Tracking Damage in the Depths

Three hundred feet below the surface, four minutes into a dive, the robot Ventana descends into utter darkness. The ocean, as we know it, ends here. And a vast, alien world--the deep sea--begins.

The sun’s rays are powerless here. The temperature plunges to just above freezing and the pressure is so intense that a human body would implode in an instant.

Aboard a research ship 16 miles off Monterey, Jim Barry sits in a darkened control room, squinting at a screen in front of him. Half a mile below him, the Ventana has cruised to a depth where no human has ever gone without a submersible--and is beaming back live images to its mother ship.

Through the robotic ship’s sharp eyes, Barry sees what he came for: thick-shelled clams that have remained undisturbed, perhaps for decades, at undersea seeps more deadly than cyanide. Carefully manipulating a remote arm, the sub’s pilot, sitting near Barry, scoops up some of the clams and the noxious sea mud. The Ventana is about to bring a bit of the ocean floor home.

Unmanned machines like this are now exploring the abyss almost daily, some descending as deep as six miles. But scientists like Barry have only just begun to grasp the complexity and diversity of the deep sea and the vital role its inhabitants play in keeping the world’s oceans healthy.

Because the oceans are prone to exploitation, not just exploration, scientists suspect that many human activities are depleting deep-sea life.

“The mid-water environment is the largest habitat on Earth, and we know so little about it, because it’s so hard to get to and hard to work in. It’s a lot easier to dig in the rain forest than in the deep sea,” said Mario Tamburri, a scientist at the Monterey Bay Aquarium Research Institute at Moss Landing, north of Monterey. The private research center operates the Ventana and another, newer submersible.

Only the top 5% of the ocean is penetrated by light from the surface. Most familiar fish and other creatures live there. Below, in the deep, dark mid-water that stretches down to the ocean floor, life bears no resemblance to the ocean people are familiar with.

A Hidden Oasis for Strange Species

The deep ocean was once thought to be too desolate, too harsh and too toxic for any creature. But in reality, it is an oasis for animals that are strange enough, tough enough and creative enough to survive in an environment where food is scarce. Creepy, glow-in-the-dark fish with needle-sharp fangs. Translucent jellies longer than whales. Elusive giant squid that have inspired myths for centuries. Clams that transform poisons into food. Tube worms tolerating volcanic temperatures.

More life exists below the surface of the sea than on the land--perhaps 100 million species, most never seen by humans.

Deep-sea creatures have a vastly complex biology, keen senses and incredible survival tools. By cycling carbon and other organic compounds, they sustain life in the oceans and influence worldwide climate. Indeed, a key part of the planet’s life-support system lies in these eternally dark waters.

Yet as invincible and remote as it seems, the deep ocean is not immune to damage from human beings.

Sylvia Earle, one of the world’s most prominent oceanographers, warns that humans are causing changes of “geologic magnitude” in ocean ecosystems but that we have been lulled into “a profound and dangerous complacency.

Scientists have documented a severe food shortage for animals living in the deep sea, and the culprit, they suspect, lies above the surface:

Global warming that many scientists believe is being caused by greenhouse gases wafting from cars, trucks and power plants may be reducing the sea’s bounty of plankton--the tiny plants and animals that make up the core of the ocean’s food web.

Fishing vessels equipped with trawls are scarring the ocean floor in a way that some experts compare with clear-cutting of forests.

Industries are routinely drilling for oil and gas in waters more than a mile deep, and exploratory drilling is expected to double that depth soon.

The most intriguing, yet disturbing, idea for utilizing the deep sea comes from the U.S. government, which has begun exploring use of the ocean as a dumping ground for greenhouse gases.

Scientists worry that the deep sea’s chemistry and biology are being altered by such activities, even though they don’t yet have the ability to understand how.

“The ocean does have a remarkable capacity to absorb pollutants,” said Scripps Institution of Oceanography scientist John McGowan. “But it is not infinite.”

Ninety-eight percent of the living space on the planet lies between the ocean’s sunlit surface and its gloomy floor. Yet the deep sea--deeper than Mt. Everest is tall--remains Earth’s least-known environment. For every dollar of federal funds spent on ocean research, $20 is spent on exploring space.

Creatures on the ocean floor live longer than sea animals near the surface. As a result, they are slower to reproduce and recover from damage and therefore more vulnerable to trawling and other human activities.

Every year, fishermen trawl an area of seabed twice the size of the continental United States and 150 times larger than the expanse of forests that are clear-cut worldwide, according to Elliott Norse, president of the Marine Conservation Biology Institute in Redmond, Wash. No one knows how long the deep marks left by bottom trawlers last, although scientists say it is likely to be decades.

Barry, who specializes in bottom-dwelling animals at the Monterey Bay Aquarium Research Institute, suspects trawling is shifting the balance of marine life from sharks, rockfish and other species that live for decades to the “lettuce of the sea”--faster-growing organisms.

McGowan has discovered another serious problem--the reduction in plankton. Since the 1950s, plankton has declined 70% in the Pacific off California. Another Scripps study of 3-mile-deep waters of the California Current found a 50% decline in food particles between 1989 and 1996.

“If this decline continues--and from everything we know it is--the long-term consequences will be severe,” McGowan said. With too little plankton, deep-sea animals could starve.

Seeking Solution for Global Warming

Because of the difficulties and expense of long-term undersea research, no one knows whether animals living in deep waters are less abundant than in the past. But anecdotal evidence suggests that they are.

McGowan recalls seeing volumes of squid, shrimp and unusual fish brought up by nets towed through half-mile-deep waters off California for scientific studies 20 years ago. “But lately,” he said, “the few trawls we’ve taken seem to have a lot less in them. That’s just an impression, though.”

Scripps scientists suspect that global warming is the cause of the plankton decline. Ocean surface temperatures increased by two degrees Fahrenheit between 1989 and 1996.

Meanwhile, some scientists are turning to the ocean for a potential solution to global warming.

Their idea focuses on carbon dioxide, a gas created by the burning of coal, oil or natural gas. Many scientists believe a buildup of carbon dioxide in the atmosphere is responsible for much of the warming trend in earth’s climate, although that link remains controversial.

The ocean’s mid-water is the planet’s biggest sink for carbon dioxide, already storing it in great volumes. The idea is to collect carbon dioxide from the atmosphere, cool it almost to a freezing point and drop it into the ocean. The carbon dioxide would form iceberg-like blobs likely to remain on the ocean floor for centuries.

The U.S. Department of Energy is investing nearly $30 million in test dumps, including one off Hawaii. Japan and a Norwegian oil company are also conducting tests.

All creatures directly hit by the mass would die instantly. And new research, showing that undersea organisms seemingly are drawn to carbon dioxide dump sites, suggests that the impacts could spread much further.

In a test done by Tamburri and other scientists, hagfish swam up to the dump, were knocked unconscious by the lack of oxygen, woke up and swam into it again.

Some experts say killing life in a small part of the ocean is preferable to a continued increase of carbon dioxide in the atmosphere. But environmentalists are horrified, and many biologists are worried, too.

The deep ocean is also increasingly being tapped by industry.

New robotic technology and techniques to stabilize giant offshore rigs have made even the deepest waters accessible.

But “the engineers’ ability to drill in deep water far exceeds knowledge of the potentially impacted ecosystem,” said Bob Carney, a Louisiana State University oceanographer.

As the technology to extract from the ocean floor advances, so does the technology for biologists to explore the impact.

Remotely operated vehicles, or ROVs, were originally developed by the oil industry for monitoring offshore machinery and pipelines. Only in the past five years have they become a scientific mainstay.

One submersible has already descended to the deepest place on the planet: Mariana Trench off Japan, 36,000 feet below the surface. In comparison, a human diver without a submersible can descend no more than 500 feet.

Monterey Canyon--bigger than the Grand Canyon and two miles deep--is the best-explored expanse of sea floor in the world. It is a mere 15 miles offshore. Scientists can sail there, view five hours of remote images from the ocean floor and sail back in a single day.

The Ventana has been dispatched on so many scientific dives--1,806 as of this week--that it takes only a minute for pilots aboard a research ship to lift the camper-sized machine on a crane, swing it out over the ocean, then drop it into the water, attached to a yellow lifeline. Some submersibles are manned, but most, like the Ventana, carry only cameras and hardware for collecting specimens.

Although Barry and the pilots are floating on the sunlit, choppy surface, smelling the salty air, the images instantaneously sent to their control room are so vivid and eerie that it seems as if they, too, are sinking into the abyss.

As it descends into Monterey Canyon, Ventana seems as if it is flying through a blizzard of “marine snow.” Made up of bits of plankton and flecks of carcasses, this dandruff is the sole diet of bizarre creatures that float in the mid-water and wait for something to die.

Most mid-water species that the Ventana captures on video can make themselves glow in the dark like lanterns, using special bacteria-filled organs or cells that generate chemical reactions.

Many have flesh as transparent as glass. Some, such as the anglerfish and dragonfish, have fierce, sharp fangs in their gaping mouths. The viperfish is so nightmarish that it seems to have inspired the horrific creature in the sci-fi film “Alien.”

Fragile, jelly-like siphonophores resemble an undersea explosion of fireworks or floating flowers. One scientist found a siphonophore that measured 120 feet--making it the longest animal on Earth, longer than even a blue whale.

The hagfish, a colorless, mushy tube, is a mystifying ancient species, predating the dinosaurs. It scavenges the dark ocean for food and, when none is around, sinks into a coma-like state. Scientists suspect the hagfish can live without food for years. While dormant, it keeps its sensory system active--sending chemical signals through the water in search of something to eat. When food is detected, the hagfish wakes up and grabs it. If another predator comes near its food, it fires a thick blob of slime from its pores.

Other deep-sea creatures make their own food, even in the absence of sunlight. Scientists once thought animals could not survive without photosynthesis, the process by which plants create food using the energy of the sun. But deep-sea researchers have discovered giant tube worms living in vents of undersea volcanoes, withstanding temperatures higher than 200 degrees Fahrenheit and creating food by chemosynthesis instead.

Possible Clues to Extraterrestrial Life

Understanding this extreme environment may help scientists explain life in the oceans--and beyond. Probing the Earth’s ocean depths could provide clues to life on other worlds. If animals can live in such an inhospitable place, why not on other planets?

“We didn’t realize the ingredients of life are so simple,” Barry said. “All you need is heat and the right mix of compounds in water.”

When the Ventana reaches the bottom, at a depth just shy of 3,000 feet, Barry spots a whitish section of the sea floor--a telltale sign of clams living in toxic spots called cold seeps.

Hydrogen sulfide seeping from the sea floor there would instantly kill a human being or any other animal on the surface. But the clams stick their feet in the mud and transport the sulfide through their gills, where bacteria transform the poison into nutrition.

Clams do not simply survive on this strange diet, they thrive. Some grow to a foot long. Barry hopes to bring some of the clams and mud to the surface so he can measure how much carbon they burn, which will reveal how much food they need to survive.

Knute Brekke, one of the Ventana’s four pilots, moves levers on a box in front of him to deploy its robotic arm and pick up an empty foot-long cylinder. Brekke uses the metal arm to push the cylinder into the soft bottom. A thick, black cloud of smoke-like sulfur and silt oozes up from the mud.

After filling a dozen cylinders like this, he then moves another arm, equipped with a net, to scoop up live clams--a delicate operation, since the Ventana’s arm is strong enough to crush a clam to bits.

Removing specimens from the ocean floor is like bringing back rocks from the moon.

It is painstaking and expensive work. Some type of unforeseen system failure--perhaps a tool that is miscalibrated, or a dead battery--winds up scrubbing a mission at least once a month. The Ventana, worth a couple million dollars and funded by a private foundation, has been caught in fishing nets and almost lost at sea.

But there is no replacing the live video and specimens that it brings to researchers.

Before submersibles, even basic questions about the deep sea went unanswered, because replicating the environment, or keeping the animals alive above the surface, is difficult if not impossible. Some fish explode like balloons when removed from their high-pressure environment. Delicate jellyfish turn to mush when caught in nets.

Before joining the research team, Brekke, like most submersible pilots, helped oil companies build or repair rigs. Now, he said, he has a new appreciation for the ocean floor as a living place rather than a wasteland.

“I’m working the same vehicle, but it’s now a platform for science,” he said. “I’ve seen some really, really neat things living down there.”

Life on Earth probably originated on the sea floor billions of years ago. Oceanographers are comforted by knowing that, no matter how much destruction occurs on the surface, life in the abyss will survive.

“Human beings, try as they might, are probably not capable of extinguishing life on Earth, and the reason is the deep sea,” said Norse of the Marine Conservation Biology Institute.

“We could easily cut every tree in the rain forest. We could kill all the gorillas and tigers and pandas. But life will always go on in the hydrothermal vents in the deep sea.”

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For more images and information about deep-sea animals and submersibles, visit https://www.MBARI.org and https://www.mbayaq.org