Deep-sea Ecologist Rewatches seaQuest DSV: Episode 9, “Knight of Shadows”

“Knight of Shadows” is magnificent. On the surface, it’s a run-of-the-mill ghost story, but add the real phenomenon of nitrogen narcosis, and the audience is left wondering what is “real” within the story and what is the result of pressurized nitrogen disrupting the nervous system. The story itself is one of the best of this season, and the narcosis-induced unreliability of the narrative combines with it for a really solid romp beneath the waves.

Captain Bridger awakens in his quarters to be confronted with a strange apparition—a ghost, perhaps—that throws him across the room before revealing the location of a legendary shipwreck. A small team consisting of the Captain, chief scientist Westphalen, Levin, and Krieg enter the ship, which is, of course, dry inside, because everything in seaQuest is inexplicably watertight, even hundred-year-old shipwrecks. What follows is a great little ghost story, complete with love triangle and maritime mutiny. It’s good enough that I won’t spoil it here, so go watch it. (seaQuest DSV is streaming on Netflix, FYI.)

But there’s also some solid science. As the team enters the wreck, Doctor Westphalen hands out badges that change color if the crew is exposed to dangerous levels of pressurized nitrogen. While these badges aren’t real, we do have a similar exposure badge for doing “hot” work—that is, anything involving radioactive materials—which alerts us if we’ve reached our exposure limits. Exposure monitors for nitrogen may not be real, but nitrogen narcosis certainly is.

First described by his holiness Jacques Yves Cousteau, nitrogen narcosis—The Rapture of the Deep—occurs when pressurized gasses interfere with brain activity. While we still don’t know the complete biophysical mechanism, the current best-available science suggests that pressurized gasses, particularly nitrogen, dissolve into the membranes around nerve cells and disrupt nerve transmission. It is exactly like being profoundly high, complete with reduced response time, poor executive function, and an impaired ability to accurately perceive reality.

The classic joke among SCUBA divers is that you can tell if your buddy is “narked” if they try to give their regulator to a fish.

Being high can be fun, but not when you’re 30 meters deep underwater, strapped to a relatively complicated life support system. Fortunately, the cure is easy: just go up a little. Most people have a specific threshold where they start feeling the effect of nitrogen narcosis (for me, it’s at about 108 feet deep). Simply rising a few feet will clear the effects.

Incidentally, the way you figure out your limit is to have a dive buddy hand you simple math problems every few feet until you can’t solve them anymore.

But the badges are a red-herring. Throughout the episode, I kept looking at them, expecting them to change, indicating that we are seeing the team’s collective hallucination, but the change never came. At least not until the very end, where, safely back within seaQuest, Captain Bridger settles back in to his bunk, and the scene fades out with an exposure badge changing from yellow to red.

So the bad air is in Bridger’s bunk? Does that mean this entire episode was all a narcosis induced dream? Did Bridger even leave his bunk?

Here’s the thing: nitrogen narcosis happens when gas is under pressure. We know that seaQuest operates at atmospheric pressure. You can’t get narked inside the submarine. For that matter, there would be some serious decompression issues if the crew went from the unpressurized seaQuest to the pressurized shipwreck and back without taking a significant trip to a decompression chamber.

So, what was narcosis-induced hallucination and what was canon within the seaQuest universe? Your guess is as good as mine.

Finally, Bob Ballard arrives to tell us a bit about shipwrecks. Bob Ballard loves shipwrecks, surprising no one.

Andrew Thaler is a deep-sea ecologist and conservation biologist who runs the marine science and conservation blog Southern Fried Science. You can support his various and sundry ocean outreach projects (like this one) on Patreon or check out his maritime-y science fictions novels. Follow him on Twitter, where he’s happy to answer question about deep sea ecology and exploration.

Want more stories like this? Become a subscriber and support the site!

—The Mary Sue has a strict comment policy that forbids, but is not limited to, personal insults toward anyone, hate speech, and trolling.—

Follow The Mary Sue on Twitter, Facebook, Tumblr, Pinterest, & Google+.