A team of researchers led by the Institute of Marine Sciences (ICM-CSIC) from Barcelona revealed the genome more than 500 marine microorganisms, of which over 80% belong to hitherto unknown species.
The details of the discovery, which show how limited our knowledge of these organisms is in one of the most remote areas on the planet, the Arctic Ocean, are collected in an article published this week in the magazine Nature Microbiology.
Knowledge of these organisms is critical to understanding and predicting their responses to environmental changes, which can have a significant impact on climate dynamics. This has implications not only for the polar zones, but also for other latitudes, as marine microorganisms are the main drivers of global biogeochemical cycles.
Marine microorganisms are the main drivers of global biogeochemical cycles
It is an especially relevant fact in the current context of global change, since the polar regions are very sensitive to climatic variations. For example, in the Arctic, the accelerated melting of glaciers, a permafrost -The permanently frozen ground layer- and changes in the extent of the thickness of the sea ice they cause environmental changes with a strong impact on ecosystems and local societies.
“To improve knowledge about the impacts of climate change on the arctic ecosystem, it is necessary to know the main microbial actors, their dynamics, their activity patterns and their metabolic potential”, explains the ICM-CSIC researcher and main author of the study. Silvia G. Acinas, which highlights that so far no one has assessed in such detail the microbial diversity of the Arctic Ocean regions.
Melting glaciers, permafrost and sea ice cause environmental changes with a strong impact on ecosystems and local societies
To carry out the work, the team of researchers analyzed seawater samples collected during the expedition. tara Polar Circle of the Oceans, the last sample of the shipment oceans of tara (2009-2013), who traveled through various regions of the Arctic Ocean through different marine protected areas for seven months.
Marta Royo Llonch, also a researcher at ICM-CSIC and first author of the study, points out that “the possibility of rebuilding microbial genomes from DNA microbial communities thanks to tools for bioinformatics and improved sequencing, along with the existence of standardized protocols for sampling plankton, allowed us to obtain the most complete dataset of uncultured prokaryotic genomes to date. We call it the Arctic Catalog of MAGs (Metagenome Assembled Genomes).
Unique and versatile microorganisms
Another highlight of the research is that it suggests that there are many species that are unique to the polar zones and have a restricted habitat distribution in the Arctic ocean, especially in deeper waters.
“We have identified the main genomes of bacteria and archaea unique to the polar oceans and specifically the Arctic, which are the most active in terms of genetic expression and, therefore, they must play an important role in the biogeochemical cycles of this ecosystem. For this reason, these microorganisms should serve as a reference base for future monitoring of the state of the Arctic Ocean”, Pablo Sanchez, another of the authors of the work.
These microorganisms have great metabolic versatility, which gives them greater resilience and allows a better adaptation to environmental changes.
Among the hundreds of microorganisms described in this catalog, there are those with great metabolic versatility and that are mixotrophs. This implies that they use different sources of energy and carbon to function, either as autotrophs –For producing complex organic compounds (carbohydrates, fats and proteins) from the carbon of simple substances–, or heterotrophs –Those who cannot produce their own food, but are nourished by other sources of organic carbon (plant or animal matter) -.
According to the authors, these characteristics can give Arctic species greater resilience, allowing them to respond better to stresses. environmental changes.
“Future studies should focus on monitoring these species, as some of them may be more susceptible to the effects of climate change due to their restricted distribution, which would help to better understand their conservation status. conservation it has the Arctic Ocean”, they conclude.
Royo-Llonch et al. “Compendium of 530 metagenome-assembled bacterial and archaeal genomes from the polar Arctic Ocean”. Nat Microbiol (2021).
CSIC Institute of Marine Sciences
Rights: Creative Commons.