Tiny marine organisms known as the ‘biofouling communities’ are set to change as the world’s oceans become more acidic, according to a new study from the British Antarctic Survey (BAS), the Centro de Ciências do Mar and the University of Cambridge.
Around $15billion is spent each year cleaning desalination and power plants. Biofouling communities form a rough surface on ships that increases drag. The cleaning process can cost as much as $7billion a year worldwide.
‘These organisms are not just fouling ships. They are a problem for the aquaculture industry, power stations, and desalination plants,’ says Professor Lloyd Peck, who led the study for the BAS. ‘Biofouling communities are also a problem for alternative energy sources like wave power,’ he adds.
The BAS study attempted to find out what was going to happen to biofouling communities in the real world and looked at a pH change in the oceans that might happen in fifty–sixty year’s time, as increased CO2 levels lead to a more acidic ocean. The experiment involved over 10,000 animals from the highly productive Ria Formosa Lagoon system in Algarve, Portugal. Communities were allowed to colonise hard surfaces in six aquarium tanks. In half the tanks, the seawater had the normal acidity for the lagoon (pH 7.9) and the other half were set at an increased acidity of pH 7.7.
Previous studies have looked at individual species and how their physiology has been affected by changes in pH levels. The BAS study differed in looking at five or six species as a community. Spirorbid worms did worst in the new conditions. ‘We had a decrease from Spirorbids making up 90 per cent down to only being 40 per cent of the communities,’ says Peck. This is good news for industries plagued by biofouling, as the Spirorbid is among the most damaging of the biofouling organisms.
‘Animals like sponges and sea squirts do much better. This could be because the worms do worse giving these organisms a better chance, or it could be these organisms just do better in more acidic conditions. We don’t know which yet,’ says Peck.
What is certain is that these marine communities and ecosystems will be different in the future.