Kubilay - Turkey
Natalie Mahowald - United States
Greg Okin - United States
Joseph Prospero - United States
Manmohan Sarin - India
Vanisa Surapipith - Thailand
Ina Tegen - Germany
Mitsuo Uematsu - Japan
Tong Zhu - China
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The initial charge for WG 38 was as follows:
I.
Assess the need for the development of new model and
measurement products for improving our understanding of
the impacts of the atmospheric deposition of nitrogen
species and dust (iron) to the ocean.
II.
Review the present information on the atmospheric
deposition of phosphorus species to both the marine
and terrestrial environments, considering both natural
and anthropogenic sources, and evaluate the impact of
atmospheric phosphorus deposition on marine and
terrestrial ecosystems. Consider whether such a review
of any other substances would be useful.
III.
Work with the WMO Sand and Dust Storm Warning and
Assessment System and with the WMO Precipitation
Chemistry Data Synthesis and Community Project to
evaluate the needs of the marine community and assist in
clearly articulating them in the development of these WMO
efforts.
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Charges I and II have been partially satisfied by 2 papers that have been published
in the peer-reviewed literature:
Okin, G., A. R. Baker, I. Tegen, N. M. Mahowald, F. J. Dentener, R A. Duce,
J. N. Galloway, K. Hunter, M. Kanakidou, N. Kubilay, J. M. Prospero, M. Sarin,
V. Surapipith, M. Uematsu, T. Zhu, “Impacts of atmospheric nutrient deposition on
marine productivity: roles of nitrogen, phosphorus, and iron, Global Biogeochem.
Cycles, 25, GB2022, doi:10.1029/2010GB003858, (2011).
Hunter, K.A., P. S. Liss, V. Surapipith, F. Dentener, R. A. Duce, M. Kanakidou,
N. Kubilay,, N. Mahowald,, G. Okin,, M. Sarin,, I. Tegen, M. Uematsu, and T. Zhu,
“Impacts of anthropogenic SOx, NOx and NH3 on acidification of coastal waters
and shipping lanes”, Geophysical Research Letters, 38, L13602,
doi:10.1029/2011GL047720 (2011).
The results of these papers were discussed at last year’s GESAMP meeting.
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In response to Charge III, you will recall that at the
first meeting of WG 38 two reports were
developed, and after review by GESAMP they were
submitted to WMO:
Report of GESAMP Working Group 38
to the
WMO Precipitation Chemistry Data Synthesis and
Community Project
and
Report of GESAMP Working Group 38
to the
WMO Sand and Dust Storm Warning Advisory
and Assessment System
These reports satisfied the initial considerations of Charge III of the
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Terms of Reference.
New York, 2012
The third paper developed under Charges I and II
was being prepared when the last meeting
of GESAMP took place, and many of the results
were presented last year. That paper was
submitted to Global Biogeochemical Cycles late
last fall and we have just received the reviews,
which were quite good. We expect the paper to
be sent back to the journal before the end of May.
“Atmospheric organic material and the nutrients nitrogen
and phosphorus it carries to the ocean” by M. Kanakidou,
R. Duce, J. Prospero, A. Baker, F. Dentener, K. Hunter, N.
Mahowald, M. Sarin, P. Liss, M. Uematsu, et al.
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Organic Carbon Deposition to the Ocean
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Nitrogen Deposition to the Ocean
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Organic Phosphorus Deposition to the Ocean
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At GESAMP 37, WMO proposed that GESAMP WG 38 hold
a third meeting in the spring of 2011. At this meeting the
WG would look in more detail at some aspects of the third
term of reference, specifically related to dust. GESAMP
WG38 was to establish a close cooperation with the WMO
Sand and Dust Storm Warning and Assessment System
(SDS-WAS) in order to exploit the already existing
modelling and observational capabilities of the SDS-WAS
project. Thus the meeting in the spring of 2011 was joint
between WG 38 and SDS-WAS. This meeting had the title
“Expert Workshop on Modelling and Observing the
Impacts of Dust Transport/Deposition on Marine
Productivity”.
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As described last year, the joint workshop meeting of GESAMP WG 39
and SDS-WAS was held in Malta from 7-9 March 2011. The meeting
was organized around three separate topics, and both plenary
discussions and individual group/topic discussions were held.
The three topics were:
Topic 1: Improving the quantitative estimates of the geographical
distribution of the transport and deposition of mineral matter and its
content to the ocean.
Topic 2: Long-term assessment of mineral dust/Fe/P input to the
ocean: In-situ observations and marine response utilizing coupled
atmospheric transport and ocean biogeochemical modeling and
remote-sensing.
Topic 3: Specifying test-bed regions for joint studies of the
transport and deposition to the ocean of mineral matter.
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The results of the Malta meeting were decribed to GESAMP last
Year. During the past year it was decided to submit these results
To the journal Environmental Science and Technology, which was
planning a special issue on the marine boundary layer. That
paper was submitted in early January, 2012.
The reviews of that paper were received only late last week and I
had a chance to look at them only this Sunday. Some work will
be necessary for this paper to be published. The paper is:
Schulz, M., J. Prospero, F. Dentener, I. Tegen, M. Sarin, S. Nickovic,
N. Mahowald, L. Ickes, A. Baker, C. Perez Garcia-Pando,
S. Rodriguez, P. Liss, and R. Duce, “The atmospheric transport and
deposition of mineral dust to the ocean - implications for research
needs”, Submitted to Environmental Science and Technology,
(2012).
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Brief Conclusions
A new research strategy is needed that
emphasizes long-term, internationally
coordinated network of surface and column
atmospheric measurements carried out on
selected islands and exposed coastal sites.
In addition, dedicated intensive campaigns and
an advancelent in measurement and modeling
technologies must be developed to attain a
consistent process understanding iof the impact
of dust on maribe biogeochemistry.
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Future research should focus on the following scientific problems:
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Suggested future atmospheric measurement stations
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Continued activities of WG 38
GESAMP 38 approved additional work of GESAMP WG 38 to address
issues related to the impact of the atmospheric deposition of
anthropogenic nitrogen to the ocean as follows:
New Charge
1) Update the geographical estimates of anthropogenic nitrogen deposition to
the global ocean made in the Duce et al. (2008) paper in Science, which were
based on data from 2005 or earlier. This would utilize newer and more
geographically distributed data on anthropogenic nitrogen concentrations
over the global ocean and its deposition to the global ocean surface as well
as improved models of atmospheric deposition and its impacts.
2) On the basis of 1), re-estimate the amount of additional CO2 that could be
drawn down from the atmosphere to the ocean as a result of the increased
productivity in the ocean resulting from the additional anthropogenic nutrient
nitrogen deposited. This would allow an update on the impact of the
atmospheric nitrogen deposition atmospheric radiative properties, relative to
the (2008) paper in Science.
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Continued activities of WG 38
3) Provide a much more accurate estimate of the impact of atmospheric
anthropogenic nitrogen deposition on the production of additional nitrous oxide
in the ocean and its subsequent emission to the atmosphere. This was certainly
one of the greatest uncertainties in the 2008 Science paper. This is very
important to evaluate accurately, since N2O is such a powerful greenhouse gas,
and the emission of additional N2O from the ocean will cancel to some extent
the effects of the additional drawdown of CO2 on the radiative properties of the
atmosphere.
4) Evaluate the extent to which anthropogenic nitrogen delivered to the coastal
zone via rivers, atmospheric deposition, etc. is transported to the open ocean,
in which regions may this happen, and what its impact is there. (In the 2008
Science paper we assumed that all nitrogen delivered to the coastal zone was
sequestered there and did not reach the open ocean, but this may well not be
true, and this is something that should be looked at more carefully.)
5) Do a much more detailed estimate of the impact of anthropogenic nitrogen
in the area of the Northern Indian Ocean (Arabian Sea, Bay of Bengal) and the
South China Sea - the areas that are expected to show the greatest increase of
anthropogenic nitrogen deposition over the next decade or so (according to
the 2008 Science paper). These very important regions are also areas for
which extensive new atmospheric data are now available compared with 5
years ago, and this should enable much more accurate estimates to be made.
To undertake this new activity we retained the old WG 38 members
who had expertise in nitrogen and added a number of additional
experts to participate in the workshop that would address these
5 issues.
The workshop participants are as follows:
Katye Altieri (US), Kevin Arrigo (US),
Alex Baker (UK), Doug Capone (US),
Frank Dentener (Italy), Robert Duce (US),
Katja Fennel (Canada), Jim Galloway (US),
Nicolas Gruber (Switzerland, Tim Jickells (UK),
Maria Kanakidou (Greece), Julie LaRoche (Canada/Germany),
Kitack Lee (Korea), Peter Liss (UK),
Jack Middelburg (Netherlands), Keith Moore (US),
Slobodan Nickovic (Switzerland), Greg Okin (US),
Andreas Oschlies (Germany), Joseph Prospero (US),
Manmohan Sarin (India), Sybil Seitzinger (Sweden),
Jonathan Sharples (UK), Parv Suntharalingam (UK),
Mitsuo Uematsu (Japan), Charlie Zender (US)
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The workshop will take place at the University of East Anglia in
Norwich, United Kingdom, from 11-14 February 2013.
Our tentative plans for the organization of the workshop is to base it
on the 5 new charges outlined above, designating at least 2
individuals to prepare background material before the workshop on
each charge and lead the discussion and subsequent modeling
or other effort related to it. We expect that likely several papers will
result from this effort.
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Thank you
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