The Mariana Trench is the deepest place in the ocean. The trench lies south of Japan and north of Australia.
What is the maximum depth in the Mariana Trench?
The answer to this question is not so simple:making measurements is very problematic due to the difficulties in delivering measuring instruments to such a depth. But then you still need to get accurate readings from them.
- In 1875, as part of the Challenger expedition, measurements at the southern edge of the trench showed a depth of 8,184 m.
- In 1899, explorers recorded a depth of 9,660 m southeast of Guam.
- In 1957, the Soviet research vessel Vityaz set a new world record for depth in the Challenger Deep (10,990 m). This value later exceeded 11 km (11,034 m).
Sound from deep
Employees of the Oregon StateUniversity in the US recorded and analyzed unusual noise from the Mariana Trench. It had an extremely wide frequency range. The recording shows an unusual booming sound with deep “groans” at low frequencies and a high-frequency “metallic tint in the finale,” the scientists write. Researchers at OSU's Hatfield Marine Science Center have named this sound Western Pacific Biotwang (WPB). twang.
It was first recorded in October and November 2014years during 38 dives. Then scientists noticed 326 sounds, and another 110 - between March and April 2015. The researchers recorded the hum using passive acoustic ocean gliders. These autonomous vessels can travel for months at extreme depths of 1,000 m. The sound lasts from 2.5 to 3.5 seconds. Frequency range from 38 Hz to 8000 Hz.
In further research, scientistsThey suggested that there was nothing mystical in these sounds. It turned out that the sound is very similar to the call of dwarf whales - minke whales. They live on the Great Barrier Reef off the northeast coast of Australia. But there's a problem with this theory. For example, baleen whale calls are often associated with mating and are heard primarily in winter, whereas WPB has been recorded throughout the year.
Mysterious life forms
Earlier during the expedition, scientists from the CaliforniaUniversity of San Diego and National Geographic engineers discovered a population of single-celled xenophyophores at a record depth of 7,500 m. organisms.
In addition, they are very durable:they are not afraid of high concentrations of lead, uranium and mercury. They can also live in the dark at low temperatures and high pressure. They are very difficult to study because these mysterious animals live exclusively in deep-sea environments.
Radiation at depth
Scientists recently discovered that radioactiveCarbon released into the atmosphere from nuclear bomb tests in the 20th century has reached the deepest parts of the ocean. Scientists at the Chinese Academy of Sciences in Guangzhou have found the first evidence of radioactive carbon from testing a nuclear bomb in the muscle tissues of crustaceans that inhabit the Mariana Trench.
Ocean. Photo: Wikimedia Commons
“Although it takes hundreds of years for ocean circulation to get carbon-14-laden water into the deepest trench, the food chain does so much faster,” the scientists explain.
Carbon-14 is radioactive carbon thatIt is formed naturally by the interaction of cosmic rays with nitrogen in the atmosphere. Scientists find it in almost all living organisms and use it to date archaeological and geological specimens.
Thermonuclear weapons tests carried out inThe 1950s and 1960s doubled the amount of carbon-14 in the atmosphere when neutrons from bombs reacted with nitrogen in the air. Levels of such carbon peaked in the mid-1960s and then dropped when atmospheric nuclear testing ceased. After the tests, carbon quickly fell out of the atmosphere and mixed with the surface of the ocean. Since then, scientists have observed elevated levels in marine organisms shortly after the bomb tests began.
To reveal all the secrets of the Mariana Trench,it will take many more years and research. For example, scientists discovered the mysterious sounds back in 2016, but continue to debate their nature. To solve this mystery, more data is needed, including genetic, acoustic and visual identification.
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Twang - onomatopoeia, originallyused to describe the sound of a bowstring vibrating after an arrow is fired. In a broader sense, twang is the vibration produced when the string of a musical instrument is plucked, and similar sounds.