Study of Early-Age Phenomena at the Concrete-Marine Biofilm Interface in Seawater for the Construction of Eco-Friendly Fowt’s

Floating Offshore Wind Turbines (FOWTs) are designed to harness the energy produced by wind. Since these structures are in deep waters, the engineering and dynamics of steel and or concrete structural elements (floaters, chains, mooring, etc.) is important to ensure significant performance. The durability of concrete in submerged zones is affected by biological and chemical deterioration mechanisms, with the latter being controlled by transport of aggressive ions. The influence of concrete on biodiversity developing on its surface plays a significant role as it contributes to the overall environmental footprint of the structure. The aim of this experimental research was to identify the surface interactions between cementitious materials such as concrete, biofouling at their surface, and seawater on short-term exposure. CEM III concrete specimens were submerged at a depth of 27m at SOLA station, Banyuls-sur-mer, France. The microstructural and chemical changes in the cementitious material were analysed with scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS) and electron probe micro analysis (EPMA). The results of SEM-EDS analysis showed the formation of three zones, namely, magnesium-rich, sulfur-rich, and chloride-rich zones. Using Environmental DNA analysis, bacterial diversity was identified, revealing high abundances of alphaproteobacteria and gammaproteobacteria, and 18s rRNA sequencing unveiling a diverse eukaryotic community.