China and Chile wrap up Atacama Trench mission as US pressure mounts

Chinese and Chilean scientists have reached the bottom of the Atacama Trench, where light does not penetrate, in what they called the “most ambitious” deep-sea expedition ever conducted in the eastern Pacific. The joint mission to one of the deepest ocean trenches – which runs parallel to the coasts of Peru and Chile – took place from January 19 to March 5. It comes as Chile’s expanding cooperation with China on science and technology has inflamed geopolitical tensions with the United States. Washington has in recent months raised concerns over China’s collaborations with South American countries, saying they could also have military purposes. Tensions escalated over the Humboldt submarine fibre-optic cable that will connect South America with Asia, resulting in Washington revoking visas for Chilean diplomats linked to the project. Chinese state-owned research vessel Tan Suo Yi Hao hosted the Atacama Trench expedition and its operations were closely monitored by the Chilean Navy. No irregular activities were reported after it concluded in the Chilean port city of Valparaiso. Scientists on the expedition collected geological sediment samples that will be used to reconstruct environmental processes from up to 5 million years ago. They also studied organisms living in food-scarce environments that can survive for a week or even a month without feeding. The mission was led by researchers from the Millennium Institute of Oceanography at the University of Concepcion in Chile and the Institute of Deep-sea Science and Engineering under the Chinese Academy of Sciences. Their aim was to uncover the mysteries of one of the eastern Pacific’s deepest places. “It is an extremely challenging environment, with only 2 degrees Celsius [35 degrees Fahrenheit] and no light,” Mauricio Urbina, an expedition leader from the Chilean university, told reporters at a briefing after the mission. The team on board the Chinese research ship – which included scientists from Germany and Denmark – made their way into the ocean’s depths on the Fendouzhe, or Striver, manned submersible, one of the most advanced vessels of its kind. They conducted some 36 dives covering 180km (112 miles) of the Atacama Trench seabed. “The discoveries have shown that hadal trenches are not isolated,” said co-lead researcher Du Mengran, from the CAS institute, at the same briefing. The hadal zone is the deepest part of the ocean. Du – who has taken part in a similar expedition in New Zealand and a Russia-Alaska mission – said there were connections between the deep-sea trenches that allowed species to share genes. She also noted the biodiversity of the Atacama Trench. “It is the first time we have observed three different hadal snailfish in this area,” Du said. The snailfish – a type of ray-finned fish with a tadpole-like shape, large head and small eyes – have adapted to live in the deep sea alongside a small number of other fish species. “We are surprised to see that even though the environment here is extremely harsh, the trench floor hosts high biodiversity,” she added. Du said the researchers noticed that tectonic activity had created fractures in the seabed, but it also transported nutrients and energy from inside the Earth to the ocean floor. “This further supports our hypothesis that there is a global chemosynthetic corridor around the trenches,” she said. Urbina said the team had found fish with haemoglobin – a protein that carries oxygen in red blood cells – despite the low temperature and unpredictable feeding patterns, adding that all of them had eyes. “Now we face the challenge of discovering whether the eyes have any function or are vestigial [organs],” he said. Animals in the hadal zone survive on scarce and sporadic food – they depend on what descends from higher waters. To analyse feeding adaptations, Urbina and Erika Jorquera, also from the Chilean university, conducted an in situ digestion experiment – providing large quantities of food to relatively small fish. They observed organisms weighing just 20 grams (0.71 ounce) ingesting some 1.5kg (3.3lbs) of food over a two-hour period. “Adaptations are required to ingest that quantity of food and maximise its absorption within the digestive system until the next feeding,” Urbina said. They compared it to a person eating 35kg of meat in one sitting and then waiting for the next meal without knowing when it could be. “We must understand how they can survive for one week or even a month without feeding. They reduce their metabolism to conserve energy and endure long periods of starvation,” he said. The scientists also collected a large number of organisms and now face the task of identifying them and searching for new species. But the main goal of the expedition was to improve geological understanding of the hadal zone. Du said the trench was one of the largest in the world, with “very active seismic activity”. To study this tectonic activity and better understand the ancient Earth, some 365 samples were collected as geological records of this process, in addition to mapping the tectonic faults with videos. According to Urbina, five samples – each of them 3 metres (9.8 feet) long – will be used to study the biogeochemistry, oceanographic and biological processes of the past 5 million years. Smaller samples of around 30cm (11.8 inches) will be used to reconstruct the last 500 years of the trench from Valparaiso to northern Chile. “After 36 dives, we have a better understanding of the trench,” Du said. She also noted the participation of women on the expedition, saying Valeria Cortes, from the Chilean university, was the first woman scientist to dive to the bottom of the trench at a depth of 7,680 metres. “We want to encourage more girls and female scientists to join deep-sea research,” Du added. She said the researchers were “looking forward to a second joint expedition”. Urbina said the Chilean team had “fulfilled a dream by carrying out this expedition with Chinese colleagues and their cutting-edge technology”. Chinese ambassador to Chile Niu Qingbao said the cooperation “strengthens a global commitment to protect marine biodiversity and ocean sustainability”. The future of Chile’s cooperation with China now rests with the newly inaugurated government of President Jose Antonio Kast, whose political coalition has historically aligned with the US.

China and Chile wrap up Atacama Trench mission as US pressure mounts

.css-1c6uqr6{color:inherit;font-weight:inherit;font-size:inherit;font-family:inherit;line-height:inherit;overflow-wrap:break-word;}Scientists on Chinese research ship aimed to uncover mysteries of the trench in ‘most ambitious’ deep-sea expedition in the eastern Pacific

Scientists on Chinese research ship aimed to uncover mysteries of the trench in ‘most ambitious’ deep-sea expedition in the eastern Pacific