User:Jkaempf/sandbox

The "Great South Australian Coastal Upwelling System" is Australia's only deep-reaching coastal upwelling system with nutrient-enriched water stemming from depths exceeding 300 m. It is a seasonal upwelling system extending from Ceduna in the eastern Great Australian Bight, South Australia, to Portland along the Bonney Coast, Victoria, over a distance of about 800 km. Coastal upwelling events occur in austral summer (Dec - April) as a consequence of frequent prevealing southeasterly coastal winds. Key upwelling centres form 1) along the Bonney Coast and 2) along the southern tip of the Eyre Peninsula. A less pronounced upwelling centre also forms off the south-western coast of Kangaroo Island. While the Bonney Upwelling has been reported and explored much earlier, the full extent of this upwelling system was discovered only recently in 2004. Extensive upwelling of nutrient-rich water produces an important marine hot spot on Australia's southern shelves. For example, this upwelling plays an important role in the life cycle of juvenile southern bluefin tuna (Thunnus maccoyii) accumulating and feeding on pilchards in the eastern Great Australian Bight during the upwelling season. Many other ecologic features of the region (e.g. colonies of sea lions, little penguins and seals, high abundance of blue whales and sharks) can be attributed to the existence of the upwelling system. The relatively high biologic productivity and biodiversity of this upwelling system is linked to the great depth of upwelling. Field data and hydrodynamic modelling suggest that end product of upwelling in the eastern Great Australian Bight follows from a chain of processes. This chain of processes starts with localized sub-surface upwelling in submarine shelf-break canyons of the Murray Canyon Group that are located south of Kangaroo Island. Canyon upwelling triggers the formation of a subsurface pool of cold and nutrient-rich shelf bottom water to the west of Kangaroo Island. This dense-water pool, named the Kangaroo Island Pool, provides the source waters for the classical wind-driven coastal upwelling process. Owing to the narrowness of the shelf along the Bonney Coast, upwelling in this region takes place without the formation of a dense-water pool. Next to the Great Barrier Reef, the Great South Australian Coastal Upwelling System and its ecosystem can be regarded as one of Australia's natural wonders. Nevertheless, its protection status is still at a relatively low level; that is, an integrated conservation approach for the entire system does not exist.