The ocean has long been a subject of deep wonder and mystery. For most of human history, this vast watery abode remained unexplored. The deep sea biome occurs in that part of the ocean and seafloor beyond the continental shelves. It covers 65 percent of the planet's surface and reaches depths of -650 ft to -36,198 ft at the bottom of the Challenger Deep in the Mariana Trench. In recent decades, technology has begun to give humans a glimpse of the deep sea landscape. Submersibles can carry people to the deepest depths of the seafloor; and autonomous vehicles can now map a geography never seen by human eyes.
Traditionally, humans have investigated the ocean from ships on its surface. But to really understand what it's like inside, one needs to be inside it. And what better way to experience the watery abode than in a manned submersible?
One of the world's first deep-sea human submersibles, Alvin, was built in 1964. Alvin made more than 4,400 dives, including dives to find a lost hydrogen bomb in the Mediterranean and exploring the wreck of the Titanic.
The sub, which is owned by the U.S. Navy and operated by WHOI, can carry three people at a time (two scientists and a pilot) and travel to a depth of 14,800 feet (4,500 meters) on dives that last six to 10 hours.
Even so, some aspects of ocean exploration are best left to robots. Remotely operated vehicles, or ROVs, are unmanned vessels controlled by scientists onboard a ship, via a tether cable. WHOI's ROV Jason is a two-part system. Pilots send commands and power to a vehicle called Medea, which relays them to Jason. Jason sends back data and live video to the ship. The ROV contains sonar equipment, video cameras and still cameras. There are manipulator arms for collecting samples of rock, sediment or ocean life to return to the surface. The Monterey Bay Aquarium Research Institute (MBARI) in California has two similar ROVs, Ventana and Doc Ricketts, which researchers there use to survey underwater volcanoes and study as-yet-unseen marine life.