The biggest threat to oceans and coral reefs comes from oil, gas and pesticides being thrown into the ocean by humans. All together, these pollutants kill many different types of creatures, animals and plants that live in the ocean.

Every year, huge amounts of oil enters the oceans from many different sources, including oil exploration, oil tanker accidents and natural seeps.

But nearly half of all oil pollution in the ocean makes its way into the oceans from the land, through car owners. This is because many people dump their used car engine oil into their house drains, which is not allowed. This oil then travels from the house drains, through the sewage and into the sea.

Sewage from farms which contains fertilisers and pesticides, chemicals that help plants grow, also harm the oceans and all living creatures inside it. Farming chemicals are made to kill insects and pests and so they have no place to be in the ocean.