Iodide in the ocean:distribution and impact on iodine flux and ozone loss

Lead Research Organisation: University of York
Department Name: Chemistry

Abstract

Over the last five years, research led by this team has made it apparent that the reaction of iodide with ozone at the sea surface plays an important role in controlling the chemical composition of the troposphere. This process directly controls the deposition of O3 to the oceans and is the dominant source of reactive iodine to the atmosphere, which leads to significant loss of tropospheric O3. Ozone concentrations are directly impacted but through changes to the atmospheric oxidants, indirect changes also occur to methane and aerosols leading to potential ramifications on climate, air quality and food security. This is likely a biogeochemical negative feedback for tropospheric O3 and oxidants, which, since it is dependent on both atmospheric O3 and ocean iodide concentrations, will have changed over time. Iodine is also an essential human nutrient. The transport of iodine from the oceans to the atmosphere and subsequent deposition over land is a pathway by which marine iodine may enter the terrestrial food chain, and iodine radioisotopes released to the sea may be dispersed. These iodine ocean-atmosphere processes are now being incorporated into chemical transport models but critical uncertainties remain. The marine iodide distribution is poorly understood, yet it is likely that it will be subject to change as a result of changes in ocean circulation, biological productivity and ocean deoxygenation.

This proposal brings together marine and atmospheric scientists in order to address uncertainties in the marine iodine flux and associated ozone sink. Specifically, it aims to quantify the dominant controls on the sea surface iodide distribution and improve parameterisation of the sea-to-air iodine flux and of ozone deposition. This will be achieved through a combination of laboratory experiments, field measurements and ocean and atmospheric modelling.

Planned Impact

We aim to impact upon five distinct areas:

A. Air Quality and Climate
Beneficiaries: Governmental research agencies e.g. the US EPA; international coordinating agencies e.g. WMO.
Iodine impacts air quality via both the direct contribution of iodide to ozone loss at the sea surface, and through atmospheric iodine chemistry destroying tropospheric ozone. In the UK, air pollution reduces lifespan by an average of 8-14 months. Ozone is also responsible for reductions in crop yields and tree growth. We will facilitate the inclusion of iodine in air quality and Earth system models by providing improved iodine flux parameterisations and iodide fields, including making available a database of global seawater iodide measurements. Understanding these fundamental processes is required to provide appropriate policy advice regarding both air quality and climate.

B. Radionuclide dispersion
Beneficiaries: Environmental consultants and applied research centres e.g. Centre for Environment, Fisheries and Aquaculture Science; government bodies and regulators e.g. Food Standards Agency; industry e.g. Sellafield Ltd.
Iodine radionuclides (129-I, 131-I) are released to the marine environment by the nuclear industry both intentionally and accidentally. Their transport and fate is dependent on their speciation, and they will undergo volatilisation in the same manner as stable iodine species. Improved understanding of these processes is thus relevant to pathway assessment of radioiodine exposure. We will discuss the inclusion of radioiodine volatilisation and speciation changes in exposure assessment tools with relevant research bodies and environmental consultants. Through inclusion in such tools, our results will impact on regulatory bodies and industry.

C. Nutritional iodine deficiency
Beneficiaries: Public Health professionals
Volatilisation followed by atmospheric transport and deposition is a major pathway by which marine iodine may enter the terrestrial food chain. Iodine is an essential human nutrient, deficiency of which is the leading preventable cause of brain damage, and so better understanding of the geochemical controls on iodine levels in food is of interest to nutritionists and epidemiologists. We will host a workshop, leading to a publication on the global iodine cycle, as a contribution to evaluating the role of environmental determinants on iodine deficiency. Deposition flux maps (directly informed by the project deliverables), will be made available for uses such as interpreting historical causes of regional iodine deficiency, developing sampling strategies for epidemiological studies and assessing the impact of changing agricultural practices on iodine levels in food.

D. Ocean deoxygenation
Beneficiaries: Marine Management professionals
The improved constraints on marine iodine cycling achieved in our work will inform the development and evaluation of the carbonate I/Ca ratio as a proxy for past ocean deoxygenation, via direct collaboration with our collaborator Prof. Andy Ridgwell. Better understanding of past ocean deoxygenation will in turn improve our ability to predict the effects of current and future ocean dexoygenation on marine life, including economically important fisheries, ecosystem services, and the biogeochemical production of greenhouse gases (N2O).

E. Public engagement and education
Beneficiaries: The general public; school children in UK and India.
Our subject matter provides an interesting, accessible example of the interactions between biological, chemical, physical and human aspects of the Earth system. We will incorporate it in a set of visualization tools and demonstrations for use in public engagement activities (e.g. Royal Society Summer Exhibition, British Science Festival, school visits). Selected material will be used for engagement with the public and schools in India through collaboration with our project partner Dr Anoop Mahajan.

Publications

10 25 50
 
Description The reaction of iodide with ozone at the sea surface plays a critical role in controlling the chemical composition of the troposphere. This process directly controls the rate of O3 deposition to the oceans and is the dominant source of reactive iodine to the atmosphere, which also leads to significant chemical loss of tropospheric O3.
Our results have reduced some of the major uncertainties that exist in the marine iodine flux and the associated ozone sink. We have:

(1) significantly increased spatial coverage of iodide (and iodate) observations in the ocean
(2) developed a significantly improved climatology for surface ocean [iodide] using this new data and a machine learning approach
(3) helped to elucidate how oceanic iodide and iodate transformations are controlled.
(4) demonstrated that the O3-iodide interaction is a negative biogeochemical feedback on tropospheric O3 and oxidants, and showing significant increases in its magnitude over the 20th century,
(5) discovered that ocean iodide may changes over longer timescales, as a result of expected future alterations in ocean acidification
Exploitation Route Ocean modelling of iodine. Using oceanic iodate as a tracer for past ocean de-oxygenation. Better understanding of tropospheric O3 in air quality models.
Sectors Chemicals,Environment

 
Description Educational - several schools talks and outreach activities Societal - informing O3 deposition and chemical schemes in air quality models (including that used by the US EPA)
First Year Of Impact 2018
Sector Education,Environment
Impact Types Societal

 
Description Chapter 6 Lead author for 2018 WMO/UNEP Scientific Assessment of Ozone Depletion
Geographic Reach Multiple continents/international 
Policy Influence Type Citation in other policy documents
Impact The 2018 WMO/UNEP Scientific Assessment of Ozone Depletion forms part of the quadrennial assessments of ozone depletion by the Scientific Assessment Panel of the Montreal Protocol. These assessments inform decisions taken by governments for the protection of ozone and climate under the Montreal Protocol.
URL https://ozone.unep.org/science/assessment/sap
 
Description European Research Council Advanced grant
Amount € 2,479,601 (EUR)
Funding ID 833290 
Organisation European Research Council (ERC) 
Sector Public
Country Belgium
Start 10/2019 
End 09/2024
 
Title INVALID ENTRY 
Description INVALID ENTRY 
Type Of Material Improvements to research infrastructure 
Year Produced 2016 
Provided To Others? Yes  
Impact INVALID ENTRY 
 
Title A novel (halogen) chemistry scheme was developed for an open-source community atmospheric chemical transport model (GEOS-Chem) 
Description A novel (halogen) chemistry was developed for an open-source community atmospheric chemical transport model (GEOS-Chem). The code has been incorporated into the main publicly-availible branch, which is freely downloadable and available to the community. The shared code has been described in a recently published paper (https://doi.org/10.5194/acp-16-12239-2016) and further updated in another recent paper (https://doi.org/10.1039/C7FD00026J). 
Type Of Material Computer model/algorithm 
Year Produced 2016 
Provided To Others? Yes  
Impact Multiple groups are already using the newly developed novel (halogen) chemistry scheme prior to release, and many more will use it afterwards as it is now part of the standard simulation. This has already resulted in publications and developed existing collaborations. Further publications and collaborations could be expected. 
URL http://www.geos-chem.org
 
Title Global predicted sea-surface iodide concentrations 
Description This dataset contains global spatially predicted sea-surface iodide concentrations at a monthly resolution. This dataset was developed as part of the NERC project Iodide in the ocean:distribution and impact on iodine flux and ozone loss (NE/N009983/1), which aimed to quantify the dominant controls on the sea surface iodide distribution and improve parameterisation of the sea-to-air iodine flux and of ozone deposition. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact This dataset provides global spatially predicted sea-surface iodide concentrations at a monthly resolution. This better captures available observations and is made publically available for use in models (e.g. composition, air quality, and climate models). 
URL https://catalogue.ceda.ac.uk/uuid/02c6f4eea9914e5c8a8390dd09e5709a
 
Title Global sea-surface iodide observations, 1967-2018. 
Description This dataset regroups the available data of measurements of iodide in the surface waters (upper 20m) of the global oceans. It includes digitised data from published manuscripts, published and unpublished data supplied by the originators themselves or provided by repositories. It contains 1342 datapoints and spans latitudes from -70°S to 68°N and data from all major ocean basins. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact The dataset has been used as imput for the global prediction of iodide concentrations generated by a machine learning approach, which will be used in global climate models. 
URL https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/7e77d6b9-83fb-41e0-e053-6c86abc...
 
Description Participation in the 2016-2017 Indian Southern Ocean Expedition (ISOE) and BoBBLE research cruise in the Indian Ocean 
Organisation Indian Institute of Tropical Meteorology
Country India 
Sector Charity/Non Profit 
PI Contribution Measurements of iodide, iodate, and total iodine on these cruises.
Collaborator Contribution Provision and support of a scientist berth on the ISOE cruise.
Impact Data of dissolved iodide, iodate, and total iodine concentrations on these cruises. Data are currently being lodged at BODC
Start Year 2016
 
Description "Iodide to feed the machine: How new iodide data from the Indian Ocean helps constrain a new approach to reduce uncertainties in modelling" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact Seminar given at UEA
Year(s) Of Engagement Activity 2018
URL https://pure.york.ac.uk/portal/en/activities/iodide-to-feed-the-machine-how-new-iodide-data-from-the...
 
Description BBC Podcast - Under the Weather 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Recorded interview on stratospheric O3 as part of BBC Podcast - Under the Weather
Year(s) Of Engagement Activity 2018
 
Description Expert Committee Meeting for the Southern Ocean Expedition 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact During the Expert Committee Meeting for the Southern Ocean Expedition our outcomes from the Southern Ocean Expedition 9 were presented under the title "Oceanic volatiles and their impact on atmospheric halogens and cloud-forming aerosols in the Southern Ocean" and proposals for the next Expeditions were discussed and assessed by funders.
Year(s) Of Engagement Activity 2017
 
Description Invited Seminar at the Chiba Iodine Resource Innovation Center (CIRIC) at Chiba University entitled: "Iodine in the atmosphere and sea-surface: New observations and modelling showing iodine's importance" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Invited Seminar at the Chiba Iodine Resource Innovation Center (CIRIC) at Chiba University entitled: "Iodine in the atmosphere and sea-surface: New observations and modelling showing iodine's importance"
Year(s) Of Engagement Activity 2018
 
Description Invited talk given at National Institute for Environmental Studies (NIES) in Japan entitled: "Predicting global sea-surface iodide using machine learning to improve modelling of air-quality and atmospheric composition" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Invited talk given at National Institute for Environmental Studies (NIES) in Japan entitled: "Predicting global sea-surface iodide using machine learning to improve modelling of air-quality and atmospheric composition"
Year(s) Of Engagement Activity 2018
 
Description Oral presentation at the The Royal Society of Chemistry's Early careers meeting on Environmental Chemistry of Water, Sediment, Soil and Air. Presentation was titled "Iodide to feed the machine". 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Oral presentation at the The Royal Society of Chemistry's Early careers meeting on Environmental Chemistry of Water, Sediment, Soil and Air. Presentation was titled "Iodide to feed the machine".
Year(s) Of Engagement Activity 2018
URL http://www.rsc.org/events/detail/28421/environmental-chemistry-of-water-sediment-soil-and-air-early-...
 
Description Participation in workshop: "Atmospheric Dry Deposition: Future Directions" 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact Attended and contributed to workshop entitled "Atmospheric Dry Deposition: Future Directions"
Year(s) Of Engagement Activity 2017
URL https://pure.york.ac.uk/portal/en/activities/atmospheric-dry-deposition-future-directions(8eb09ada-9...
 
Description Presentation (poster) at the American Geophysical Union's Fall Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A presentation (poster) was given at the American Geophysical Union's Fall Meeting. Numerous requests for the end data product (ocean surface iodide values) were received.
Year(s) Of Engagement Activity 2017
URL https://agu.confex.com/agu/fm17/preliminaryview.cgi/Paper228821.html
 
Description Presentation: Iodide to feed the machine: a machine-learning built parameterization for sea-surface iodide using new observations, which impacts the ozone budget and iodine emissions. (Joint 14th iCACGP Quadrennial Symposium/15th IGAC Science Conference) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Poster presentation given at the Joint 14th iCACGP Quadrennial Symposium/15th IGAC Science Conference. The title of the presentation: "Iodide to feed the machine: a machine-learning built parameterization for sea-surface iodide using new observations, which impacts the ozone budget and iodine emissions."
Year(s) Of Engagement Activity 2018
URL http://icacgp-igac2018.colorado.edu/melamed/Abstracts/3.070_Sherwen.pdf
 
Description Solas workshop: "Frontiers of ocean-atmosphere interaction: Air-sea interface and fluxes of mass and energy" 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This workshop will address the issues surrounding air-sea fluxes of mass and energy. Through plenary sessions and thematic break-out sessions the following topics were addressed: (1) Developments in air-sea flux observations. (2) Translating upper ocean turbulence observations into parameterisations and models. (3) The role of waves in modifying air-sea fluxes. (4) The sea surface microlayer and its effect on air-sea exchange processes. New directions in research were discussed.
Year(s) Of Engagement Activity 2017
URL http://airsea.nuigalway.ie/cargese/introduction
 
Description Solas-IGAC workshop "Influence of coastal pollution on marine atmospheric chemistry: effects on climate and human health" 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact The workshop focused on challenging topics in the field of air-sea interactions and atmospheric chemistry, organised jointly by SOLAS and IGAC. The workshop especially addressed the influence of the coastal pollution (air and water) on the chemistry of gas and particles in the marine environment, as well as the effects on climate and human health.
Year(s) Of Engagement Activity 2018
URL http://www.solas-int.org/workshop-1.html
 
Description Talk at Science Live: A -level (Birmingham Event) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Talk at "Science Live: A -level" (Birmingham Event) - one of three Chemistry events for A-level students, organised by "Science Live". http://www.alevelsciencelive.net/
Year(s) Of Engagement Activity 2018
URL http://www.alevelsciencelive.net/
 
Description Talk at Science Live: A -level (London Event) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Talk at "Science Live: A -level" (London Event) - one of three Chemistry events for A-level students, organised by "Science Live". http://www.alevelsciencelive.net/
Year(s) Of Engagement Activity 2018
URL http://www.alevelsciencelive.net/
 
Description Talk at national/regional A-level Chemistry events "Science Live A level" at Birmingham, Manchester and London 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact designed for A-level Biology, Chemistry or Physics students to hear scientists who are working at the cutting edge of their specialisms and how science can lead to an interesting career.
Year(s) Of Engagement Activity 2019
URL https://www.alevelsciencelive.net
 
Description YorNight 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Through a presentation of the atmospheric research done at the University of York, the visitors of the York Researchers' night had the opportunity to participate in a few experiments and interact with the researchers present where many questions concerning air quality and climate change were discussed.
Year(s) Of Engagement Activity 2018
URL https://www.york.ac.uk/news-and-events/events/yornight/2018/