Thousands of white crabs grazing on an extensive mussel bed: Up to now such high biomasses in the deep sea were only known from hot vents. Now scientists from the MARUM at the University of Bremen have found such scenes at a cold vent off the coast of Pakistan.
Another first was achieved by the videos they took of the cold-vent fluids seeping from the sea floor. Furthermore, the scientists were astonished at the wide variety of seep types. The scientists returned from an expedition with the RV Meteor heavily laden with new data. The expedition investigated the continental margin south of Pakistan from 31 October to 27 November.
Widely accepted doctrine has suggested that life at hot vents, such as black smokers, is much more bountiful than on cold vents. But the images sent up by the deep diving vehicle, Quest, of the Marum_Research Center Ocean Margins in Bremen told a different story: Mussel beds of more than 30 meters in diameter literally crawling with white crabs. "This puts to rest the credo that cold vents generally are less lively than hot vents", says Gerhard Bohrmann, leader of the expedition. "The organisms seem to have a similar amount of chemical energy - in the form of methane or hydrogen sulfide - available to them as hot-vent organisms. This results in an equally high biomass."
More surprises were in store for the scientists, like the variety of seep types: "We had a close look at nine separate seeps, and every one was different. The oxygen level in the water, which varies strongly with depth in the research area, is especially influential on the seep communities", explains Gerhard Bohrmann.
The great differences in seep types are also a product of the geological subsurface. "On satellite images the Pakistani coast north of the area we investigated looks wrinkled. The wrinkles continue under water off the coast. This is because the whole area is being compressed; at a speed of four centimetres a year the Arabian plate is being pushed beneath the Eurasian plate. While diving underneath Pakistan the muddy sea-floor sediments on the Arabian plate are literally being squeezed dry. The water, containing a heavy load of methane, hydrogen sulfide, and a host of other compounds, bubbles out of the sea floor at the so-called cold vents. "Normally such muddy sediments are about two to four kilometres thick, here they reach an astonishing seven kilometers". A good reason to look for vents in this area. "Where there is a lot of sediment to be squeezed, more fluids can seep out ", reasons Gerhard Bohrmann.
For the first time, the scientists from Bremen were able to observe fluids without associated bubbles seeping from a cold vent directly: "This is due to the extremely high-resolution video images of MARUM's diving vehicle, Quest. This has very likely never been seen before", enthuses Gerhard Bohrmann. Up to now such seepages have been postulated from measurements, but never directly observed because of technical limitations in the image quality. Cold seeps were either found through gas bubbles escaping with the fluids or because of the associated organisms growing at the seep sites.
"Seepages at the sea floor are of great importance to us, because they link the crust of the Earth and the ocean", reflects Gerhard Bohrmann about the relevance of the research. "Underwater vents transport enormous amounts of material like methane, sulfides and others as well as heat into the ocean, and therefore into the atmosphere. However, our understanding of these processes and how they shape the Earth are still sketchy." After all, methane is 30 times stronger as a greenhouse gas than carbon dioxide. "Every expedition teaches us more about how these systems work. On this one, we made a big step towards a better understanding of cold seeps at the ocean floor", resumes Professor Bohrmann.Furhter Information / Images / Interviews:
Kirsten Achenbach | idw
Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Chemists at FAU successfully demonstrate imine hydrogenation with inexpensive main group metal
22.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology