A Voyage to our Mysterious Sea: The Atacama Trench

Saturday, February 10, 2018

A great door to observing and directly studying the enigmatic underwater world off the Chilean coast—our last frontier—has opened. A door that will make it possible for the curious minds of new generations to research and learn about the ocean, and which will be a source of inspiration for artists, philosophers and writers. A door that also represents a wonderful opportunity for technology development and innovation based on marine sciences. In order to face this big challenge, a major national effort—both public and private—will be required, as well as a new institutional framework such as the creation of the urgent and much-needed Ministry of Science. Therefore, we are calling on everybody to join us in this odyssey to our mysterious sea, so that Audacia will have successors and our efforts will not become an isolated event or a lost opportunity.

Hades is the dark underworld into which the mythical Greek hero Odysseus—Ulysses for the Romans—descended, managing to come back without any harm, which only a handful of mortals and demigods had accomplished. The hadal zone is the oceanographer’s Hades, the ocean’s deepest zone, with depths varying between 6,000 and around 11,000 meters, the deepest point in the sea. Due to extremely high pressures, it is exceedingly difficult to access and study this zone, which is why it has remained almost completely unexplored although it has kindled the interest of the scientific community. The hadal zone comprehends more than twenty oceanic trenches, most of which are part of the Ring of Fire, where the earth swallows part of its crust as a result of a plate moving underneath another—thus originating mountain chains such as the Andes—and a high seismic and volcanic activity.

Just as in Homer’s epic, only three people have visited this obscure world and survived to tell the tale, a figure that stands in contrast to the twelve astronauts who have walked on the moon. In 1960, aquanauts Jacques Piccard and John Walsh descended in the bathyscaphe Trieste into the Challenger Deep, located in the Mariana Trench, in the North East Pacific off the island of Guam, reaching a depth of more than 10,900 meters. This is deepest point on the surface of the planet and even surpasses the magnitude of the elevation of Mount Everest (8,848 meters) by more than 2,000 meters. Nevertheless, Piccard and Walsh were only able to remain on the bottom of the sea for about twenty minutes before they had to start returning to the surface because a Plexiglas viewing port had cracked. It took over fifty years for filmmaker James Cameron—the same one who directed famous films such as Titanic and Avatar—to be the next one to descend into the Challenger Deep, in 2012, becoming the third person who has observed an oceanic trench and the first one who has done it by himself. The extremely high pressures also caused him trouble and, for example, interfered with the proper working of his submarine’s robotic arm. Since manned missions are expensive, dangerous and not very productive from a scientific standpoint, explorations and research into hadal zones have been carried out through autonomous unmanned submergible vehicles in recent years, and the situation will probably not change in the near future.

Located off the Chilean coast, the Atacama Trench is the world’s longest and tenth deepest oceanic trench, with a maximum depth of 8,065 meters according to sonar tests. In 1997, an international expedition on board the Chilean Navy’s research vessel Vidal Gormaz studied the fauna and the sediments on the bottom of this trench. This pioneering research project was carried out through an agreement between the University of Genoa and the University of Valparaíso, and several Chilean researchers took part in it. Both the money and the main instruments required for the expedition were contributed from Italy, in particular traps for collecting organisms, the sediment corer and 11 meters of rope that were used to bring this instrumentation into the seabed. After working hard and even having to operate the traps and the sediment corer manually, the team managed to collect samples from a point in the trench at a depth of 7,763 meters.

After more than 20 years, the Atacamex expedition tried to access this dark, cold, extreme point of Chile once more, on board the modern Chilean research vessel Cabo de Hornos—which replaced Vidal Gormaz—and supported by the National Commission for Scientific and Technological Research (CONICYT), the Millennium Science Initiative and private individuals. This expedition has just ended and was organized and carried out by Chilean researchers working at several institutions who are members of the Millennium Institute of Oceanography, a center of excellence focusing on open- and deep-sea research based in the University of Concepción. In this expedition we used a modern deep-sea vehicle built and designed by engineer Kevin Hardy, who worked with Cameron during his expedition into the Mariana Trench and now took part in Atacamex. Landers, which derive their name from their similarity to the spacecrafts that have landed on the moon, are thrown into the sea without being tied to the vessel, descend into the seabed by gravity and return to the surface by positive buoyancy when they are ordered to release weight through an acoustic signal sent from the vessel or an internal command previously scheduled in the timer. Our lander, named Audacia (Audacity in Spanish), was thrown into the sea three times and reached the bottom of the trench up to a depth of 8,081 meters, collecting organisms and water samples, and taking pictures. There were problems with the acoustic communication system, the batteries and the camera that had to be dealt with on the run: The extremely high pressures were causing trouble again!

A great door to observing and directly studying the enigmatic underwater world off the Chilean coast—our last frontier—has opened. A door that will make it possible for the curious minds of new generations to research and learn about the ocean, and which will be a source of inspiration for artists, philosophers and writers. A door that also represents a wonderful opportunity for technology development and innovation based on marine sciences. In order to face this big challenge, a major national effort—both public and private—will be required, as well as a new institutional framework such as the creation of the urgent and much-needed Ministry of Science. Therefore, we are calling on everybody to join us in this odyssey to our mysterious sea, so that Audacia will have successors and our efforts will not become an isolated event or a lost opportunity.

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