Durham County Council plans to create oyster and kelp farms off the coast of County Durham to help cut its carbon footprint by 80% in a decade. Kelp and seaweed absorb CO2, while oysters and clams filter and purify seawater, improving marine ecosystems. The quality of the seawater in the area has improved significantly since the end of the region’s mining industry, said Durham’s low carbon energy principal officer, Stephen McDonald. The council’s decarbonisation programme includes using LED lightbulbs and generating more of its energy from solar, but it admits decarbonising transport and heating systems remains challenging.
Why does this matter? Greenpeace has highlighted that improving the health of oceans, the largest carbon sink on the planet, could be a critical step in mitigating the effects of climate change.
Oysters filter ocean water, and large beds can help to maintain the cleanliness of surrounding habitats, allowing other ocean life to flourish while potentially removing harmful chemicals from waterways.
Unfortunately, pollution, erosion and other environmental hazards have removed up to 85% of the world’s oyster beds, according to one study. Overfishing has also played its part in depleting stocks.
Research has suggested, however, farmed oysters can actually withstand rising levels of acidity in oceans – one consequence of increasing levels of CO2 in the atmosphere. It’s possible selective breeding could allow oyster beds to be established in coastal areas where the water contains pollutants that could be filtered out by the shellfish.
The reintroduction of oyster reefs is gaining interest globally due to these benefits and other services these ecosystems can provide – including coastal protection from storm surges as well as biodiversity enhancement. A large oyster reintroduction project from BLUE in the Solent – the first of its kind in the UK – has placed mature oysters in cages hung beneath pontoons, to release millions of oyster larvae into the strait between the UK mainland and the Isle of Wight.
Another solution to combat both ocean acidification and climate change is making use of farmed kelp. One suggested process involves growing kelp to maturity and then sinking it to the bottom of the ocean, to permanently sequester the CO2 it has absorbed. The kelp effectively captures CO2 and thus also has the ability to reduce the acidity of surrounding waters.
The catch, however, is the technology to sink seaweed to the ocean floor is still at a primitive stage, and some argue this would be wasting a resource that could be put to good use on land.
Source: Hartlepool Mail