Are breeding oysters, mussels and clams are ultimate green foods?

Imagine an environmentally friendly food. Can your mind turn to the humble lens, but is it possible to eat more luxuriously while remaining green? Bivalves such as oysters, mussels, clams and scallops already have green references, thanks to their ability to clean polluted water. Now, some researchers argue that they can even mop carbon dioxide. Could cultivated bivalves be ultimate green food?

Food production is to be blamed for about a third of greenhouse gas emissions, in addition to all the other damage it makes, therefore the identification of foods that minimize this damage is essential. Regarding seafood, agriculture is generally considered more durable than catching wild fish. But farming fish need at least a few wild fish in their diet and, according to a study last year, the quantity of wild fish captured to feed on farming fish has been extremely underestimated. The park parks also produce a lot of pollution from excretions of fish and unsuccessful food.

The enormous advantage of bivalves is that they do not need active food. These are filter feeders who eat tiny particles of nutrients in seawater, including plankton. Most coastal waters are now overloaded with nutrients due to the pollution of nitrogen and phosphorus, so that the harvest of farming bivalves helps to eliminate part of this excess, cleaning water as by-product of food production.

Harvesting wild bivalves can be harmful – for example, dredging for wild scallops destroys the life of seabed such as sea fans, corals and sponges. But bivalve agriculture has relatively few drawbacks, in particular compared to razing tropical forests to feed butcher’s cattle.

But wait, there is more: in the past decade, an increasing number of studies have said that breeding bivalves capture carbon – an assertion which, if it could allow farms to claim carbon credits like another source of income.

However, Fabrice Pernet at the University of Brest in France, whose team recently examined more than 50 studies on the problem, is not convinced. Most of these studies are based on theoretical models which assume that the formation of calcium carbonate shells removes CO₂ of the oceans.

But this is only true on a geological time scale. Over a few decades or centuries – this is what matters with regard to global warming – carbonate formation releases CO₂.

In addition, says Pernet, it is common that waste shells are cremated, releasing more CO₂ in the atmosphere, instead of being returned to sea to reverse the CO₂– Liberation process. As for carbon in the flesh of animals, which is released as co₂ After consuming it.

Some researchers now make a different affirmation that more carbon in the form of organic matter is found in sediments on bivalve farms, making it a net carbon well.

The latest affirmation of this type is based on a study of oysters that develop in five 150 cubic meters enclosures. But Pernet says that and similar studies have faults, such as CO₂ The measurements are only carried out during and in summer when photosynthesis occurs.

The team behind the study indicates that this did not affect the result. “The budget shows that the accumulation of carbon and sequestration prevail over the carbon harvested in the shells,” said Shuang-Lin Dong at Ocean University in China in Qingdao. But Pernet is still not convinced. “Today’s evidence suggests that bivalve agriculture issues co₂ Overall, ”he says.

Do not yet cancel your reservation at the Oyster bar. Although bivalve agriculture is probably a net transmitter, it’s not many – only 1.4 kilograms of CO₂ or the equivalent per kilogram of edible weight according to a 2021 study. It is less than wheat or corn, and without the requirements of earth and fresh water.

“So yes, breeding bivalves are one of the greenest foods,” explains Pernet. Feast on.

Arctic Marine Biology Expedition Cruise: Svalbard, Norway

Embark on an unforgettable marine expedition in the Arctic, accompanied by the Marine Biologist Russell Arnott.