Recently, scientists haveThe discovery of a mysterious source of oxygen, or “dark oxygen,” on the floor of the Pacific Ocean is a remarkable scientific discovery that challenges our conventional understanding of marine ecosystems and how oxygen is produced. What is going on?

Discovery background

The discovery comes from a research team led by marine ecologist Andrew Sweetman of the Scottish Association for Marine Science (SAMS).

Since 2013, the team has conducted a series of studies on seafloor ecosystems and their oxygen consumption in the Clarion-Clipperton Zone (CCZ) in the Pacific Ocean, a vast submarine plain between Hawaii and Mexico that is rich in biological communities and polymetallic nodules.

research process

During the study, the research team used a deep-sea lander that sank to the seabed and pushed a cylindrical chamber into the sediment to enclose a small area of ​​the seabed and a certain volume of seawater above it, thereby creating a "seabed microenvironment" isolated from the outside world.

They had expected that in a closed environment, oxygen levels would slowly decrease over time as microorganisms respired. However, the actual measurement results were unexpected: instead of decreasing, the oxygen content showed a slowly increasing trend.

Preliminary speculation and verification

Faced with this abnormal phenomenon, the research team initially suspected that it was a sensor failure, but after multiple calibrations and repeated experiments, they confirmed the authenticity of the phenomenon. Subsequently, the research team focused on polymetallic nodules (also known as manganese nodules) on the seabed. These nodules are mainly composed of metal elements such as manganese, iron, cobalt, nickel, and copper, with manganese and iron oxides as the main components.

In the laboratory, the researchers measured the potential difference on the surface of polymetallic nodules and found that the potential difference could reach up to 0.95 volts. Although this is lower than the 1.5 volts required to decompose water molecules, the research team speculates that when multiple polymetallic nodules are gathered together, they may generate higher voltages through the "series" effect, thereby triggering the electrolysis process of seawater and decomposing water molecules into hydrogen and oxygen.

Research results and significance

This discovery was reported in detail in the journal Nature Geoscience and has attracted widespread attention in the scientific community. Researchers believe that polymetallic nodules may act as a natural "geological battery" that continuously produces oxygen in the dark conditions of the deep sea. This discovery not only challenges our traditional understanding of the ocean oxygen cycle, but may also provide new clues for the study of the origin of life.

In addition, this discovery is also of great significance to deep-sea mining activities. The CCZ area is rich in polymetallic nodules and is a key target for deep-sea mining companies. However, if these nodules are removed, the ecosystems that rely on the oxygen they produce to survive may be seriously affected. Therefore, the researchers emphasize that before advancing deep-sea mining, the potential impact of this new discovery on the environment must be fully considered and scientifically supervised.

New understanding of ocean oxygen cycle

It has long been generally believed that oxygen in the ocean is mainly produced by photosynthesis in the surface water and transported to the deep sea through vertical movement of water. However, this study found that polymetallic nodules (manganese nodules) can produce oxygen through non-biological processes (such as seawater electrolysis) under lightless conditions in the deep sea, which directly challenges the traditional theory of ocean oxygen cycle. It shows that in addition to photosynthesis, there are other important oxygen production mechanisms in the deep sea.

The study also expands the complexity of the oxygen cycle. The ocean oxygen cycle is a complex process involving multiple aspects such as biology, chemistry and physics. This discovery reveals another important link in the deep-sea oxygen cycle, namely the contribution of abiotic processes to oxygen production. This helps us to more fully understand the complexity and diversity of the ocean oxygen cycle and provide more perspectives and ideas for future marine science research.

At the same time, it also provides new clues to the origin of life. The origin of life is one of the major issues that the scientific community has long been concerned about. The traditional view is that the oxygen needed for life is mainly produced by microorganisms such as cyanobacteria through photosynthesis. However, this study found that oxygen can also be produced in the deep sea under lightless conditions, which provides a new direction for thinking about the origin of life. It suggests that life may originate and develop under a wider range of environmental conditions, not just limited to surface waters with light. This helps us re-examine the theoretical framework of the origin of life and explore new research directions.

This study also affects the assessment of deep-sea ecosystems. The deep-sea ecosystem is one of the most mysterious and fragile ecosystems on Earth. This discovery shows that there may be an oxygen production mechanism in the deep sea that we have not yet fully understood, which is of great significance to the assessment and protection of deep-sea ecosystems. It reminds us that when assessing the health and stability of deep-sea ecosystems, we need to fully consider the impact of non-biological processes on the oxygen cycle. At the same time, this also provides new ideas and methods for the protection and management of deep-sea ecosystems.

Finally, the author believes that this study will inevitably guide deep-sea mining activities. With the continuous development of deep-sea resources by humans, deep-sea mining activities are increasing. However, the impact of deep-sea mining activities on the marine environment is not yet fully understood. This research finding shows that polymetallic nodules in the deep sea may have important ecosystem functions, such as producing oxygen. Therefore, before advancing deep-sea mining activities, it is necessary to fully consider their impact on the deep-sea ecosystem and conduct scientific assessments and supervision. This will help ensure the sustainability and environmental friendliness of deep-sea mining activities.