What is a Pneumatocyst?

A pneumatocyst is a gas-filled bladder found in certain algae, particularly in brown algae like kelp. It helps these organisms float and remain buoyant in the water, maximizing their exposure to sunlight for photosynthesis. By adjusting the gas within the pneumatocyst, the algae can control their depth in the water column. This adaptation is crucial for their survival in various marine environments.