Seagrasses: The Unsung Guardians of Our Oceans

By Ifham Nizam

As the world celebrates the third annual World Seagrass Day, on March 1, marine conservationists, scientists, and environmentalists are raising their voices to shed light on the critical role of seagrass ecosystems. Despite their vital contributions to marine biodiversity, coastal protection, and climate change mitigation, these underwater meadows remain largely unrecognised and vulnerable to destruction.

Seagrasses, flowering plants that grow in shallow coastal waters, are the foundation of marine ecosystems. They provide shelter and food for countless species, act as natural barriers against coastal erosion, and play a significant role in capturing carbon—helping to regulate the planet’s climate. However, pollution, habitat destruction, and climate change pose growing threats, making seagrass conservation more urgent than ever.

Seagrasses: The Hidden Powerhouses of the Ocean

Seagrasses are often overshadowed by coral reefs and mangroves when discussing marine conservation. However, these aquatic plants are just as crucial to the health of our oceans. Found in shallow waters along coastlines worldwide, seagrasses support a vast array of marine life, from tiny crustaceans to large predators.

According to the Blue Resources Trust, seagrasses are among the most widespread coastal habitats, covering between 300,000 and 600,000 square kilometers globally. In Sri Lanka, research has identified 15 true seagrass species, mostly inhabiting areas such as the Gulf of Mannar, Jaffna Lagoon, Puttalam, Chilaw, Batticaloa, and Trincomalee Bay. Despite their ecological importance, these habitats face increasing pressure from human activities.

“Seagrasses are silent warriors in the fight against climate change, capable of sequestering carbon at rates far greater than tropical rainforests,” speaking to The Island

Susantha Udagedara, a marine researcher from Blue Resources Trust, says: “If we lose them, we not only endanger marine biodiversity but also compromise the livelihoods of coastal communities that depend on healthy marine ecosystems.”

A Lifeline for Marine Biodiversity

Seagrass meadows are biodiversity hotspots. Their dense blades provide shelter and breeding grounds for fish, crabs, shrimp, sea turtles, and even dugongs. These ecosystems serve as nurseries for juvenile fish, ensuring sustainable fisheries that support millions of people worldwide.

Many commercially valuable fish species, such as snappers and groupers, depend on seagrasses for survival. The loss of these habitats could significantly impact local fishing communities, particularly in Sri Lanka, Indonesia, the Philippines, and other coastal nations where fisheries are a major source of food and income.

In Sri Lanka, seagrass habitats also support endangered marine species like the dugong (Dugong dugon). Often referred to as “sea cows,” dugongs rely on seagrass meadows for sustenance. However, habitat destruction and human activities have pushed these gentle giants to the brink of extinction.

“We often hear about coral reef conservation, but seagrasses play an equally vital role in maintaining marine biodiversity,”

says Udagedara. “Without them, entire ecosystems could collapse.”

Seagrasses as Nature’s Coastal Defenders

One of the most overlooked benefits of seagrasses is their role in coastal protection. These plants form dense underwater meadows that help stabilize sediments and reduce wave energy, minimizing coastal erosion.

With rising sea levels and increasingly powerful storms due to climate change, the ability of seagrasses to protect shorelines is more valuable than ever. Research shows that seagrass meadows can reduce wave energy by up to 80%, acting as a natural buffer against coastal erosion.

Plastic waste on seagrass beds

In Sri Lanka, where coastal communities are highly vulnerable to climate change impacts, protecting seagrass meadows could mean the difference between stability and disaster. The Coast Conservation and Coastal Resources Management Plan (2018) estimated Sri Lanka’s total seagrass coverage at 37,137 hectares, but significant gaps remain in data collection due to past conflicts and limited research.

“If we invest in seagrass restoration, we are investing in the long-term protection of our coastlines and communities,”

Udagedara emphasizes. “Ignoring their role could lead to increased flooding, loss of property, and economic hardships for those living near the coast.”

Seagrasses as Climate Change Warriors

In addition to coastal protection, seagrasses play a crucial role in mitigating climate change. These underwater plants capture and store large amounts of carbon dioxide in their sediments, a process known as blue carbon sequestration.

Remarkably, seagrass meadows can sequester carbon up to 35 times faster than tropical rainforests per unit area. This makes them one of the most effective natural solutions for combating climate change.

However, when seagrass meadows are destroyed—whether by dredging, pollution, or trawling—the stored carbon is released back into the atmosphere, contributing to greenhouse gas emissions. This underscores the need for urgent conservation efforts to protect existing seagrass meadows and restore degraded ones.

Susantha Udagedara

“We talk about planting trees to fight climate change, but we should also be restoring seagrass ecosystems,”

says Udagedara. “They are one of nature’s most efficient carbon sinks.”

Global Commitments and Local Actions

The recognition of World Seagrass Day by the United Nations General Assembly in 2022 marked a major milestone in marine conservation.

Sri Lanka played a key role in advocating for this recognition

, making it one of the country’s most significant environmental achievements.

The 2030 Seagrass Breakthrough, an initiative aligned with the Kunming-Montreal Global Biodiversity Framework, the Paris Agreement, and the UN Decade on Ecosystem Restoration, aims to restore and protect seagrass ecosystems worldwide. It provides a roadmap for governments, conservation organizations, and local communities to work together in safeguarding these critical habitats.

However, Udagedara warns that policy commitments alone are not enough.

“We need real action on the ground. Local communities, governments, and researchers must collaborate to ensure that seagrass conservation is integrated into coastal development plans,”

he says.

Community-led conservation projects, such as seagrass monitoring programs and habitat restoration initiatives, are gaining momentum in countries like the United Kingdom, Australia, and Indonesia. These efforts demonstrate that grassroots participation is key to long-term success.

The Future of Seagrass Conservation

Despite their immense ecological value, seagrass meadows are still declining at an alarming rate. Studies suggest that globally, seagrass coverage has been shrinking by approximately 7% per year, a rate that could accelerate if urgent action is not taken.

To reverse this trend, experts recommend:

· Strengthening marine protected areas to include seagrass meadows.

· Implementing sustainable fishing practices

to prevent habitat destruction.

· Raising public awareness

on the importance of seagrass conservation.

· Investing in seagrass restoration projects

to rehabilitate degraded meadows.

“If we want to secure the future of our oceans, we cannot afford to ignore seagrasses,”

says Udagedara. “They are not just patches of underwater plants; they are the lungs of our seas, protectors of our coasts, and providers of marine life.”

As the world marks World Seagrass Day, the message is clear: seagrasses are an essential part of our planet’s ecological balance. Their contributions to biodiversity, climate change mitigation, and coastal protection highlight the urgency of protecting these underwater forests.

By investing in conservation and sustainable management, we can ensure that seagrass meadows continue to thrive for generations to come.

“The fate of seagrasses is in our hands,” Udagedara reminds us. “If we act now, we can preserve these vital ecosystems before it’s too late.”