These unstable currents can be small, on the kilometre scale, or huge. It's like a garden hose thrashing around on the grass when the flow is too great. The current wobbles back and forth until eventually the wobbles form a coherent circle - an eddy - or adding to an existing one. What we do know is that warm eddies along Australia's east coast can be fed by the East Australian Current when it becomes unstable. That's because they can store large amounts of heat and can temporarily increase coastal sea levels. It's important to better understand how eddy currents grow, move and decay better. Sea life is often very finely attuned to temperature, so a sudden heatwave like this can heavily impact ecosystems. That's because warm eddies can bring in masses of warm water and keep it there for months. Just as storms can in the atmosphere, ocean eddies can drive extreme 'ocean weather'. That's because they draw up nutrients like nitrogen and phosphorous from the deep sea, which become food for plankton. Warm eddies are like ocean deserts with little life, while cold eddies are typically much more productive. But ocean eddies can shape the ocean's patterns of life. Like weather patterns, they can be warm or cold.

If it moves close to shore, it could trigger another coastal marine heatwave.Įddies are the ocean equivalent of storms in the atmosphere. And the temperatures deep underwater are up to 3☌ above normal. Its currents are spinning at 8km per hour. Our estimates suggest this 400km wide beast holds 30 per cent more heat than normal for this part of the ocean. We have just returned from a 24-day research voyage on CSIRO's research vessel RV Investigator to explore this monster eddy. An even bigger eddy is forming about 50km off Sydney. Our new research demonstrates the link between a warm ocean eddy and a record-breaking marine heatwave which struck off Sydney from December 2021 to February 2022. It turns out these eddies drive change underwater by spawning marine heatwaves. They're usually hundreds of kilometres across (100–300km), up to 2km deep and can be visible from space. Oceanographers describe these spinning water bodies as 'eddies' - but they're not the small eddy currents you see in creeks or rivers. Right now, there's something big spinning off the coast from Sydney - a giant rotating vortex of sea water, powerful enough to dominate the ocean currents off south-eastern Australia.

Youtube huge ocean waves