Ireland attempts to use oysters to clean water

A rather unlikely ally at first glance. However, these molluscs could be the solution to restoring biodiversity in our oceans.

In the marina of Dún Laoghaire, ten kilometers south of Dublin, the Irish capital, Paul Brookes, a marine ecologist at UCD University, pulls a basket from the water, attached to the pontoon just below our feet. “There, I open the box which contains 12 oysters. They look healthy!”he rejoices.

But food lovers don’t get too excited: these oysters are not intended for consumption. “Hopefully the seals won’t catch them either, nor the seagulls.”hopes David Lawlor, a business leader, at the origin of the project which wants to use molluscs to filter water.

“The oysters are here because they have a water-cleaning job to do.”

David Lawlor, Green Ocean Project Manager

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“Each oyster filters approximately 190 liters of water every day, and this is important because once the water is clear, sunlight can penetrate the seabed. This allows seagrass beds, which are great carbon sinks, and other algae to spread. And of course, once we have this habitat in place, fish and invertebrates will be able to avoid their predators, and therefore multiply, creating a functioning ecosystem.”continues David Lawlor.

Paul Brookes is delighted with the return of oysters to Ireland. “In the 17th century, oysters were very present on several reefs around Dublin Bay. They were considered a cheap, easily accessible foodexplains the ecologist. But with increasing pollution rates due to city expansion and the arrival of a disease called bonamia, oyster reefs were hit hard around the 1950s.”

“It completely decimated the oyster population, not only in Dublin, but also in other parts of Ireland,” concludes the ecologist. These new oyster reefs could also help cushion the effects of storms, which with climate change have become more frequent and violent in recent years.