With climate change taking a toll on the mussel population, there is a possibility that mussel-based dishes could be taken off the menu in the near future.
Climate change is affecting the Earth's atmosphere, surface and waters. Oceans, for instance, are becoming more acidic as they absorb more carbon dioxide. Water typically reacts to carbon dioxide and forms carbonic acid, which lowers the pH level of oceans. The drop in the pH levels of ocean water could happen -- from the current 8 to 7.7 -- toward the end of this century.
Experts believe that the shells of mussels consist of an organic material that is created by the mussels via biomineralization and using calcium carbonate.
Mussels get bicarbonate ions via seawater and use their body proteins to make calcium carbonate crystals that form their shells. The outer layer of the shell consists of calcite, while aragonite makes the inner shell layer. Fewer bicarbonate ions are available in high acidic water. This disturbs the mussel's ability to create their shells.
Dr. Susan Fitzer of the University of Glasgow's School of Geographical and Earth Sciences led the research that used common blue mussels. She housed these mussels in lab tanks and controlled the temperature as well as the pH levels of the water. This enabled the researchers to simulate different types of ocean waters that are predicted to change in the next few decades. The researchers also changed the light levels in the tank to mimic changes in the season during a year.
Dr. Fitzer suggests that the increased acidification of the water in the tank created a negative impact on the mussels' ability to make shells.
The research also enlisted the help of the university's school of engineering to study the mussel shells' toughness in high acidic water compared with their toughness in controlled conditions suitable for the creatures. The study found that acidic water made the mussel shells more brittle and more likely to be fractured when under pressure.
"This could mean that mussels growing in the wild in the future could be more vulnerable to attack from predators, as well as from the effect of ocean forces. As blue mussels are commonly used for human consumption, it could also have an effect on the yields of mussels available for the fishing industry," said Dr. Fitzer.
The shellfish market is worth over £250 million ($388 million) per year to the UK economy, with oysters and mussels as major contributors. The food industry may also be affected if mussels are taken off the menu.
The study was published in the Royal Society's journal Interface.
