The accumulation of living organisms on submerged surfaces

The introduction of invasive aquatic species within the marine environment as a result of port operations, vessel traffic and their movements, affects biological diversity and has cumulative effects on ecosystems, altering their natural evolution.

Biological pollution¹ is the second cause of biodiversity loss according to the United Nations Development Programme (UNDP). Some of the most representative examples are the zebra mussel (Dreissena polymorpha), which reproduces very rapidly, causing damage to habitats and even industrial, agricultural, and urban supplies by clogging filters and pipes. Another example is the Caulerpa taxifolia also known as "killer alga", a species native to tropical seas that has arrived in the Mediterranean where it is threatening native species of algae and endangering the entire ecosystem. In its natural habitat, predators are immune to the Caulerpa toxin, but in the Mediterranean the toxin is very harmful.

In addition to the well-known antifouling paints based on organic biocides and copper derivatives, other solutions are beginning to be implemented, such as antifouling by means of adhesive film without biocides, in which the non-stick effect of silicone-based paints is used to prevent fouling. More recently, electrochemical signal-based systems are being experimented with, which produce an environment around the area to be protected that is uncomfortable for the development of fouling.

Furthermore, in relation to the effect of biological fouling on climate change, practices such as more effective hull maintenance (and therefore lower fouling rates through the use of antifouling elements), advanced coatings and correct polishing of propellers, contribute to reducing energy consumption on vessels, which means a reduction in greenhouse gas emissions.

The IMO (International Maritime Organisation) is developing an interesting project² to highlight the importance of applying effective measures to prevent fouling and the migration of invasive species in shipping and recreational boating practices.

Ideas/recommendations:

• Contact scientific bodies to collaborate with projects that study invasive species.
• Collect and treat water used for cleaning hulls in boatyard.
• Encourage the use of pump-out facilities to empty tanks.
• Apply good practices in the cleaning of boats in sailing centres.

Recourses: 

• Glofouling partnerships
• Invasive species protection – Green Blue RYA

1 Accumulation of aquatic organisms, such as micro-organisms, plants and animals on surfaces or structures submerged or exposed to the aquatic environment. This contamination can be microbiological or macrobiological.