Hobbies And Interests
Function of Air Bladders
All brown algae are photosynthetic, meaning they produce their own food from sunlight. In larger brown algae species, like kelp, the blades (leaves) have air bladders because they would otherwise be too heavy to float on the surface of the sea, and thus they would not be able to access the sunlight they need for photosynthesis.
Structure of Air Bladders
The air bladders of brown algae seaweeds, known as pneumatocysts, are small, balloon-like structures located at the bases of the blades. They are filled with a mixture of oxygen, nitrogen and carbon dioxide resulting both from the metabolic activity of the surrounding cells and from equilibration between the gases in the bladder and gases in the surrounding water.
Additional Information
Brown algae seaweeds live mainly in cold water, and the larger species are so numerous that they can sustain entire ecosystems in their own right. The air bladders of giant kelp are so buoyant that sea otters are able to use the blades as anchors to prevent themselves from floating away when they sleep.