World Seaweed Day 2025: Saving the ocean’s sustainable powerhouse

World Seaweed Day, celebrated on June 4, shines a spotlight on a vital yet often overlooked marine plant. Seaweed plays a key role in ocean ecosystems, supports diverse marine life, and benefits a wide range of human industries – from nutrition and agriculture to scientific research and climate solutions.

The day aims to boost awareness and inspire greater investment in this valuable resource. As seaweed farming expands, so too does global interest in its wide-ranging potential.

World Seaweed Day needs global attention

Seaweed forms the base of many coastal ecosystems. One of the most important types is kelp – a large brown seaweed that grows in cold, nutrient-rich waters. It attaches to rocks on the seafloor and rises toward the surface, forming thick underwater forests.

Kelp forests support high biodiversity. Fish, crabs, sea urchins, and sea otters all live, hunt, or breed among the kelp. Juvenile fish use the dense fronds as shelter from predators. Many invertebrates feed directly on the kelp or on the microorganisms living on its surface.

Kelp grows quickly – some species grow up to half a meter per day. As it grows, kelp absorbs carbon dioxide from seawater and produces oxygen. This helps reduce local ocean acidification. Kelp also slows water movement, which protects shorelines from erosion.

Indicators of ocean health

In regions like California, Tasmania, and British Columbia, kelp forests are key parts of the coastal food web. They also support commercial fisheries and ecotourism.

When kelp declines due to warming waters or sea urchin overgrazing, the entire ecosystem feels the impact. That’s why scientists monitor kelp closely as an indicator of ocean health.

Seaweed also protects coasts. It stabilizes sediment and slows wave action. These functions reduce coastal erosion. Seaweed adapts better than coral to temperature shifts and acidic waters. That makes it a useful tool in marine conservation.

Researchers continue to study how seaweed interacts with other species and how it might reduce ocean acidification.

A traditional and modern food

In many countries, people have eaten seaweed for centuries. It is part of everyday diets in Japan, Korea, China, and parts of India. It offers key nutrients such as iodine, calcium, iron, and vitamin K. It also adds natural flavor, especially umami.

Now, global markets are adopting seaweed as a food product. It appears in snacks, sauces, and health supplements. It is low in calories and high in fiber. It also suits vegan and gluten-free diets.

Seaweed farming does not use soil or fresh water, which makes it more sustainable than many land crops. As global food systems face pressure, seaweed provides an efficient and low-impact option.

Seaweed farming and local economies

Seaweed farming is simple and low-cost. Farmers tie seaweed to ropes and let it grow in coastal waters. In countries like Indonesia, India, and the Philippines, these farms create jobs, often for women.

Besides supporting income, seaweed farms improve the environment. Seaweed absorbs excess nutrients such as nitrogen and phosphorus. These nutrients cause algae blooms in polluted waters. Seaweed helps reduce that risk and restore balance.

Governments and NGOs are working to scale seaweed production. The goal is to improve both rural incomes and marine health.

World Seaweed Day and climate action

Seaweed absorbs carbon while growing. Some researchers suggest that large-scale seaweed farms could help remove carbon from the atmosphere. This process is still being studied. One idea involves sinking harvested seaweed deep into the ocean to store carbon long-term.

Another tested solution involves livestock. Adding small amounts of red seaweed to cattle feed reduces their methane emissions. Trials show up to 80 percent reduction in some cases.

Seaweed will not solve climate change alone. But it can support broader strategies through carbon capture and reduced agricultural emissions.

Industrial uses and new research

Seaweed has applications far beyond food. It appears in cosmetics, fertilizers, packaging, and pharmaceuticals. Extracts from seaweed act as thickeners, antioxidants, and anti-inflammatory agents.

Researchers also study seaweed-based materials for biodegradable plastics and fabric. In construction, seaweed-derived products may improve insulation. Interest is growing because seaweed is renewable, versatile, and relatively easy to grow.

Innovation in this field depends on research funding, fair supply chains, and environmental monitoring.

Challenges of seaweed farming

Despite its benefits, seaweed farming still faces challenges. Many farmers lack secure access to coastal waters. In some regions, laws are unclear or missing. Infrastructure is often weak, and small producers have limited market access.

Uncontrolled harvesting also poses a threat. Some regions cut seaweed from wild stocks without considering long-term impact. Poor practices can damage ecosystems.

To avoid these risks, governments must support training, regulations, and monitoring. A balance is needed between industry growth and environmental protection.

Take action on World Seaweed Day

Taking action on World Seaweed Day can start with something as simple as learning more about the role seaweed plays in ocean health and climate solutions.

You can support sustainable seaweed products by choosing foods, cosmetics, or packaging made with responsibly harvested or farmed seaweed.

Sharing what you learn on social media or with friends helps spread awareness and encourage others to take interest.

If you live near a coast, you might look into local seaweed farming initiatives or marine conservation programs to volunteer with or support.

Even small actions like asking for more seaweed-based options at your grocery store can help drive change. You can also donate to organizations that support seaweed and ocean sustainability, such as the Kelp Forest Foundation.

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