Towards a purposeful construction of a new generation of artificial reefs: Comparative analyses of the intrinsic factors favouring their colonization from micro to macro-scale

Artificial reefs are submerged structures deliberately placed on the seabed to mimic certain characteristics of a natural habitat, they have been used for thousands of years by humans in order to improve their fishing practices and recently they are also used for the protection or even the restoration of certain marine habitats. Despite these various objectives, there is still a lack of scientific basis for determining the quality of these structures put in the water in order to assess their effectiveness. The present works, focused on the study of their intrinsic characteristics, namely their materials and their structures

A combined monitoring of the biofilm and the macrofouling on different substrates, supplemented by an analysis of their heavy metal content made it possible to highlight the quality of certain substrates used for the construction of artificial reefs. The simple monitoring of the biofilm has proven to be a good indicator for highlighting these differences in a simple and rapid way to validate the use of a particular substrate.

In addition, the development of a method to assess the complexity and heterogeneity of artificial reefs has made it possible to give a relevant classification of the various existing structures. This standardized method will allow to assess in situ the influence of structural parameters of artificial reefs on recruitment, abundance, distribution and / or diversity. A first study on a microscopic scale has revealed the influence of the structure of the substrate both on the abundance of biofilm and on the photosynthetic activity of these communities.

All of these results provide a more precise scientific framework for approaching the construction of artificial reefs based on the choice of their materials and designs. Future guidelines may be issued to optimize the effectiveness of any project of artificial reef immersion.



Keywords: Artificial reefs, colonisation of artificial reef substrates, substratum, biofouling, biofilm, macrofouling, extracellular polymeric substances, metagenomic, Hight performance liquid chromatography, heavy metals contamination, Imaging Pam, structure, 3D CAD model, complexity, Heterogeneity