Researchers discover giant bacteria in mangrove ecosystems

photo of Guadalupe magroves
Hugo Bret/Courtesy
In a collaboration among research institutions, researchers discover giant bacteria visible to the naked eye in Guadeloupe marine mangrove systems.

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Researchers at the Lawrence Berkeley National Laboratory, or Berkeley Lab, discovered giant bacteria in Guadeloupe marine mangrove systems, notably unusual due to their visibility to the naked eye.

According to a Berkeley Lab press release, the study was conducted in collaboration with Université des Antilles in Guadeloupe, the Laboratory for Research in Complex Systems and the U.S. Department of Energy Joint Genome Institute, or JGI, an Office of Science user facility located in Berkeley Lab.

JGI scientist Jean-Marie Volland said in a press release the bacterium is “vermicelli-like” in appearance and is 5,000 times larger than most bacteria.

“To put it into context, it would be like a human encountering another human as tall as Mount Everest,” Volland said in the press release.

Volland added the bacterium is made more unusual because of its structure. According to Volland, DNA normally free-floats within the cytoplasm of most bacteria cells; in the giant bacterium, the DNA is contained in a membrane-covered structure — dubbed by the scientists as “pepins” — which Volland described as “unexpected.”

Researchers first found the bacteria in 2009 when they observed thin filaments in the water of mangrove ecosystems, Volland said. Volland added the filaments were confirmed to be bacteria after microscopic observation.

Silvina Gonzalez-Rizzo, a co-first author on the study and an associate professor of molecular biology with Université des Antilles, named the bacteria Ca. Thiomargarita magnifica, according to the press release.

“ ‘Magnifica’ because ‘magnus’ in Latin means ‘big’ and I think (the bacteria is) gorgeous like the French word magnifique,” Gonzalez-Rizzo said in the press release. “This kind of discovery opens new questions about bacterial morphotypes that have never been studied before.”

Gonzalez-Rizzo used rRNA gene sequencing to identify and classify the bacteria, according to the press release.

As for what the presence of this bacteria means for the larger mangrove ecosystem, researchers are still unsure, Volland said.

“They are among the good microbes that are helping pump carbon dioxide out of the atmosphere,” Volland said. “We have not quantified their contribution to the larger carbon cycle or the sulfur cycle.”

Volland also said the bacteria’s discovery and any further research conducted on it can answer “big questions” in biology about life and evolution.

He added that one aspect of future research may look into how bacteria is evolving towards adopting larger and more compartmentalized structures.

“We are pushing a little bit the concept of what a bacterial cell can be,” Volland said. “We may be using that in the future to try to understand how complex life evolves.”

Kavya Gupta and Amber X. Chen contributed to this story.

Contact Kavya Gupta and Amber X. Chen at [email protected].