Water mass in North Atlantic changing

U.S. researchers say they are seeing a reversal of water mass trends in the North Atlantic.

The American Geophysical Union said recent data showing an increase in the temperature of the upper levels of the ocean and a decrease in temperatures at intermediate depths is a reversal of a 20-year trend.

Data collected in 1959 and 1981 showed temperatures were decreasing in the upper levels and increasing at intermediate levels.

The report said the changes seen by the data “implies that complex mechanisms drive oceanic responses to global warming,” the AGU said Friday in a news release.

The researchers said temporal changes in wind fields may be influencing temperatures in the upper ocean layer, while the intermediate waters are controlled by changes in source waters from the Labrador and Mediterranean seas.