Leeuwin Current Physical Oceanography Robert Jarrett II Source: Dept. of Fisheries Western Australia

Location Western Coast of Australia Starts at North West Cape Flows south then curves east around Leeuwin Cape Continues towards Tasmania 5,500 km long – Longest continuous boundary current

Formation Trade Winds move warm Pacific waters east Some water pushed through Indonesian Throughflow Creates sea surface pressure gradient Warm, low-salinity at Indonesian Throughflow Cooler more salty south of Western Australia ½ meter difference in sea surface height Only 300 meters deep – shallow compared to others

Downwelling The current flows south along western boundary Downwells water, keeping surface warm and nutrient poor Different from others Most western boundary currents flow north They upwell water Eg. Benguela Current and Humbolt Current Much less productive fisheries

Ecology Without upwelling overall less productive Organisms adapted to lower nutrients Clear waters from lack of productivity Light reaches benthic zone Supports seagrasses, macroalgae, and corals Filter feeding invertebrates instead of finfish

Coral Reefs Warm water is conducive to coral reefs Southward flow creates most southern true coral reef Around Abrolhos Island off of Geraldton Coral spawning along with other species are timed to strengthening of the current Allows for better transport

Questions?

References Western Australia Department of Fisheries. (2012, May 1). Living with the Leeuwin Current. Retrieved December 2, 2015, from Leeuwin-Current-InDepth.pdf Feng. (2012). Leeuwin Current. Retrieved December 2, 2015, from port_card_extended/category/leeuwin_current