Deep Sea Floor Surprises
We have better maps of the moon than of the ocean floor. But a partly Swedish-led initiative has now collected data covering a quarter of the deep oceans.
‘There is still a lot undiscovered down there,’ says researcher Martin Jakobsson.
– There are surprises in the form of very large volcanic peaks sticking up. You can definitely find something similar to the Swedish mountain Kebnekaise massif.
Martin Jakobsson is responsible for the Arctic Ocean in an initiative called Nippon Foundation Gebco Seabed 2030, which aims to compile depth data, mainly from sonar, into a global map of the seabed.
Keeping track of the ocean depths is important not only for the energy and communication cables that are now in vogue, but also for predicting how tsunamis occur and move, and how coasts are affected by climate change.
Although humans have sailed the seas for millennia, we still have a very poor understanding of what is down there. It was only with the breakthrough of sonar technology from the First World War onwards that ships had a convenient way to read the underwater terrain.
Enormous fjord
But Martin Jakobsson says that the blind spots are still many and large. Really big.
– North of Greenland and the Canadian archipelago, for example, there are areas like the whole of Sweden that are basically mapped with a few dots here and there. It’s incredibly poor in some places, he says on the phone from Svalbard.
– For example, we were the first ship to enter the Lincoln Sea and reach a fjord called Victoriafjorden last summer – there has never been a ship there at all. And the fjord is huge.
It can be seen as an illustration that a lot of work remains to be done. No one really knows how much. A lot of ships use sonar to read the environment underneath, so a lot of Seabed 2030’s work is getting operators, owners and governments around the world to share the data.
– Then we have developed a “gridding”. We call it gridding when you put together and make the model itself. We have developed a method that runs on supercomputers, runs through all these depth data points and creates a model of the seabed.
– They provide the data, we take care of it, says Jakobsson.
Rejects dissolution
Although the project is far from complete, demand is already high. One example Jakobsson mentions is the communication and energy cables that are now being laid criss-cross under the oceans, and which have become highly relevant with the issue of suspected sabotage in the Baltic Sea and elsewhere.
– When we look at the distribution of planned new undersea cables, it is our data that is used in the base in this first phase.
However, Seabed 2030 deliberately refrains from higher resolution in the data.
– We don’t go into more detail than one depth value every hundred metres.
– It also has to do with the fact that many nations see this as military strategic data, so we have sort of stopped where it starts to get so detailed, says Jakobsson.
Would have made a difference
The implications of this can be illustrated by the much-publicised search for MH370, the airliner that disappeared over Asia in 2014 with 239 people on board and is believed to have crashed somewhere in the Indian Ocean. With Seabed 2030’s resolution, the aircraft would not be visible on the seabed – but Jakobsson emphasises that it would still have made a huge difference if these areas had been mapped at the time.
– It was very poorly mapped. There were very few points, tens of miles apart and so on. And then you can’t plan detailed surveys with a submersible. You can’t really see in the terrain what it looks like.
So there may be whole mountains, as big as Sweden’s largest, down there that nobody knows about. Which is important in many contexts.
When it comes to other things, such as how a tsunami travels across the seabed, you need this intermediate resolution so that you can see that the topography will steer the tsunami here or there. We produce data to that level.
Lagging behind
The result can be seen if you zoom out into the oceans on electronic maps most of us use.
I’ve seen that they haven’t updated the latest up in the Arctic. I’m going to send them an e-mail telling them to be quicker with the updates – they have full access to our grid that they use,’ he laughs.
– Yes, absolutely, all those you see are basically our product,’ says Jakobsson – who, however, somewhat jokingly complains that the IT giants are not quite keeping up.
– Google Maps is actually a bit behind.
Although we usually talk about oceans, there is really only one – a global mass of salt water that sits together and covers over two-thirds of our planet.
This global ocean can be relatively shallow in some corners, such as our own Baltic Sea. But overall it is very deep – averaging over 3 500 metres. This means it holds a huge amount of water: over 97% of the world’s water.
The largest part is the Pacific Ocean, which alone is larger than the entire land surface of the Earth. It also has the greatest depths, in the Mariana Trench between Papua New Guinea and Japan. This arcing underwater gorge, over 2 500 kilometres long, contains many places deeper than Mount Everest is high.
Sonar (from the abbreviation ‘sonic navigation and ranging’) is a technique for emitting sound and using echoes to map the environment.
The first users can be said to be certain animal species, such as dolphins and bats, which have been navigating via echoes for millions of years. For humans, Leonardo da Vinci was an early adopter of the technology, in the late 15th century. In modern form, sonar equipment was developed to deal with the threat of submarines in the First World War.
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