Lecturers: professor in biogeochemistry Bo Barker Jørgensen, Institute for Bioscience, Aarhus Universitet | professor in biogeochemistry Ronnie N. Glud, Biological Institute, Syddansk Universitet og Tokyo University of Marine Science and Technology.
The deep sea covers more than half of the Earth’s land and most of it is unexplored. On the one hand, it is very difficult to take measurements and collect material at the deepest depths of the sea, and on the other hand, it was previously mistakenly believed that the processes in the deep sea are not important for the conditions of life on Earth.
The deepest parts of the oceans, from 6 to 11 kilometers of sea depth, are called ‘the hate zone’ – after the death of Hades. The zone includes 27 huge graves that extend thousands of miles along the continents’ geologically unstable edges – where seabed and continental plates collide.
The latest research surprisingly shows that these graves are “oases” for life in the deep sea. The turnover of organic matter is very high and you always find unknown organisms adapted to the extreme pressure in the graves. Using advanced robots with scientific equipment capable of operating under the extreme pressure, scientists are now discovering the secrets of the deep sea.
No animals live under the seabed in the deep sea – it is the world of microorganisms. They live on dead algae and animals from the water column whose organic remains are buried deep in the seabed. The organic matter never escapes, but after millions of years it is extremely slow to react. Life here takes place in slow motion where the bacteria have generation times up to thousands of years. Although only a small fraction of the buried organic material remains in the end, this residue is a prerequisite for oxygen in the atmosphere to allow us and other animals to breathe.
On expeditions with long-lived vessels that can drill into the seabed, the researchers study the life of the seabed at great depths.
A few years ago, the first scientific drilling expedition was carried out in Danish waters. The results told about the Baltic Sea’s climate development over the last 15,000 years and about the rich bacterial communities that have lived on the seabed since the ice age.
03 Nov 18:00