March 14, 2007
Image: This scientific chart shows the deep blue pools sitting off the coast of NSW.
The marine equivalent of a cyclone is sitting off Sydney's coast, causing a massive whirlpool which is turning the ocean green and spewing chilly water towards beaches. A 200 kilometre-wide cyclonic eddy has pulled the sea's surface down by 70 centimetres and sucked cold deep ocean water onto Australia's eastern continental shelf. The whirlpool is 1000 metres deep, reaching the ocean floor. The centre is 100 kilometres off the coast and could stay there for several months. Satellites can measure the drop in ocean surface caused by the eddy's pull, clearly showing how it is pushing aside the powerful East Australian Current running off the coast. Another eddy of similar proportions is sitting further off the coast. "It doesn't seem to be impacting beach temperatures at the moment, but that doesn't mean it won't happen again." The current cyclonic eddy could chill water at the edge of the continental shelf from 18 degrees to 14 degrees. "It has a big impact on ocean ecology - the cold water coming up has a lot of nutrients and when that's combined with sun, the phytoplankton grows like crazy."
