In 2019 Ailbhe Flynn, a young teenager from Ballymoney, Co Wexford, was on her summer holidays in Quilty, a small village between Milltown Malbay and Doonbeg in Co Clare. One afternoon on the beach with her family, Ailbhe came across a small rocky cove and decided to explore the water further. But instead of sand at her feet she unexpectedly found herself wading knee-high in what she thought was soft, silky seaweed.
What Ailbhe had discovered was a verdant bed of seagrass. These lush underwater flowering meadows store carbon in their roots up to 35 times faster than forests on land. They are the Amazon rainforests of our salty waters, the raised bogs of our oceans.
If you’re trying to imagine what they look like don’t think about seaweed. Seagrasses aren’t algae; they evolved millions of years ago from plants on the land, with leaves, roots and veins producing seeds and flowers. Their green, ribbon-like blades, up to 2 metres in length, branch out of a network of large root-like structures called rhizomes, which secure them to the sandy floor.
The two main species off the Irish coast photosynthesise energy from the sun, as plants do on land, so the more transparent the water the better. Zostera marina has long blades and prefers to be covered in seawater all the time; it doesn’t grow too far off the coast so your best chance of spotting it is on a paddle-board or kayak. The other species, the diminutive Zostera noltii, grows between high and low tide marks and can be seen in full glory when the tide is out.
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Seagrasses are like the best pupil in the class. Although they cover just 0.1 per cent of the ocean floor they store up to 18 per cent of the world’s oceanic carbon. They act like a nature reserve for species such as seahorses, sea hares, juvenile cod and haddock, flounder, mullet and tiny sharks called dogfish. They are also a critical ally in our efforts to deal with coastal erosion, absorbing the sea’s energy and reducing the impact of waves that hit our coasts by about 40 per cent.
And yet the equivalent of one GAA field of seagrass is being lost every hour across the world. They are under pressure from coastal development, urban wastewater, bottom trawling and dredging, mining and pollution from industry. Excessive use of nitrogen and phosphorous in agriculture is a significant threat. These nutrients find their way into our estuaries and coasts and fertilise the water, causing macroalgal blooms to flourish to the detriment of seagrasses.
According to scientist Dr Liam Morrison of the University of Galway, we don’t have an adequate baseline to compare the current status of seagrass with the past, but herbarium records reveal their historical presence in areas where they are not found today. Seagrass meadows have disappeared in places such as Clonakilty and Courtmacsherry, where algal blooms are now a severe problem.
Morrison is part of an EU-funded project called “CLIMAREST”, an initiative to restore life to our oceans and waters. This summer he is leading a seagrass restoration project in Tralee Bay, Co Kerry. Over the past few weeks he and his team have snorkelled along the bay, collecting seagrass samples for genetic analysis and transplantation to other areas where they have disappeared.
Preserving seagrass beds is a vital task. Ecologist Karin Dubsky, who grew up on a farm in Wexford and founded the environmental organisation Coastwatch, remembers playing mermaids in the seagrass meadows off Bannow Bay as a child. They’re long gone now, and their absence is a sign that water pollution has taken hold. Seagrasses tell us something about our environment, and it’s for this reason the Environmental Protection Agency (EPA) uses their presence as a positive indicator of water quality.
In order to protect seagrasses into the future over the past few years Dubsky has enlisted the help of the public to identify beds. A few years ago in Lough Swilly, for example, local fisherman Keith Hardy discovered some small seagrass beds and worked with oyster fishermen in his local coop to ensure that these areas were not dredged.
Given their astonishing capacity to soak up carbon we would do well to take a bit more notice of seagrasses – particularly if they are allowed to be included in our national greenhouse gas inventories in the future. They are not protected under the law and we have no map of their full distribution and health. Unlike Northern Ireland, we don’t even have a seagrass action plan. Given their effectiveness in helping to solve some of our urgent climate and nature problems, it’s a weak position to be in.
Back in Clare the seagrass bed discovered by Ailbhe Flynn, who is now 17, is named after her: “Ailbhe’s Quilty Bed”. She says that seagrasses are a precious resource and need protection. We should heed this teenager’s wisdom before it’s too late.
