The Mariana Trench Is Deeper Than Everest Is Tall

The vastness of our planet's oceans hides topographical extremes that dwarf those on land. The deepest of these is the Mariana Trench, a crescent-shaped scar in the Earth's crust located in the western Pacific Ocean. This immense feature is the product of a geological process called subduction, where the ancient and dense Pacific tectonic plate slides beneath the younger, lighter Mariana plate, pulling the seafloor downward. The age of the Pacific plate, at around 180 million years old, makes it cooler and denser, causing it to sink more steeply into the Earth's mantle and creating the planet's deepest known point, the Challenger Deep.

The environment at the bottom of the trench is one of the most hostile on Earth. There is complete darkness, the temperature is just above freezing, and the water (Review) pressure is over 1,000 times that at sea level. Despite these crushing pressures, life has found a way to thrive. Expeditions to the Challenger Deep, first successfully undertaken by Jacques Piccard and Don Walsh in 1960, have revealed a unique ecosystem. In this extreme environment, scientists have discovered organisms like giant, single-celled amoebas called xenophyophores, small crustaceans known as amphipods, and translucent sea cucumbers, all specially adapted to survive in a place once thought to be devoid of life.