PADI Divemaster Certification 2025 – 400 Free Practice Questions to Pass the Exam

Upwelling is a process where deep, cold, nutrient-rich water rises to the surface, and one of the primary mechanisms that can cause this phenomenon is through the action of deep currents. When these deep currents encounter obstacles such as the continental shelf or underwater topography, they can be deflected upward toward the surface. This movement brings nutrients to the photic zone, which can enhance productivity in marine ecosystems.

While other factors, such as wind, play a significant role in upwelling, the influence of deep currents is particularly important in areas where topographic features promote the rise of water. This process is essential in various regions of the ocean, such as along the coasts of continents, where the combination of currents and geographical features creates optimal conditions for upwelling to occur.

The other options may relate to ocean dynamics but do not directly cause the upwelling phenomenon. For example, solar radiation mainly affects surface temperature and stratification, and while water temperature can influence water density and flow, it does not directly lead to the upward movement of deeper water. Similarly, sea level fluctuations may indicate broader environmental changes, but they do not specifically facilitate the upward movement of water masses.