Even as human actions sharply alter the world's oceans, there is still a lot we don't know about them. But one important hydrological phenomenon is no longer a mystery: Australian researchers have determined that a deep sea current that flows past Sydney is a long-looked for "missing link" between all the world's southern oceans.

Being called the "southern hemisphere supergyre," the current may be an important regulator of world climate. According to the Sydney Morning Herald,

Ken Ridgway, a scientist with the CSIRO Ocean Flagships research program, said yesterday that because the current travelled at great depths its temperature and salinity, as well as the nutrients swept along with the flow, changed little.

As a result it played an important role in stabilising the world's temperatures, and ensuring the survival of sea life. Monitoring changes in such a stable system should provide pointers to global climate change.