The hidden landscape of the deep

A 65,000 km seam of volcanic mountains winding around the globe, where plates pull apart and brand-new sea floor is born. It is the longest mountain range on the planet — almost all of it underwater.

Deep, narrow gashes in the sea floor where one tectonic plate dives beneath another. The Mariana Trench plunges nearly 11 km — deeper than Everest is tall.

Volcanoes that rise from the sea floor but never break the surface. Currents sweep nutrients up their slopes, turning each seamount into an oasis swarming with fish and corals.

Immense, almost perfectly flat expanses blanketing the deep-ocean floor, buried under a soft ooze of sediment. They are among the flattest and least-explored places anywhere on Earth.

Mineral chimneys that gush superheated, chemical-rich water where magma meets the sea. Whole ecosystems thrive here on chemosynthesis — feeding on the Earth’s chemicals instead of the Sun.

The gently sloping, sunlit rim of each continent before the sea floor plunges to the deep. Most of the world’s fish, seaweed and fishing grounds are packed into these shallow waters.

A ring of coral reef enclosing a shallow lagoon, left behind as the volcanic island it once fringed slowly sinks beneath the waves — a process first explained by Charles Darwin.

A seamount with a strangely flat top — once an island whose peak was planed off by waves, before it sank below the surface over millions of years.

Steep-sided canyons carved into the continental slope, some rivalling the Grand Canyon in size. They funnel sediment, nutrients — and marine life — down into the deep sea.

Places where chemical-rich fluids ooze slowly from the seabed. Like vents but cold, they host tube worms, mussels and clams that live on methane and sulphur.