Blue Planet viewers can't believe that lakes exist under the sea

According to the show, brine pools full of super salty water created by erupting methane gas can collect in the depths of the sea. The water is so salty that when an eel dives in to prey on some of the lifeforms that gestate around it - as seen below - it goes through toxic shock, and must rise out of the pool in order to survive.

If this is the first time you're hearing about these deep sea pools, you're not alone; lots of viewers took to Twitter during the show to share their incredulity at the news:

It's also gone a way to prove that Spongebob Squarepants is more realistic than we had realised:

Decades in the game, and Attenborough is still well able to blow our minds. Bravo.