Editor's note: Chinese scientists have been on board the Xuelong-2 icebreaker since July 12 for the 13th Arctic Ocean scientific expedition. They are investigating the geology and geophysics of the mid-ocean ridge as well as key environmental factors related to atmosphere, maritime and climate change. The team is expected to return in September. Follow us for the latest stories from the expedition. You can find our previous piece here.

China's 13th Arctic Ocean scientific expedition team is now working in the Chukchi Sea. During the roughly 80-day journey, the crew will have about 40 days to carry out scientific research.

"Our expedition this time focuses on the ecosystem changes against the rapid changes in the Arctic with four major tasks," Wang Jinhui, leader of the scientific expedition team, told China Media Group (CMG).

Wang elaborated on the four tasks, which include the investigation of the ecological environment of the Pacific sector in the central Arctic Ocean and the comprehensive survey of sea ice; the geology and geophysics of the Gakkel Ridge; research on circulation and sea ice; international cooperation, including the survey of microplastics in the Arctic by China and Thailand; and the geological and geophysical survey of the Gakkel Ridge by China and Russia.

It is the second time that China conducts a survey on the Gakkel Ridge, a mid-ocean ridge stretching about 1,800 kilometers in the Arctic.

The Gakkel Ridge, a new volcanic ridge, is the Earth's slowest-spreading mid-ocean ridge, which is important in studying the expansion of global tectonic plates, said Wang.

"Through investigation on this voyage, we can further reveal the structural changes and spreading processes of the ridge, which will provide some solid foundations for uncovering the hydrothermal circulation mechanism of the ultra-slow expanding mid-ocean ridge," said Wang.

Marine aerosol study

A survey of aerosols in the Arctic is also underway.

With the special equipment known as aerosol-scattering lidar, the researchers can observe the vertical distribution of aerosol concentration and other related physical parameters from the near surface to the altitude of 10,000 meters.

It can also generate real-time data maps, based on which the researchers can make preliminary assessments.

"The Arctic Ocean is currently a hot destination for marine aerosol research," Le Fange, a member of the scientific expedition team, told CMG.

"The special hydrological environment in the area, such as the change of sea ice cover and density and the change of local plankton species, are the influencing factors that may significantly affect the generation and emission of aerosols," said Le.

However, the related influencing mechanisms and processes remain unclear. "That's also an important reason for us to carry out aerosol observation in the Arctic Ocean," Le added.

Saltier ice in the Arctic

The Arctic ice is saltier than that from the Antarctic in general, another crew member, Chen Xiaodong, told CMG.

In addition to floating ice formed by frozen sea water, there are icebergs formed by glaciers in the polar regions.

"Glaciers are formed by the accumulation of snow over the years, so the glacier itself is free of salt; therefore, the icebergs are free of salt as well. They are commonly known as freshwater ice," Chen explained.

As Antarctica is a continent with a lot of glaciers, it harbors a large amount of icebergs, while the Arctic is dominated by the ocean, which has little freshwater ice, said Chen. "That is why Arctic ice is generally saltier."

Study on polar regions 'of great significance'

Polar scientific research is an important field for mankind to understand the mysteries of nature and explore new spaces for development, said Wang.

"China has conducted 39 expeditions to the Antarctic and 12 to the Arctic, and we have accumulated a large amount of data in polar glaciology, oceanography, geology, bioecology and climatology, contributing to some important achievements and scientific discoveries," said Wang.

More importantly, the Arctic and Antarctic are the cooling chambers for our planet, which serve as the drivers of atmospheric circulation.

"They play a very important role in the stability of our global climate system and are of great significance to global sustainable development and the survival of mankind," said Wang.