“…New Caledonia is a tropical island located in the Southwest Pacific with coastal waters enriched in trace metals (Ambatsian et al 1997, Le Grand et al 2013). Indeed, one-third of the main land surface is covered by ultramafic substrates rich in nickel, iron, chrome, cobalt, and manganese trace metals but poor in nitrogen, phosphorus, and potassium (Pelletier 2007, Merrot 2019. These metals are naturally present in coastal ecosystems due to leaching and natural erosion via ultramafic catchments (Bird et al 1984, Biscéré et al 2017, Merrot et al 2022.…”