Coastal erosion is accelerating worldwide due to climate change and human activity, threatening homes, habitats, and coastal communities. Seagrass meadows play a vital protective role by stabilising sediment, reducing erosion, slowing wave energy, capturing carbon, and improving water quality. With global seagrass in steep decline, large‑scale restoration efforts, such as those led by Swansea University, UK, are essential to protect coastlines and support planetary health.
Image by Dr David Buss created using OpenAI
The impact of coastal erosion
Given that nearly 70% of the Earth’s surface is covered by
the sea, coastal erosion (the weathering and loss of coastal land, beaches,marshes, rocks, or cliffs caused by waves and tides) has become a serious problem in many parts of the world. Coastal erosion can lead to the loss of
homes, natural habitats, infrastructure, and community livelihoods, resulting
in huge economic costs and, tragically, sometimes loss of life.
Having been born in an area with a long coastline and now
living on an island, I am well aware of its impact. I have witnessed beaches
shrink over time and coastal communities become fragmented.
Climate change and human activities play a crucial role in
accelerating coastal erosion. Sea levels are rising due to warming oceans and
melting ice sheets. Even small increases in temperature can reshape coastlines.
Scientists are now recognising that seagrasses could play an important role in preventing erosion.
Seagrass and its impact
Seagrasses are the only flowering plants that grow in marine
environments. Several species exist, many with long, narrow leaves resembling
land grasses. Their underground roots spread across the seabed, forming
extensive underwater meadows that provide habitat for diverse marine wildlife
and, during low tide, non‑marine species such as birds.
Seagrasses are among the most widespread marine ecosystems on Earth, covering
around 300,000 km² of seabed across 159 countries.
Research indicates that seagrass can act as a critical
natural defence against coastal erosion. Their root mats trap and anchor
sediment, reducing shoreline erosion by up to 70%. Seagrass meadows also slow
wave energy, effectively acting as a buffer during storms.
In addition, seagrasses capture carbon from the atmosphere, reportedly
up to 35 times faster than tropical rainforests, and absorb pollutants,
improving water quality. Overall, they play a vital role in maintaining
planetary health. In recognition of this, the United Nations has designated 1March as World Seagrass Day.
Decline of Seagrass
Despite their importance, global seagrass coverage is
declining due to human activities such as rampant coastal development,
pollution, climate change, dredging, and damage from boat propellers. The UK
has lost approximately 90% of its seagrass meadows, with half of that loss
occurring in the last 30 years. Seagrasses in the USA are also experiencing extraordinary decline, with losses of over 90% recorded in Florida’s Big Bend.
Seagrass restoration in the UK
Reversing this decline requires active conservation:
protecting remaining meadows and restoring those that have been lost. One notable initiative is led by researchers at Swansea University, under Dr Richard Unsworth. They are developing methods to restore seagrass meadows at
scale.
With the planting of 2‑hectare meadows, the team is
undertaking one of the UK’s largest seagrass restoration
projects. They are now involved in restoration efforts in North Wales, the
Solent, and the Firth of Forth in Scotland. Working with research partners,
they are developing scalable restoration techniques that could help reverse the
decline of this endangered ecosystem on which the health of our planet
depends.
Extensive and Continuing Loss of Seagrasses in Florida's Big Bend (USA) - PubMed




