50 Years of Atlantic Ocean Data Studied

A long-term British study of Atlantic Ocean temperature, pressure and salinity is helping scientists monitor how climate change will affect oceans.

In 2004, temperature, pressure, and salinity data were taken at various depths in the Atlantic between Africa and the Bahamas, representing the fifth such line of data collected from that section of the Atlantic Ocean. The other trans-Atlantic hydrographic data were reported in 1957, 1981, 1992 and 1998.

Stuart Cunningham and Steve Alderson of the National Oceanography Center, located in Southampton, England, analyzed the five sets of data to assess temperature and salinity changes occurring during the 50-year period.

They found waters shallower than about 5,840 feet have been warming and salinizing at least since 1981 and in 2004 were significantly warmer and saltier than at any time since 1957. At depths of 10,040 feet below the sea surface, water has been continuously cooling and freshening since 1957.

The researchers argue such changes are consistent with the expected reduced southward flux of deep water and with other observed fluctuation trends of temperature with depth.

The research appears in the journal Geophysical Research Letters.