October 6, 2021 — Imagine climbing through a remote rain forest in the dead of night with nothing but a flashlight to guide your way. There are no trails, no landmarks and no destinations. As you clamber through the trees, the creatures you encounter are bizarre and infinitely better at navigating the darkness, though most of them flee from your light’s bright beam before you can catch a glimpse.

This is what it’s like to explore the ocean’s midwater — the largest and least understood ecosystem on Earth. With more than a billion cubic kilometers of living space, this section of the ocean between the surface and the seafloor holds more species, animal biomass and individual organisms than anywhere else on the planet.

“There are millions of animals down there, no matter where you go,” said Karen Osborn, a zoologist and curator of marine worms and crustaceans at the Smithsonian’s National Museum of Natural History. “It’s not a couple of jellies here and there, it’s millions and billions of animals, and they’re all just as interesting as anything we have up here.”

Unlike rain forests, the deep sea is extremely difficult for humans to study, let alone travel to. Few people — most of them scientists like Osborn — have directly witnessed the midwater’s menagerie through the windows of deep-diving submersibles, making it difficult to garner support for conservation and research.

And yet, each time we descend into the depths of the ocean, we discover new species, new medical and tech applications and ecological connections beyond our imagination.

Read the full story at Smithsonian Magazine