Narrator: The five oceans on Earth play a huge part in keeping our planet healthy.

They produce half of the world's oxygen and absorb half of all man-made carbon dioxide. The waters are constantly moving around in patterns called currents, which cycle water from one place to another, over and over again.

This is important in regulating the Earths climate and weather. But water doesn't move around just in the oceans. It also moves around through the air. The sun heats up the water in the oceans, rivers, lakes and seas, turning it into tiny droplets called water vapour.

These tiny water vapour droplets rise into the air and gather together to from clouds. The rain that falls on land, washes into the lakes and rivers. Which eventually makes its way back to the sea. This happens over and over which is why it's called the water cycle.

The oceans are home to millions of species, with more being discovered every day. But our actions are putting the health of our oceans at risk. Air pollution and poisonous waste from things like pesticides, sewage, plastics and metals, end up in the oceans and coastal waters.

With the oceans doing so much for our planet and billions of people rely on them for food and jobs, we need to return the favour and do some thing for our oceans.