Freshwater-saltwater mixing, salinity gradients, and brackish habitats
Hover to sample salinity · Click to drop probe marker
An estuary is where rivers meet the sea, creating a salinity gradient from fresh (0 ppt) to marine (~35 ppt). Brackish water (0.5-30 ppt) supports unique species. High river flow pushes the mixing zone seaward (salt wedge estuary). Strong tides create well-mixed conditions. The halocline marks the boundary between fresh and salt layers. Estuaries are critical nursery habitats for fish.