Dive under the ocean

Dive under the ocean

We know more about the moon than we do about our own ocean. Come exploring with Planet Science as we dive into the deep sea...

Until recently we thought that the deep ocean was lifeless; too dark and cold to support life. We were wrong! Although there is no sunlight in the depths of the ocean, life still exists. How?!

Deep under the ocean there are hydrothermal vents: cracks in the sea floor from which superheated water erupts. The water gushes out of these vents at temperatures of 464 degrees Celsius. As the pressure down at the bottom of the ocean is so high, water is still a liquid at these temperatures; on Earth it would have boiled into a gas. To make conditions even more extreme, the water is also acidic. No humans could survive down here.

Extreme bacteria!

Life on the surface of the Earth depends on sunlight. Plants photosynthesise to turn energy from the sun into starch. Animals then feed on plants and gain energy from the starch that the plants have stored. At the bottom of the ocean life has had to find a different method of creating energy, as sunlight can't reach to these depths. Here, baceria use chemosynthesis: they turn chemicals in the water pouring from hydrothermal vents, mostly hydrogen sulphide, into food. These bacteria are known as extremophiles. This means that they thrive in conditions that are too hostile for most other species.

What else is down there?

It's not just bacteria at the bottom of the ocean. Weird and wonderful animals feed on the bacteria, and on each other! Tube worms, found surrounding hydrothermal vents, let the extremophile bacteria live inside them. These bacteria provide nutrients for the tube worm and the tube worm provides hydrogen sulphide for the bacteria. It's a good example of symbiosis: a relationship between two organisms where both of them benefit.

You can see a great video of tube worms here: BBC Wildlife Finder.

Loads more species have been discovered in the deep ocean since these hydrothermal vents were found. These include crabs, eyeless shrimp and even an Eel City:

Or view the video in YouTube.

So, life at the bottom of the ocean is far from boring. I wonder what we'll find there next!