Compendium of 530 metagenome-assembled bacterial and archaeal genomes from the polar Arctic Ocean

Abstract

The role of the Arctic Ocean ecosystem in climate regulation may depend on the responses of marine microorganisms to environmental change. We applied genome-resolved metagenomics to 41 Arctic seawater samples, collected at various depths in different seasons during the Tara Oceans Polar Circle expedition, to evaluate the ecology, metabolic potential and activity of resident bacteria and archaea. We assembled 530 metagenome-assembled genomes (MAGs) to form the Arctic MAGs catalogue comprising 526 species. A total of 441 MAGs belonged to species that have not previously been reported and 299 genomes showed an exclusively polar distribution. Most Arctic MAGs have large genomes and the potential for fast generation times, both of which may enable adaptation to a copiotrophic lifestyle in nutrient-rich waters. We identified 38 habitat generalists and 111 specialists in the Arctic Ocean. We also found a general prevalence of 14 mixotrophs, while chemolithoautotrophs were mostly present in the mesopelagic layer during spring and autumn. We revealed 62 MAGs classified as key Arctic species, found only in the Arctic Ocean, showing the highest gene expression values and predicted to have habitat-specific traits. The Artic MAGs catalogue will inform our understanding of polar microorganisms that drive global biogeochemical cycles.

The Ocean Gene Atlas v2.0: online exploration of the biogeography and phylogeny of plankton genes

“…530 bacterial and archaeal MAGs containing 1 million genes ( 18 ). This Arctic_MAGs dataset was built using the Tara Oceans Polar Circle expedition.…”

Considerations for constructing a protein sequence database for metaproteomics

“…Also, public databases are currently very incomplete with regards to genome coverage for microbial communities [87] , [88] , [174] . As evidenced by the fact that 80%-90% of the MAGs in metagenome projects belong to unnamed species absent from public repositories [172] , [173] . Restricted reference databases: this approach uses prior knowledge of the community’s composition to acquire taxonomically relevant reference proteomes.…”

“…Also, public databases are currently very incomplete with regards to genome coverage for microbial communities [87] , [88] , [174] . As evidenced by the fact that 80%-90% of the MAGs in metagenome projects belong to unnamed species absent from public repositories [172] , [173] .…”

Whole-genome scanning reveals selection mechanisms in epipelagic Chaetoceros diatom populations

“…We further investigated the global connectivity level between the MAG populations in the different Arctic Ocean regions. For this, the Arctic stations were divided based on their geographic location, as was previously done by (Royo-Llonch et al 2021, p.). Five regions were identified: Pacific-Arctic, Kara-Laptev, Atlantic-Arctic, Arctic archipelago and Davis-Baffin (see Supplementary Figure S12 for the polar view of the Arctic Tara Oceans stations).…”