Understanding pollution and fighting it

Microplastics (< 5 mm) are a real scourge for wildlife, both terrestrial and marine. These tiny fragments penetrate organs, accumulate in tissues and can even enter cells. Adopting a novel transdisciplinary approach, the MicroPOW project is studying the biological consequences of this exposure to microplastics, from the cellular to the organismal level. Shearwaters from Lord Howe Island (Australia) will be examined as a model species and compared according to their level of microplastic ingestion, with results that can be extrapolated to humans.

While macroplastic pollution is now widely recognized and has been studied for over 50 years, it is only very recently that microplastics have been identified as invasive and dangerous. Being able to infiltrate all levels of the organism, these tiny fragments are suspected of having serious pathological effects on wildlife and humans alike. Combining biomedical techniques and species conservation ecology, the MicroPOW project team aims to uncover the biological consequences of microplastic ingestion on wildlife cells, tissues and organs. They are particularly interested in two species of shearwaters from Lord Howe Island (Australia), seabirds that are highly exposed to plastic pollution: pied shearwaters ingesting a lot of plastic will be compared to their cousins, the common shearwaters, which are 10 times less contaminated. As all vertebrates show very similar physiological responses, the results of this study can be reasonably extrapolated to humans.

Protecting marine biodiversity and restoring ecosystems

Tropical coral reefs are the ecosystems most threatened by climate change. Warming surface waters and increasing marine heat waves are causing coral bleaching and the disappearance of reef-dwelling species, which account for about 1/4 of the world's marine life. 98% of the Australian Great Barrier Reef is affected, and more than half of the corals have died in the last 20 years. Almost all current reef replenishment initiatives consist of cuttings of still resistant adult corals, with the short-term objective of maintaining the ecosystem services they used to provide (including fishing resources and tourist attraction). But these colonies of the same genetic heritage (clones) are particularly sensitive to bacterial and viral infections, and offer no guarantee of resistance to further warming. Sexual reproduction of corals allows for genetic innovations, and favors long-term resilience of the reefs, but less than 1% of larvae reach adulthood. Jennifer Matthews' team has developed an energy mix in the form of lipid nanoparticles, allowing 46% of larvae to eventually form new colonies. The project aims to (1) adapt the quality and quantity of the cocktail to the water temperature, and (2) develop a simple feeding strategy, to make it affordable and easily replicable by local stakeholders. It includes a double phase of ex-situ experiments in laboratory nurseries before reintroduction, and in-situ experiments on some high value sites of the Great Barrier Reef. The results will be shared in the form of methodological guides and demonstration videos to encourage wider adoption, and thus hope to improve the resilience of warm-water coral reefs.