Xuelong 2 Maps Rare Antarctic Marine Secrets

China's polar icebreaker, Xuelong 2, also known as Snow Dragon 2, has officially completed the country's 42nd expedition to the Antarctic, achieving several breakthroughs in technological innovation and international cooperation, along with large-scale application of domestically-developed polar equipment.

Antarctic Ocean health checkup

During its summer oceanographic survey, Xuelong 2 focused on two key regions: the waters adjacent to the Antarctic Peninsula and the Cosmonaut Sea. In just 32 days, the team conducted a thorough, multidisciplinary survey across six transects and 38 stations, ensuring comprehensive coverage of the water column, sediments and other environmental factors.

As key species within the Antarctic ecosystem, Antarctic krill and mesopelagic fish (deep-sea marine species), serve as both food sources for predators and "indicators" of climate change. The expedition team conducted multiple trawling operations, cumulatively capturing over 1,000 krill and nearly 900 fish, including Antarctic lanternfish. This provided crucial support for research into the structure of the Antarctic ecosystem and the mechanisms of climate adaptation.

Furthermore, in the basin and continental slope regions of the Cosmonaut Sea, the team successfully retrieved two high-quality sediment cores with a combined length of approximately seven meters. Cao Shunan, leader of the expedition's Ocean Team, said: "These columnar sediment cores allow researchers to directly obtain invaluable geological records of two typical ventilation scenarios in the Southern Ocean. This enables them to decipher the complete intrusion process of Circumpolar Deep Water — warm water found in the ocean depths — as it upwells from the ocean basin. This preserves a precious geological archive for forecasting global climate change trends."

Autumn-winter scientific research

In March, Prydz Bay in Antarctica entered the transitional period between autumn and winter. After completing the autumn voyage in the Ross Sea during China's 41st Antarctic Expedition, China broke through seasonal constraints once again by launching the 2026 Joint Antarctic Expedition to Prydz Bay (hereinafter referred to as the Joint Expedition).

The Joint Expedition brought together 97 scientific researchers from 19 research institutions across six nations, including Australia and the United States.

Over the course of 23 days, the team conducted surveys at 41 stations, focusing on three core scientific questions: melting ice shelf, carbon sequestration mechanisms and biological overwintering strategies.

The research team collected over 5,700 seawater samples, 2,289 filter membrane samples and 829 biological samples in total. According to Chen Jianfang, the deputy leader of China's 42nd Antarctic Expedition and chief scientist of the Joint Expedition, preliminary investigations revealed signals of supercooled water at certain depths near the front of the Amery Ice Shelf and within the Mackenzie Polynya. Low-temperature signals were detected on the northwestern continental slope of Prydz Bay, and signs of Circumpolar Deep Water intrusion were observed on the northern continental slope. However, it appeared that high-density shelf water was unable to flow off the continental slope during this particular season.

The Joint Expedition also conducted stratified surveys of various biological organisms, thereby providing the crucial data needed to construct a year-round operational model of the Antarctic ecosystem.

High-precision observation network

On the night of April 16, amid the strong westerly winds, the Xuelong 2 crew deployed 28 monitoring buoys in the core regions of mesoscale eddies. This marked the first time China had deployed a network for observing mesoscale eddies in the Southern Ocean. Mesoscale eddies are crucial for transporting matter and energy, however observational data for autumn and winter remain scarce. The deployment of China's domestically developed 6,000-meter "Deep-Sea Basalt" buoy, which made its maiden voyage in the Southern Ocean, will provide the first set of in situ observational data to support research on deep-sea warming.

Domestically produced equipment also played a pivotal role in the 42nd Antarctic Expedition. During the summer phase, team members deployed 15 ocean-bottom seismometers manufactured in China in the waters surrounding the Antarctic Peninsula, thereby establishing China's first ocean-bottom seismic observation array in this region.

Cao said: "These ocean-bottom seismometers act like sensitive 'stethoscopes' for the deep sea, capable of continuously capturing natural seismic waves and recording minute tremors within the Earth's crust." Through them, researchers can conduct year-long passive-source ocean-bottom seismic observations to acquire natural seismic signals from this area and its surrounding regions.

This expedition challenges the traditional reliance on the summer season for Antarctic scientific research and provides a valuable model for achieving continuous, year-round observations in the polar regions. Furthermore, international collaboration and data sharing in polar research serve as a global public good, highlighting China's significant contribution to international cooperation in this field.

Source: Science and Technology Daily