Seagrass meadows may not be as well-known as coral reefs or rainforests, but they play a crucial role in maintaining the health of our oceans. These underwater plants not only provide a habitat for countless marine species, but also have a significant impact on water quality by acting as natural filters. Seagrass restoration efforts are therefore vital in preserving the delicate balance of our marine ecosystems.
Seagrass and climate change
Seagrass meadows can be found in coastal areas around the world, from shallow waters to depths of up to 40 meters. They are incredibly efficient at absorbing and storing carbon dioxide, making them one of the most effective natural tools we have in combating climate change. Given that seagrasses can capture carbon at rates up to 35 times faster than tropical rainforests, and account for 10% of the ocean’s total burial of carbon (despite covering less than 0.2% of the ocean floor), they are one of our most important natural solutions to the climate change crisis.
Additionally, seagrass beds act as a nursery for many commercially important fish species, providing shelter and food for younger fish and other marine organisms.
Why is seagrass so important?
One of the most important functions of seagrass is its ability to improve water quality. The plants have long, ribbon-like leaves that trap sediment and particles suspended in the water column. This filtration process helps to clarify the water by removing excess nutrients, pollutants, and sediments, resulting in cleaner and clearer water.
Excess nutrients in the water, such as nitrogen and phosphorus, can lead to harmful algal blooms and oxygen depletion, causing harm to marine life. Seagrass meadows naturally absorb these nutrients from the water, preventing their accumulation and subsequent negative impacts. By restoring and protecting seagrass habitats, we can effectively reduce the risk of harmful algae blooms and improve overall water quality.
Furthermore, seagrass meadows also play a crucial role in stabilising coastal sediments. Their extensive root systems bind the sediment together, preventing erosion and coastal flooding. This is particularly important in areas prone to storms and rising sea levels, as seagrass meadows act as a natural defence against erosion and provide a buffer zone between the land and the ocean.
Why are seagrass restoration projects necessary?
In a 2021 research study, University College London found that at least 44% of the UK’s seagrass has been lost since 1936 – most of it since the 1980s. Pollution from industry, mining and farming, along with dredging, bottom trawling and coastal development are to blame, with only 8,500 hectares (32 sq miles) of seagrass meadow left in the UK – an area smaller than Newcastle upon Tyne.
This loss of seagrass threatens to have a hugely detrimental effect on our ability to fight climate change, maintain the cleanliness of our water, and preserve marine habitats.
Any activity that increases turbidity or reduces light penetration in water over seagrasses limits the growth and survival of the plants. Sewage release is a human-related factor that has a significant impact, and while recreational boaters may not be as big a threat to seagrass beds as commercial water companies who discharge sewage into rivers across the UK on a daily basis, the release of conventional marine hygiene products into our waterways can release harmful toxins which damage seagrass beds.
What is seagrass restoration?
Seagrass restoration involves planting or transplanting seagrass shoots into degraded or lost habitats. This can be a challenging and time-consuming process, as seagrass requires specific conditions to grow. However, with careful planning and monitoring, successful restoration projects have been carried out in various parts of the world.
One such project that is currently in progress on the South Coast is the Solent Seagrass Restoration Project. This project, led by Hampshire & Isle of Wight Wildlife Trust aims to restore seagrass habitats in the Solent to their historical levels, supporting increased biodiversity and sustainable fisheries, promoting greater ecosystem services, cleaner water and creating a natural carbon solution to mitigate the effects of climate change.
The benefits of seagrass restoration are numerous. Besides improving water quality, seagrass meadows provide valuable ecosystem services such as carbon sequestration, fishery support, and coastal protection. They also promote biodiversity by providing habitat for a wide range of marine species, including turtles, seahorses, and numerous fish species.
In conclusion, seagrass restoration is crucial for maintaining the health of our oceans and improving water quality. By recognising the importance of these underwater meadows and implementing effective restoration strategies, we can ensure the long-term survival of seagrass habitats and the countless benefits they provide.
While environmental organisations and policymakers have a role to play in safeguarding the health and wellbeing of our marine ecosystems, so too do recreational boaters and sailors whose effluent and harmful cleaning products are discharged into our seas and rivers. We are all responsible for ensuring that the waterways which give us so much enjoyment are preserved for future generations, and that the seagrass beds which are so important in the fight against climate change are not adversely affected by our leisure activities.