A research team found that a group of tiny ocean bacteria called Pelagibacterale may represent some of our most powerful allies in the fight against global warming. Researchers found that the small creatures produce large quantities of a cloud forming gas that regulates our planet’s climate.
Study authors noted that the microorganisms regulate atmospheric and oceanic temperatures despite their small size. The microscopic animals compensate with their large numbers: scientists estimate that there are about half million of them in a single teaspoon of salt water. Plus, Pelagibacterales are so many that they account for about one-third of all microorganisms dwelling on the ocean surface.
Furthermore, the bacteria play a major role in climate regulation, scientists hadn’t been aware of. The team discovered that the bugs are behind a reverse-feedback loop that helps keep oceans cool and atmospheric temperatures down. The process is described by the CLAW hypothesis.
The loop generates more cloud droplets that enhance the Earth’s albedo, i.e. it can reflect more sunlight when the climate warms too much.
Researchers found that the phytoplankton at the surface of the ocean multiplies exponentially when temperatures rise. As a result, the levels of dimethylsulfoniopropionate (DMSP), a chemical compound produced by some ocean bacteria also rise.
When DMSP exceeds a certain threshold, however, Pelagibacterale’s bodies break down the chemical into dimethylsulfide (DMS), which promotes cloud formation.
The resulting thicker and whiter clouds curb the amount of sunlight reaching the ocean, lowering atmospheric and sea temperatures worldwide. Prof. Ben Temperton from the U.K.-based University of Exeter noted that the tiny bacteria play a huge role in climate stability since they are a major source of the cloud-inducing gas.
Prof. Temperton added that climate models that try to track DMS’s impact on weather should take into account the small bacterial group as a major contributor. The professor was fascinated with the “simplicity and elegance” of the natural mechanism.
Researchers underlined that Pelagibacterales have one of the smallest genomes on the planet. The team believes that small genomes require fewer resources to replicate, so the bacteria adapted to their resource-limited environments through a less complex genome.
Prof. Temperton also said that other small ocean organisms present kinetic regulation too, but no bacterial group plays such a major role in a critical biogeochemical process like Pelagibacterales.
As a side note, CLAW is a shortened form comprising the initials of the authors who proposed the hypothesis: Robert Charlson, James Lovelock, Meinrat Andreae, and Stephen Warren. Lovelock is also known as the promoter of a four-decade-old Gaia hypothesis, which sees our planet as a self-regulating complex system.
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