BIOGEOCHEMICAL-ARGO PROGRAM

Program

Biogeochemical-Argo is developing a global network of biogeochemical sensors on Argo profiling floats. The concept of global robotic biogeochemical measurements was first articulated in a Community White Paper (Gruber et al., 2007) that was supported by the International Ocean Carbon Coordinating Project (IOCCP) and the US Ocean Carbon and Biogeochemistry Program (US-OCB). This was followed by a Scoping Workshop funded by the US Ocean Carbon and Biogeochemistry Program (Johnson et al., 2009) and an International Ocean Color Coordinating Group (IOCCG) supported working group ( IOCCG, 2011). Extensive discussions were held at the OceanObs 09 meeting and were subsequently reported into two community White Papers (Gruber et al., 2010; Claustre et al., 2010). Recommendations from these meetings called for integrated deployments of larger numbers of profiling floats with biogeochemical sensors to demonstrate the feasibility of operating biogeochemical arrays. Following these reports, a variety of regional arrays have been developed with great success. In parallel, great strides have been made in sensor operation and calibration. These efforts demonstrate the feasibility of operating a global system that is designed to address fundamental science questions and needs for ocean resource management.
As a result of this effort, BGC-Argo was integrated with the international Argo program by participating in Argo Steering Team discussions from 2011 and subsequently taking a seat at the Argo Data Management Team. The design for a global network was sealed in 2016 during a workshop held in Villefranche-sur-mer (Biogeochemical-Argo Planning Group. 2016). The array size requirement was determined for a target level of 1000 floats even spaced throughout the global ocean in waters deeper than 2 km. In 2019, best practices were defined (Bittig et al., 2019) and the OneArgo concept was first presented (Roemmich et al, 2019). In 2022, a BGC-Argo Project Officer (UNESCO/IOC) was appointed to support the network in its ongoing development. At the same time, a Technological Task Team was established to address issues related to sensor technologies, following the diversification of the number of providers within the network. In 2025, coinciding with the UN Ocean Conference (UNOC), the OneArgo paper (Thierry et al., 2025) was published, aiming to better reach end-users and position OneArgo as a key system for addressing environmental and societal challenges related to the oceans.
Currently, 16 nations are involved in the BGC-Argo mission. The community is now entering an exciting yet challenging new phase, marked by emerging governance issues, as BGC-Argo moves toward becoming a reference system in this field.

Timeline History

Advancing ocean monitoring and knowledge for societal benefit: the urgency to expand Argo to OneArgo by 2030
Thierry, V. et al (2025),Frontiers in Marine Science, 2 June 2025 / doi:10.3389/fmars.2025.1593904
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On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array
Roemmich, D. et al (2019),Frontiers in Marine Science, 2 August 2019 / doi:10.3389/fmars.2019.00439
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A BGC-Argo guide: Planning, deployment, data handling and usage
Bittig, H. et al (2019),Frontiers in Marine Science, 22 August 2019 / doi:10.3389/fmars.2019.00502
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The scientific rationale, design and implementation plan for a Biogeochemical-Argo float array
Biogeochemical-Argo Planning Group (2016) / doi:10.13155/46601
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IOCCG (2011). Bio-Optical Sensors on Argo Floats
Claustre, H. (ed.), Reports of the International Ocean-Colour Coordinating Group, No. 11, IOCCG, Dartmouth, Canada.
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Adding Oxygen to Argo: Developing a Global In Situ Observatory for Ocean Deoxygenation and Biogeochemistry
Gruber, N. & Co-Authors (2010).
Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (Vol. 2),Venice, Italy, 21-25 September 2009, Hall, J., Harrison, D.E. & Stammer, D., Eds., ESA Publication WPP-306, doi:10.5270/OceanObs09.cwp.39.
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Bio-Optical Profiling Floats as New Observational Tools for Biogeochemical and Ecosystem Studies: Potential Synergies with Ocean Color Remote Sensing
Claustre, H. & Co-Authors (2010).
Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (Vol. 2), Venice, Italy, 21-25 September 2009, Hall, J., Harrison, D.E. & Stammer, D., Eds., ESA Publication WPP-306, doi:10.5270/OceanObs09.cwp.17.
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Observing biogeochemical cycles at global scale with profiling floats and gliders: prospect for a global array
Johnson, K. et al (2009)
Oceanography. 22: 216-225 | DOI: 10.5670/oceanog.2009.81
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The Argo-oxygen program: A white paper to promote the addition of oxygen sensors to the international Argo float program
Gruber, N. et al (2007).
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