Cool-water kelp forests are being eaten by tropical species moving south on warming waters.
The open oceans are the world's "wild west", falling outside any nation's jurisdiction. UN negotiations are aiming to draft new laws for the high seas.
Mining the deep oceans for minerals may soon become a reality, but the risks involved are many. So who is able to regulate this emerging industry?
As the world's land-based economies struggle with around 2% GDP growth, the global marine economy – often talked about as "the blue economy" – is a bright light on the horizon.