The deep sea retains an air of mystery because many portions of the deep have not yet been explored. Scientists have discovered the deep is not a hospitable environment for man. The lack of sunlight makes the temperatures drop quickly as the pressure increases steadily with depth.

In 1872 the British government began an intensive investigation of the organisms found in the ocean. This investigation was performed on the ship known as the H.M.S. Challenger and was, therefore, titled the Challenger Expedition. For nearly four years, the H.M.S. Challenger explored the world’s oceans, discovering 715 new genera and 4,417 new species. Their discoveries initiated an interest in some of the creatures found in the deepest parts of the world’s oceans.

In order to explore the resources of the deep, specialized equipment is needed. In 1934 Dr. William Beebe and Otis Barton were the first humans to descend to depths of greater than 900 meters. They accomplished this monumental task in a piece of equipment known as a bathysphere. The bathysphere was relatively simple, composed of a steel sphere with small viewports made of quartz. Beebe described creatures, via a telephone wire, that had not been seen or described by any other human being. However, the bathysphere was limited in its capacity for exploration. It could only be raised and lowered by a cable attached to a ship and could not move of its own accord. Deep sea technology continued to develop, and in 1954 the Swiss physicist, Auguste Piccard, descended to 4000 meters in his bathyscaphe. The bathyscaphe was a navigable deep sea vessel composed of a pressurized sphere that retained buoyancy because of a gas filled float. The deep sea submersibles used today are even more advanced and are equipped with underwater lights, cameras, television systems, mechanical manipulator arms to collect samples, and computer systems that relay information from the submersible to surface vessels. Robotic submersibles known as ROVs (Remotely Operated Vehicles) are unmanned and can generally descend to depths greater than the manned submersibles. ROVs relay information to the surface vessels via a feedback loop. A feedback loop is essential to the navigational systems of a ROV and allows information about an ongoing task to be continually transmitted to the person controlling the research.

Another technique used for deep sea exploration is echo sounding, which allows surface vessels to determine the depth of the ocean bottom without the use of a submersible. Sound waves or acoustic pulses are sent from the ship, bouncing off the bottom and back to the ship. Scientists then calculate the time it took the sound wave to travel to and from the object, thereby determining the distance from that object. This process is known as sonar, which stands for sound navigation and ranging.

Other instruments used in deep sea exploration include high-resolution television cameras, thermometers, pressure and flow meters, and seismographs. Deep sea currents are monitored by floats that carry ultrasonic sound that enable research vessels to follow and monitor the rate of flow.

Investigations of the deep sea have demonstrated that many varied and unique creatures thrive under the harsh conditions associated with a lack of sunlight and great depths. Giant squid, six and seven gill sharks, large tubeworms, vampire squid, and a host of other creatures inhabit the deep sea. As man continues to explore the oceans, more discoveries are being made that assist researchers in better understanding how marine creatures can and do affect the lives of human beings. Not only are marine organisms used as food, but the medicinal values of many of these creatures are just being realized. The cures for many human diseases may lie in the deep. While the anthropogenic impacts on the depths of the oceans are most likely less than those on shallower waters, disposing of hazardous chemicals, the mining of minerals, and other human activities can have a negative impact on this undiscovered and untapped resource. It is imperative that the deep ocean environment and its resources be managed properly to ensure the conservation and preservation of this vast, relatively unexplored area of our planet.