🌊 Seawater Salinity & Density

Investigate ocean physics and the thermodynamic equation of seawater (TEOS-10). Calculate in-situ density ($\rho$), freezing point depression ($-1.91^\circ\text{C}$), sound speed ($c$), and thermohaline circulation drivers.

Salinity ($S$) PSU or g/kg (Open Ocean ~ 35)

Water Temp ($T$) °C

Depth ($D$) Meters (0 = Surface)

In-Situ Density ($\rho$)

1,025.9 kg/m³

σₜ = 25.9 kg/m³ anomaly

Freezing Point ($T_f$)

-1.91°C

Salt depression: -1.91°C

Sound Speed in Seawater ($c$)

1,507 m/s

Mackenzie ocean equation

Hydrostatic Pressure

1.0 atm (Surface)

+1 atm per ~10m depth

Thermohaline Circulation Secret: For fresh water, density peaks at 3.98°C. But salt lowers the peak density temperature below the freezing point! Thus, cold salty polar seawater continually becomes denser as it chills, sinking to the abyss and driving the planetary oceanic conveyor belt.