What effect does carbon dioxide buildup have on a diver?

The buildup of carbon dioxide (CO2) in a diver's body leads to a condition known as hypercapnia. This occurs when there is an excess of CO2 in the bloodstream, which can significantly disrupt normal physiological functions. Hypercapnia can result in a variety of symptoms, including headaches and dizziness, due to the associated decrease in blood pH and the subsequent increase in the acidity of the blood. It can also affect a diver's cognitive function and overall ability to perform tasks, further emphasizing the importance of effective ventilation and air management while diving.

Understanding the physiological impact of carbon dioxide is crucial for divers, as managing CO2 levels is essential for maintaining safety underwater. The other options do not accurately describe the effects of CO2 buildup; for example, enhanced underwater vision and increased oxygen absorption rates are not linked to hypercapnia, while decreased buoyancy control could be influenced by various factors, not specifically CO2 levels.