Thanks to one Spanish chef, the very bottom of the food chain — plankton, the tiny organisms that provide sustenance for fish and whales — is moving up in the culinary world. Spanish chef Ángel León, of the two-Michelin-star restaurant Aponiente, near Cadiz, has turned whale food into human food. The best part? Sometimes, it glows.

In Spain, León is known as “The Chef of the Sea” for his all-seafood restaurant and his embrace of sustainable practices. He uses fish discards — either parts of the fish that other chefs trim away, or types of fish that fishermen would typically throw back into the water — and has learned that they have surprising benefits beyond just avoiding food waste. Through some experimentation with various types and parts of fish, he’s found that he can make them emulate meat.

I “was looking for a pig in the ocean,” León said during a visit to Washington. (Jordi Paronella, a sommelier for José Andrés’s restaurant group, provided translation.)

He has made charcuterie and cheeses out of fish discards. A skin of a moray eel can imitate chicharrón. Tuna bone marrow stands in for beef bone marrow. He has even made “cheese” out of fish fat.

It was these experiments with fish that led him to plankton, a dish that hasn’t traditionally been a food source for humans. León “became obsessed with plankton,” he said. “It reflects the flavors of the ocean.”

León set up a system to collect plankton in very fine nets, but it’s an arduous process: Leaving the nets in the ocean for five hours returns only one gram of the microscopic organisms. He then farms plankton in tanks, in a room that looks like a mad scientist’s laboratory, full of beakers of green ooze. The plankton reproduce and multiply in the tanks. After about six months, he freeze-dries the plankton into a fine green powder that looks like matcha. When it’s reconstituted in water, he uses it as an ingredient in dishes like risotto, or in cocktails. Plankton is nutritious — high in Omega-3s. And as a cooking ingredient, it adds an oceanic saltiness to dishes, but also richness. León says that he never needs to use butter in a dish that contains plankton. 

Eating lower on the food chain has environmental benefits, particularly when it comes to meat, which requires a lot of resources to produce. In seafood, the use of plankton could mitigate the burden of overfishing, which has become a critical problem. Because León farms his plankton, he is not depleting resources for fish. Still, plankton is not a very accessible ingredient for most chefs. León developed his plankton with Plancton Marino, a Spanish company that named him its “ambassador,” and sells the ingredient to other chefs in Europe. One kilogram of freeze-dried plankton from the company costs 3,000 euros, or about $3,330. But a little bit goes a long way: León says 10 grams can flavor enough risotto for 50 people.

León is “looking at the ocean more as a biologist than a chef.” He works with biologists, too; scientists at the University of Cadiz aid him in his experiments with plankton.

“When you are thinking about the ocean, you are always thinking about salt,” said León, but he was “dreaming that the ocean has sugar.” He discovered that while most plankton tastes briny, like the ocean, one species of plankton is sweet — so he uses it for desserts. Plancton Marino classifies the plankton as suitable for vegans, celiacs and those with seafood allergies, because it is a micro-algae.

But his greatest discovery may have been the one that let him take marine bioluminescence — when an animal emits light through a chemical reaction — onto his guests’ plates.

My “dream was to transmit the light of the ocean, and transform it into a dish,” he said. “Now a human being is going to eat the light of the ocean.”

He studied several types of plankton but found that some were too small and others were too toxic. But he was able to take one tiny and safe luminescent species and bind it to dehydrated crab particles to achieve the effect he desired, when activated with water: a surreal, glowing bowl of blue. Future guests to his restaurant will experience it, too, as they dine in the dark for certain courses.

Leading a trio of interested onlookers into a totally dark room, León poured water onto the finely ground mix of crab and plankton, and everyone gasped. The effect was stunning: Staring into the bowl was like looking up at the starry night sky. León played with the mixture, taking a big glug of the plankton and letting it dribble out of his glowing mouth. Then he flung it around the room, lighting up the walls with specks of glowing water. The effect lasts about 25 minutes, and the mixture tastes like seawater.

Reminding people of their connection to the sea is the entire purpose of León’s work. Half of the world’s oxygen is produced by phytoplankton photosynthesis.

“You are here because of the plankton,” León said.