Oceans: Blue heart of the planet 

BBC online: Science

Earth is a blue planet.

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Almost three quarters of the earth’s surface is covered in water and around 90% of all the living space on Earth is contained in the oceans.

These vast reserves cradled early life and continue to be home to a wealth of extraordinary creatures. At least 230,000 unique species have been documented, although as humans have only explored a small fraction of the depths, there may be as many as two million.

As well as being home to everything from whelks to whale sharks, the oceans offer a range of critical services, including acting as a source of food and regulating the atmosphere.

In particular, the oceans are also vital as sponges for green house gases, taking carbon dioxide out of the atmosphere through two processes - dissolving straight into the water column and also through photosynthesis by phytoplankton.

Today, the oceans soak up around one third of all of human carbon emissions

But this comes at a terrible cost. The composition of the oceans is changing to become more acidic, threatening the tremendous diversity  of creatures that call them home.

In this film, veteran wildlife cameraman Doug Allan, sustainability advisor and author Tony Juniper, British Antarctic Survey scientist Dr Emily Shuckburgh and ecological economist Dr Trista Patterson reveal not only the huge diversity of life in the ocean but also the great contribution they make to cleaning our atmosphere.