Explorers marvel at 'Brittlestar City' on seamount in powerful current swirling around ...(low. Although the base of Brittlestar C...)

Intrigued by the dynamics of the Antarctic Circumpolar Current as it passed over and through ridge gaps, physicists aboard the Tangaroa calculated its speed over the top of the seamount at a rattling 2 knots (about 4 km per hour).

This current is estimated to be 110 to 150 times larger than all the water flowing in all the rivers of the world, says Dr. Mike Williams of NIWA. In terms of the worlds oceans, New Zealand sits right beside the motorway.

The Macquarie Ridge creates a strategic marine junction. Understanding this current will shed light on how much water flows into the Pacific as opposed to continuing to circumnavigate Antarctica. This is important for understanding, and ultimately predicting, the impact of potential changes in the current on climate throughout the Southwest Pacific.

Data was collected from nine strings of metering instruments, anchored a year earlier in two gaps or "choke points" in the Ridge, through which the current squeezes. Experts were astonished to find the current had pushed the top instruments on some strings to a depth of one kilometer below the surface.

Scientists also took this ocean areas temperature and salinity readings for the first time since the 1960s, looking for climate-related changes, and obtained water samples to measure and compare levels of marine life nutrients.

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