What Lives in the Dark: Research Notes from the Deep

The ocean covers 71% of the Earth's surface. We've mapped less than 25% of it.

That number stopped me cold the first time I read it. Less than a quarter. The rest is darkness, pressure, and things we haven't named yet. For a fantasy and science fiction writer, that's not a problem — it's an invitation.

The deepest parts of the ocean are called hadal zones — named after Hades, the Greek underworld. They begin at around 6,000 meters and descend to nearly 11,000 at the bottom of the Mariana Trench.

The pressure at that depth is over 1,000 times what you feel at sea level. The temperature hovers just above freezing. There is no light. And yet things live there.

Snailfish. Amphipods. Bacteria that metabolize chemicals instead of sunlight. Life that evolved in complete isolation from everything we consider normal about being alive.

I've spent a lot of time thinking about what it means to evolve in the dark. What it does to a creature's relationship with visibility, with being seen, with the concept of a surface world that exists but is utterly unreachable.

Roughly 76% of deep-sea creatures produce their own light. Not reflected light — generated light. Cold, chemical, purposeful.

Some use it to hunt. Some use it to communicate. Some use it to confuse predators. The anglerfish dangles a glowing lure in front of its mouth and waits for something curious enough to approach.

There's a metaphor in there that I've been turning over for two years. The light that draws you in. The thing behind the light that you don't see until it's too late.

I'm not going to say more than that.

A few things that have shaped the world I'm building:

"The Deep" by Claire Nouvian — a photography book of deep-sea creatures that reads like a field guide to nightmares. Every image is extraordinary. I've returned to it dozens of times.

"Kraken" by Wendy Williams — a history of humanity's relationship with the giant squid, which is also a history of how we mythologize the things we can't see. Relevant.

The MBARI (Monterey Bay Aquarium Research Institute) video archive — hours of ROV footage from the deep ocean, freely available online. I've watched more of this than I can account for. The silence of it. The way creatures move when there's no current, no surface, no up or down.

The novel uses all of this. The pressure, the darkness, the bioluminescence, the evolutionary logic of creatures that have never seen the sun.

But it's not a nature documentary. The science is the foundation, not the ceiling. What I'm building on top of it is something else — something that requires the real world to be strange enough that the invented world feels inevitable.

I think the real ocean is strange enough. I think it's been waiting for someone to write it properly.

That's what I'm trying to do.

More soon.

— J. Hillary