Development of a Standardized Marine Biofouling Consortium

In the context of the expanding conquest of the oceans and the use of marine resources within the blue economy, maritime structures are becoming increasingly numerous. In contact with the marine environment, these structures are subject to the development of biofouling, an accumulation of micro- and macro-organisms that are responsible for numerous problems. These problems are both financial and environmental. The accumulation of organic matter on structures impacts their energy consumption (especially for ships and submarines) and requires costly maintenance operations to prevent the biodeterioration of the structures. This has been a financial drain noted by the U.S. Navy since the beginning of the century. The second problem is environmental; in some cases, materials are colonized by invasive species. Traveling ships can transport species into different bodies of water that were not previously present in that environment, which can lead to an ecological disaster, replicating the well-known invasions linked to ballast water (e.g., the ctenophore Beroe in the Mediterranean). The other aspect of the environmental problem of biofouling is related to pollution. Numerous methods exist to limit the bio-colonization of materials, most often using copper- or silver-based anti-fouling coatings, as well as biocides. These molecules are released into the environment and can have a significant impact on the development, reproduction, or even the entire life cycle of marine species.

It was following these studies that the BIOSTEM project was conceived. My thesis project, which is part of this project led by the company CORRODYS, has an economic and industrial purpose, as well as an environmental one. The main objective of this work is to develop a standardized marine biofouling consortium to be able to pre-test anti-fouling materials to verify their effectiveness and, in the long term, their toxicity. This consortium will be designed to include common colonizing species found in all bodies of water, so that materials can be tested by modeling the environmental response regardless of the geographic location of immersion. This project will be divided into three axes:

1. Characterization of environments and identification of bio-colonizing species on coatings used in the naval sector in different ports of the English Channel.
2. Isolation and cultivation of representative biofouling organisms to recreate a consortium in the laboratory.
3. Selection of the consortium and material testing.

The final objective of the thesis will be to offer a functional mesocosm to manufacturers who wish to test their anti-fouling coatings. This mesocosm will contain bio-colonizing species ranging from micro- to macro-organisms, allowing for the simulation of the impact of the marine environment on the coating and vice-versa.

Keywords: standardized consortium; marine biofouling; anti-fouling coating