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"It's amazing, beautiful and scary to work here."
This is how researcher Liz Thomas describes her feeling of working on the inhospitable island of Bouvet, a small volcanic rock in the South Atlantic, a territory located in the middle of the ocean, south of Antarctica, with high cliffs covered with ice. from miles of civilization.
The time that he does not help. Weather conditions can deteriorate unpredictably. In a moment, the sky is clear, but in the other, you are surrounded by clouds and mists. It is not surprising that browsers regard Bouvet as the most remote island in the world and writers and sci-fi filmmakers mention it or describe it in books and scripts.
But this isolated island is attracting more and more attention from scientists on how it can tell us about the Antarctic climate in the past.
Bouvet is in a privileged position to provide valuable information at the heart of a western wind belt that profoundly affects climate change.
They contribute, for example, to the rise in sea level by rising to the surface of the warm waters of the ocean floor, which then melts glaciers.
"What interests us is whether this increase in wind strength is the result of natural variation. They increase in speed then decrease or is unusual, an effect of the human impact on the climate? he asked.
Thomas and his fellow researchers recently flew to the island by helicopter – the only way to get there – to collect samples of an ice carrot The compacted snowflakes are like a film that records the past
The stronger and faster the wind blows, the more snow it has to incorporate into the core, and there are other markers. a small seaweed – which live on the surface of the ocean are transported from water to snow.
The more wind, the more the presence of these organisms is concentrated in the snowy layers of Bouvet Island.
Ice on the sea
And the team of Thomas does not just want to record the wind.
The group wants to know the magnitude of the annual movement of Antarctic ice.In a few years, chains even go as far as pushing ice to Bouvet.
Amy King, study As a Ph.D. student, examine the core of a specific organic compound that has arrived on the island and can serve as a basis for understanding sea ice conditions in the past.
This organic compound is a chemical badociated with an alga that blooms in the sea when the volume of ice decreases (loss of photographic pigments), thus releasing colors.
"The more ice there is on the water in winter, the greater its volume." When the ice melts in the spring, the phytoplankton has a larger growth area, "says King.
" The more phytoplankton there are, the more metasulfonic compounds and acids will be found in the ice core, so if we see compounds of these origins in the ice, it means that there has been a greater volume of ice on the waters this year (from the Antarctic) ..
The Thomas team's findings were presented in the American Geophysical Uninon the largest annual gathering of scientists studying Earth and space.
The 14-meter piece of ice taken at Bouvet by the researchers only provides data on ice conditions in 2001 according to water and wind. But scientists are convinced that if the group can return to the island, it will find areas of ice and snow with older records.
"We only stayed in Bouvet for a few hours because we could only work in good weather and we had to leave the island quickly when the clouds started to fall," says Thomas.
"But I really think that it's possible to come back there and collect a deeper ice core that will bring information hundreds of years, if not thousands, on climate variations. "
Thomas's research was conducted in collaboration with the universities of Maine, the United States, and Copenhagen, Denmark. It was conducted as part of the Antarctic expedition led by the Swiss Polar Research Institute.
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