A new analysis of long-term ocean warming trends has discovered that deep ocean waters below 700 meters (2,300 feet) have heated up unexpectedly since the year 2000. The research was published on May 10, 2013 in the journal Geophysical Research Letters.

The deep ocean warming appears to be unprecedented, the researchers say. They think that changes in surface wind patterns may be partly responsible for driving heat away from the surface layers and into deeper waters.

How Argo floats work. Image Credit: National Oceanography Centre, UK.

Sampling the deeper reaches of the ocean is challenging. In 2000, an international ocean observation program called Argo was developed to help gather data on temperature and salinity throughout the depths of the ocean. Argo is named after the ship sailed by Jason during his search for a golden ram’s fleece in Greek mythology.