Research team on the deep sea: Only a third of the living beings are known

A team of researchers has analyzed billions of DNA sequences from 15 deep-sea expeditions. A large part of life on the deep sea floor remains hidden: almost two thirds of the organisms are unknown.

Only a third of the organisms living in the deep sea are known. Almost two thirds, however, cannot be assigned to any previously known group. This was announced by the Senckenberg Research Institute in Frankfurt am Main. It is based on an analysis of two billion DNA sequences by an international team of researchers.

The researchers analyzed DNA sequences from deep-sea sediments from all major ocean basins, using almost 1,700 samples from 15 international deep-sea expeditions. At depths of up to 9585 meters, a large number of different organisms ensure that sinking organic and inorganic substances, mostly originating from plankton, are recycled or bound.

Basis for “healthy functioning of the food web”

Life on the deep sea floor is the basis for “the healthy functioning of the food webs in the oceans and the binding of atmospheric carbon,” explained Senkenberg scientist Angelika Brandt. “Both have a decisive influence on our global climate,” she added. The abundance and composition of the plankton DNA analyzed for the study in deep-sea sediments therefore confirms that the polar regions act as “hotspots” for carbon sequestration.

“It is important to understand that and then to be able to take appropriate protective measures,” explained Brandt. “Because the ecosystem of the deep sea is under enormous pressure caused by humans – climate change, deep-sea mining, oil and gas exploration, trawling and pollution threaten life in the depths of the sea.”