What is the bubbles on bladderwrack called?

The bubbles on bladderwrack, a type of brown seaweed, are called "air bladders" or "float bladders." These structures help the seaweed stay buoyant, allowing it to access sunlight for photosynthesis. The air bladders enable bladderwrack to float close to the water's surface, maximizing its exposure to light while also providing stability in turbulent waters.