Wonders and Mysteries of the Deep

ENCASED in their tiny submersible vessel named Alvin, two scientists and their pilot descended into the Pacific Ocean off the coast of Ecuador. Their destination? A place called the Galápagos Rift. Equipped with searchlights, camera, and numerous scientific instruments, the Alvin plunged downward through 9,200 feet [2,800 m] of liquid space into a world of eternal night never before seen by human eyes.

Have you ever wondered what lies hidden in the mountains, canyons, and rifts beneath the dark depths of the world’s oceans? If so, then you will enjoy reading about the discoveries that began in 1977 with the Alvin’s pioneering dive mentioned above. What the crew saw may surprise you; even to highly trained scientists, it was like seeing life on another planet.

The objective of the Alvin’s mission was to find hydrothermal springs—undersea geysers that shoot jets of heated water into the ocean. The Galápagos Rift was a promising site because it is part of a highly volcanic undersea rift cradled by a complex, globe-encircling chain of mountain ranges called the mid-ocean ridge system. Over 40,000 miles [65,000 km] long, this colossal system weaves around the entire planet like the seam on a tennis ball. Were the oceans stripped away, it would “easily [be] the most dominant feature on the face of the planet, extending over an area greater than that covered by all major terrestrial mountain ranges combined,” writes Jon Erickson in his book Marine Geology.

A particularly significant feature of the mid-ocean ridge system is that it is essentially a twin system—two mountain ranges running parallel to each other and rising 10,000 feet [3,000 m] above the ocean floor. Between the ranges are the greatest chasms on earth—canyons up to 15 miles [20 km] wide and 4 miles [6 km] deep—four times deeper than the Grand Canyon of North America! At the foot of these chasms lie highly volcanic rift zones. When scientists first studied the Atlantic segment of the ridge system, called the Mid-Atlantic Ridge, their instruments revealed such intense volcanic activity “that it seemed as though the Earth’s insides were coming out,” says Erickson.

 After a 90-minute descent, the Alvin leveled off just above the seafloor, and the men turned on the Alvin’s searchlights. The scientists could be excused for thinking that they were on a different planet. Their lights revealed a number of shimmering warm-water vents on the seafloor, where the water is normally near freezing. Close to the vents, something even stranger appeared—entire communities of previously unknown living creatures. Two years later, researchers aboard the Alvin discovered superheated vents called smokers on the East Pacific Rise off the coast of Mexico. A number of these vents formed ghostly chimneys, some up to 30 feet [9 m] tall. Many of the same animals seen at the Galápagos Rift were found at this location. In the following article, we will take a closer look at these amazing life-forms and the world of mind-boggling extremes that is home to them.

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COVER and page 3: OAR/National Undersea Research Program