Ecosystem: The Ocean covers 2/3s of the Earth's surface.

Ocean covers two-thirds of Earth's surface and contains a variety of ecosystems with greater diversity than those found on land, from the frozen polar reaches, to the warm coral reefs of the tropics and down into the deep and lightless trenchs. There are three main oceans: the Atlantic, the Pacific and the Indian, through which great ocean currents swirl, some carrying warm water, others cool. These influence the world's weather systems.

Life in the oceans ranges from microscopic plankton to the massive blue whale, it is populated with terrifying hunters, deepsea creatures that look to have crawled from your nightmares and other life forms so strange that it is hard to believe they are real. The ocean floor is referred to as the benthic habitat whilst the water itself is the pelagic, both supporting a plethora of life. It is the coral reef, however, that is perhaps the richest in diversity.

There are many threats the ocean and its inhabitants must face, including over-fishing, bottom trawling and pollution. 80% of litter in the water comes from land: anything that ends up in our waterways eventually ends up at sea. Plastic bags, bottles and other non-biodegradable litter has been carried by the currents to form a massive patch of rubbish, known as the Great Pacific Garbage Patch. This plastic disintegrates into smaller and smaller pieces, being consumed by creatures and eventually killing them.