Upwelling

A side view of the ocean water column shows the process of upwelling, the physical movement of deep, nutrient-rich water from deeper water to the ocean surface. A yellow number one is by large dark blue arrow labelled “Nutrients”. The arrow is pointing upwards from the deep nutrient-rich water to the ocean surface. The nutrients arrow is pointing to a green circle at the surface representing a phytoplankton bloom labelled with a yellow number two. The sun is shining down on the phytoplankton bloom and wind is blowing at the surface. Several circles representing oxygen molecules surround the phytoplankton bloom with a yellow number three. Fish are swimming in a school with a yellow number four. On the right side of the graphic is a nutrient arrow pointing upwards from the deep ocean. The arrow is blocked by a light blue circle with white blocks representing melting ice. Arrows are shown deflecting downwards in the water from the ice with a yellow number five.

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Upwelling is an important physical process supporting life in the oceans

1. Upwelling brings nutrients from deep water to the sunlit upper layers at the ocean's surface.
2. Nutrients and sunlight are needed for phytoplankton to grow.
3. Like other plants, phytoplankton use carbon dioxide (CO₂) and produce oxygen (O₂).
4. Phytoplankton growth, known as primary productivity, provides food for many species and supports the entire food web.
5. Freshwater on the surface, for example from melting ice, can prevent deep water from mixing upwards.