Newly discovered bacteria named “Chonkus” could be an asset in the fight against climate change

By Lainie Beauchemin

Microbiologist Max Schubert and his team took to the waters of Italy’s Vulcano island, where they believed the bacteria found there could help decrease the amount of carbon in the atmosphere. **Courtesy of NEOM via Unsplash**

It’s all hands on deck in the fight against climate change, and scientists are looking in some of the weirdest corners of the earth for help. Microbiologist Max Schubert and his team from the Wyss Institute at Harvard recently took to the waters of the coasts of Italy’s Vulcano island, where shallow volcanic seeps — undersea vents through which heat from volcanic activity at tectonic plate boundaries is released — continuously release carbon dioxide (CO2). The team hypothesized that the bacteria found there may be exceptionally good at metabolizing CO2, making them good candidates for decreasing the amount of carbon in the atmosphere.

When it comes to fighting global warming, reducing atmospheric carbon is the name of the game. While some green technologies, such as electric vehicles and renewable energy sources like solar and wind aim to reduce carbon emissions, some technologies aim to actually extract carbon from the atmosphere. So-called carbon-negative approaches usually act to sequester carbon from the atmosphere in some way, whether through direct air capture, where special filters absorb CO2 from the air, enhanced mineral carbonation, in which carbon is reacted with minerals to be trapped in stable compounds, or even just by growing photosynthesizing organisms like plants or cyanobacteria. These organisms literally eat CO2 for breakfast, converting it into energy and releasing oxygen.

Using cyanobacteria to sequester CO2 from the ocean and, in turn, the atmosphere, is nothing new, but the active research is in isolating novel cyanobacteria from interesting environments. These environments have applied selective pressures on the cyanobacteria species which in some cases make them better suited for effective sequestration. For instance, a species discovered and published in 2022 was isolated from an environment that gave it a higher tolerance for light than its closest evolutionary relative, and made it exceptionally fast at reproducing. Other species have been selected for their tolerance to high pH environments, or their unusually-high biomass density, both of which are a result of the environment from which they were isolated.

It’s for this reason that Schubert and his team decided to look for candidates near the volcanic seeps off the coast of Baia di Levante. The CO2-rich emissions and acidic atmosphere would, they figured, select for bacteria which could survive in high-carbon environments. And indeed they found UTEX 3222, fondly named Chonkus, a cyanobacterium that not only withstands high-carbon environments and grows at exceptional speeds, but also forms a dense and readily-sinking biomass, likely due to its large cell size. This is especially advantageous because Chonkus will sink to the bottom of the ocean after reducing carbon concentrations near the surface, promoting continuous sequestration and removal.