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Finding 15 000 year old climate information 3000 meters below surface

The core sampler surfaces from 3000 meters depth with the see-trough plastic tubes about half filled with bottom samples. Stig Monsen and Øyvind Paasche are pleased with the samples which are sealed and stored. Content analysis will tell us a lot about climate variability 15 000 years ago.


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Øyvind Paasche og Stig Monsen removes four tubes with bottom samples. (Photo: Kjartan Mæstad)

- These samples are absolutely spot on. This could not have been better, Øyvind says.
The project he is working on is called PALEODRAKE. The name is a combination of Paleo which is Greek for old and Drake from the Drake Passage. For thousands of years the Drake Passage has been an important area where ocean currents flow from the Antarctic area to the Pacific Ocean as well as the Atlantic Ocean. This is the largest ocean current in the world and it is roughly 10 times the size of the Gulf Stream.
 

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One of the test tubes from the multicorer. (Photo: Kjartan Mæstad)

The researchers at Bjerknes Centre for Climate Research at the University of Bergen, Norway, hope that knowledge about prehistoric climate variability in this area can increase our understanding of changes in today’s climate.

The researchers have sampled the ocean floor at three different sites between the southern tip of the South American continent and South Georgia.
- This is a vast area where we know little about the natural climate variation. Our main aim is to track and reconstruct the natural climate variability in the ocean currents, which also influence weather fronts and wind systems, Paasche explains.

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The multicorer is lifted into the ships hangar. (Photo: Kjartan Mæstad)

Up in the instrument room at G.O Sars fifth deck Dag Inge Blindheim watches closely the TOPAS echo sounder display. This echo sounder not only gives a picture of the ocean floor some 3000 meter below but can also give information about its content. He uses this information to choose where to drop the core samplers.
- I’m looking for a relatively flat area with thick layers of sediments, he says.

Down in the ships hangar other cruise participants from Bjerknes apply both a single long core sampler and a multi sampler which takes four core samples at a time. The former is sent deep into the ground by heavy weights. The latter is used to get uninterrupted samples from the top layers which the monocore sampler tends to disturb. Both samplers are lifted out of the hangar and lowered 3000 meters down.

We are approaching South Georgia where core samples will be taken at 250 meters in the Cumberlain Bay. Three of five researchers from Bjerknes will then leave the ship to continue taking core samples on the island. The other two will continue with G.O. Sars all the way to Cape Town.

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More or less dissolved organismes from a water sample from one of the tubes. (Foto: Lars Naustvoll)
 

 

 

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