This form of brown algae is doesn’t have roots or stems that fix it in one place. The bladders, about the size of BBs, are filled with tiny air bubbles that keep the masses of Sargassum at the surface of the water. The mats of seaweed can be 3-4 feet deep, can create shade underneath where lots of developing creatures, like sea turtles and juvenile eels can develop, shelter, and feed. It’s so productive it’s even been called a “golden rainforest.”