Reporter's Diary: Diving in a Deep-Sea Sub

Chad Cohen
National Geographic Today

July 8, 2002

National Geographic Today sent science producer Chad Cohen on a
mission to explore underwater mountains (seamounts) in the Gulf of
Alaska. He joined up with a team of scientists on the research vessel
Atlantis and traveled to the Patton Seamount, 250 miles (400
kilometers) south of Kodiak Island, Alaska. In a brief missive direct
from the ship Cohen describes his journey in a deep-sea submersible
called Alvin to explore an unknown world of bizarre spider crabs
and exotic corals. The mission is sponsored by the National
Oceanic and Atmospheric Administration's Office of Ocean Exploration.

Well, I don't even know where to start. To begin, the day was just beautiful—blue skies, blue waters.

The way Alvin is launched from the deck is an experience in itself. The 24-foot (7-meter) white and orange sub is slowly rolled out of the hanger on the deck, and we climb in. A giant A-frame lifts us off the deck and swings the sub into the water.

A small rubber powerboat is waiting just off the stern and swimmers dive into the freezing water to disconnect us. When they're done, the ship, the R/V Atlantis, pulls away and within minutes our pilot fills our pressure chambers and we begin to go down.

As soon as we're off the surface, the sub stops rocking back and forth with the waves and becomes eerily stable, supported on all sides by the Pacific. The color of the water descends through an entire spectrum of beautiful blues, gradually getting darker and darker until finally, about 30 minutes into the dive, it is pitch black.

We don't turn lights on until we hit bottom, or the desired research area, in order to save power—which is the limiting factor for every activity in the deep ocean.

Within minutes there was a firestorm of bioluminescence—tiny jellyfish, bacteria, and who knows what else were flying erratically around the entire sub, glowing like a flurry of stars.

After 45 minutes, we continue to descend, getting deeper and deeper till we hit a patch of the slope 3,000 feet (914 meters) below the surface. The base of the seamount, which is rising off the bottom of the seafloor, still lies about 12,000 feet (3,660 meters) below. It's cold now—from 60ºF (16ºC) on the surface to just a degree or two above freezing. There is no heat, again because of power. (It is interesting, that 3,000 feet (914 meters) below surface near the Gulf of Alaska the temperature is the same as 3,000 feet below the surface in the Pacific near the Galápagos.)

Lights come on about a hundred feet from bottom. Peering down, we still see nothing, and then it appears, like landing on the moon—first a barren landscape, or seascape rather, of rocks and sediment, then long squiggly gray rockfish, crabs, and corals. For the next six hours, starting at 3,000 feet (915 meters) and working our way up, we maneuvered around on this lunar landscape, picking crabs with the robot claws (claw against claw) and clipping corals for genetic studies.

Our resident crab expert, Brad Stevens, found what he was looking for. He had taken dives near here previously in search of a variety of crab species, but he could never find any juvenile crabs. He found them today.

We also picked up a pair of crabs mating—coitus interuptus. Male crabs can hold onto females in one spot on the ocean floor for two weeks while waiting for her to molt. They like their women soft, apparently.

Before I knew it, we were out of power and the dive was over. We dropped two sets of weights, 108 pounds (49 kilograms) each, onto the seafloor, and up we went. It took about 30 minutes from 1,500 feet, which is where we ended up.

It's strange, I'd already seen hours of this terrain from videos of other Alvin dives this week, but even though they were video, they were really just snapshots. Being there instantly brought all of the elements together.

What struck me most, I think, was the randomness of it all—sea stars in one place at one depth, crabs at another, and corals at yet another. Of course I realize it's not random at all. But to an alien like me, I just couldn't comprehend the arrangement. I couldn't help but think that if the sub happened to land just 100 feet (30 meters) to the west or east, I'd be seeing something just as completely wonderful but very different.

I guess that's where the frustration comes in. We hear all the time how the earth is 70 percent water, and that we've only explored 5 percent of it, but this experience just makes that so much more vivid to me—and daunting.

If there was ever a motivator for ocean exploration, this is it.

It's a whole other world down there.

Look for television coverage of Chad's dive on an upcoming episode of National Geographic Today.

National Geographic Today, at 7 pm. ET/PT in the United States, is a daily news journal available only on the National Geographic Channel. Click here to learn more about it. Go>>

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