How should a diver respond if they experience a sudden loss of buoyancy?

When a diver experiences a sudden loss of buoyancy, the appropriate response is to inflate their Buoyancy Control Device (BCD). This is essential because the BCD is designed to help divers control their buoyancy while underwater. By adding air to the BCD, the diver can increase their buoyancy, which will help them return to a neutral or positive buoyancy state. This control is crucial for safety as it allows the diver to ascend slowly and safely to the surface if needed, avoiding rapid ascents that can lead to decompression sickness.

Other responses can lead to potentially dangerous outcomes. Swimming down to regain buoyancy can exacerbate the issue, making it more difficult to achieve proper buoyancy control. Removing weights might seem like a logical option, but it can lead to uncontrolled ascents, which pose serious risks. Similarly, remaining still and hoping for improvement does not address the problem and could lead to increased anxiety or a dangerous situation. Thus, inflating the BCD is the most effective and safest immediate response to regain proper buoyancy control.