geochemical gradients

How bacterial communities reveal estuary health through sediment gradients

Bacterial communities in Knysna Estuary sediments tell a clearer story of ecosystem health than the water above them. Sediment microbes act as a richer, more compositionally heterogeneous reservoir, their specialised communities tightly linked to local geochemistry, particularly metals like cobalt, lead, and nickel. This partitioning matters because nearly half of South Africa's estuaries face nutrient pollution. Understanding these microbial gradients gives us a measurable, integrated tool for monitoring degradation before it becomes irreversible.