Which physiological effect is caused by increased depth during diving?

The correct choice emphasizes the significant impact of increased pressure on gas solubility as a diver descends. As divers go deeper underwater, the pressure increases substantially—approximately one atmosphere for every 10 meters (33 feet) of seawater. This increase in pressure has a direct and crucial effect on the solubility of gases in the body’s tissues and blood.

According to Henry's Law, the amount of gas that can be dissolved in a liquid is proportional to the pressure of the gas above the liquid. Therefore, at greater depths, gases such as oxygen and nitrogen become more soluble in body tissues. This principle is particularly important for understanding how divers manage gases to prevent conditions like nitrogen narcosis and decompression sickness. Managing these physiological changes requires divers to adhere to specific dive tables and decompression protocols to ensure safety.

In contrast, reduced buoyancy can result from increased depth, but it is mainly a function of the compression of air in the lungs rather than a direct physiological effect related to gas solubility. Increased temperature does not typically occur with increased depth; instead, water temperature can vary independently of depth in some environments. While decreased vision clarity may happen due to environmental factors like increased particles or other conditions in the water, it is not