Underwater Hot Springs around Bangka Island

Close to Bangka Island there are several dive sites that have these underwater hot springs. Water is heated up by geothermal activity within the earth’s crust and this water is pushed out through a hydrothermal vent. The vent is a fissure in the planet’s surface from which geothermally heated water escapes. Hydrothermal vents exist because the earth is both geologically active and has large amounts of water on its surface and within its crust. The areas around submarine hydrothermal vents are biologically more productive, often hosting complex communities fueled by the chemicals dissolved in the vent fluids. Chemosynthetic bacteria and archaea form the base of the food chain, supporting diverse organisms, including giant tube worms, clams, limpets and shrimp.

Have a look at this video of this phenomenon by our own Cameras@Lembeh Photo Pro Sascha Janson.

Some fun facts about underwater hot springs :

1. Hydrothermal vents are the result of seawater seeping down through fissures in the ocean crust. The cold seawater is heated by hot magma and comes back to the surface to form the vents. Seawater in hydrothermal vents may reach temperatures of over 750 degrees Fahrenheit (400 degrees Celsius).

2. Hot seawater in hydrothermal vents does not boil because of the extreme pressure at the depths where the vents are formed.

3. We measured 41 degrees Celsius water temperature at the hot spring shown in the video, while the surrounding water is 29 degrees Celsius.

4. The surrounding sand also has a very pleasant temperature and is nice to warm yourself when you got cold during the dive.