Final answer:
A decrease in pH lowers hemoglobin's affinity for oxygen, causing the oxygen dissociation curve to shift to the right, indicating decreased hemoglobin saturation at a given oxygen concentration.
Step-by-step explanation:
When pH decreases, typically because of an increase in carbon dioxide which reacts with water in the blood forming hydrogen ions, the affinity of hemoglobin for oxygen decreases. This response is described by the Bohr effect. Consequently, the decrease in pH causes the oxygen dissociation curve of hemoglobin to shift to the right. This shift indicates that at a given concentration of oxygen in the blood, hemoglobin will be less saturated with oxygen compared to when the pH is higher. Increased body temperature can also cause a similar rightward shift in the curve.
The blood pH will decrease and hemoglobin affinity for oxygen will increase. The curve will shift to the right.