Recherche D’especes Bioindicatrices De La Pollution Plastique Dans Un Contexte Perlicole En Polynesie Française

The fame of Polynesian cultured pearls has long crossed the country's borders. This sector generates billions of Pacific francs annually and represents the second-largest economic resource of French Polynesia. However, since the 1990s, pearl farmers have abandoned natural materials in favor of a more durable one: plastic. The massive use of plastics, coupled with poor waste management, has gradually led to the accumulation of significant amounts of marine litter in the pearl farming lagoons. In the laboratory, previous studies have shown the negative impact of pearl farming plastics on pearl oysters, Pinctada margaritifera, and ultimately on the pearls. If no measures are taken, pearl farming may well bring about its own downfall. To determine the harmful thresholds of pearl farming plastic pollution for tropical marine ecosystems, we developed several approaches. The experiments considered the chemical, biological, and physical constraints induced by the presence of plastics in the marine environment. Thus, we developed toxicological approaches on tropical species, some of which had not previously been studied in this context. We also conducted mesocosm experiments to track the changes induced by increasing plastic concentrations on the bacterial compartment. Finally, we evaluated the potential of Pinctada margaritifera as a bioindicator species of microplastic contamination in lagoons by monitoring 1200 oysters across four atolls over more than six months. These results allowed us, firstly, to highlight the effects of plastics on under-studied tropical species as well as on marine bacteria, and secondly, to propose some of these species as candidate bioindicators of plastic pollution in tropical marine environments.