Photo of the Day
Each day, we highlight one extraordinary photograph from National Geographic. Check out more of our photos here.
A close-up photo of the underside of a red long-spined sea urchin.
September 15, 2026 | Saving the Sea Urchin
Long-spined sea urchins (Diadema antillarum) like this one are among the most important algae grazers in Caribbean coral reefs. However, during a mass die-off event in the 1980s, the marine invertebrates were almost completely wiped out by an unknown cause, and their population has struggled to bounce back since. Researchers since have identified one of the biggest bottlenecks in sea urchin recovery: early larval survival. At The Florida Aquarium in Tampa, University of Florida scientists are testing a newly developed “baby formula” that dramatically improves sea urchin survival during the earliest stage of life. Ninety-nine percent of urchins do not survive to adulthood, meaning that improving early survival by even one percent could double the number of urchins available for reef restoration.
