The researchers gathered mussels from the shore in Musselburgh, outside Edinburgh, and tested their response to noise in the lab at the St Abbs Marine Station near Eyemouth. Previous studies have analyzed how noise affects large marine creatures like whales and dolphins, however little was known before about how marine invertebrates like mussels react to this noise.
Dr Karen Diele from Edinburgh Napier University and Co-Director of Research at the St Abbs Marine station, explained that mussels do not have ears but they can detect changing sound levels in their environment.
The team recorded and played the sound of a ship's motor to a sample of blue mussels in a controlled setting, and measured biochemical and behavioural changes in the mussels. For the first time in a marine species, they detected noise-induced changes in DNA integrity, indicating an underlying source of stress.
In addition, Dr Matt Wale, also from Edinburgh Napier, mentioned that the mussels exposed to noise consumed 12% less oxygen, which would lead to increased energy use and possibly slower growth.
The filtration rate, or how much algae they consume, decreased by over 80 percent and there was a 60 percent increase in valve gape, which means the mussels are spending more time vulnerable to predators
What is more,iven the wide distribution of mussels in areas where they may be exposed to noise, the impact of noise does not appear to be fatal or immediately dangerous for mussels, according to Dr Mark Hartl from Heriot-Watt University. However, this fact does not mean that the noise does not have a long-term effect on mussel populations in high noise areas. Namely, it could be affecting their growth, reproductivity and may help explain the decline of mussel banks in some areas of the UK.
The work received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland), as well as support by the St Abbs Marine Station, a charity focused to marine science, conservation and education.