How does a diver maintain neutral buoyancy?

A diver maintains neutral buoyancy primarily by adjusting buoyancy through breathing and utilizing weight systems. Neutral buoyancy occurs when a diver’s weight is perfectly balanced with the weight of the water they displace, allowing them to neither sink nor float.

To achieve this balance, divers can manipulate their buoyancy by changing their lung volume through controlled breathing. Inhaling deepens their air volume, which increases buoyancy because air is less dense than water. Conversely, exhaling decreases lung volume, which lowers buoyancy and can assist in descending. Additionally, divers use weights, often in the form of lead shot or other materials, to counteract the buoyancy of their wetsuits and gear. By adding or removing weight, they fine-tune their overall buoyancy to achieve that state of neutral buoyancy, allowing them to sustain a constant depth comfortably without expending unnecessary energy.

The other methods listed, such as swimming constantly, holding breath, or remaining completely still, do not provide the control necessary for achieving or maintaining neutral buoyancy effectively. These actions may lead to unintended fluctuations in buoyancy or exert additional effort, making them less practical for sustaining a desired depth in the water.