For the first time, Chinese scientists have found gaseous water in the hydrothermal zone of the deep sea

According to the official website of the Institute of Oceanography of the Chinese Academy of Sciences, the “Science” scientific research vessel of the Institute of Oceanography of the Chinese Academy of Sciences has observed evidence of the presence of gaseous water for the first time in the deep-sea hydrothermal zone. The results were officially published today (May 28) in the geophysical research letter, an authoritative journal of geosciences, and the discovery of this heavy scientific research was also reported by CCTV today.

The official website of the Institute of Oceanography of the Chinese Academy of Sciences reads as follows:

The phase state of water is controlled by the temperature and pressure conditions in which it is located, and when the temperature exceeds the gas-liquid separation temperature at the pressure at which it is located, the liquid water is transformed into gaseous water. At an atmospheric pressure, pure water is gasified at 100 degrees Celsius, the origin of “white water”. But in the deep sea floor high-pressure environment, the gasification temperature of sea water can reach several hundred degrees Celsius, then in the deep sea there is a large number of ultra-high temperature gaseous water?

In the 2018 “Science” scientific research vessel deep-sea hydrothermal voyage, the research team of the Institute of Oceanography of the Chinese Academy of Sciences, using China’s independentresearch and developed deep-sea laser Raman spectral in situ detection system (RiP) and deep-sea hydrothermal temperature probe, first observed evidence of the presence of gaseous water on the icy seabed. The results were published May 28 in Geophysical Research Letters, an authoritative journal of geosciences.

Deep-sea hydrothermal systems, which are rich in mineraland and genetic resources and are thought to be related to the origin of life, have been of great concern to the scientific community. Phase separation is a process of separation of fluid components in deep-sea hydrothermal systems, which has an important influence on the evolution of hydrothermal fluid chemical components. When the temperature of the fluid exceeds the two-phase separation temperature at its pressure, the gas phase of low density, low salinity and gas-rich components will be separated from the brine phase. But as the gas phase rises and spews out the sea floor, the temperature drops rapidly, making it impossible for the steam phase to remain above the sea floor. In the deep-sea hydrothermal zone, the researchers found an inverted lake formed by a large number of “mushroom-type” hydrothermal chimney structures, filled with glittering bodies of water, through the high-definition camera of Discovery ROV. This is due to a strong layer of light reflection formed by large temperature and density differences, which makes the lake surface of the upside-down lake look as flat as a smooth mirror. The Raman spectral capture and temperature measurement are carried out for different layers of water bodies in inverted lakes through the deep-sea laser Raman spectral insiticosis detection system and deep-sea hydrothermal temperature detection. The measurement results of Raman spectroscopy show that the water body in the inverted lake in this area presents a “sandwich” layering structure, with the high temperature steam phase, the hydrothermal fluid mixed with sea water and the normal sea water phase at the bottom from top to bottom. Temperature measurement data show that the temperature of the top fluid of the “mushroom type” structure can reach up to 383.3 degrees C, which has exceeded the temperature of phase separation (378.1 degrees C) of the water depth (2180m) condition in the region, and further verifies the measurement results of the Raman spectrum, with gaseous water mixed with CO2, CH4, H2S and other gas components at the top of the lake.

For the first time, Chinese scientists have found gaseous water in the hydrothermal zone of the deep sea

Inverted Lake Elevation View by Discovery ROV

For the first time, Chinese scientists have found gaseous water in the hydrothermal zone of the deep sea

Temperature data collected by hydrothermal temperature probes and Raman spectral data collected by RiP systems

Gaseous water can survive on the bottom of the area, thanks to the region’s unique hydrothermal chimney structure. The “mushroom-type” chimney structure forms a semi-enclosed system that isolates overheated high-temperature fluids from the surrounding low-temperature seawater. High-temperature hydrothermal vents spread slowly to the sea water through the mirror of the upside-down lake (gas-liquid interface), and this special eruption pattern facilitates hydrothermal sulphide slowers at the edge of the chimney, thus reducing the impact on the marine environment. The dissolution and transportation of metal elements are controlled by fluid density, so the low-density gas phase and supercritical phase hydrothermal venting systems differ significantly from conventional hydrothermal systems in the process of element distribution and sulphide mineralization. At present, the supercritical phase and gas phase hydrothermal injection system is only observed in the hydrothermal region of the mid-ocean ridge, and the gas-phase hydrothermal venting system observed in the hydrothermal zone after the arc has a more stable eruption condition compared with the supercritical phase and gas phase eruption system of the mid-ocean ridge. In-situ detection of such gas phase hydrothermal venting systems helps to reveal the process of hydrothermal sulphide mineralization of such low-density gas phase hydrothermal venting systems and their impact on the deep-sea environment.

The above discovery was made using the first genealogical Raman spectral probe (RiP) that can be directly inserted into a deep-sea hydrothermal vent at 450 degrees C. In situ detection of high temperature hydrothermal vents has always been a worldwide technical problem, due to the harsh high temperature, high pressure, strong acid (alkali) and turbid fluid environment, deep-sea hot hydrothermal vents have been considered a no-go area for optical lenses. RiP high temperature hydrothermal Raman spectral probe successfully broke through the common optical lens resistance to high temperature and poor particle attachment performance and other technical difficulties, for the deep-sea hydrothermal high temperature fluid geochemical nature research provides the first multi-parameter in situ optical detection sensor, for the study of hydrothermal fluid on the marine environment and global changes provides a new method.

Dr. Li Lianfu is the first author of the article and Zhang Xin researcher is the author of the newsletter.

Li, L., Zhang, X., Luan, Z., Du, Z., Xi, S., Wang, B., et al. (2020). Hydrophoto-phase fluids on the seafloor: Evidence from in situ observations. Geophysical Research Letters, 47, e2019GL085778.

https://doi.org/10.1029/2019GL085778

For the first time, Chinese scientists have found gaseous water in the hydrothermal zone of the deep sea

The formation principle of the mirror of the upside-down lake and the formation model of the “mushroom-type” structure

For the first time, Chinese scientists have found gaseous water in the hydrothermal zone of the deep sea

Worldwide proven distribution of active hydrothermal regions and hydrothermal region locations with similar structures

(Original title: Heavy!) For the first time, Chinese scientists have found gaseous water in the hydrothermal zone of the deep sea.