BREST Marine biologist Marjolaine Matabos shows a picture of a gray worm, a giant tubeworm. He thinks it’s the strangest creature on earth. The worm can grow up to three meters long.
Living at a depth of kilometers in the dark, cold and under the pressure of enormous water pressure, the tubular worm, as its name suggests, does not need photosynthesis or actually food, because it grows its food in its stomach.
It gets its energy from undersea hot springs.
Researchers from the French Institute of Marine Research, Ifremer, have spent November studying the worm’s homes, undersea hot springs.
They are found, among other things, in the mid-Atlantic ridge, in the middle of the ocean on the undersea mountain range between Europe and America. There, at a depth of more than three kilometers, the researchers descend by submarine.
Matabos, a marine biologist, was not on the expedition this time, but he has experience with them. In this story, Matabos tells what it looks like deep at the bottom of the ocean.
Even the surface of the Moon and Mars is better known
Why do you have to drill the seabed? There are many reasons for exploring the depths. First, the oceans cover two-thirds of the Earth’s surface, and their bottoms are not very well known. Even the surface forms of the Moon and Mars have been mapped better than them.
However, it is known that there are huge amounts of metals and minerals on the seabed. In some cases, instead of digging, they could be collected with some kind of sweeping device. But how and where should it be done, and how would it affect the sensitive ecosystems of the seas? The research tries to find answers to these questions.
In addition, there are animals and plants living in the sea that humanity can use. Like rainforests, new species are found in the seas all the time, and some of them contain useful substances in the manufacture of medicines, for example.
The clearest example of the direct benefit produced by marine research is the enzyme used in DNA testing and copying, which was found on the seabed and with which the tests became much faster than before.
The trip to the bottom takes a couple of hours
Matabos, a marine biologist, has been on numerous research trips. He has also descended on the Nautile submarine to a depth of more than three kilometers to study the strangest of the undersea sources, the so-called black smokers – and the ecosystems next to them.
– The view down there is incredible, because a large part of the seabed is almost dead, except for the surroundings of these springs.
Elsewhere it seems lifeless, as all the little life makes use of the biomass that falls from the surface, such as algae and dead fish.
At the springs, on the other hand, real bacchanals are going on – they are teeming with life.
The journey to the seabed takes a couple of hours. Matabos admits that he is always a little nervous at the beginning of a dive, but after that the excitement covers the lingering fear. He is also comforted by the knowledge that Nautile has already made more than 2,000 dives without problems.
Before conducting surveys and driving around the target area on the seabed, the submarine is allowed to sink down freely. During this time, there is only darkness outside the boat, and the only connection to the outside world is an acoustic signal, which is meant to let you know that everything is going well.
– When we reach the bottom and turn on the floodlights, it’s like we’re on another planet, Matabos describes.
Underwater mountain peaks and canyons
The research trip started in Brest, located in the northwestern corner of France, where Ifremer’s headquarters is located. The port city has been a traditional departure point for French expeditions since the 16th century.
Pourquoi pas? -research vessel sailed out of the harbor on October 12 with 30 researchers. The sea voyage lasting one and a half months will end at the beginning of next week, when the researchers will return to Brest.
The ship spent most of the time in the mid-Atlantic ridge, exploring the approximately 800 km long area between the continental plates. Undersea mountain peaks, six-kilometer-deep canyons and several black smokers are hidden there below the surface.
– At the site, researchers dive to a depth of more than three kilometers every day, says Matabos.
More than 30 dives were made on this trip. They are done on the Nautile submarine, which is one of the few vessels in the world that can reach a depth of kilometers.
The area has already been explored several times, but we learn more about it each time. The hot springs in the geologically active area between the continental plates are particularly exciting. In them, the water sinks into the tunnels at the bottom of the sea and rushes up from the other tunnels heated by the lava.
Light, dark or colorless water flows from the springs, depending on the minerals and other substances in the water.
Minerals and heat gather life around them. For example, deep-sea shrimp thrive so well near springs that there may be an area the size of more than 10,000 parking spaces.
The Riftia pachyptila tubeworms mentioned by Matabos, which grow up to three meters long, are also addicted to smokers. They live in symbiosis with peculiar bacteria. Worms take oxygen and sulfur compounds from the water with their gills, with which the bacteria produce food for the worm. The bacteria have red hemoglobin, so they appear red inside the almost transparent worms.
– They have no mouth or digestive tract. No food goes in, nothing comes out. It’s a bit like growing lettuce in our stomach and using it as our food, Matabonos describes.
Matabos expects that the researchers will bring back more information about these worms as well. They have been studied for years, but scientists still don’t know how exactly the symbiosis of worms and bacteria works. Even that is still a mystery, how the worms are able to reproduce in the difficult conditions of the seabed.
It was decided to do the research trip at the end of autumn, because black smokers and their habitats have not been studied at this time of the year.
Underwater observatories
Researching the seabed is hampered by the fact that deep dives are rarely done and the trips are rather quick blips.
However, it would be important for the research that observations are obtained regularly over a long period of time and from as many places as possible. In addition to images, the researchers need information on temperature, salinity and earthquakes on the seabed, among other things.
Observations are also made with underwater, automatic observatories, which started to be built at the beginning of the 21st century. The images and measurement data collected by them are transmitted via cables to land or they are stored on memory cards, which are typically retrieved every six months.
– Maintaining observatories in the deepest places and collecting data is still difficult, regrets Nadine Lanteri. He leads the work of the French in the international EMSO project.
EMSO (European Multidisciplinary Seafloor and water-column Observatory) is a large European marine research program. Its purpose is to launch automatic observatories to the depths, coordinate observations made with them and share information among researchers.
The installation of the deepest observatories is usually done with the help of remote-controlled diving robots. The development of robots has made operating undersea equipment more affordable and convenient.
Thanks to robots, work at the bottom of the oceans has also become more convenient for, for example, oil drillers and others who use underwater technology. The installation of gas pipes and communication cables is also easier.
Underwater observatories and Ifremer’s expeditions produce a huge amount of material. Researchers do not have time to go through all the images, so interesting things are also searched for with computers and artificial intelligence.
However, artificial intelligence has to be taught, so Ifremer has opened Merten secret police website. There, the public is expected to look at the pictures and tag fish, corals and other organisms in them.
Website texts are in French and English.