White Gold, Blue Carbon: The Science Comes to Our Salinas
A team from CCMAR — Centro de Ciências do Mar — spent the day at our salinas, sampling soil, mud, and water for Project SAL C, the cross-border study of how traditional salt pans store carbon. A look at the fieldwork, in photos.
This week, the science came to us.
A team from CCMAR — Centro de Ciências do Mar spent the day at our salinas in Venta Moinhos, sampling the soil, the mud, and the water of the talhos. It is part of the ongoing fieldwork for Project SAL C, the cross-border study of how traditional salt pans store carbon.
Traditional salt pans are not just food production systems. They are carbon sinks.
What CCMAR came to measure
Through the morning, the researchers worked their way along the reservoirs and the crystallisation talhos — drawing sediment cores from the pan floor, sealing mud and soil samples into labelled jars, and collecting water with extension samplers from the deeper reservoirs.
Soil, mud, water: the three layers that together make up the carbon ledger of a working salt marsh. Each sample is logged against its exact location and the day’s conditions, then taken back to the laboratory for analysis.
What Project SAL C is
SAL C — Valorização das Salinas para o Sequestro de Carbono e Mitigação das Alterações Climáticas — is a research initiative developed by the BLUEZ C Institute and funded by Fundación “la Caixa”. Its partners include the Castro Marim Municipality, Made in Sea, and the Guadiana Eurocity cross-border authority.
Its focus is something we have believed for a long time but lacked the scientific language to prove: traditional salt pans are not just food production systems. They are carbon sinks. The marshes around our 142 talhos in the RNSCMVRSA — the microalgae, the halophyte plants, the tidal channels — absorb CO₂ and lock it away. This is what climate scientists call Blue Carbon: carbon sequestered by coastal and marine ecosystems rather than forests.
What keeps that system functioning is the daily work of the marnoto — the manual maintenance of the channels, the management of water flow, the repair of the clay walls. When traditional salt farming disappears, the marsh dries out, and stored carbon returns to the atmosphere. This is not a metaphor. It is hydrology.
A shared estuary
The fieldwork on our pans is one half of a cross-border picture. Portugal and Spain share the Guadiana estuary; the salt pans of Castro Marim and the marshes of Ayamonte are part of the same living system. What happens on one bank affects the other — as we saw this winter, when dam discharge and storm surge pushed fresh water across the whole estuary, diluting the água mãe of producers on both sides at once.
On 9 June, Project SAL C holds a cross-border working conference in Ayamonte that brings together scientists, producers, and municipal partners from both banks. Anyone working in salt production, coastal ecology, climate policy, or sustainable food is welcome — registration and the full programme are available through the project partners.
What this means for our salt
We have always said that choosing Sal Correia is about more than seasoning. The 2026 Safra will be harvested from pans that are part of an actively studied, scientifically documented carbon-sequestration system. That is not a marketing claim. It is a measurable fact that the BLUEZ C Institute is working to quantify and publish.
When the QR code on your bag links to a harvest date and a lab result, it will one day also link to the carbon data of the ecosystem that produced it. That is the full picture of what Radical Transparency means.
We will keep reporting as the data comes in.
Nature provides. We protect.
— From Castro Marim to your table — rooted in every grain.