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海洋学子(145)| 20,000 Leagues Under the Indian Ocean——2015级硕士生廖健林

   浏览数:87   日期:2017年12月01日

【编者按】廖健林,2015级海洋地质专业硕士研究生,海洋地质与地球化学研究所,师从孙晓明教授。该文章发表在《China Pictorial》,作者Shu Yun、廖健林。




20,000 Leagues Under the Indian Ocean

On the February 19, 2017, China’s ocean scientific survey ship, Xiangyanghong 10, lifted anchor at Port Louis in Mauritius and set off south across 37 degrees south latitude for a lengthy journey.

On March 8, the ship crossed paths with a strong typhoon throwing seawater eight meters high. Thick, white waves shot up from the dark blue surges, pulling the ship forward like a galloping horse. Cups and tableware fell to the ground and drawers opened and closed like an impromptu symphony.

The trip was only the third leg of the 43rd ocean expedition by Chinese scientists. The first country to sign a contrac granting rights to polymetallic sulfide exploration in the southwestern Indian Ocean, China dispatched the team to conduct primary exploration of the contract zone.

“Good Rush” in the Deep

Whether roaring waves or silky tranquility, the crew is constantly engulfed by boundless blue. What is hiding beneath the several thousands of meters of mysterious water?

A robotic arm and deep-sea grab bucket fitted with a camera drops deep into the water. After about an hour, it reaches 2,000 meters down. Nothing can be seen, not plants or fish. The monitor displays only black basalt and sandy sediment.

If you are patient, however, the world will surprise you. Occasionally, the camera finds red coral, white sponges and a few unknown creatures.

Due to the darkness, low temperatures and high pressure, life is severely restricted on the deep sea floor. “It’s hard to believe that anything could survive down there at 2 to 4 degrees centigrade,” opines Lv Shihui, assistant to the chief scientist overseeing the mission.

Compared to the colorful vistas scuba divers might see, veteran oceanic explorer Lu prefers solid rocky ribbons of taupe, red and yellow, which indicate the possibility of deposits for which they hunt: polymetallic sulfide-a mineral rich with metals such as copper, zinc, and silver and a potential resource that some countries have already explored.

The Chinese team consists of more than 60 members, who study the middle ridges of the southwestern Indian Ocean at 2,000 to 4,000 meters in depth.

In 2011, China Ocean Mineral Resources R&D Association (COMRA) signed a contract with the International Seabed Authority (ISA) giving it exclusive rights to explore polymetallic sulfide in 10,000 square kilometers of the international seabed for 15 years. As contracted, the Chinese party should complete primary exploration in 2017, and fulfill its obligation to return 50 percent of the contracted zone by 2019 and 75 percent by 2029, after which time the remaining 2,500 square kilometers of the seabed will remain its exclusive mining area.

All of this will be worthwhile if large deposits of polymetallic sulfide are located. After hours of efforts by the scientists, the bucket finally retrieves some “soft mud” from the sea floor.

The fine mud has a granular feel. The team looks at it under a microscope and notices that most of the granules are spherical shells of planktonic foraminifera, a species of plankton found throughout the ocean and its floors. After they die, their calcium carbonate shells gradually fall to the sea floor, creating heaps and becoming one of the major sediment in the sea.

As explained by Deng Xianming, chief sientist of the mission, the team uses appropriate devices to measure the chemical elements, especially metals like copper, iron, and zinc in the sediment to estimate the possibility of polymetallic sulfide deposits.



Life on the sea

Adventure creeps near as the surface of the sea melts from Cambridge blue to deep navy.

“I thought of myself as a sea lover,” writes crew member Chang Dingyue in her journal. “After days and nights on the real ocean, I realized that I just loved the beach.”

For many novices, the first challenge is seasickness. In some cases, it feels like a never-ending earthquake or roller coaster ride. Xiangyanghong 10, with a tonnage of 4,500, is still an insignificant speck on the vast sea.

Most people start to overcome it in 72 hours, but the entire process of acclimating to the rocking environment is a war of willpower. Everyone develops his or her own methods to overcome seasickness. Some play cards or chess, work out in the gym or purposely inflict pain to shift focus, and others choose to stand on the deck and enjoy the sea breeze as they see every up and down of the waves. This strategy is inspired by the belief that the driver never suffers from carsickness.

As conditions deteriorate, the worst is still yet to come. The daily toll of such an expedition is understandably high, so the crew works in shifts around the clock.

In the transitional season between summer and autumn, more frequent typhoons make exploration even more dangerous.

When the machine reaches between 2,000 and 3,000 meters deep, each attempt to raise or lower it is a fierce fight. Once, the device almost got permanently stuck in a precipitous cliff. The external protective layer of rigid titanium alloy was severely warped, leading to an equipment failure and lost signals. The operation was canceled, and the device was hauled up to be repaired on deck.

Along with the suffering, the sea also creates beautiful memories. As night falls, a brilliant blanket of stars shatters the darkness, creating a moment of happiness beyond description. Few feel loneliness thanks to the company of crewmates. Each time it stops, the ship is quickly surrounded by hovering birds. The crew feeds them, because they’re considered a symbol of peace.