Night Crawlers of the Abyss

May 19th, 2010, 7:34pm

Shining back at me like a green laser, the shark’s eye reflected the beam of my dive light surprisingly well. I felt a rush of adrenaline as I froze, not daring to move my light off of the creature. The sound of my breathing through the regulator filled my ears as I watched the predator slowly move along the reef. Suddenly, with a sharp snap of its muscular tail, the shark turned and shot directly towards me faster than I’ve ever seen anything move. Within half a second it had halved the distance between us. Jackknifing to the right, it turned away just as suddenly and slowly wandered away. My heart was pounding, and it happened so quickly that any reaction was embarrassingly late. Oblivious to the entire episode, looking in another direction, my dive buddy hadn’t seen a thing.

Diving at night can be a disorienting endeavor: navigation, avoiding obstacles, and the possibility of equipment failure all add additional workload. Without an underwater light to help orient yourself, it’s difficult to know which way is up. There is, of course, what divers find most thrilling on a night dive: the living things that roam the night’s dark waters. Hunting begins at the fall of darkness, and the only creatures you’re likely to bump into will be predators. Everything else is wise to hide deep within the coral’s crevices.

After jumping into the black water, I made a circle with my light, giving the boat the “OK” signal as I bobbed on the surface, waiting for my dive buddy to enter. Putting my mask to the water, it was impossible to see anything save for the eerie blue of the boat deck’s fluorescent light as it quickly faded, unable to penetrate the silent depths. The ceaseless surface waves of the ocean twisted and bent the light, making it dance in a chaotic rhythm that reminded me of the Aurora borealis. With a loud splash my dive buddy entered the water, and I looked up to return her “OK” signal. We swam along the surface towards the mooring buoy, our only reference point outside the boat.

Descending from the buoy, we followed the thick rope of the mooring line down at a forty-five degree angle to the bottom. Covered in soft, silky, brown-yellow-green algae, we descended either side of the line, alternating between pointing our lights along it and downwards, looking for another reference point. With the pull of the massive dive boat keeping the line taught, it sighed up and down with the cumulative movement of countless tiny waves. Without any other visual reference points, we were just along for the ride.

Despite the high clarity of ocean waters, my dive light’s reach was disappointingly short. Able to see in only the narrow sweep the light is pointed in, it’s as if you’re wearing blinders at a time when you’re trying to control your movement in three dimensions, never quite sure what’s coming next. As a result you find yourself busily swinging the light around, trying to fabricate a mental map of the world around you and pointing it at the slightest movement caught out of the corner of your eye.

Finally, a sandy bottom came into view, and my light revealed a fleeting glimpse of a school of rays, disturbed from their sleep under the sand, headed for deeper and quieter waters. Like saucer-shaped birds, they gently flapped their edges, levitating a few inches above the sand, their expressionless, beady eyes watching me as they searched for darkness. As I adjusted my own buoyancy a few feet above the bottom, a school of batfish swam by, each two feet across, cruising along the edge of the reef. They disappeared again into the depths as quietly as they had appeared. We oriented ourselves to the mooring line’s anchor, our lifeline back to the boat, and started exploring the reef.

The coral heads present a maze, casting flickering shadows all around you. Knowing that you’re surrounded by life, adrenaline keeps you alert as you push away childhood memories of monsters in the shadows cast by a nightlight. You could be forgiven for mistaking a coral reef as dead if your only experience of it was at night. Fearfully aware of their own mortality, the reef’s inhabitants, actively flitting about their homes during the day, are nowhere to be found at night. The reef is uncannily silent and still.

The bright dive lights will sometimes startle a small fish out of hiding, which will then quickly dart back and forth, confused and trying to escape the beam of light. Larger predator fish will often follow around divers at night, looking for an opportunistic meal. Their larger eyes are adapted to find prey at night, but if a spotlight is being provided, why do any extra work? As if playing a cruel, merciless god, they will swim anywhere you point, gobbling up any small prey captured in the light.

Shining my light under an outcrop of coral, I was rewarded by a rare and colorful sight: a large stoplight parrotfish lay motionless, wedged against the coral, wrapped in an all but invisible bubble of mucus. Only its eye moved slightly, confused by the sudden appearance of light as I short-circuited millions of years of evolution. A parrotfish this large was in no danger from any but the largest predators, though curiosity got the better of a hungry red snapper that had been following me for most of the dive. Annoyed that my view was being blocked, I swung the light, pointing it away from the reef towards the open ocean. A few shadows moved in the distance, quickly moving away from the light. We were surrounded by life, glimpses of it the only hints of hidden activity.

Turning my attention back to the reef, I began to notice a distinctive flicker to my dive light. For a moment I thought my dive buddy was signaling me with her own light, but every time I looked towards her, she was busily exploring a new section of coral a few feet away. Confused, I began to swim towards her, shaking my light. It was definitely coming from my light. Was the bulb filament somehow loose? This light also seemed distinctly yellow compared to the torches we’d used the night before. Banging it with my other hand, the flicker responded in turn, the light somehow angled downwards. Finally, I pointed the light towards my face and looked in horror as I saw the clear space in front of the bulb half-filled with seawater.

Without any light we would be in serious trouble, and it was only a matter of time before my lamp gave up in the corrosive saltwater. Amazed that my light was still working at all given the severity of the leak, I shook my dive buddy’s arm. Startled, she turned quickly, and I pointed at my impotent dive light, water swishing around the clear plastic. Her blue eyes widened as she raised her eyebrows, and bringing her two index fingers together, she signaled that we should stay together and rely on her light for the remainder of the dive. Agreeing that the chances of both lights failing was pretty slim, I gave the “OK” signal, but just as soon as I had, I grabbed her arm again. I pointed at her light: it, too, was half full of water. Circling my index finger vertically, I gave the signal to return to the boat. She quickly nodded.

I tried to keep my breathing under control as we increased our pace underwater, hurrying back to the buoy’s anchor before both lights failed. From there, even if blind, we could follow the line to the surface and the safety of the dive boat. Both dive lights? How was this possible? Someone had screwed up on the dive boat preparing the equipment and we were lucky enough to end up with a pair of duds. Now that I understood what was going on, it seemed kind of obvious. Normally blinding, the lights were incredibly dull and yellow, struggling to penetrate the water. Gradual malfunction is much harder to notice than sudden failure.

Reaching an area with a sandy bottom, I knew we were close to the anchor. An otherworldly blue glow emanated from the other side of the coral heads. No more than 20 feet away, the other divers in our group had no idea of our predicament. Easily within shouting distance above water, it’s incredibly difficult for humans to communicate underwater, even with your dive buddy a few feet away, let alone someone on the other side of the reef. Our inability to communicate and dependence on the failing electric lights were reminders of how ill-equipped we are as visitors to this alien world.

A wave of relief came over me as the concrete block of the anchor point came into dim view. It wasn’t much further now. The thick metal chains chinked together as the dive boat rocked in the waves at the other end of the line. We swam to the top of the chain and held on to the thick rope, covered in slimy algae. Framed by our dive masks, our eyes met, the only small window of facial expression exposed through our dive equipment. We each gave the “OK” signal. I checked my air supply: 2100psi. Plenty. She gave a thumbs up signal, and I nodded, agreeing that we should ascend.

The mooring line between us, we gently swam up, each with one hand on the rope as a guide. Difficult to judge in the dark, I periodically checked the dive computer on my other wrist, making sure our ascent rate was under control. The seabed was now out of sight and we were floating in a featureless void, the thick braided rope our only reference point, angled upwards for an unknown distance. Looking back, the rope quickly faded into nothingness telling no tales of the living world beneath. The glow from the dive boat was coming into view, and soon our fading dive lights would be useless.

Our dive computers beeped, and we stopped at 15ft of depth for our 5-minute safety stop. Opposite one another, we held on and simply breathed. Like the tufts of algae clinging to the rope for survival, I looked at my hand holding onto the mooring line, my skin pale in the half light, the hairs on the back of my hand moving with the water. Bobbing up and down with the ship, the rope would sometimes move several feet at a time, and our bodies waved from our handheld anchor point, mimicking the algae. Never still, the ocean condemns its inhabitants to forever be in motion. I switched my light off, extinguishing it. Looking up, I watched the bubbles of my exhaled breath rise to the surface, breaking up as they rose and expanded, taking with them the excess nitrogen in my blood, back to our world.

Willing my eyes to penetrate the darkness, I stared into the abyss, searching for that last glimpse of life before our return. I imagined the rays that fled our lights earlier, their outlines buried in the unseen sand below us, beady eyes vigilant and watching me, above, grappling with the impenetrable waters, disabled by the failure of a simple light. The sandy bottom failed to emerge from the depths, filled instead by a series of ghostly shapes that materialized out of the fog. Gently pulsating in a futile attempt to control their destiny, a group of moon jellyfish drifted with the gentle current. Watching their graceful domes pass by, I was distracted by movement at the stern of the boat in the distance. Illuminated by the fluorescent lights on the rear deck, a huge school of large fish was swarming right where we would exit the water. My dive computer’s alarm sounded: our safety stop was over.

We gave each other the “OK” signal and let go of the rope. My eyes had adjusted to the dim light cast by the boat, and I motioned to my dive buddy to turn off her dive light. Swimming through the clear water we were in easy reach of the boat, and it felt liberating to be swimming undetected and free in the dark ocean, lone observers to the frenzy in front of us. The stern of the ship was silhouetted by the light, its single four-bladed propeller and rudder frozen in the water. Shadowy and secluded, large fish often lurk underneath moored boats, slowly circling the keel. Instead, this group of large pelagics was focusing on the volume lit by the rear deck’s light.

As we neared the stern I was finally able to see what was happening. A shoal of baitfish had been unlucky enough to wander into the light cast by the boat, and they were being devoured by a school of great trevally. The only way out of the water was through the feeding fish. We paused at the edge of the writhing mass. Bathed in light and swarming around the twin ladders hanging into the water, we were reluctant to continue. As we watched, the baitfish were visibly decreasing in number as the dwindling survivors were being forced toward the surface. In general, fish actively avoid being touched and schools of fish will part as you pass through them. I’d never been near a school of feeding fish, but we didn’t have a choice. I looked at my dive buddy and shrugged. Onwards.

Slowly ascending through the feeding fish, I was mesmerized. The water was alive with tiny silvery reflections and large saucer eyes. The baitfish moved in a spastic zigzag pattern doing everything possible to avoid being eaten. The trevally drifted by in all directions, their eyes calmly focused on their prey. With a sudden burst of energy one of them would swallow an unwitting victim. No matter which direction I looked, the scene was the same. Keeping my arms close, I felt brisk currents all around me as the trevally feasted, but none of them brushed against me. Looking upward, I watched both predator and prey dive out of the water, but the odds were clearly stacked in favor of the trevally with their large eyes and swift bodies. It was just a question of time. The ladder was near, and I could see the shimmering refraction of one of the crew waiting for us. I exhaled one last time.

Bursting through the surface, the world was suddenly busy and loud. The hungry fish around us were flopping on the surface as they dove after their prey. The metal ladder I was standing on clanged against the deck as waves splashed over the side. The grinding, rhythmic whine of the ship’s generator was blaring and out-of-place. We slapped our fins onto the deck and clunked down the two broken lights, now filled with water.

“You two are back early! What happened?”

The horizon was black in every direction, not a single sign of human presence, and even the trevally now seemed quiet, leaving no hint of life beneath the dark, undulating waters.