Hydrothermal Vents
Fissures on the ocean floor near volcanically active mid-ocean ridges that vent geothermally heated, mineral-rich seawater into the ocean.
Governing formula
Geothermally Heated Seawater T ~ 350–400 °C
SI unit
°C (Vent Fluid Temperature)
In depth
Cold seawater percolates into oceanic crust, is heated by shallow magma chambers to >350 °C, dissolves metal sulfides, and spews out at 'black smokers', supporting chemosynthetic ecosystems.
Examples in the real world
Black smoker vents at mid-ocean ridges sustaining tubeworms and chemosynthetic bacteria without sunlight.