Anthropogenic land-based disturbances can cascade into the sea, altering coastal ecosystems over long timescales. Mining exemplifies this land-sea connectivity, yet its full environmental footprint is underestimated when marine impacts are overlooked. Here, we investigate long-term coastal changes associated with nickel mining using a paleoecological approach in New Caledonia. A 226-cm sediment core spanning ~1000 years was analysed, combining an [...]