Dynamics of Suspended Sediments during a Dry Season and Their Consequences on Metal Transportation in a Coral Reef Lagoon Impacted by Mining Activities, New Caledonia

Research reveals that particle aggregation reduces metal concentrations in suspended particulate matter (SPM) during dry seasons, significantly impacting metal transportation in coral reef lagoons affected by mining activities. The study quantified vertical fluxes of SPM and metals across three bays in New Caledonia's lagoon system—Boulari Bay (moderately impacted), St Vincent Bay (highly impacted), and Dumbéa Bay (weakly impacted)—finding average SPM fluxes of 37.70 ± 14.60 g·m²·d⁻¹, with fine particles dominating. Wind and tidal cycles emerged as key drivers, particularly in St Vincent and Dumbéa Bays, where metal dynamics were closely tied to clay, iron minerals, and carbonate transport from rivers and lagoonal sources. The decline in metal distribution constants (Kd) underscored the role of aggregation in mitigating metal loads, offering critical insights for managing mining impacts on these fragile ecosystems.

Fernandez, J.-M., Meunier, J.-D., Ouillon, S., Moreton, B., Douillet, P., & Grauby, O. (2017). Dynamics of Suspended Sediments during a Dry Season and Their Consequences on Metal Transportation in a Coral Reef Lagoon Impacted by Mining Activities, New Caledonia. Water, 9(5), 338. https://doi.org/10.3390/w9050338