Flocculation in coastal waterways is a process in which particles of clay and organic matter stick together, through chemical interactions with divalent calcium and magnesium ions, to form larger flake-like particles (flocs or floccules) that may come out of solution. Flocculation influences the transport of fine-grained sediment, and enhances its deposition rate . Because particles belonging to various size classes can form flocs, the sediment that is deposited is often poorly sorted . Flocculation contributes to the formation of a turbidity maximum in coastal waterways (Figure 1), and can also cause patches of nutrients to form on the seabed, providing food for micro-organisms.
Figure 1. Conceptual illustration of the flocculation process (modified from illustration in )
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