Aboard Atlantis

Tuesday, September 19, 2006

In the still darkness more than a mile beneath Atlantis' keel, a battle is raging. Pitted against each other, earth's elemental forces - plate techtonics, volcanism, the biological imperative, and the sea. The Atlantis has traveled to the front line of this timeless conflict, the Juan de Fuca Ridge, 135 miles northwest of Astoria, Oregon. Alvin pilots returning from the battlefield recently surfaced with evidence of the conflict.

At first glance, the samples on Min-Hiu Lin's sample table appear ordinary enough. A dozen rough hewn fragments, charcoal black and streaked with a lattice of white marbling. A thermos-sized geode, split in half, burnt to ash and lined with fool's gold. The blackened stump of a stalagmite. Identification tags inscribed with blue ball point pen lay alongside each sample. They say "Finn," "Hot Harold" and "Hulk."

Smelling of brimstone and sulfur, the samples appear unlikely objects of scientific curiosity. In this case, however, appearances are deceiving. In oceanographic circles they are among the most sought after of prizes, trophies still so rare that scientists are willing to descend to depths of the ocean, and hope someday to travel into the depths of space, to obtain them.

Lin, a dimunitive Taiwanese researcher with spiky black hair, said that the Juan de Fuca Ridge is an area known for its tectonic activity. "The Axial Seamount on the Juan de Fuca Ridge has been studied continuously since 1983," she said. It has given scientists an opportunity to study the dynamics of volcanism and tectonism on Juan de Fuca's hydrothermal vents."

On a recent dive, Alvin explored "Faulty Towers," a complex of what scientists call polymetallic sulfide chimneys. Composed of metal, sulfides, mostly, chimneys form along undersea mountain ranges called mid-ocean ridges. Ridges form when tectonic plates collide, or in the case of the Juan de Fuca Ridge, separate. As the plates pull apart, the seafloor spreads. Fissures or cracks form, and magma rises to fill the gap. The magma heats invading seawater to more than 700 degrees F. Hydrostatic pressure at 2,500 meters is two tons per square inch, enough to prevent water from boiling.

The superheated water erodes and mixes with surrounding minerals, forming a fluid rich in metals and sulfides. Pressure pushes the fluid up though the seafloor in hot springs called hydrothermal vents. The hot fluid meets and mixes with the surrounding, cold salty seawater. Metal sulfides in the fluid condense into plumes of black "smoke." Over time, the particle-rich plumes precipitate, forming smokestack-like structures called black smoker "chimneys." The samples on Min-Hiu Lin's table are pieces of three such chimneys - Finn, Hot Harold and Hulk.

Over the years many chimneys have been identified along the Juan de Fuca Ridge, part of the Ring of Fire. Roane, Giraffe, Mothra, Salty Dawg, Sasquatch, Sully. Giraffe is 22 meters tall. Barren in 2000, Sully now sports a luxuriant carpet of 2-meter-long tubeworms. In 1977 when hydrothermal vents were first observed near the Galapagos Islands, scientists first documented the existance of giant tube worms. Some grow to 10 feet in length, and bright red blood - iron-rich hemoglobin - courses though their bodies.

In the decades since their discovery, scientists have sought an answer to a fundamental question: How can tubeworms and the other denizens of the hydrothermal vent community - giant clams, worms, shrimp, and bacteria that survive on sulfur - exist at the bottom of the ocean, in darkness, in freezing tempertures and under crushing pressures, close to energetic plumes of superheated fluid saturated with lethal amounts of methane, manganese and iron?

To answer that question, Dr. Jeffery Cramer, a scientist from the University of Washington, studies heat-loving bacteria called thermophiles. "Thermophiles are representations of earth's earliest life forms," he said. Though they have evolved over the eons, he said, compairing contemporay thermophiles to Formula One racing cars, and their primordial ancestors to horse and buggy, "some scientists believe that life on this planet began billions of years ago in
hydrothermal vents just like the ones we see now, and that every organism on earth - including us - evolved from thermophilic bacteria."

Thermophiles live inside hydrothermal vents. They line the narrow chambers and arteries of sulfur chimneys, clinging to deposits of pyrite - fool's gold - coating relatively cool passages filled with a sand-like mineral. Unlike plants, which anchor a food chain based on photosynthesis, thermophiles are chemosynthetic. They derive their sustenance from the chemicals spewing from the vents. Able to tolerate temperatures of 212 degrees F, they eat sulfur and exhale ferrous iron. Oxygen poisons them.

Thermophiles also thrive inside the bodies of tubeworms like those living on Sully. Tubeworms have a specialized organ that contains billions of thermophillic bacteria. From the sulfur they absorb, the bacteria generate organic material that nourishes the host worm. The worms have no need for a mouth or digestive tract, which they lack. This symbiosis between organisms and bacteria extends to the clams, shrimp and other chemosynthetic organisms living near the vents.

The existance of such a specialized ecosystem has raised other questions. If life on earth arose from chemosynthetic bacteria living in hot springs billions of years ago, where did the bacteria come from? Comets or asteroids? Perhaps, said Cramer, although he cautioned the answer may never be answered irrefutably. Besides hydrothermal vents, thermophile-like microbes called extremophiles have been discovered living in the beds of dried alkaline lakes, under glaciers, and in methane seeps. Some thrive in radiation that would quickly kill any other organism. Others eat hydrocarbons - oil. Because of their tenaciousness, "it's possible that some extremophile may be able to survive in the freezing vacuume of space also," said Cramer.

Could thermophilic bacteria exist elsewhere? Scientists speculate that the moons of Jupiter, particularly Europa, may contain two ingredients that vastly increase the possibilty of life - volcanism and liquid water. The Hubble space telescope has observed volcanic eruptions on Europa, and under Europa's icy crust liquid oceans may flow. Nasa has proposed sending a probe to Europa. It may be equipped with a radioactive heat source that would melt through the ice and descend into the ocean below. The probe would seek out heat sources like hydrothermal vents.

"There's a very real possibilty that Europa could sustain chemosynthetic life similar to our terrestrial versions," said Cramer. "If it does, then life may be much more common than we thought."

Wednesday, September 06, 2006

Among the misfortunes that befall ships at sea, none inspires more fear than fire. Storms, collisions, grounding - they're mere princes in the kingdom of hazards. Fire is king. One spark, one smoldering ember, one short circuit. An oily rag, a tuft of insulation, a greasy oven. It only takes a minute. And in that minute a fire can grow into an inferno hot enough to warp steel, boil paint, and incinerate anything it encounters.

That's why Atlantis holds weekly fire and boat drills. Regular emergency training, it is hoped, will instill a reflexive response to the smell of smoke. A response, that is, that diverges from the usual reflexive response - panic. Nothing seizes the attention like the smell of smoke. It stimulates the adrenal gland and stokes the imagination. It quickens the pulse and elevates blood pressure. Pupils dialate, hands shake. The mouth dries. The lizard brain stirs. Fight or flight, except there's no where to run.

Word of the drill spread. The crew gathered in the galley, dropping their life jackets and survival suits beside their chairs. At precisely 10:20 am, the general alarm bell mounted on the galley bulkhead erupted in a shrill, ear-splitting metallic clatter. Simultaneously, the ship's horn sounded a 10-second blast, the standard alarm for fire and emergencies. The captain's voice sounded over the intercom. "Fire, fire, fire. This is just a drill. Fire, fire, fire. Go to your fire and emergency stations."

The crew jumped to their feet, purpose guiding their movements. Atlantis' 22 crewmember (and 6 Alvin crewmembers) must quickly extinguish any fire or risk the loss of the vessel. Each crewmember is assigned a fire and emergency station. Each station has a designated meeting place - the bridge, for example, or outside the damage control locker - and each crewmember must perform a specific duty. Engineers start fire pumps and close the ship's water-tight doors. Cooks search all cabins for unconscious personnel. Electronics technicians send out distress signals. Able-bodied and ordinary seamen crew the emergency squads. Led by ship's officers, the emergency squads are the early responders. They must find and extinguish any fires.

Atlantis' damage control lockers contain a managerie of firefighting equipment, everything from firefighting suits and oxygen breathing apparatus, to fire extinguishers and extra fire hoses. Everything a squad of amateur firefighters needs to fight a fire. But without adequate training, they might as well just launch the life rafts.

And so we train. For our voyage's first drill, Atlantis' chief mate, Carl, volunteered me, fellow deckhand, Steve, and galley messman, Brendon, to don firefighting suits. While I peeled off my sweatshirt and kicked off my boots, other squad members unzipped the heavy canvas bags containing the suits.

My suit was the classic firefighter's ensemble - thick rubber boots, yellow insulated pants, red suspenders, and a heavy jacket with shiny metal clasps and leather elbow patches. The plus-sized pants hung from my waist like clown pants. Balaclava for the head and neck, check. Thick leather gloves and shiny yellow helmet with drop down visor. Check. Someone placed an oxygen breathing apparatus on my back, and hands guided my arms though its straps. I leaned forward, felt the weight, and pulled the staps tight.

A face mask filled my hand. Check the seal. Place mask against the face, hold palm across bottom of the trunk-like air hose hanging beneath. Inhale. Should create a vacuum. The mask sucked tight to my chin, cheeks and forehead. Good. An airtight seal. Unseen fingers pulled the mask's straps tightly around the back of my neck and head. The air hose is connected to the air tank, and the valve is opened. Cool, dry air floods my mask. I breathe deeply. I sound like a scuba diver. I put on gloves and a helmet. I'm ready to go. I feel empowered, capable, competent. I glimpse my reflection in a crewmate's reflective sunglasses. Oh well, you can't have everything. I look away. Standing men crowd the galley. They orbit Steve and Brendon like attendents dressing a Venetian courtesan. The two men, encased in their face masks, helmets, and silver, pseudo-aluminum fire suits, look like spacemen in a 1950's B-movie.

Meanwhile, in the main science lab, Atlantis' complement of 24 scientists gathered for an orientation. In the event of an emergency, you'll muster here in the main lab, a ship's officer tells them. Bring your life jackets and survival suits, as I see you've done. Good. Your primary job will be to stay safely out of the way. But if needed, you may be asked to relay messages between ship's officers and members of the emergency squads. Of course that means someone's probably died, ha ha. But no, seriously...

The horn and emergency alarm sound again. Seven short blasts followed by one long. Abandon ship. "Now hear this." The captain's voice again. "All hands, abandon ship. Go to your abandon ship stations."

If fire is the king of the kingdom of hazards, sinking is queen. The royal pair nearly always travels as a couple. While the crew dispersed to their assigned stations, science's orientation continued. The ship's officer fingers a cherubic University of Washington undergrad. Put on the survival suit? His cheeks redden, but he's game. He kneels and considers the "gumby" immersion suit.

Thick, orange neoprene adorned with strips of reflective tape. Flat, formless feet, and baggy, shapeless legs. Voluminous midsection bisected by waterproof metal zipper. Two shapeless arms terminating in two insensate gloves. Tight fitting hood, Velcro face flap. Inflatable floatation bladder behind neck. Ugly, distorted and unfashionable, the gumby suit nevertheless assumes a beauty that grows in proportion to the proximity of the invading sea.

Designed to be entered fully clothed, the survival suit's thick neoprene acts as a barrier between the human body and hypothermia. Cold water steals body heat. The body responds by drawing warm blood from the extremities and pumping it into the lungs and vital organs. Deprived of blood, the arms and legs stiffen and cramp. Staying afloat becomes difficult. Fatigue sets in. Respiration shortens into shallow gasps. Panic rises. Hard to breath without swallowing salt water. The end nears.

The cherub opens the suit and jams his boot into one of the legs. It catches on a fold and stops. He pulls harder, but it's no use. He tries again, aware of the eyes watching him. He pulls so hard his face grimaces. The ship rolls, sending him hopping one-legged across the deck. Sit down and try working the suit over your boot, says the officer. It works. Good, now the other. Good. The cherub stands, pulls the suit up to his waist and plunges one hand and then the other down into the suit's arms. He hops up and down several times. He stretches and reaches and swings both arms until his hands seat in the gloves. Good. Now the hood. He misses at first. He's working by feel, but he can feel nothing through the neoprene fingers. He succeeds finally and the hood swallows his head. He grabs the zipper cord near his crotch and yanks it upward until just his face is exposed. He closes the face flap over his mouth. Good. It's just that simple. Sympathetic applause rewards the wheezing student. Now everybody try...

Three short horn blasts and three rings of the general alarm signal the end of the drill. Fourty minutes have passed. The Atlantis continues at full speed on its westward course.