New species and genera of marine bacteria discovered

Scientists have discovered, identified and characterized around twenty new species and genera of marine bacteria of great biogeochemical importance.

The new species have a global distribution but have been found in the Bay of Blanes (Girona), where there is a permanent sampling point of the Institute of Marine Sciences (ICM), dependent on the Higher Council for Scientific Research (CSIC), in Spain .

The study in which this discovery was made was carried out by specialists from the ICM, the University of Valencia (UV) and the Autonomous University of Barcelona (UAB).

The team has described 26 new strains of marine bacteria. These bacteria, present in all oceans, could play important roles in global marine biogeochemical cycles.

To carry out the study, the research team worked with samples from the aforementioned Blanes Bay, a permanent sampling point that the ICM has in the Catalan province of Girona. The samples were collected during the four seasons of the year, which allowed us to analyze how the microbial community varies throughout the year. Specifically, the researchers examined the morphology and physiology of the isolated bacteria and sequenced their genomes to characterize their function and classify them taxonomically.

The analyzes revealed the existence of 23 new bacterial species and six new genera distributed in the following classes: Alphaproteobacteria, Gammaproteobacteria, Bacteroidia and Rhodothermia. According to genomic studies, these bacteria could play crucial roles in the cycles of carbon, nitrogen, sulfur, phosphorus and hydrogen in the ocean, participating in processes such as carbon fixation, denitrification or the oxidation of sulfur compounds.

These processes are key to maintaining the health of marine ecosystems. Thus, for example, denitrification is essential for the health and stability of the oceans, while the oxidation of sulfur compounds contributes to the degradation of toxic compounds such as hydrogen sulfide and the production of organic matter in dark environments, such as the deep ocean.

Five of the new species have been named after female microbiologists (Photo: Xavier Rey / ICM / CSIC).

The research also revealed that these groups of bacteria are widely distributed in all seas and oceans, with those belonging to the Flavobacteriaceae family being the most abundant and widespread. This finding was possible thanks to access to the metagenomes of the Tara Oceans expedition, which provide information on the sequences of all the genomes present in a sample and allow comparison of the genome sequences of the new bacteria to calculate their abundance in each sample analyzed. .

“Massive sequencing helps us understand bacterial communities as a whole, but without cultures we cannot characterize experimentally or publish new taxa (species, genera, etc.) in a valid way. This is one of the reasons why isolating and cultivation remains essential, and its combination with sequencing and bioinformatics analysis technologies is extremely powerful,” explains Xavier Rey Velasco (ICM), co-author of the study.

“Although Blanes Bay is possibly the most studied coastal marine ecosystem in the world from a microbiological point of view, we still discover new species and new aspects of its ecology every time we stop to look in detail. If we know so little about the best-known place, what we still need to know about the rest of the marine ecosystems is enormous,” emphasizes Josep M Gasol, ICM researcher and one of the authors of the research.

Most of the new bacteria have been assigned names in reference to their place of isolation (such as blandensis, from the Latin name of the city of Blanes), the time or the characteristics of the culture (shape and color). However, five of them were named in honor of prominent microbiologists: Zoe Rosinach Pedrol, Ruth Patrick, Katrina Edwards, Isabel Esteve and Pepita Castellví. The latter was director of the ICM and the first woman to direct a scientific base in Antarctica. This gesture is especially significant, since currently 84.4 percent of the names of bacteria that honor people do so referring to men.

The new study opens additional avenues to investigate the functioning of marine bacterial communities and their influence on the global environment, and underlines the importance of these organisms in the balance of ocean ecosystems.

The study is titled “Genomic and phenotypic characterization of 26 novel marine bacterial strains with relevant biogeochemical roles and widespread presence across the global ocean.” And it has been published in the academic journal Frontiers in Microbiology. (Source: Institute of Marine Sciences / CSIC)