Exploring the biology of the deep sea

Before metals for flat screens and smartphones can be extracted from the sea floor, researchers like Thomas Dahlgren from Uni Research Miljø, SAM-Marin, have to catalogue the animal life there. 

By Andreas R. Graven

Here are Thomas Dahlgren and his fellow researchers with one of the tools, a kind of claw, used in their environmental studies of life 4,000 metres down in the Pacific Ocean. (Photo from the researchers’ blog)

Now Dahlgren and an international research team are studying the bottom of the Pacific Ocean 

Mineral reserves deep down beneath the sea are resources that mining companies would like to extract. Not surprisingly, as the value of these reserves has been estimated at billions of kroner.

But before anything can be extracted from the deep, researchers have to step in to carry out environmental studies: that means mapping biodiversity and ecosystems several thousand metres down.

With a scraper dragged across the seabed, and a kind of shovel to dig up pieces, Dahlgren and his colleagues are gathering valuable information on the marine fauna and discovering new species. Altogether they have 11 different collection tools.

Known metal reserves, unknown species

Thomas Dahlgren is looking for species and life forms in samples from a depth of around 4,000 metres. (Photo from Helena Wiklund’s Twitter account @helena_wiklund)

The researchers have spent more than six months planning the second instalment of the ‘Abyssline’ expedition in the Pacific Ocean.

Dahlgren and colleagues from six other research institutions are studying the fauna where mining companies hope to extract metals such as cobalt, nickel and copper.

Find out more in the researchers’ blog here. 

“It’s basically all types of metals used in modern electronics like computers, smartphones and flat screens – including rare metals.

Areas with metal reserves have been known for many years, but knowledge of the fauna has been quite limited,” says Dahlgren. 

Right now, the studies are looking at the fauna around 4,100 metres down in the central Pacific, in the waters off the coast of Mexico. 

See the ship’s position here.  

The organisms in the deep-sea fauna range from bacteria and polychaetes to corals, fish and various types of echinoderms, such as starfish.

Quite similar to studies in the North Sea
“Companies that have prospecting contracts in these areas have to commission baseline studies before they can take the next steps. This is where we researchers come in; by looking at the conditions with the current environmental impact, we can see whether or not diversity is threatened,” says Dahlgren. 

“These environmental studies are quite similar to those that SAM-Marin carries out for oil and gas companies in the North Sea. The main difference is that, in the Pacific, we don’t have the map giving us the same overview of the fauna. Filling these gaps in our knowledge is one of the main aims of the baseline study,” he goes on.

The SAM-Marin laboratory at Uni Research Miljø, which has been carrying out marine environment studies since the 1970s, also investigates the environmental impact in lakes and waterways for both public and private-sector clients.

Important functions in the ecosystem
The 42-day Pacific voyage on the ship Thomas G. Thompson set out from San Diego on 12 February and is due to return on 25 March.

“With a few exceptions for some larger fish, the animals we find here on the sea bottom are mostly no more than a few centimetres long. But they are still important,” says Dahlgren.

Altogether, the researchers are using 11 different types of tool, which are sent down several thousand metres to carry out environmental studies on the ‘Abyss line’ expedition in the Pacific Ocean. Here we see a plankton pump. (Photo from Thomas Dahlgren’s Twitter account @mucofloris)

It is just as vital to name the animals at the bottom of the Pacific as it is in the Sognefjord, he points out:

“The small deep sea organisms perform important functions in the ecosystem; they metabolise nutrients which are in turn eaten by fish and which float down to the bottom to become food there too.”

He explains that the seabed in the areas mapped so far appears to be quite flat.

“But there are some exceptions; we have discovered several underwater rock formations that are around 500 metres high. These do not appear on any map today,” he says.

From their studies on the voyage, the researchers can say something about the situation before human intervention (metal extraction) on the seabed.

Analysing the consequences for both species and whole ecosystems is another important field for Dahlgren and his fellow researchers at SAM-Marin.

Dahlgren hopes that, in the future, DNA analyses will supplement traditional taxonomy, to further increase the capacity and quality of environmental studies.
“We need as much knowledge as possible of the consequences of the way we humans are affecting the environment in the ocean,” says Dahlgren.

Feb. 24, 2015, 8:57 a.m.

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cp: 2018-12-17 00:16:28