Blue carbon is back in the spotlight with new research and agreements that focus on coastal ecosystems as allies in the fight against climate change. From Catalonia to the Colombian Caribbean, mangroves, salt marshes, and seagrass meadows are emerging as natural carbon sinks whose health and rigorous monitoring make all the difference.
While Spanish teams are making progress in technology, monitoring and scientific evidence , a regional summit in Santa Marta is promoting the standardization of MRV systems so that blue carbon capture and storage have comparable data, robust foundations and access to climate finance.
Catalonia accelerates applied research with BlauCat
The BlauCat project , led by Eurecat 's Center for Climate Resilience , is using cutting-edge technology to analyze the role of Catalonia's coastal ecosystems as carbon sinks. Wetlands, salt marshes, and seagrass meadows are being studied to quantify carbon capture and storage , improve their management, and strengthen their integration into climate strategies.
According to its scientific leadership, these areas act as climate buffers and guarantors of biodiversity, making it urgent to refine maps, inventories, and monitoring protocols. The approach combines in-situ measurements , sensors, and modeling to provide useful metrics for management and local stakeholders.
Cadiz: Sunscreens compromise carbon sequestration
A team from INMAR (University of Cádiz) and ICMAN-CSIC evaluated how sunscreens affect the marine phanerogam Cymodocea nodosa , abundant in the Bay of Cádiz . This pioneering work in the area shows that continuous exposure to these substances alters its ability to capture carbon and modifies the associated microbiome, impacting its health and resilience.
To replicate realistic conditions, a mesocosm trial was designed with three groups of plants: control, medium concentration, and high concentration of a mixture of five commercially available European creams . Variables such as photosynthesis, carbon release , plant tissue condition, and bacterial composition were monitored for one month.
The results indicate a reduction in photosynthetic efficiency to the point of shifting the system from an autotrophic state (net carbon uptake) to a heterotrophic state (emission). A nighttime increase in dissolved organic carbon , loss of microbial diversity, and greater foliar damage were also detected , with necrosis particularly pronounced at high doses.
As a potential response, an increase in starch was observed in the rhizomes , an indicator of reserves, although insufficient to compensate for the stress. The team emphasizes that reef-safe or eco-friendly labels are not regulated or always supported by evidence, and therefore propose reviewing formulations and standards to safeguard these key seagrass meadows for blue carbon.
- Realistic methodology: a mix of sunscreens and concentrations based on busy beaches.
- Metabolic effect: decline in photosynthesis and shift in balance towards emissions.
- Ecological impact: less bacterial diversity and more potential pathogens.
- Managerial Accounting: need for regulation and lower impact alternatives.
The region hosted the International Conference on Blue Carbon and Wetlands (IBCWC) in Santa Marta, which facilitated regional cooperation for the standardization of MRV systems . At this meeting, Colombians, Panamanians, Surinamese, and Jamaicans committed to creating shared systems to measure and report the benefits of coastal ecosystems, promoting coordinated policies and access to climate finance.
After visiting areas such as the Ciénaga Grande de Santa Marta , participants observed artisanal fishing practices , sustainable tourism, and mangrove restoration projects, in which local communities actively participate in the conservation and monitoring of these habitats. These actions strengthen climate resilience and ensure the protection of carbon sinks that already provide essential services.
As a result of these meetings, the monitoring, measurement and conservation of key ecosystems for blue carbon will be strengthened , ensuring that scientific knowledge translates into effective decisions for their future protection.