Theme 3: Atmospheric deposition and ocean biogeochemistry

Atmospheric deposition is an important nutrient source for marine ecosystems, with consequences on local, regional, and global biogeochemical cycles, as well as on the climate system. Theme 3 focuses on the relationships between natural and anthropogenic atmospheric inputs, the marine carbon and nitrogen cycles, and feedbacks to climate. The fundamental processes driving aerosol emissions, transportation, chemical reaction, and deposition may change atmospheric fluxes and surface mixed layer turnover times. In turn, microbial communities respond to changing atmospheric inputs, which may result in significant effects on the marine carbon and nitrogen budgets, as well as on atmospheric carbon dioxide uptake.

Theme 3 team

 

Team leaders

Santiago Gassó (United State, santiago.gasso@nasa.gov)
Jun Nishioka (Japan, nishioka@lowtem.hokudai.ac.jp)
 

Team members

Maurice Levasseur (Canada, maurice.levasseur@bio.ulaval.ca)
Katye Altieri (South Africa, katye.altieri@uct.ac.za)
Phil Boyd (Australia, philip.boyd@utas.edu.au)
William Landing (United States, wlanding@fsu.edu)
Akinori Ito (Japan, akinorii@jamestec.go.jp)
Alex Baker (United Kingdom, alexander.baker@reading.ac.uk)
Peter Croot (Ireland, peter.croot@nuigalway.ie)
Cécile Guieu (France, guieu@obs-vlfr.fr)
Natalie Mahowald (United States, mahowald@cornell.edu)
Alessandro Tagliabue (United Kingdom, a.tagliabue@liverpool.ac.uk)

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

Main sources, cycling, processes, and species relating to Core Theme 3 (processes are indicated in italics).

Research questions

Key questions to be addressed within this theme are:

  • How do biogeochemical and ecological processes interact in response to natural and anthropogenic material input from the atmosphere across different regions?
  • How do global warming, ocean acidification, and other anthropogenic (such as ocean acidification) stressors synergistically alter the uptake of atmospheric nutrients and metals by marine biota in different oceanic regions?
  • What are the large-scale impacts of atmospheric deposition to the ocean on global elemental cycles (e.g., C, P, and N) and climate change feedbacks in major marine biomes?

 

Priorities

Global key areas
Focus on key regions where atmospheric depositions and their impacts are important to marine primary production and biogeochemistry. These regions include the Mediterranean Sea, the Southern Ocean, the Tropical Atlantic, and the North Pacific.
Coupled atmosphere-marine time series stations
Encourage the setup and maintenance of time series sampling stations (over the ocean, on islands, and/or in coastal areas) to monitor and accurately estimate atmospheric depositions and fluxes (vertical and horizontal) of bio-available nutrients to the marine environment.
Comparative studies and modelling
Support comparative studies on the budgets of bio-available nutrients in the surface waters of the key regions mentioned above in order to address the role of atmospheric deposition, particularly in nitrate-, phosphate- and iron-limited regions. With these comparative studies, regional coupled modelling can address both the atmosphere and the ocean.
New tools
Use new and improved tools to effectively study the impacts of atmospheric deposition on ocean biogeochemistry, such as isotope tracers and molecular biology techniques (genomics, transcriptomics, and proteomics). Also, new remote sensing platforms have become available in the recent years and may provide significant advances. Specifically, the new network of Geostationary satellites (GOES 16/17, Himawari 8/9, GOCI, and others) make observations of the ocean basins every 10 minutes (day and night). A much better understanding of aerosol transport evolution and deposition will be gained through these new tools. While only one of them has dedicated channels for ocean observations (GOCI), its observing region is the North Pacific, a key of interest for aerosol-ocean interactions. An improved understanding of wet deposition over the ocean by precipitation is expected with the new merged data base of senior and newest measurements from the constellation of satellites in the Global Precipitation Mission (GPM) into the Integrated Multi-satellitE Retrievals for GPM (IMERG; https://gpm.nasa.gov/gpm/imerg-global-image) with a half hour frequency and 6 hr latency.

 

 

 

Planned activities

See SOLAS Activities 2020-2021 table here

Iron model intercomparison

With the increase of trace metal surveys in all ocean basins, we now have a better understanding of the nutrient flows and it is clear the importance of not only oceanic Fe sources but also those of atmospheric origin. Therefore , a coherent explanation for the biological response to input nutrients needs knowledge of both atmospheric and oceanic inputs of Fe. This subject is the core theme of SCOR Working Group 151 FeMIP.

SCOR WG 151: https://scor-int.org/group/151/

Research programs on atmospheric deposition and ocean biogeochemistry

Current national and international programs investigating atmospheric deposition and ocean biogeochemistry include the “Impact of atmospheric multi-stressors to coastal marine systems in a changing climate scenario” (AMBIEnCE) and the Tudor Hill Marine-Atmospheric Observatory. Information on planned observational programs and work-shops can be found via the respective program websites:

Trace metal deposition

Because of the overlapping nature of many SOLAS and GEOTRACES activities, closer interactions between the two organizations are being pursued, particularly in the area of atmospheric and water column sampling, where each program has different strategies and different overall goals. A first attempt to bring the two communities together towards coordinating common goals and protocols resulted in a recent publication (Meshkidze et al., 2020, Perspective on identifying and characterizing the processes controlling iron speciation and residence time at the atmosphere-ocean interface, https://doi.org/10.1016/j.marchem.2019.103704).

Aerosol transport and deposition in the North Pacific

Given the recent discovery of dust deposition in the NE Pacific from North American sources and the large volume of research output from the East Asian community on the subject of aerosol deposition, the team leaders recommend investigating whether there is US and Asian interest for a joint study focusing on aerosol transport and deposition in the North Pacific. The team leaders will contact individual key scientists on both sides of the Pacific and evaluate if there is interest for a coordinated initiative. The topic session “Atmospheric nutrient deposition and microbial community responses, and predictions for the future in the North Pacific Ocean” was accepted for the PICES-2020 and -2021 annual meetings.

Sponsors

Funders