SOLVE magazine Issue 01 2020 - Page 16

SUSTAINABILITY AND THE ENVIRONMENT: LIVING SEAS The world is our oyster Overfishing, disease, pollution, poor water quality and dredging have changed the marine environment within our coastal waters, bringing some marine species close to extinction. The researchers’ ally in turning around this perilous situation is Europe’s humble native oyster. Oysters are no ordinary molluscs. They’ve been around for over 500 million years. They were flourishing eons before early humans discovered them as a food source, then as a deity and today as a seafood delicacy – and they retain a special place in our folklore and culture. But it is not the myth of Aphrodite, the goddess who emerged from the sea on a (very large) oyster shell, or Giacomo Casanova’s boundless passions, for which he credited his oyster diet, that make oysters special. Oysters are the ocean’s kidneys A single oyster filters up to 200 litres of seawater a day, removing pollutants and keeping the surrounding water clean for other sea life to thrive. And oysters would have been even more productive in prehistoric times when they were much larger – up to one metre in diameter. This filtration role has been crucial to the health of coastal marine life by providing clear water that allows sunlight to reach important habitats such as seagrasses. Beyond this, oyster reefs create habitats able to nurture a much higher level of biodiversity than a flat seabed. This includes PHOTO: JOANNE PRESTON Oyster restoration In addition to repopulating with caged oysters (see next page), The Solent Oyster Restoration project has put 20,000 oysters on the seabed in a large estuary-wide experiment in the River Hamble ahead of a large-scale national restoration plan. Research is also helping to discover how the commercially and ecologically devastating disease bonamiosis is spread is between oysters, and to find out if there is a genetic basis for resistance to this disease. "We are also working to understand other challenges that the native oyster faces, such as invasive species like the American slipper limpet (Crepidula fornicata) and Pacific oyster (Crassostrea gigas),” Dr Joanne Preston says. “These are widespread in the Solent and affecting the recovery of the native oyster.” Other research involves mapping and calculating the value of the services that marine habitats provide for humans – known as natural capital valuation. Habitats such as seagrasses, saltmarshes and oysters reefs are important in controlling water quality and carbon storage, and Dr Preston’s team is estimating their monetary value. 16 ISSUE 1 / 2020