[Science Report]:Reduction in Deep Sea Current


This is the VOA SpecialEnglish Science Report.

Scientists say there has been a reduction in the flow of a deepsea current during the past fifty years. The current of extremelycold water comes from the Arctic Ocean. It enters the Atlantic Oceanbetween Iceland and Greenland.

Bogi Hansen is a scientist for the Faroese Fisheries Laboratoryin the city of Torshavn in the Faroe Islands. He led a team ofresearchers from Norway, Scotland and the Faroe Islands. Theymeasured the current in an area of sea between the Faroe Islands andScotland. There is a large piece of earth about five-hundred metersbelow the surface there. The coldest, saltiest water does not flowover this ridge. The water is too heavy. It sinks to deeper levelsalong the side of the ridge.

However, there is a place on the ridge that drops to more thaneight-hundred meters below the surface. Cold, heavy, deep waterflows through the ridge and into the Atlantic Ocean. Then the waterdrops thousands of meters to the sea bottom.

The researchers began measuring the flow through the opening inthe ridge in Nineteen-Ninety-Five. They found the water flowdecreased by two to four percent each year. They used other methodsof measurement to estimate the decrease since Nineteen-Fifty. Theresearchers say there has been a twenty percent decrease in theamount of water in the past fifty years.

Mister Hansen also says there is an increase in the speed atwhich the area is losing its cold deep water. He says the flow hasdecreased faster in the last five years than it did over theforty-five years before.

The current is part of a flow of water that travels thousands ofkilometers. Scientists say there is much they still do notunderstand about this flow of water. They say it can change greatlyin different areas over different periods of time. Mister Hansen'sstudy gathered measurements over a longer period of time than anyother study of the flow through the ridge. However, he says themeasurements must continue before scientists can learn what iscausing the decreased flow through the ridge. He says there is notenough information to decide whether the change is linked to warmingof the atmosphere caused by human activity.

This VOA Special English Science Report was written by CatyWeaver.

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