Scientists have identified a new oxygen source, termed “dark oxygen,” in ocean depths below 4,000 meters where sunlight does not penetrate. This discovery was published in “Nature Geoscience.”
The oxygen, generally produced through photosynthesis, in this case, originates from a unique process involving polymetallic nodules found on the seafloor in the Clarion-Clipperton Zone, stretching from Mexico to Hawaii. This zone, larger than India, is not under any country’s jurisdiction.
Polymetallic nodules, also known as manganese nodules, form on the seafloor by accumulating iron and manganese hydroxides around a central core, which could be a small rock piece or a shell fragment. These nodules grow very slowly, layering over millions of years, and can vary greatly in size. They contain commercially significant concentrations of metals such as nickel, copper, and cobalt, making them interesting for deep-sea mining and crucial for modern technologies like solar panels and electric car batteries. Researchers have discovered that these nodules can naturally split water into hydrogen and oxygen, a process previously deemed unimaginable. Professor Andrew Sweetman, the research leader from the Scottish Association for Marine Science, initially dismissed these findings because it was commonly known that oxygen only comes from photosynthesis, thus considering the sensor readings erroneous. However, further studies he conducted in 2021 and 2022 confirmed these extraordinary results, showing that a process of oxygen production occurs at the ocean floor involving the nodules decomposing water into hydrogen and oxygen.
Additional laboratory studies showed that the electric voltage generated by nodules about the size of a fist is comparable to AA batteries, suggesting the possibility of directly electrolyzing seawater at the ocean bottom.
Many companies in the deep-sea mining sector are developing technologies to collect these nodules and bring them to the surface. In the context of deep-sea mining, even though the Clarion-Clipperton Zone contains vast amounts of these valuable resources, many organizations, including the U.S. National Oceanic and Atmospheric Administration (NOAA), warn of potential threats to marine ecosystems. A petition signed by over 800 oceanographers from 44 countries calls for halting the exploitation of these resources until a better understanding of the potential environmental impacts is achieved.
Ultimately, the discovery of “dark oxygen” not only highlights the significance of the oceans for our planet but also poses new challenges and questions regarding the responsible use of natural resources.
Source: https://www.nature.com/articles/s41561-024-01480-8
About the author
Grzegorz Bubak
My fascination with marine aquariums began over two decades ago when I stumbled upon an article about this topic in a magazine. Since then, the underwater world has become my obsession and passion, shaping my everyday life. I started my adventure with marine aquariums with soft corals, which were my first step into this fascinating world. Over time, captivated by the diversity and beauty of SPS corals, I decided to focus on their cultivation, which continues to fill me with constant wonder.
Thanks to my experience and passion for marine aquariums, I am ready to share my knowledge and expertise with other enthusiasts in this field. I am happy to be part of the Reef Pedia community, which serves as an invaluable source of information for all marine aquarium lovers.