Can microbes produce oxygen in the dark?

Updated - January 11, 2022 12:00 pm IST

Published - January 08, 2022 08:05 pm IST

Oxygen source:  Ammonia oxidising archaea play a key role in the nitrogen cycle

Oxygen source: Ammonia oxidising archaea play a key role in the nitrogen cycle

Scientists say there would be no oxygen on Earth were it not for sunlight: the key component in photosynthesis. Now researchers from University of Southern Denmark have discovered that oxygen is also produced without sunlight, possibly deep below the ocean surface. Researchers have discovered that some of the invisible microorganisms living in water columns produce oxygen in an unexpected way.

Nitrogen cycle

A few microbes are known to make oxygen without sunlight, but so far they have only been discovered in very limited quantities and in very specific habitats.

But the ocean living microbe Nitrosopumilus maritimus and its cousins, called ammonia oxidising archaea play an important role in the nitrogen cycle. For this, they need oxygen. So it has been a long-standing puzzle why they are also very abundant in waters where there is no oxygen. The researchers found that these micro-organisms make their own oxygen, according to a University of Southern Denmark press release.

Keeps it going

The researchers conducted tests in the lab and found that N. maritimus was using the oxygen present in water but the oxygen levels started increasing again in water. They micro-organisms were able to make oxygen even in a dark environment. Not sufficiently high to influence oxygen levels on Earth, but enough to keep itself going.

N. maritimus couples the oxygen production to the production of gaseous nitrogen. By doing so they remove bioavailable nitrogen from the environment.

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