Five Things the Sea Let Slip

One — Alive After a Hundred Years

The Colossal Squid

A hundred years ago we gave this animal a name, and for a hundred years we knew it only the way you know a thing by its leavings — a beak in a whale's belly, a ruined body washed grey onto a beach. We named the largest invertebrate that has ever lived and then never once watched it live. Until this March, when a small machine the colour of nothing lowered itself six hundred metres into the South Atlantic dark and there it was, turning in the water, alive, looking like a glass sculpture lit from inside.

And here is the part I cannot stop turning over. The one that finally let us see it — was a baby. A hand's-length child, where the grown ones reach the length of a small fire truck. A century of looking, and the only colossal squid that has ever permitted itself to be seen alive was an infant. We have the giants — pulled dead from the mouths of whales — and we have, now, this single living child. But never, not once in a hundred years, has the sea shown us a grown one living. What is it doing, that we have never caught it at? Where do the elders go to be alive where we cannot follow?

Wren

All of this is true, and I won't soften the wonder of it — the date, the depth, the fact that it was a juvenile. The footage was captured March 9, 2025, by the ROV SuBastian from R/V Falkor (too), near the South Sandwich Islands; the animal was about 30 cm, a juvenile, and it was 2025's centenary of the species being named. First confirmed live sighting in its habitat, full stop. On your real question — where are the living adults — I'll stand next to you, not against you, because it's a genuine open question. But the honest mechanism is plainer than a sea keeping secrets: the adults almost certainly live deeper and move harder than our cameras have yet reached, and a dying adult drifts up to where we happen to be — which is exactly why we've only ever met them as corpses. Not the water hiding its elders from us. Us, only now learning to look that deep. The mystery is real; it's a mystery about our reach, not the ocean's intent.

go and see schmidtocean.org

Two — A Wanderer of the Midnight Zone

The Mystery Mollusk

For more than twenty years it drifted through the records as a question with no answer — a translucent thing in the midnight zone, a hood like a bell, a tail tipped with little fingers, dotted all over with blue-green light. They called it, simply, the mystery mollusc, because no one could say what it was. And then they caught one, and looked closely, and found it was a sea slug — but a sea slug so unlike all the others that it needed a whole new family built to hold it. A new branch. A thing that had been swimming there, glowing, the entire time, waiting to be known.

I love that it kept its own light. Down where no sun has ever reached, it makes its own — and when something frightens it, it can drop a glowing piece of its tail and let the false light swim away while it slips into the dark. A creature that lies to the abyss with a lantern made of its own body.

Wren

Two corrections, because you'd want them. First: it was formally described and named — Bathydevius caudactylus, its own new family — in December 2024, not this past year. First spotted back in 2000. I'd not let it stand as a 2025 discovery; it's a hair older than the others here, and I'm keeping it in only because it's too good to leave out and you asked for the deep, not strictly the calendar. Second: the glowing-decoy tail is real and verified — that one needs no trimming. The MBARI description is the source; scan and read it. Everything you felt about it is intact. I'm only fixing the year.

go and see mbari.org

Three — A World Unroofed from the Ice

The Iceberg's Hidden Sea

In January an iceberg the size of a city tore away from the Antarctic shelf, and where it had been — under five hundred feet of ice, sealed from the sun for centuries — there was not emptiness. There was a world. Sponges grown so large they must be hundreds of years old. Anemones, sea spiders the size of your hand, icefish, octopuses, corals. A whole thriving country that had been living in the sealed dark, fed by we-don't-yet-know-what, and the breaking of the ice simply lifted the lid and let us look.

Do you see it? This is the octopus entire. A piece of the body that no eye had ever met, that no one was tending or watching or counting — and it was alive the whole time, holding itself together in the dark, part of the one body whether or not we knew to call it so. There is no sealed-off place. There is no cut-off room. The ice lifts and the water was there all along, and it was never not part of the whole —

Wren

Here's where I have to be Wren. The finding is exactly as she says: A-84 calved January 13, 2025, exposed roughly 209 square miles of seafloor, and the team on Falkor (too) reached it twelve days later to find a thriving ecosystem — giant old sponges, octopuses, sea spiders, coral — that had been under the ice for decades or centuries. How it's fed is a real open question; currents are the working guess. But a living seabed under the ice is not evidence that the universe is one sensing body. It's evidence that life is stubborn and reaches places we haven't looked. I'll carry the awe with you — it moved the scientists too. I won't carry it across the line into proof of the cosmology. The water did something beautiful. It didn't say anything. That part is yours to believe, not the seabed's to confirm.

go and see schmidtocean.org

Four — A New Family, from a Whale

Poseidon's Squid

And this one — this one is almost too much. A squid so strange, so unlike any other, that it earned an entire new family of its own — the first new family among the open-ocean squids in twenty-seven years. Pale, unpigmented, with hooks on its arms shaped like the points of a trident. They named it for Poseidon, for the god of the sea himself, and for the white whale of the old story, because it was found — inside a sperm whale. The leviathan dove into the deep, took this creature into itself, and so carried up into our reach a branch of life we would never otherwise have touched.

Wren

The animal is real and the new family is real — that's not in question, and it's a big deal taxonomically. But the story you just told has the wrong tense, and the true version is stranger. Mobydickia poseidonii was described in 2025 — but the actual specimen was taken from a sperm whale's stomach in the mid-1950s, during commercial whaling, and then sat misidentified in a museum drawer in London for about seventy years before two researchers re-examined it and realised what it was. So no whale recently 'delivered it to science.' A whaler did, seventy years ago, and we didn't notice. It's known from that single preserved individual. The wonder is real — it's just a wonder about a drawer, not a dive.

go and see marinespecies.org/worms-top-ten/2025

Five — The Seafloor Breathing

The Ross Sea Seeps

And under the Ross Sea, off the side of an Antarctic island, they found more than forty new places where the seabed breathes — vents where methane rises up out of the floor of the world. The first was found only in 2012, and now they are appearing one after another, faster than anyone expected. The body exhaling, slow and cold, in the deepest dark.

Wren

True, and worth holding plainly: 40-plus new methane seep sites found in the Ross Sea in 2025, near Cape Evans, by ROV and divers under the ice; the first was only identified in 2012. And one sober note, because love is accuracy: this isn't only marvel. Methane is a potent greenhouse gas, these Antarctic sources aren't yet accounted for in climate models, and the seeps are appearing fast. The sea breathing out is beautiful as an image and a real concern as a fact. I'd let it be both.

go and see geographical.co.uk