Findings from a recent ocean research indicate that the vast majority of microorganisms living in deep water are dormant

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The majority of deep-water microorganisms, according to a team of researchers from the University of Vienna and a colleague from the University of Tsukuba, are largely dormant. In the journal Nature Geoscience, the group discusses its extensive investigation of bacteria at very deep levels in the Atlantic, Pacific, and Mediterranean seas.

Ocean biologists believed for a very long time that the world’s seas were swarming with bacteria that would consume anything that occurred to perish in their waters. And while it has been discovered that this is true, it is not true in the ways that were believed, at least not in light of the results of this recent study.

Certain regions of the deep ocean may be absent of bacteria or home to microbes that do not devour biomatter, according to earlier studies. Even after 10 months submerged in water, a bologna sandwich discovered in a buried submersible with its hatch open showed no sign of deterioration. The undersea environment is undoubtedly diverse, with certain regions favoring biomolecular breakdown more than others.

These findings prompted other researchers to hypothesize that some kinds of seaweed may absorb carbon from the atmosphere, sinking at death and carrying the carbon with it, where it would be stored in extremely cold, deep water. But given recent data suggesting that not all oceanic bacteria are the same, it does not seem realistic.

The researchers used fluorescent probes instead of hauling samples aboard their ship, where they might change due to pressure differences, to obtain samples while they sailed around the entire planet in order to learn more about the microbes in the deep waters. Microbes with higher respiration rates looked brighter, which the researchers used as a method of measurement. They also gathered a handful of the many microbial species onto their boat to carry out genetic research.

The researchers were shocked to learn from their data that only 3% of the microorganisms they examined were capable of converting oxygen to CO2. According to the researchers, the pressure was the main reason why the rest were generally idle. Additionally, they discovered that the distribution of greenhouse gas emissions that end up in the ocean is extremely unbalanced, indicating that it is now impossible to use the oceans to store additional CO2. It also demonstrates how little is currently known about ocean chemistry among ocean experts.


Chie Amano et al. (2022). Limited carbon cycling due to high-pressure effects on the deep-sea microbiome, Nature GeoscienceDOI: 10.1038/s41561-022-01081-3