What does upwelling refer to in oceanography?

Upwelling refers to the movement of cold, nutrient-rich water to the surface of the ocean. This process is crucial in marine ecosystems because the nutrient-rich water promotes plant growth, which serves as the foundation of the oceanic food web. When surface waters are driven away—often by wind—deeper water rises to replace it, bringing with it essential nutrients like nitrates and phosphates. These nutrients support phytoplankton growth, which in turn supports a variety of marine life, including fish and larger marine organisms. Understanding upwelling is essential for comprehending marine productivity and the dynamics of ocean ecosystems.