Until now scientists were clueless on mechanism behind Antarctica’s declining glaciers, finally robotic dolphins have shed light on the mechanism and helped scientists in determining the cause which has been a great matter of concern in recent years.
According to a new study published in the journal Nature Geoscience on Nov. 10, Andrew Thompson, assistant professor of environmental science and engineering at the California Institute of Technology, and colleagues used six feet long robotic dolphins (yellow robot ocean gliders) to explore temperature, salinity, oxygen level and depth of the Weddell Sea in West Antarctica.
Gliders very small in size compared to large ships, thus are energy efficient and can collect water sample for a longer period of times. Researchers controlled them remotely to identify ocean features that could not have been feasible to study using other means. “One of the challenges of using ship-based oceanography is that it’s difficult to stay out for long periods of time. Life gets in the way, sometimes,” Thompson said.
After every few hours, researchers collected the data from the robots through satellite mobile phone technology. Each glider places a satellite call about five or six times a day. The showed unexpected results, eddies (instabilities that are caused by ocean currents) are one of the prime reason for the decline area covering ice as warm and salty water that reaches the Antarctic continental shelf is transported to top surface of the ocean by eddies which results in melting of ice.
“Eddies are instabilities that are caused by ocean currents, and we often compare their effect on the ocean to putting a spoon in your coffee,” Thompson said. “If you pour milk in your coffee and then you stir it with a spoon, the spoon enhances your ability to mix the milk into the coffee and that is what these eddies do. They are very good at mixing heat and other properties.”
As eddies occur beneath the ocean surface and seems to spin towards the ice carrying warm water, ocean’s middle layer, the warmest ocean layer, appears to be transporting heat towards the top.
“We show that the eddy transport and the surface wind-driven transport make comparable contributions to the total overturning circulation,” the researchers wrote. “Eddy-induced transport is concentrated in the warm, intermediate layers away from frictional boundaries.