In every drop of water is a hidden world. Scuba divers can’t see it through their masks; neither can snorkelers swimming among the coral reefs. To really enter this world, you need to look through a magnifying lens. There you’ll see a vast array of vanishingly small plankton, including crustaceans known as copepods. They come in some 13,000 known species, from glimmering-blue sea sapphires to noodle-shaped cod worms. Some roam freely, while others cling to plants or animals. One copepod species can swim into the womb of a gestating shark and attach itself to her calf.

Sea cucumber larva
A sea cucumber larva floats freely through the water. When it reaches adulthood, it will develop its signature elongated shape. Angel Fitor
Mating copepods
Mating copepods. Rather than insert an organ, the male attaches a sperm packet to the female’s abdomen. Some sperm may reach her ova. Angel Fitor

“Copepods are the most numerous animal on the planet,” says Chad Walter, an emeritus researcher at the Smithsonian’s National Museum of Natural History who has been studying them for 40 years. “People think insects are. But 70 percent of the planet is covered by water, and copepods inhabit all of that.” These tiny invertebrates can be found in the deepest ocean trenches and the highest alpine lakes, even in damp mosses and wet leaf litter. Walter once got a call from an Orthodox Jewish organization wanting to know if there were pieces of non-kosher creatures floating in the New York City tap water. The answer was yes. It’s hard to avoid these relatives of shrimp and lobster—Walter has studied them all over the world, in the Red Sea as well as Antarctica. Wherever there’s water, copepods thrive.

Angel Fitor, a Spanish wildlife photographer, has been working long days to capture this unseen world. Fitor has a degree in marine biology, but he has spent most of his career as an artist, taking pictures of aquatic creatures from seahorses to sharks, usually while snorkeling or scuba diving. A few years ago, he grew curious about the organisms he couldn’t see, the tiny plankton that float with the ocean currents. Many of these creatures are too small to photograph without special scientific tools. But copepods typically range from about 0.2 to 1.7 millimeters in length, just large enough to magnify using conventional lenses and equipment. “I imagined each water droplet as an aquarium,” he says.

Angel Fitor
Angel Fitor, a marine scientist and wildlife photographer, is passionate about illuminating a hidden world that’s all around us. Angel Fitor
bead of water
A bead of water dangling from Angel Fitor's micro pipette contains a single Sapphirina, a genus of copepod that has bioluminescent capabilities. Angel Fitor
Calanoid, hyperiid amphipod, decapod larva and pteropod
Clockwise from bottom right: a calanoid copepod, a hyperiid amphipod, a decapod larva and a pteropod, with jaws at its base and an anus at its pointy top. Angel Fitor

It took Fitor three years of surgically precise work to get the jewel-like images you see here. First, he would take a boat out on the Mediterranean Sea and dive in to collect water samples, usually 30 to 50 feet below the surface. He’d bring the samples straight back to his home studio in the coastal village of Alicante, south of Valencia on Spain’s eastern coast. Then he’d get straight to work: When copepods die, they quickly lose their color and look like dull brown beetles. Fitor wanted to capture the vivid blues and golds of the living organisms, and he wanted to show them in action just as he does when he photographs any other marine animal.

harpacticoid copepods and armored protozoan
Society and solitude in drops of water. On the left are immature harpacticoid copepods, distinguishable by short antennae. On the right is an armored protozoan with an intricate mineral skeleton. Angel Fitor
The Copilia, a member of the Sapphirinidae family, has distinctive eyelike lenses but no actual eyesight; instead, it relies on sensory chemoreceptors. Angel Fitor
Tentaculated comb jelly
A tentaculated comb jelly harpoons a crab larva. Along with the visible barbed tentacle, the comb jelly is sending out smaller barbs, which often contain toxins. Angel Fitor
A calanoid is an order of copepods noted for their long first antennas, which are at least half the length of their bodies. Angel Fitor

That also meant coming up with a studio setup that wouldn’t cause the water to evaporate or overheat the creatures. (His solution included LED lighting and heavy blasts of air conditioning.) He used ordinary binoculars to peer into each container and pulled up water droplets with a micro pipette. “It was like trying to fish,” he says. If he got lucky, the sample contained something worth photographing. Sometimes, Fitor spent eight hours trying to get a single picture. “At the end of the day, it was eye-breaking photography,” he says.

sea worm carrying egg clutch fends off shrimp-like larva
A dramatic scene in a water droplet one-fifth of an inch long: Top, a sea worm carrying an egg clutch fends off a shrimp-like larva. Bottom, the worm swims off while whipping the larva with her tail. Angel Fitor
Brittlestar larva
A brittlestar larva floats at a droplet’s edge. Its long spines help it drift through the water until it reaches adulthood and takes up residence on the seafloor. Angel Fitor
A male Sapphirina. The species is outfitted with iridescent plates on its back, which reflect sunlight and send out shimmering signals through water. Angel Fitor
The resulting photographs—gorgeously illuminated and in vibrant color—capture copepods as they’ve never been seen before. Fitor caught the creatures doing a wide range of activities, including eating and mating and freeing themselves from predators. “It was like a window into a totally new world for me,” he says. “It’s a project that I don’t want to end, and it probably will never end, because every time I go into the sea I find a new form.”

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This article is a selection from the January/February 2023 issue of Smithsonian magazine

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