Theme 5: Ocean biogeochemical control on atmospheric chemistry

Ocean emissions of reactive gases and aerosols influence atmospheric photochemistry and oxidising capacity, air quality, and stratospheric ozone. Theme 5 focuses on the role of marine biogeochemical controls on the release and atmospheric chemistry of reactive and climate active gases, and how that will evolve in the changing ocean and atmosphere. Reliable characterisation is still missing of the chemical composition of sea surface emissions of reactive volatile gases (e.g., organohalogens, VOCs, OVOCs), how these are formed at the sea surface, and how a changing ocean is affecting the biogeochemistry of these emissions.

Theme 5 team


Team leaders

Laura Gallardo (Chile,
Mohd Talib Latif (Malaysia,

Team members

Maria Cristina Facchini (Italy,
Anoop Mahajan (India,
Jurgita Ovadnevaite (Ireland,
Karine Sellegri (France,
Maurice Levasseur (Canada,
Katye Altieri (South Africa,

Processes and impacts/stressors associated with long-lived greenhouse gases.

Simplified schematic depiction of the most important couplings between ocean biogeochemical cycles and atmospheric chemistry.

Research questions

Key questions to be addressed within this theme are:

  • What are the marine biogeochemical controls on the release of reactive gases into the atmosphere
  • What are the characteristics and chemical interactions of biotic and abiotic volatile organic compounds from ocean in the atmosphere?
  • How do photochemistry and oxidation influence the fate of atmospheric gases and aerosols in the atmosphere?
  • How will future changes in ocean biogeochemistry and anthropogenic emissions (NOX, VOCs) interact to influence tropospheric photochemistry and stratospheric ozone?



Process-oriented campaigns
Conduct process-oriented campaigns to simultaneously study surface ocean cycling, sea-air gas exchange and atmospheric chemistry. These will include marine biogeochemical studies to determine the link between gas emissions and the biological factors controlling their production (e.g., bloom dynamics, microbial ecology). The atmospheric component will provide the rates and mechanisms of atmospheric cycling of reactive emissions including their potential feedback processes with the ocean and anthropogenic pollution in coastal areas. The provision of information of reactive gases from satellite instruments will be an important component of such studies.
Reactive volatiles
Conduct laboratory investigations of the reaction mechanisms and rates of formation of reactive volatiles at the sea surface.
Combined modelling studies

Combine modelling studies to improve mechanisms at the process level and to upscale from the local and regional scale to the global scale to study climate and biogeochemical impacts. These modelling studies must involve information from the remote sensing of reactive gases.





Planned activities

See SOLAS Activities 2020-2021 table here

Research programs on biogeochemical control on atmospheric chemistry

Current national and international programs investigating biogeochemical control on atmospheric chemistry include “Sea2Cloud: Are marine microorganisms influencing clouds?”, and “Shipping Emissions in the Arctic and North Atlantic Atmosphere” (SEANA). Information on planned observational programs and workshops can be found via the respective program websites:


Satellite remote sensing of atmospheric trace gases is done by Sentinel 5P, which was launched in 2017, and conducts the following ozone measurements: nitrogen dioxide, sulfur dioxide, formaldehyde, aerosol, carbon monoxide, methane, and clouds.
Sentinel 5P:


2020 16th IGAC Science Conference, September 12-16, 2021, Manchester, UK.
Session: Sea-atmosphere interaction