Challenges and opportunities in addressing the spread of Sargassum across the tropical Atlantic Ocean

Virtual event, 2 June 2021

“Sargassum is here to stay. Sustainable management of Sargassum influx requires both local action and international coordination and collaboration. A strong inter-regional cooperation between the Wider Caribbean and West Africa countries is essential,” Cesar Toro (IOCARIBE)

This side event presented and discussed the challenges, solutions, and opportunities behind the spread of Sargassum across the Tropical Atlantic. During the event, experts introduced the state-of-the-art research on the spread mechanisms, various impacts and the present capacity of monitoring and forecasting of Sargassum.

“The negative impacts of sargassum influxes are multi-sectoral affecting fisheries, tourism, the environment, public health, maritime transport and coastal living. Sargassum-kissed shores have been a catalyst for innovation, inspiring cutting-edge research and development in harvesting equipment and sargassum related products. Exploring sargassum uses can provide solutions for a sustainable and equitable blue recovery to the COVID-19 crisis,” Dr Shelly-Ann Cox, CERMES, Barbados

The event also introduced the Sargassum Information Hub ( and the UNEP – Cartagena Convention White Paper on Sargassum. A panel session with experts and stakeholders served to catalyse linkages, actions, and coordination across the Atlantic Ocean. By showcasing solution strategies and creating space for discussion and collaboration between scientists, engineers and stakeholders, the event provided powerful insight into the opportunities.

“The European Commission fosters collaborations across the Atlantic Ocean and contributes to tackling the Sargassum Challenge through our policies, through our programmes and through our partnerships,” John Hanus (European Commission)

Co-hosted by Dr Audrey Hasson, the GEO Blue Planet EU coordinator, supported by EU4OceanObs, this was an official side event at the All-Atlantic 2021 R&I for a Sustainable Ocean High-level Ministerial & Stakeholders Conference, which took place from 2 – 4 June 2021. The panel was moderated by by Dr Cesar Toro from the IOCARIBE of IOC UNESCO.

Download the speakers’ presentations (pdf format)

Once confined to the Sargasso Sea, thousands of tons of Sargassum now make their way to beaches in the Caribbean, East Americas, and West Africa. Sargassum is a genus of large brown algae, with two species in the Atlantic found in free-floating mats, held afloat by gas-filled bladders. These rafts serve as a critical habitat for threatened loggerhead sea turtles and as a nursery shelter for a variety of commercially important fishes such as mahi-mahi, jacks, and amberjacks. In 2011, floating Sargassum began to impact coastal communities around the tropical Atlantic Ocean. Washed up Sargassum rots, attracts flies, deters tourists and causes respiratory problems due to release of hydrogen sulphide and ammonia. Floating mats and mounds near beaches harm marine ecosystems and disrupt recreation, tourism and fishing, costing local communities millions of dollars.  

On-going research efforts and developments are led to understand the mechanisms behind its basin-wide spread, its impact on both marine life and local communities as well as providing solutions for mitigation and beyond. This is a social, economic, and ecological challenge that requires a multi-disciplinary approach. In this context, the Sargassum hub ( launched in 2020 serves as a singleentry point to access information and tools for the monitoring and management of sargassum blooms for all stakeholders from scientists to local fishermen. The Sargassum Hub is developed by the GEO Blue Planet Initiative, in collaboration with IOCARIBE of IOC-UNESCO, AtlantOS, the Atlantic International Research (AIR) Center and other partners. The side event will also be the opportunity for UNEP Cartagena Convention to launch their white paper compiling background information for a strategic status update and critical situational analysis that informs and elicits feedback from key regional stakeholders. It focuses on influxes in the Caribbean, with reference to other impacted regions as appropriate. 

This side event presented and discussed challenges, solutions and opportunities behind the spread of Sargassum across the Tropical Atlantic. Experts presented challenges and state-of-the-art research on the spread mechanisms, various impacts and the present capacity of monitoring and forecasting. The event showcased solution strategies and created a space for discussion and collaboration between scientists, engineers and stakeholders, providing insight into the opportunities for addressing the Sargassum problem across the Atlantic Ocean.

Welcome and workshop overview – Dr. Audrey Hasson (GEO Blue Planet/ EU4OceanObs) (5 min)

16:05-16:25 UTC – (1) Challenges – State of the art

  • General background on Sargassum –Speaker: Prof. Hazel Oxenford (Centre for Resource Management and Environmental Studies (CERMES, Barbados)
  • Monitoring and forecasting Sargassum Speaker: Dr. J. Jouanno (French National Research Institute for Sustainable Development (IRD, France)
  • Sargassum and Marine Life – Speaker: Dr. Brigitta van Tussenbroek (Universidad Nacional Autónoma de México, Mexico
  • Impacts on Society – Speaker: Dr Shelly-Ann Cox (CERMES, Barbados)

16:40-17:10 UTC – (2) Solutions – Towards informed mitigation

  • Cartagena Convention White Paper Launch – Speaker: Ileana Lopez (UNEP)
  • Sargassum Hub – Speaker: Dr. Emily Smail (GEO Blue Planet) 
  • Local to regional solutions: Lydia Barfleur (Région Guadeloupe, France) 
  • Sargassum as a resource – Jason Cole (C-Combinator)
  • Sargassum Mitigation for the Tourism Industry – Jake Kheel (Fundación Grupo Puntacana)

17:20-18:00 UTC – (3) Opportunities – Discussion with experts and stakeholders 

Introduction – Cesar Toro (IOCARIBE)

Panel Discussion:

  • Dr Shelly-Ann Cox (CERMES, Barbados)
  • Mika Odido (IOC Africa)
  • Emily Smail (GEO Blue Planet)
  • Kwasi Appeaning Addo (University of Ghana)
  • Ana María Núñez (UNDP)
  • Ileana Lopez (UNEP Cartagena Convention)
  • Jacques Abe (UNEP Abidjan Convention)


Q1: I wondered if any of the presenters had any views about the influence of nutrients pollution on sargassum influxes whether from land-based sources and activities and/or from air pollution.  This may offer an opportunity for greater collaboration and integration between pollution prevention and sargassum.  

Response by Prof. Hazel Oxenford (CERMES, Barbados): This is a burning question!  We know very little about the growth of this sargassum from the new source region and how much growth occurs as it travels towards its stranding locations. It seems likely that sargassum will to continue grow or accelerate growth as it meets higher nutrient levels  

Q2: By doing Carbon budgets I would like to know if any of the panelists have had the opportunity to assess a Carbon balance: Carbon storage by Sargassum and CO2 atmospheric uptake by sargassum?  

Response by Dr Shelly-Anne Cox (CERMES, Barbados): Please follow the link :  

Q3: Seaweeds are now seen as an avenue of combatting climate change from an absorption point-of-view (carbon emissions), for instance. Has there been studies that have looked into this angle specifically on the Sargassum species?  

Response by Dr Shelly-Anne Cox (CERMES, Barbados): Please check this paper out:  

18 panellists and 87 attendees from 29 different countries around the world participated in this event. The event was open to policy makers, research communities, academic institution representatives, industry representatives, innovation clusters, and projects related to blue economy from countries around the Atlantic. 

  • GEO Blue Planet (A. Hasson and E. Smail)  
  • AtlantOS (I. Sousa-Pinto, A-C. Zinkann, S. Ketelhake) 
  • AIR Center (J. Moutinho) 
  • IOCARIBE (C. Toro) 
  • SPAW-CAR (C. Caumette)
  • UNEP Cartagena Convention (Ileana Lopez) 

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