World's Saltiest Bodies of Water: Seas and Hypersaline Lakes

Salinity Scale

Average ocean salinity: 35 parts per thousand (ppt) or 3.5%. Higher values indicate restricted circulation, high evaporation, and limited freshwater input.

Saltiest Seas (Marine)

• Red Sea: 40-41 ppt (high evaporation, no river inflow, limited exchange with Indian Ocean)
• Persian/Arabian Gulf: 40-45 ppt (shallow, extreme evaporation, restricted Strait of Hormuz)
• Mediterranean Sea: 38-39 ppt (net evaporation > precipitation + river input; Atlantic exchange at Gibraltar)
• Adriatic Sea: 38-39 ppt (northern arm of Mediterranean, similar drivers)

Hypersaline Lakes (Far Saltier)

• Don Juan Pond (Antarctica): ~440 ppt (CaCl₂ brine, never freezes)
• Lake Vanda (Antarctica): ~350 ppt
• Dead Sea (Israel/Jordan/West Bank): ~340-350 ppt (NaCl + MgCl₂ + KCl; terminal lake, extreme evaporation)
• Lake Assal (Djibouti): ~350 ppt
• Great Salt Lake (Utah, USA): 50-270 ppt (variable by arm and water level)
• Lake Urmia (Iran): ~200-300 ppt (shrinking dramatically)

Why It Matters

High salinity limits biodiversity to specialized extremophiles. It affects water density (stratification), mineral precipitation (evaporites), and human uses (desalination cost, mineral extraction, buoyancy tourism). The Dead Sea's salinity creates effortless floating; Don Juan Pond's calcium chloride brine remains liquid at -50°C.