What do the heart rate and oxygen consumption rate patterns suggest about seal diving
The correct answer and explanation is:
Correct Answer:
The patterns of heart rate and oxygen consumption during seal diving suggest that seals use diving bradycardia and oxygen conservation strategies to extend their time underwater.
Explanation (Approximately 300 Words):
When seals dive, they exhibit a physiological response known as diving bradycardia, which is a significant slowing of the heart rate. This response is part of a broader diving reflex that includes peripheral vasoconstriction (narrowing of blood vessels in non-essential organs) and blood shunting toward vital organs like the heart and brain.
The heart rate pattern shows a marked decrease during a dive compared to when the seal is at the surface. This bradycardia minimizes oxygen consumption by reducing the metabolic demands of the body, particularly in muscles and organs that can temporarily tolerate low oxygen levels. By lowering the heart rate, the seal limits the rate at which oxygen is used from its stored reserves (in blood and muscle).
Similarly, the oxygen consumption rate decreases during a dive. Seals rely on aerobic metabolism using oxygen stored in the lungs, blood (hemoglobin), and muscles (myoglobin). As the dive progresses, oxygen stores are depleted slowly due to the reduced metabolic rate. Some dives may even shift toward anaerobic metabolism if oxygen runs low, especially during prolonged or deep dives.
Once the seal resurfaces, there is a rapid rebound in heart rate and oxygen consumption, which supports the replenishment of oxygen stores and removal of metabolic waste such as lactic acid. This pattern of oxygen conservation allows seals to dive for extended periods—some species can remain submerged for over an hour.
In summary, the observed patterns of decreased heart rate and reduced oxygen consumption during dives, followed by increases upon resurfacing, indicate that seals have evolved highly efficient physiological mechanisms to conserve oxygen and sustain long, deep dives in search of food.