Bonney Upwelling

Upwelling events occur in the Australian summer (from November to May) when seasonal winds blow from the southeast. These winds blow parallel to the shoreline at certain areas of the coast, which forces coastal waters offshore via ‘Ekman Transport’ and draws up cold, nutrient-rich waters from the ocean floor. During upwelling events, local sea surface temperature drops by 2-3 degrees Celsius, having a wonderful moderating influence on our maritime climate and provides consistent temperatures during our growing and ripening season. The Bonney Upwelling is the largest and most predictable upwelling, extending from Portland VIC to Robe SA. In this area of coastline, the edge of the continental shelf is around 20 kilometres offshore and waters from the ocean floor are funnelled to the surface through a series of submarine canyons during upwelling events.
More information is available here.