Microscopic baby sea urchin crawling with tubed feet is among video winners of Nikon Small World in Motion competition

A small juvenile sea urchin crawling on red algae.
The photographer identified the species as Arbacia lixula — a black sea urchin. As juveniles they show have a distinct reddish coloration compared to the typically black adults. (Image credit: Dr. Alvaro Migotto/Nikon Small World in Motion 2025)

Stunning microscopic footage has captured the moment a translucent baby sea urchin crawled across a bed of red algae. The video earned fifth place in the annual Nikon Small World in Motion competition.

Alvaro Migotto, a zoologist at the University of São Paulo in Brazil, captured the mesmerizing video of the juvenile sea urchin as it moved across its habitat and identified the species as Arbacia lixula — a black sea urchin that is commonly found along the Brazilian coast and throughout the Mediterranean. Migotto discovered the tiny creature while examining debris that had washed ashore near the Center for Marine Biology where he works.

"It was simply by chance. While I was examining various materials — such as algae, pebbles, and seashells washed ashore — under the stereomicroscope in search of other organisms, I unexpectedly came across this tiny sea urchin calmly walking on a piece of red calcareous algae," Migotto told Live Science in an email.

"The scene struck me as perfect — not only was the animal moving naturally over a substrate it typically inhabits in the wild, but the combination of these two elements also created excellent contrast and pleasing colors," he added.

Related link: How to photograph your microscope specimens

Sea urchins are marine invertebrates in the group Echinodermata and are found in oceans around the world and in nearly every climate. They have round, spiny bodies and hundreds of tiny tubed feet.

Nikon announced the winners and honorable mentions of the competition on Sept. 24.

The top prize went to microscopist Jay McClellan for his time-lapse video capturing the self-pollination of a thyme-leaved speedwell (Veronica serpyllifolia). Photographer Benedikt Pleyer was awarded second place for a swarm of Volvox algae in the central hole of a Japanese 50-yen coin.

Other noteworthy mentions include an 18-hour timelapse capturing the growth of a chick's sensory neurons, a 3D composite of a male dung beetle (Sulcophanaeus imperator) built from more than 7,000 images and a recording of mitochondria and calcium waves in the muscle cells of a contracting human heart.

Elise Poore
Editorial assistant

Elise studied marine biology at the University of Portsmouth in the U.K. She has worked as a freelance journalist focusing on the aquatic realm.

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