Background Deep-sea hydrothermal vents are highly productive, yet ephemeral biodiversity hotspots in the deep ocean supported by chemosynthetic microorganisms that play critical roles in the maintenance and development of these extreme ecosystems. While several studies have investigated the microbial diversity in both active and inactive sulfide chimneys that have been extinct for a long time, little is known about chimneys that ceased activity more recently as well as the microbial succession occurring during the transition from active to inactive chimneys.
Results Genome-resolved metagenomics was applied to an active and a recently ceased (~7 years) sulfide chimney from the 9°50'N hydrothermal vent field on the East Pacific Rise. Full-length 16S rRNA gene and a total of 173 high quality metagenome assembled genomes (MAGs) were retrieved for comparative analysis. In the active chimney (EPR-L), sulfide- and/or hydrogen-oxidizing Campylobacteria and Aquificae with the potential for denitrification were identified as the dominant community members and primary producers, fixing carbon through the reductive tricarboxylic acid (rTCA) cycle. In contrast, the microbiome of the recently extinct chimney (EPR-M) was largely composed of heterotrophs from various bacterial phyla, including Delta -/ Beta -/ Alphaproteobacteria and Bacteroidetes . Gammaproteobacteria were identified as the main primary producers, using the oxidation of metal sulfides and/or iron oxidation coupled to nitrate reduction to fix carbon through the Calvin-Benson-Bassham (CBB) cycle. Further analysis revealed a phylogenetically distinct Nitrospirae cluster that has the potential to oxidize sulfide minerals coupled to oxygen and/or nitrite reduction, as well as for sulfate reduction, and that might serve as an indicator for the early stages of chimneys after venting has ceased.
Conclusions This study shed light on the composition, metabolic functions, and succession of microbial communities in deep-sea hydrothermal vent chimneys. Collectively, microbial succession during the life span of a chimney could be described to go from a "fluid-shaped" microbial community in newly formed and actively venting chimneys to a "mineral-shaped" community after hydrothermal activity has ceased. Remarkably, the transition appears to happen early on, after which the communities stay stable for thousands of years.
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On 30 Jun, 2020
On 28 Apr, 2020
On 28 Apr, 2020
On 27 Apr, 2020
On 27 Apr, 2020
Posted 10 Mar, 2020
Received 03 Apr, 2020
On 03 Apr, 2020
Received 23 Mar, 2020
On 14 Mar, 2020
Invitations sent on 11 Mar, 2020
On 11 Mar, 2020
On 04 Mar, 2020
On 03 Mar, 2020
On 03 Mar, 2020
On 03 Mar, 2020
On 30 Jun, 2020
On 28 Apr, 2020
On 28 Apr, 2020
On 27 Apr, 2020
On 27 Apr, 2020
Posted 10 Mar, 2020
Received 03 Apr, 2020
On 03 Apr, 2020
Received 23 Mar, 2020
On 14 Mar, 2020
Invitations sent on 11 Mar, 2020
On 11 Mar, 2020
On 04 Mar, 2020
On 03 Mar, 2020
On 03 Mar, 2020
On 03 Mar, 2020
Background Deep-sea hydrothermal vents are highly productive, yet ephemeral biodiversity hotspots in the deep ocean supported by chemosynthetic microorganisms that play critical roles in the maintenance and development of these extreme ecosystems. While several studies have investigated the microbial diversity in both active and inactive sulfide chimneys that have been extinct for a long time, little is known about chimneys that ceased activity more recently as well as the microbial succession occurring during the transition from active to inactive chimneys.
Results Genome-resolved metagenomics was applied to an active and a recently ceased (~7 years) sulfide chimney from the 9°50'N hydrothermal vent field on the East Pacific Rise. Full-length 16S rRNA gene and a total of 173 high quality metagenome assembled genomes (MAGs) were retrieved for comparative analysis. In the active chimney (EPR-L), sulfide- and/or hydrogen-oxidizing Campylobacteria and Aquificae with the potential for denitrification were identified as the dominant community members and primary producers, fixing carbon through the reductive tricarboxylic acid (rTCA) cycle. In contrast, the microbiome of the recently extinct chimney (EPR-M) was largely composed of heterotrophs from various bacterial phyla, including Delta -/ Beta -/ Alphaproteobacteria and Bacteroidetes . Gammaproteobacteria were identified as the main primary producers, using the oxidation of metal sulfides and/or iron oxidation coupled to nitrate reduction to fix carbon through the Calvin-Benson-Bassham (CBB) cycle. Further analysis revealed a phylogenetically distinct Nitrospirae cluster that has the potential to oxidize sulfide minerals coupled to oxygen and/or nitrite reduction, as well as for sulfate reduction, and that might serve as an indicator for the early stages of chimneys after venting has ceased.
Conclusions This study shed light on the composition, metabolic functions, and succession of microbial communities in deep-sea hydrothermal vent chimneys. Collectively, microbial succession during the life span of a chimney could be described to go from a "fluid-shaped" microbial community in newly formed and actively venting chimneys to a "mineral-shaped" community after hydrothermal activity has ceased. Remarkably, the transition appears to happen early on, after which the communities stay stable for thousands of years.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
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