Resumo. Abstract Aim Anthropogenic modifications in the landscape are accelerating biogeochemical cycles and causing unbalances in terrestrial and aquatic ecosystems with still unknow impacts on biotic and abiotic processes. Therefore, there has been increasing scientific interest in the links between human activities and ecosystems functions. Methods Here we review the role of aquatic sediments in the carbon and pollutant cycle. Results We briefly explore the historical context, origin, and composition of the sediments, as well as the factors that influence the processes of carbon and contaminants cycling and the role of sediments in the greenhouse gases emissions in aquatic ecosystems. Conclusions Aquatic sediments can help to understand the terrestrial and aquatic ecosystem changes, once they are good sentinels, reflecting key biogeochemical processes over time.