On March 10, the Chinese Academy of Sciences‘ research vessel “Discovery One”, loaded with a submersible “Deep Sea Warrior”, set sail from the port of Nanshan, Sanya. Prof. Ma Hui and Associate Researcher Liao Ran from Tsinghua SIGS boarded the vessel for the 20-day TS16 voyage.
In this series, a rare glimpse into the research diaries of two experts help unravel some of the mysteries of the underwater world, as well as the daily lives of scientists on an expedition in the South China Sea.
The goal of the expedition is to investigate the ecology, geology and environmental pollution of seamounts and canyons in the South China Sea. Supported by Key R&D projects of the Ministry of Science and Technology and National Natural Science Foundation, Profs Ma Hui and Liao Ran have been using a self-developed Mueller microscope and a polarization camera to examine polarization characteristics of tiny organisms on the sea floor, suspended particles, and monitor stress in the optical windows.
With over 60 members onboard, the expedition is organized by the Institute of Deep-sea Science and Engineering (IDSSE), Chinese Academy of Sciences, and the research team includes members from Tsinghua SIGS, Zhejiang University, Sun Yat-sen University, the MNR Second Institute of Oceanography and IDSSE.
Overcoming Seasickness
After setting sail, the team encountered its first challenge — seasickness.
"Meals on board are delicious. We get four dishes and a soup — the soup is my favorite, but I only started enjoying it because of seasickness,” Liao wrote in his diary. Seasickness affects many on board, and some have to lie down to let the awful sensation pass. Prepared for 20 days on the research vessel, both Ma and Liao brought different types of medication to fight off the nausea.
“I take tablets, but Prof. Ma is able to manage without taking any medicine,” said Liao.
Apart from scientists conducting research on board, a crew of submariners are responsible for the operation, maintenance, deployment and retrieval of the "Deep Sea Warrior" submersible. Each time, one to two people would dive to conduct investigations such as sampling of plastic pollution and seamount ecosystems. A frogman is responsible for untangling or tying the hoisting and towing cable when the vehicle enters the water or rises to the surface.
"The frogman must be light and fast,” said Liao. Although the submarine crew only consists of 9 members, each person is capable and professional in various aspects of machinery, electronics, software, system integration and operation.
Treasures of the Ocean
A dedicated team helps maintain and operate the "Deep Sea Warrior" submersible, but researchers are responsible for deciding what task the vehicle performs when it dives into the sea.
The night before each dive, scientists fill the sampling basket mounted on the submersible's front end with various scientific equipment and samplers. Often placed in the basket are one or two “bio-boxes”, tanks which keep and maintain the temperature of biological samples at the sampling site until it arrives at the research vessel. Before a dive, researchers check to see if a small gap is left at the side of the bio-box.
“This is an essential step. If the bio box is tightly shut and air remains inside, it may explode under high pressure when diving. The consequences are unthinkable -- leaving a small gap allows seawater to enter the box, balancing the internal and external pressure,” said Prof. Liao.
Once the submersible returns and the sample basket is brought back, scientists immediately divide the collected treasures. There was one time when a sea cucumber was brought back.
“Dr. Li from the team immediately ran to the laboratory with it and missed dinner. We learnt later that they had to dissect the sea cucumber and give it to other researchers that needed it. He only kept the intestinal bacterial samples," said Prof. Liao. Even at sea, it is common for researchers to be completely absorbed in their work for the sake of scientific discovery.
Diving with the “Deep Sea Warrior”
On this expedition, some researchers also had a chance to dive with the "Deep Sea Warrior", a journey that lasts about 9 hours.
At 13:30 on March 17, Prof. Ma Hui of Tsinghua SIGS entered the submersible. He was very inspired after his return, and shared many unexpected findings.
"I did not expect the underwater world to be so lively, and that operating the submersible was so complicated. I also did not expect the functions of the polarization camera to be so limited, and that tasks designed on land were difficult to be carried out on the sea floor,” said Prof. Ma. He believed that many technologies in optics and big data could be used, and that improvements had to be made to the polarization camera.
Upon his return, Ma was greeted with a “water ceremony”. This was a celebration for those returning smoothly from their first dive, and is a unique way for the team to express affirmation of their courage.
Tips from the Experienced
On March 22, Associate Researcher Liao Ran completed his first deep-sea dive. To ensure the best conditions for his 9-hour journey, he asked for advice from experienced seniors on board, and summarized them into three tips: Avoid spicy or heavy foods the day before; Have enough rest at night; Consume a light breakfast and avoid drinking too much water before the dive.
Prof. Liao made careful preparations, but still could not sleep the night before due to the excitement. At 8:00 next morning, Prof. Liao entered the sea with the "Deep Sea Warrior".
"The dive process was simple and quiet. Lights of our submersible were turned off, as it helps avoid collisions with large animals. Our surroundings slowly turned dark and cold, but we could see tiny glowing sea creatures and jellyfish outside. These creatures swept past our window, and some moved a distance with the submersible," said Prof. Liao, as he recounts the memorable and strange experience.
At a depth of 4,300 meters, the submarine reached the seafloor of point A. The movement created a cloud of dust, and Liao quickly raised his camera. When the surroundings cleared up, the team began to carry out the planned work of the day.
Moving to point B at 4,000 meters, the team closely observed the seafloor, which is mostly white matter (calcium carbonate mud) covered with a layer of brown material. Mobile phones do not work well inside the cabin, but there are high-definition cameras on the front, side, rear, and bottom of the submersible. Particulate matter was rich, and the concentration was high. Tiny sea creatures swimming around looked like gingko leaves dancing in the water.
After an intense day of work, the submersible resurfaced promptly at 16:45, and Liao was given the water ceremony to celebrate the end of his first dive.
That day, Prof. Liao collected a variety of samples for further examination: 3 sea cucumbers, 6 push cores, 2 bottles of seawater, and a batch of data. Although the journey was 9 hours long, Liao still found that time was very limited. Together with two submariners in the cabin, he had to focus on operating research instrument, but was also drawn to the beautiful underwater scenery at the same time.
After his adventure, Prof. Liao shared this piece of advice from the team leader in his research diary: "Many people may dive at the same location, but each will have different takeaways depending on one’s background. An archeologist may find porcelain from the Song and Yuan Dynasties; others may dive and discover something else. It is important to conduct research with curiosity, dive with a target in mind, and be sensitive to what you see. That’s what makes a good dive.”
Among many challenges and new experiences, this advice is yet another valuable tip that he has gained during this 20-day scientific expedition on “Discovery One”.
At 15:00 on April 2, the “Discovery One” research vessel arrived at the port of Nanshan, Sanya.
“This is an end and a beginning. This memorable voyage and experience will be reflected upon and treasured,” said Prof. Liao. One of the most difficult things is saying farewell to the group of researchers whom they have worked with for twenty days, but Liao believes that they will meet again in the future. At 15:30 on April 3, Professors Ma Hui and Liao Ran returned safely to Shenzhen, drawing an end to their South China Sea Expedition.
Source: Tsinghua Shenzhen International Graduate School
