Martin Jakobsson – Scientists

nophoto.jpgMartin Jakobsson
Associate Professor
Department of Geology and Geochemistry
Stockholm University, Sweden

What questions related to the Arctic are you trying to answer? How did the Arctic Ocean evolve to what it is today? When and how did we get the perennial sea ice cover? Has the sea ice cover disappeared during any of the previous interglacial periods (periods in between ice ages, like we live in today)? How large were the glaciers during past ice ages? How did the present Arctic Ocean circulation system evolved?

How will answers to those questions help us understand more about our world? By learning more about the history of the climate system we might get insights into where we are going with the present global warming trend. For example, the perennial sea ice cover reflects a large part of the incoming solar radiation (albedo effect).
Without the white sea ice cover we know that more heat will be absorbed from the sun [into the dark-colored ocean water]. If the ice cover disappears, how fast can it be re-established? To learn more about this we need to combine studies of the past climate system with numerical modeling experiments.

How are you trying to find the answers to those questions? Through studies of marine sediment records and numerical modeling. The sediment accumulated on the seafloor works like a large library where the layers are like the books containing information of the past conditions in the ocean. Studies of microfossils, chemical changes etc (the pages in the books) will tell us about the past conditions.

Recount for us one of your field days in the Arctic.

This is an excerpt from my diary from the last expedition. Click here

August 27, 2007

At about four a clock in the morning the seismic streamer (an instrument used for taking seismic measurements of the sea floor) got stuck in the ice that closed up in the wake behind the [icebreaker ship] Oden. We could see the streamer pinched and entangled around extremely large blocks of ice.

It was decided to attach a rope around the streamer and try to pull it loose using the helicopter. The helicopter pulled on the streamer for nearly an hour while [another icebreaker ship]drove very close in attempts to break nearby leads (open sections of water between the ice floes) to release the ice pressure. Despite some very skillful maneuvers by the helicopter pilot and the Russian ice breaker captain and his mates, the streamer did not want to come loose.

The rescue maneuver was finally called off. But our Russian companions did not want to give in and offered to try pulling out the streamer with the ship. This required extreme skills as 75000 horsepower easily could snap a streamer or at least stretch it out like a rubber band. But the rescue succeeded and parts of the streamer could be saved….

[Because we could no longer take seismic measurements] due to the loss of the streamer, we decided to take a core. An accident seldom comes alone. The old coring winch (the oldest piece of equipment on board the otherwise modernly equipped Oden) got a sudden hydraulic oil leak and half the oil leaked out on deck. After this was repaired, the winch broke down completely due to an electrical short in one of the magnetic valves that steers the hydraulics. It looked really bad, what could we do without a winch?

August 28, 2007

Chief Engineer Dan Skantze had narrowed down the problem with the coring winch and come up with a solution. He rebuilt a new magnetic valve and installed it. When the winch started again and worked, we all were mighty impressed and pleased! It meant that we could go for more cores.

What do you find most rewarding about being a scientist? To understand how things are working and to see that your work is being used.


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