Pioneering project is launched to replant seagrass meadows, helping the ocean breathe

Benidorm’s neighbor, the Serra Gelada Natural Park on Spain’s Alicante coast, is set to host a multi year plan to expand Posidonia oceanica seagrass meadows. The effort brings public agencies and private partners together to plant and track new patches over at least five years.

The core aim is simple and serious. Grow more living seagrass on the seabed along a protected shoreline where the species already belongs.

Restoring Posidonia seagrass

The plan rolls through prospecting, careful harvesting of donor fragments, nursery cultivation, seabed planting, and long term monitoring that checks survival and growth. 

It also adds ecological moorings, anchors that avoid scraping the seabed, to reduce damage in busy boating seasons.

The work is anchored at the Mediterranean Institute for Advanced Studies (IMEDEA), part of Spain’s National Research Council (CSIC) and the University of the Balearic Islands (UIB). Its researchers focus on seagrass ecology, restoration methods, and long term monitoring.

The Generalitat Valenciana and Redeia describe Serra Gelada as the starting point, with the intent to expand to other coasts in the region. 

“Posidonia seagrass is a true blue lung that mitigates climate change, protects the coasts, improves water quality and harbors extraordinary biodiversity,” said Vicente Martínez Mus, Minister for the Environment.

Why posidonia seagrass matters

Posidonia is a native, slow growing seagrass that builds dense meadows on sandy sea floors. These meadows trap particles, keep waters clearer, and create shelter for fish, invertebrates, and other marine life.

Scientists call the carbon stored in seagrasses blue carbon, carbon stored in coastal plant habitats. In Mediterranean meadows, much of that carbon sits in the seafloor soil for decades to centuries once it is buried.

Healthy seagrass can blunt waves and stabilize sediment, a service confirmed across Europe by coastal engineering research. That same structure slows currents near the bed and helps sand settle, which supports beaches that otherwise erode fast in storms.

Carbon storage depends on how much organic matter settles and how long it stays buried. A 2016 study found that soil carbon in Posidonia meadows is shaped by a mix of plant traits, sediments, and local water dynamics.

The legal path behind the push

Valencia already protects seagrasses under a 2022 decree that maps meadows and restricts damaging activities. It requires safeguards in port areas and sets out monitoring plans so managers can check meadow conditions over time.

In May 2025, a new coastal law added an integrated framework for planning and safeguarding the shoreline. The law prioritizes environmental quality, resilience to storms and sea level, and the recovery of degraded habitats.

The legal framework matters because it limits anchor damage, sand mining, and poorly planned shoreline works. It also clarifies who does what on the water, which reduces confusion when agencies and private partners share a project.

How carbon credits could fund care

The project links restoration with a regional climate program that tracks verified emissions cuts and carbon capture. The climate change registry lists absorption projects and offers incentives for verified efforts.

Here the key concept is carbon credits, tradable units representing reduced or stored emissions. If monitoring shows new meadow growth and carbon gains, credit sales can help pay for maintenance, monitoring, and future plantings.

Counting carbon from seagrass requires caution and clear rules. Verified methods look at how much new biomass and soil carbon are added, and how durable that storage is over time.

How the team will avoid common pitfalls

Seagrass restoration can fail if fragments are poorly chosen, planted at the wrong depth, or left unprotected from anchors. The plan’s use of sequestration, long term storage of carbon by ecosystems, adds a second reason to measure survival and soil change carefully.

Site selection is crucial because Posidonia likes clear, sunlit water and stable sands. Planting too deep or in turbid zones leaves shoots light starved and vulnerable.

Long term monitoring is not a luxury. It is how teams catch early declines, adjust mooring lines, or add protection before small losses turn into bare patches.

What success could look like in Serra Gelada

Short term, success means high survival of planted fragments and new shoots along the edges of transplant plots. It also means fewer anchor scars and more protective marine phanerogams, flowering seagrasses that live underwater, in mapped zones.

Over several years, success means denser canopies that reduce suspended particles and improve water clarity. Denser meadows can also help dampen wave energy at the seabed during ordinary storms.

The project’s public private design matters, because coastal work needs boats, divers, lab support, and outreach. It also needs local clubs and tour operators to stick to mooring rules, since one dragging anchor can undo weeks of careful planting.

The team expects the first five years to guide what scales next along the Valencian coast. That timeline aligns with the slow growth of Posidonia, which builds lasting meadows when it is given space, light, and time.

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