New ‘mud technique’ reveals Arctic sea ice record

November 14th, 2007 - 2:21 am ICT by admin  
The researchers say the mud from the seabed in the fabled Northwest Passage could cast valuable historical light on why some famous expeditions to the region were successful while others were doomed to failure.

The research could also guide computer forecasts of future climate, they say.

They say the thin layers of sediment, which build up on the ocean floor, act a storehouse of information about the patterns of past conditions, something seen also in tree-rings and coral growth.

Firstly, the sediments are cut into thin slices, each representing about 15 years’ accumulation.

The presence in the mud of a particular kind of lipid - an oil - released by microscopic forms of algae indicates how much ice was present each Arctic spring.

According to Dr Guillaume Masse from the University of Plymouth, the presence of more lipid indicates the abundance of algae during any given period, which consequently means the presence of more sea-ice during that said period.

Prof. Simon Belt is of the opinion that the technique should allow a sea-ice record to be generated stretching back hundreds of years - certainly far further back than the 20-30 years of satellite data so far gathered.

“The satellites show the sea ice retreat in summertime from 1979, but before then there’s virtually no record at all. We believe this lipid acts as a fingerprint for past sea ice,” said Prof. Belt.

“The indications are that the natural cycles of change over the past have been very rapid - but the likelihood is that we’re now seeing the effects of manmade warming on top of that,” the BBC quoted him, as saying.

The team says their research into sediments off the coast of Iceland has provided a very accurate match with recorded historical accounts of the sea ice there over the past millennium.

Now they plan to provide a similar insight into the advance and retreat of the ice in the Canadian Arctic.

“Our method for historical sea ice determination not only shows remarkable agreement with known historical events, but it has allowed us to provide some information for periods where records are scarce or absent,” said Dr Masse.

“Significantly, periods of sea ice cover frequently coincide with dramatic changes to human populations due to famines and illnesses,” he said. (ANI)

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