Are the world’s seagrass meadows healthy enough to combat climate change?

Carbon sequestration superstar

Effective protection and management of the world’s seagrass meadows could play a vital role in mitigating climate change. How? By sequestering carbon dioxide dissolved in the ocean resulting from our emissions.

Seagrass, a deciduous marine plant that excels at photosynthesis, exhibits astonishing carbon sequestration efficiency. According to the WWF, seagrass:

• Captures carbon up to 35 times faster than tropical rainforests;

• Covers 0.2 % of the seafloor; and

• Accounts for more than 10 % of the total ocean carbon storage.

Seagrasses can help countries reduce carbon emissions significantly and measurably. Ocean carbon capture can help remove carbon dioxide from the air and decrease greenhouse gas emissions. Capturing and storing carbon is such a large global focus as we aim to meet targets to combat climate change, the importance of protecting and enabling expansion of seagrasses will be one of the most vital ecosystem services we can provide.

The Intergovernmental Panel on Climate Change (IPCC) recognises seagrasses as one of the most effective natural solutions to combat climate change due to their carbon sequestration capabilities. In fact, the IPCC named seagrass as one of the world’s three ‘blue carbon’ ecosystems (along with mangroves and salt marshes).

Highly productive ecosystem

Seagrass meadows are important for biodiversity. They provide a home for many different types of animals such as fish, crustaceans, and molluscs. Seagrasses are the perfect nursery for young marine organisms, providing protection and food as they grow.

Seagrasses perform many important additional functions, including:

• Dampening the force of waves, thereby mitigating wave damage.

• Providing effective protection against coastal erosion.

• Recycling nutrients.

• Enabling other ecosystems to thrive, such as mangroves and coral reefs.

• Filtering seawater, improving its quality by removing bacterial pathogens. Experts estimate that this service reduces the annual incidence of cholera by around 600,000 cases a year.

Seagrass meadows are important for the planet. They help with biodiversity, protect coastlines, filter water, recycle nutrients, and fight climate change on a global scale. Preserving and restoring them is vital.

Where are the world’s seagrasses?

Many people assume that this flowering marine plant thrives only in shallow, sheltered coastal waters. However, most of the world’s seagrass meadows can be found in far deeper water, growing on the seabed up to 50 metres below the surface.

Seagrass meadows are crucial for the planet's health, but only 20% have been studied. Many areas, like the Indian Ocean, have limited information available. Moreover, the reporting to date merely indicates whether seagrasses are present in a location or not.

Given the Earth’s climate emergency, there is an urgent need to map, monitor and manage seagrass worldwide. Importantly, it’s not just the location and size of the seagrass meadows that need to be monitored – assessing their health is even more important.

What’s affecting seagrass health?

Since 1980, the world has been losing about 110 square kilometres of seagrass meadows every year. It seems like the rate of loss is getting faster. Numerous factors contribute to this decline, including destructive bottom trawling, pollution, sedimentation, nutrient enrichment, and climate change. Understanding the reasons behind the deterioration of these critical ecosystems and their health is essential to realistically hope for their restoration and thriving preservation.

Why is seagrass health important?

Healthy seagrass meadows efficiently sequester carbon from seawater, partially storing it in the sediment (though not all is retained – some is released and remineralised). As seagrasses grow, their storage capacity increases. Over time, accumulated organic matter forms an interwoven mat of vegetation, holding the seagrasses in place while securely locking away carbon.

However, when seagrass health declines, carbon sequestration becomes less efficient. Persistent issues lead to the destabilisation of the decaying mat, releasing captured carbon back into the system. This deterioration also releases other climate gases, posing significant concern from a climate-change perspective.

Mapping and monitoring urgently needed

Despite their exceptional carbon sequestration abilities, seagrasses are often overlooked due to a lack of data about their distribution and health. This resulting lack of recognition and protection could explain why seagrass meadows often don’t feature in policy-making and decisions about how best to tackle climate change.

The UN’s 17 Sustainable Development Goals (SDGs) include Goal 14 (Life below water), highlighting the importance of conserving and sustainably using the oceans, seas, and marine resources. However, in 2022, the UN stated that Goal 14 had received the lowest amount of public funding among all the SDGs.

Urgent efforts are needed to map seagrass meadows worldwide, monitor their health regularly, and identify the causes of any changes occurring. Armed with this knowledge, governments can take action to protect and nurture these critical ecosystems. To maximise the ocean’s enormous carbon sequestration potential, seafloor restoration and preservation projects need to start immediately – and financial considerations must not impede progress.

Fugro and PlanBlue partnership

Fugro and PlanBlue have forged a collaboration to advance habitat mapping technology, using diverse cutting-edge methodologies. Conventional ground-truthing techniques for large-scale mapping are laborious and time intensive. To address this challenge, PlanBlue has developed a sensor payload and streamlined process optimised and accelerated through artificial intelligence (AI).

As the global Geo-data expert, Fugro specialises in comprehensive multi-scale hydrographic solutions. Its expertise encompasses a wide array of technology, including remote and autonomous underwater vehicles equipped with advanced sensors. In parallel, PlanBlue brings proficiency in advanced (hyperspectral) imaging and AI-driven data processing to the partnership, ensuring a well-rounded collaboration.

The combined strengths of Fugro and PlanBlue promise to revolutionise habitat mapping, offering innovative solutions for environmental conservation and management. PlanBlue's technology uses hyperspectral imaging to quickly and accurately assess the health of seagrasses by detecting chlorophyll levels. This helps identify areas that need restoration.

Fugro and PlanBlue both play important roles in working together, sharing their expertise for mutual benefit. The partnership will study and document important marine ecosystems like seagrasses and corals. This will help improve underwater mapping and modelling, leading to better decisions for ocean conservation and use.

Waking up to the importance of seagrass

Seagrass comes in various types, with some species maturing faster than others. However, as a general rule, they take between one and five years to reach maturity., Therefore, the quickest way to bolster seagrass population is by nurturing existing ones.

The partnership between Fugro and PlanBlue signifies a dedication to driving positive change through technological innovation. It stands as one of many significant strides taken to maximise the global carbon sequestration potential of seagrass.

Italy's government is working on a project called Marine Ecosystem Restoration (MER). The project aims to restore marine habitats and improve monitoring of marine and coastal ecosystems. This initiative is part of Italy's National Recovery and Resilience Plan.

In this endeavour, the collaborations between Fugro and PlanBlue will play a pivotal role. Our efforts will encompass comprehensive mapping of coastal habitats across the entire Italian coast, with specific focus on seagrass meadows. The world is starting to recognise the importance of its seagrass habitats.

We must protect these precious ecosystems that have evolved over millions of years, and mitigate harmful human activity, such as too much coastal development and the presence of pollutants, before the effects of climate change take hold.

Food for thought

Seagrasses play a crucial role in maintaining our planet’s equilibrium by sequestering carbon and securely locking it away in the seafloor. To thrive, seagrasses require undisturbed growth within a healthy ocean – clear blue water at the optimal temperature, free of pollution, and eutrophication.

Encompassing around two-thirds of the Earth’s surface, the ocean is often described as the cradle of life, playing an immense role in supporting our planet’s health.

Without urgent and sustained action to conserve, protect, and restore the ocean and its seagrasses, we all may face dire consequences.