On 12 July, RTE hosted two scientific meetings and the progress meeting of the ABIOP+ project at its premises in Paris. This was an opportunity for intense collaborative work and to take stock of various aspects of the work intended to take biofouling into account by means of quantification protocols useful for engineering:
- The data from the measurements carried out on the samples of mooring lines immersed for 18 months in the Etel ria are currently being analysed. The first observations revealed a consistent and homogeneous colonisation of the different types of lines and a significant predation of the biofouling by starfish. The ultimate goal is to establish a protocol including the means of measurement to be deployed to characterise a site and thus predict the biocolonisation of the systems that will be immersed there.
- A genomic analysis was carried out on PVC plates immersed at different points in the Etel ria and then recovered regularly. Thanks to the establishment of a protocol adapted to macrofouling, it was shown that the spatial distribution and enrichment differ according to hydrodynamics and current.
- A database has been set up from photos, biofouling characteristics and environmental conditions recorded by the Phare et Balises team on about fifty buoys in the Atlantic. It will provide a better understanding of the composition of biofouling on offshore sites and allow inter-site comparisons.
- Good results have been obtained on the analysis of biofouling images by learning a classification algorithm that allows species to be determined from photos. A segmentation approach is now being developed, in which each photo will be cut into a mesh of small areas on which the various species present will be determined.
- Tests to quantify the thermal resistance of biofouling were carried out on 3 of the 4 study sites. They will allow the determination of thermal resistance and heat exchange coefficients by group of species. A numerical model will then be used to simulate homogeneous or heterogeneous colonisation, depending on the temperature of the external envelope of the dynamic cable. The ultimate goal is to optimise the maintenance plan.
- Three fouling-release class antifouling coatings were tested on different new generation materials based on the facilitation of organism release. Tests in static immersion and reproducing the effect of hydrodynamics showed a significantly more effective coating in all conditions and locations.
Photo credit: Thomas Pavy