Carbon Microbes
New Ocean Microbe Could Unlock Secrets of Earth’s Carbon Cycle
Marine biologists have discovered a new species of ocean-dwelling microbe that may play a pivotal role in the planet’s carbon cycle. This tiny organism, found in the mesopelagic zone of the Pacific Ocean, appears to consume carbon in a highly efficient and previously undocumented way.
The microbe belongs to a class of archaea and was identified during a deep-sea expedition led by the Monterey Bay Aquarium Research Institute (MBARI). Using autonomous sampling vehicles and high-throughput genetic sequencing, the team isolated the organism from water samples taken at depths between 500 and 1,000 meters. This region, often called the ocean’s twilight zone, is poorly understood but believed to be crucial in long-term carbon storage.
What makes this new microbe exceptional is its ability to fix carbon not just through traditional photosynthesis or chemosynthesis, but via a hybrid metabolic pathway. According to the study published in Nature Microbiology, the organism utilizes both ammonia oxidation and dissolved organic matter to drive carbon assimilation. This dual process allows it to operate efficiently in low-light, low-nutrient conditions.
The implications are significant. If this metabolic strategy is widespread among other deep-sea microbes, it may mean that the ocean has an even greater capacity for long-term carbon sequestration than previously estimated. This could impact climate models and inform geoengineering approaches aimed at mitigating atmospheric CO₂.
Researchers are now working to culture the microbe in lab conditions to study its genome, protein structures, and potential biotechnological applications. There is also interest in understanding how widespread this microbial strategy might be in other parts of the world’s oceans.
This discovery highlights the value of exploring Earth’s least known ecosystems. As scientists learn more about the microscopic life in the deep sea, they may uncover vital mechanisms that regulate climate and sustain marine biodiversity.
Sources https://www.nature.com/articles/s41564-025-01567-3 https://www.mbari.org/news/new-carbon-sequestering-microbe-2025/