What is upwelling

Upwelling is the movement of cold, deep, often nutrient-rich water to the surface mixed layer; and downwelling is the movement of surface water to deeper depths. Downwelling occurs when surface waters converge come together , pushing the surface water downwards. Regions of downwelling have low productivity because of the nutrients get used up and are not continuously resupplied by the cold, nutrient-rich water from below the surface. Upwelling occurs when surface waters diverge move apart , enabling upward movement of water.

Upwelling brings water to the surface that is enriched with nutrients important for primary productivity algal growth that in turn supports richly productive marine ecosystems. Upwelling regions are often measured by their productivity due to the influx of nutrients to the surface mixed layer and euphotic zone sunlit layer by upwelling currents.

Picture this: Stepping through the doors into the Great Hall of the Bodega Marine Laboratory , you are immediately greeted with a spectacular ocean view through the glass doors down the hall. You walk over to get a better view of the waves crashing into the rocky bluffs on the Reserve, open the doors, and… pow! A forceful gust of wind immediately swoops in to greet you. These strong winds in the springtime are one of the most iconic features of Bodega Bay and the rest of the northern California coastline - they are also the main driver of a phenomenon known as coastal upwelling.

Water from the ocean depths is then pulled up - or upwelled - to the surface to take its place. Upwelling intensity along the west coast of North America is variable due to differences in environmental and oceanographic conditions, and northern California is home to the most intense upwelling. The California Current, encapsulating Bodega Bay, is one of just four major upwelling-driven ecosystems in the world - the interesting and unique research opportunities created by this feature of the region are one of the things that have made Bodega Marine Laboratory a magnet for researchers for over 50 years.

So, surface water is pushed offshore and replaced by bottom water - why does that matter? Although at first, it may seem that all seawater is the same, water from the depths is actually much different in temperature, nutrient content, and chemical composition than that of surface water.

Bottom water tends to be colder due to a lack of sunlight, more nutrient-rich due to the decomposition of settling organic matter, and more acidic and less oxygenated.

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Connect with us. Safeopedia Explains Upwelling. What Does Upwelling Mean? Encyclopedic Entry Vocabulary. Upwelling usually results in rich fisheries. Photograph by Bates Littlehales. Coriolis effect.

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