Exploring the Role of Dark Oxygen Production in Deep-Sea Biogeochemical Cycles: Implications for Ecosystem Dynamics and Deep-Sea Mining

• Mikhail Siddiqui

  Barrington High School, USA

  Author

Oxygen is at the very core of life on Earth and plays a vital role in many biochemical processes, which include respiration and oxidation. While the presence and influence of oxygen are relatively well studied in surface environments, this is not the case with deep-sea ecosystems. Most recently, "dark oxygen" has been uncovered nearly 13000 feet below the ocean surface. It is currently known as a mysterious form of oxygen that is produced without light and photosynthesis, which has just now opened up new lines of scientific investigation into how oxygen might influence geochemical and biological processes in the deep ocean. The phenomenon of “dark oxygen”—the production of molecular oxygen (O2) in the absence of sunlight - has recently been reported in abyssal deep-sea environments and has potential implications for deep-sea mining. This meta-analysis synthesizes peer reviewed studies (2022–2024) on dark oxygen generation mechanisms and assesses their validity and relevance to mining. Key evidence includes Sweetman et al. (2024), who observed an oxygen increase in benthic chamber experiments over polymetallic nodule fields and hypothesized electrochemical splitting of seawater. The literature reveals conflicting perspectives: some studies report widespread microbial oxygen production in anoxic environments, while others emphasize conventional benthic O2 consumption and question the energy balance of proposed geo-electrochemical mechanisms. If dark oxygen production by nodules is real, it raises urgent questions about deep-sea mining: removing nodules could disrupt localized O2 generation and affect benthic ecosystems. Moreover, mining inherently disturbs sediments and releases metals (e.g., Zn, Cu) into the water, further altering oxygen dynamics. In conclusion, dark oxygen has plausible scientific merit but remains controversial. Its existence would necessitate the careful evaluation of deep-sea mining impacts on ocean oxygen regimes and ecosystem health. Suggesting that mining these nodules could be disastrous for their respective ecosystems.

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