PHOTOGRAPH BY LAURENT BALLESTA, NATIONAL GEOGRAPHIC

Emperor penguins head for the open ocean in search of food. The brownish patches above them are microalgae that cling to the sea ice and start to photosynthesize in spring. The photographer’s day camp was on one of these floes. Aptenodytes Forsteri (penguins)

This photo was originally published in “Deepest Dive Ever Under Antarctica Reveals a Shockingly Vibrant World,” in July 2017.