660 feet to 3,300 feet (200-1,000 m)
The pressure of the middle waters, or layers, presents the biggest obstacle to human exploration of this zone. The first humans to experience what life is like here were Americans William Beebe, a geologist-explorer, and Otis Barton, an inventor-engineer, who penetrated the mesopelagic zone in their bathysphere in the late 1920s and early 1930s. It was an ideal partnership, as Barton had the technical expertise to design and build a vehicle that could get into what was then considered “the deep” and back in one piece, no mean feat in the early or even the late 20th century.
All contact with the sun was lost. But it wasn’t just all black. Albeit intense and pervasive, the black was only the background, and all was forgotten when one monster or another loomed into view.
Beebe, who couldn’t drive a car but was determined to copilot the bathysphere, had sketched designs for a few cylindrical deep-sea vehicles, keeping in mind the pilots’ comfort. But Barton knew that the vehicle had to be small and spherical, with 1¼- to 1½-inch-thick (3–4 cm) walls made of single-cast, first-grade, open-hearth steel. The inside of the sphere was just 4½ feet (1.4 m) in diameter and could be entered only by crawling through a 14-inch-diameter (35 cm) hatch.
On their second dive, 14 feet (4 m) of inch-thick (2.5 cm) telephone cable that linked the bathysphere to the surface came shooting into the sphere like a giant squid tentacle. Beebe and Barton got tangled up in the equipment and hoses and even with each other in the cold, clammy steel crawl space that was the capsule. On another dive, water started trickling in through the door seal, and Beebe had to call the surface and ask that the bathysphere be lowered quickly. The additional pressure sealed the door, as they had hoped. Once, on an unmanned descent, the seals failed, and when the craft was pulled to the surface, the heavy door shot across the deck with the force of a cannonball.
Eventually, after some of the deep dives, the two six-inch (15 cm) quartz portholes failed pressure tests and had to be scrapped. Venturing deep was a risky business. Yet despite Beebe’s technical failings in some areas, he was a fearless diver and a veteran expedition leader as well as a great proponent and popularizer of science who could raise money for imaginative projects and then chronicle it all in pure poetry. Beginning in the late 1920s and persisting through the early years of the Great Depression, Beebe and Barton completed some 26 descents in the “tank,” as they called the bathysphere, becoming the first humans to glimpse the middle layers and to penetrate to their very limit. In a 1934 dive off Bermuda, they reached 3,028 feet (923 m), beating their own records and penetrating five times deeper into the ocean than the previous record depth for humans. At the greatest depth, Beebe experienced “the cosmic chill and isolation, the eternal and absolute darkness,” but much of the descent was just blue growing ever darker: “The blue which filled all space admitted no thought of other colors.”
The last glimmering of gray light at 1,900 feet (580 m) faded to pitch-black by 2,000 feet (610 m), and all contact with the sun was lost. But it wasn’t just all black. Albeit intense and pervasive, the black was only the background, and all was forgotten when one monster or another loomed into view. A single electric light helped illuminate some of the creatures as they slipped in from the darkness to inspect the vehicle, but it was mainly the animals’ bioluminescence that revealed the creatures to Beebe. Everywhere he looked on his various dives, he witnessed “the flash of long fangs” and “the passing of dozens of bright lights” corresponding to multiple fish. Some fish less than a foot (30 cm) long might carry hundreds of lights.
Beebe’s observations on dives at 1,600 to 2,200 feet (490–670 m) included an encounter where he “watched one gorgeous light as big as a sixpence coming steadily towards me until, without the slightest warning, it seemed to explode so that I jerked my head backward away from the window.” The creature had struck the glass, and the light had intensified at the point of contact. Later, Beebe saw the illuminated outline of a never-before-seen deep-sea fish that suddenly disappeared as it turned toward him, although he sensed its maw was opening. At the same depth, a sighting of two six-foot-long (2 m) fish, “the general shape of barracudas” and larger than the bathysphere, more than adequately argued the case for sea monsters, even without a precise identification. The fish had pale bluish lights all along their bodies, like the illuminated portholes of an ocean liner plying the sea at night. Beebe also reported a huge “undershot jaw ... armed with numerous fangs [and] two long tentacles hanging down, each tipped with a pair of separate, luminous bodies, the upper reddish, the lower one blue. These twitched and jerked along beneath the fish.” The mouth of one fish was wide open. Beebe called the fish Bathysphaera intacta—“the untouchable bathysphere fish.”
On the bathysphere’s historic 3,028-foot (923 m) descent, Barton largely took care of the camera while Beebe used his eyes to see what, in many cases, a camera couldn’t capture because of the limited light and field of vision and the limited technology of the time. Of course, Beebe could collect no samples to dissect and assign to a class, family, genus or species. Just to view the outlines of a creature or even to gaze into its eyes and mouth is not considered enough to assign it a species name, and Beebe’s descriptions were so fantastic, they were not believed by some. However, Beebe worked closely with a professional illustrator, who drew from his detailed descriptions, often within hours of his return to the deck of the ship. Some animals Beebe recognized from actual deep-sea specimens he had previously seen and studied.
Many animals were only barely seen or were too strange for Beebe to attempt to draw, much less name. One of these—the big one that got away on his record dive—involved a massive, colorless 20-foot-long (6 m) fish at 2,450 feet (747 m). Beebe missed the face as well as the fins of the behemoth as it glided into and then immediately out of view. He called for Barton to check it out, but by the time Barton looked through his porthole, the creature was gone. Beebe left it at that. Most of his descriptions fit creatures that we know today inhabit the middle layers, just where he saw them. His powers of description, florid as they sometimes were, did not oversell the bizarre qualities of the creatures he encountered, although he did occasionally come up short with such phrases as “indescribable beauty.” He also sampled the deep more than 1,500 times, using nets and other contraptions, and caught more than 115,000 specimens representing at least 220 species of midwater life. The condition of deepwater species was poor once they were hauled to the surface with these crude samplers, yet many of the species had never been seen or examined before, bloated or skinned, dead or alive.
Beebe’s “untouchable bathysphere fish” turned out to be a new species of dragonfish. Other fish described by Beebe, such as the viperfish and the little devilfish, can be positively identified through his illustrations. The little devilfish is none other than the anglerfish Melanocetus, which typically grows six inches long (15 cm). Our iMonstercam meets several of these poster fish—the post-Jaws sea monster in miniature—with its long, sharp teeth resembling slender shards of glass, each tapering to a needle point. When this bright orange deep-sea fish made the cover of Time magazine on August 14, 1995, the deep sea can be said to have reached the forefront of mass public consciousness in the United States, at least for a fleeting moment, even though Beebe had done so much to popularize some of the same creatures 60 years earlier.
As Beebe and Barton’s bathysphere descended, it disturbed the water, causing much of the bioluminescence they witnessed. Yet here, too, Beebe made some startling observations. He claimed that he could distinguish various species of lantern fish according to the patterns of light they displayed. Indeed, we now know that within the lantern fish genus Diaphus, there are at least five different bioluminescent patterns corresponding to species, and most lantern fish species in other genera also have unique patterns of photophores.
Bioluminescence is simply light that originates from living animals and plants. Found to some extent in surface waters, bioluminescence is used by nearly 70 percent of mesopelagic creatures, but its use tapers off rapidly in the deeper waters below the mesopelagic zone. These middle layers represent the main bioluminescent biome on Earth. If you could go anywhere in the world to witness or research bioluminescent light shows, this would be the place.
Bioluminescence is familiar to many as the light emitted by fireflies and glowworms. Relatively rare on land, bioluminescence is almost unheard of in fresh water. But those who have sailed or canoed in the sea, especially on moonless nights, will have observed a glow or sparkle in the water. In this case, the movement—whether from a boat sailing through the water or from an oar dipping into the water or a seal swimming near the surface—usually emanates from the disruption of thousands of phytoplankton called dinoflagellates. During a “red tide” dinoflagellate bloom, blue streaks in the water at night can be stimulated by waves crashing on a beach and are bright enough to photograph. Deep underwater, bioluminescence is even more spectacular because of the dark world in which it occurs. It is also much more various, bizarre and alluring. In this otherwise gloomy environment, an astonishing diversity of species, including fish, squid and jellyfish, have evolved numerous uses for light, such as defense, communication and surprise attack.
Many deep-sea creatures use bioluminescence as a defensive reaction designed to startle predators (the “boo” effect) or to blind them temporarily (the “flashbulb” effect). The arrangement of lights is confusing, so a predator doesn’t know which end of the prey to chase. Alternatively, lights on the underside of an animal may act as camouflage against the sparkle of light coming from above, with the same effect that a white belly has near the surface.
All contact with the sun was lost. But it wasn’t just all black. Albeit intense and pervasive, the black was only the background, and all was forgotten when one monster or another loomed into view.
Deep underwater, bioluminescence is even more spectacular because of the dark world in which it occurs. It is also much more various, bizarre and alluring. In this otherwise gloomy environment, an astonishing diversity of species, including fish, squid and jellyfish, have evolved numerous uses for light, such as defense, communication and surprise attack.
Bioluminescence is also used for communication among individuals of the same species. It helps members of some species come or stay together and can be important for finding and signaling one’s readiness to mate and attracting a mate. Researcher Edie Widder of the Ocean Research & Conservation Association in Fort Pierce, Florida, has dedicated her career to learning more about bioluminescence in the sea and employing science to reverse the trend of marine ecosystem degradation. She confesses a fascination for the “language of light.” Some researchers think it may well be comparable to a spoken or sung language—as rich and complex as is the number of species that have evolved to use it. Those linguistic mysteries are still at an early stage of being unraveled.
In Widder’s TED talk in the Galápagos Islands in April 2010, she explained that the first time she went down to 880 feet (268 m) in a special WASP deep-sea diving suit and turned out the lights, “I was totally unprepared for how much bioluminescence there was and how spectacular it was. I saw chains of jellyfish called siphonophores that were longer than this room, pumping out so much light that I could read the dials and gauges inside the suit without a flashlight, and I saw puffs and billows of what looked like luminous blue smoke and explosions of sparks that would swirl up out of the thrusters—just as when you throw a log on a campfire and the embers swirl up, but these were icy-blue embers. It was breathtaking.”