Edith Widder - Below the Edge of Darkness: A Memoir of Exploring Light and Life in the Deep Sea

There was a high-pitched whine coming from the starboard side of the sub. I leaned to my right, trying to pinpoint the source. It didnt necessarily sound alarming, but it was different, and one thing I have learned from diving in submersibles is to pay attention to different. Since this was the untethered single-person submersible Deep Rover, I was both pilot and crew, and there was no one to ask, Do you hear that? I was alone, just passing 350 feet beneath the oceans surface, surrounded by water as far as the eye could see in every direction, and descending toward darkness. The whine, initially almost imperceptible above the whir of my scrubber fans, was growing louder and more concerning. Trying to identify the cause, I shifted around in my seat, a padded pilots chair in the center of the five-foot clear acrylic sphere. I bent at the waist, contorting to bring my right ear almost level with the instruments in the armrest. As I did, my stockinged feet slid down the inside of the sphere, into something you never want to encounter inside a submersible: seawater. Lots of it.

This was bad. Abject terror was the appropriate response, which I certainly felt in spades. Fortunately, I was able to maintain just enough of my faculties to begin taking action to save myself. Locating the source was step one. No problem: The water was flowing in through an open valve below my seat on the starboard side. Stopping it was step two. Big problem: The valve handle was missing! There was only the valve stem, which I couldnt possibly turn without leverage. The water kept streaming in through the small orifice, the whines rising pitch providing an audible measure of the sub getting heavier and sinking faster as the water rose. I blew my ballast tanks and jammed on my vertical thrusters while my mind raced. Is it too late? Am I already past the point of no return?

The fact that I am writing this proves, of course, that I wasnt too late. I made it to the surface and was pulled to safety, but it was definitely more harrowing than I would have liked, and I cant deny that the memory lingers. but it did happen early in my career and could have cost me my life, so why, you might ask, do I keep doing it? Honestly, it never crossed my mind to stop.

I became hopelessly addicted in 1984, on my first dive using a metal diving suit called Wasp. That initial spine-tingling exposure to deep-sea bioluminescence occurred during an evening dive off the coast of Santa Barbara. I was dangling on the end of a cable at what at the time seemed an incomprehensible depth800 feetwhere the pressure outside my protective metal shell was 355 pounds per square inch (24 atmospheres). I was there to explore and learn about life in the largest living space on the planet, the oceans midwater. I hoped I would see bioluminescence, which is why I turned out the lights. I wasnt disappointed. In fact, I was so dazzled, the experience changed the course of my career.

The first major scientific collecting cruise of marine life in the diverse Sea of Cortez was organized by Ed Ricketts and John Steinbeck in 1940. Their explorations and scientific discoveries were published in The Log from the Sea of Cortez, which was written by both of them but is generally ascribed solely to Steinbeck. Their vessel was a chartered purse seiner called the Western Flyer. During their expedition, Steinbeck and Ricketts and the rest of their crew made most of their collections at low tides. With their bent-over posture and slow head-scanning movements, they would inevitably draw questions from the locals:

What did you lose?

Nothing.

Then what do you search for?

This line has always made me laugh, not least because Ive been asked this question or something close to it many times in my forty-year career of exploring the ocean. And the truth is, Ive asked it of myself more than a few times.

Encounters with bioluminescence at scale can make that question seem quaint. The open ocean is a fantastically strange and wonderful place. In this world without apparent hiding places, the game of hide-and-seek is played out on a daily basis with life-and-death consequences. One successful survival strategy is to hide in the depths during the day, below what we call the edge of darkness, and come up only to feed in food-rich waters at night, as the edge of darkness makes its way toward the surface. This is such a common solution to the problem of no hiding places that it is responsible for the most massive animal migration pattern on our planet.

Vertical migration happens every day, in every ocean, and the masses of ascending animals form a layer so dense that more than one ships captain, scanning with sonar at sunset, has been fooled into believing they were about to run aground. Because so many of the oceans inhabitants have adopted this survival strategy, these migrants spend most of their lives in near darkness. To compensate, almost all of them make their own light.

Drag a net behind a ship almost anywhere in the ocean below the edge of darkness, and most of the animals you bring up in that net will make light. Given the volume of the open ocean and the vast watery realm between the oceans surface and its bottom, which constitutes the largest ecosystem on the planet, were talking about a world teeming with light makers. To put this in perspective, if most of the animals in the ocean are bioluminescent (from single-celled bacteria to colossal squid), then a majority of the creatures on the planet are communicating using language-of-light dialects that we dont comprehend.