Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front
Ultraslow spreading ridges account for one-third of the global mid-ocean ridges. Their impact on the diversity and connectivity of benthic deep-sea microbial assemblages is poorly understood, especially for hydrothermally inactive, magma-starved ridges. We investigated bacterial and archaeal diversi...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-04-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fmicb.2019.00665/full |
| _version_ | 1819065293134102528 |
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| author | Gilda Varliero Gilda Varliero Christina Bienhold Christina Bienhold Florian Schmid Florian Schmid Antje Boetius Antje Boetius Antje Boetius Massimiliano Molari |
| author_facet | Gilda Varliero Gilda Varliero Christina Bienhold Christina Bienhold Florian Schmid Florian Schmid Antje Boetius Antje Boetius Antje Boetius Massimiliano Molari |
| author_sort | Gilda Varliero |
| collection | DOAJ |
| description | Ultraslow spreading ridges account for one-third of the global mid-ocean ridges. Their impact on the diversity and connectivity of benthic deep-sea microbial assemblages is poorly understood, especially for hydrothermally inactive, magma-starved ridges. We investigated bacterial and archaeal diversity in sediments collected from an amagmatic segment (10°–17°E) of the Southwest Indian Ridge (SWIR) and in the adjacent northern and southern abyssal zones of similar water depths within one biogeochemical province of the Indian Ocean. Microbial diversity was determined by 16S ribosomal RNA (rRNA) gene sequencing. Our results show significant differences in microbial communities between stations outside and inside the SWIR, which were mostly explained by environmental selection. Community similarity correlated significantly with differences in chlorophyll a content and with the presence of upward porewater fluxes carrying reduced compounds (e.g., ammonia and sulfide), suggesting that trophic resource availability is a main driver for changes in microbial community composition. At the stations in the SWIR axial valley (3,655–4,448 m water depth), microbial communities were enriched in bacterial and archaeal taxa common in organic matter-rich subsurface sediments (e.g., SEEP-SRB1, Dehalococcoida, Atribacteria, and Woesearchaeota) and chemosynthetic environments (mainly Helicobacteraceae). The abyssal stations outside the SWIR communities (3,760–4,869 m water depth) were dominated by OM1 clade, JTB255, Planctomycetaceae, and Rhodospirillaceae. We conclude that ultraslow spreading ridges create a unique environmental setting in sedimented segments without distinct hydrothermal activity, and play an important role in shaping microbial communities and promoting diversity, but also in connectivity among deep-sea habitats. |
| first_indexed | 2024-12-21T15:44:09Z |
| format | Article |
| id | doaj.art-b0e59ae579c44a9fa21a853be0290c98 |
| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-12-21T15:44:09Z |
| publishDate | 2019-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Microbiology |
| spelling | doaj.art-b0e59ae579c44a9fa21a853be0290c982022-12-21T18:58:25ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2019-04-011010.3389/fmicb.2019.00665445716Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar FrontGilda Varliero0Gilda Varliero1Christina Bienhold2Christina Bienhold3Florian Schmid4Florian Schmid5Antje Boetius6Antje Boetius7Antje Boetius8Massimiliano Molari9Max Planck Institute for Marine Microbiology, Bremen, GermanySchool of Biological Sciences, University of Bristol, Bristol, United KingdomMax Planck Institute for Marine Microbiology, Bremen, GermanyHGF-MPG Joint Research Group on Deep Sea Ecology and Technology, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, GermanyHelmholtz Centre for Ocean Research Kiel, GEOMAR, Kiel, GermanyMARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, GermanyMax Planck Institute for Marine Microbiology, Bremen, GermanyHGF-MPG Joint Research Group on Deep Sea Ecology and Technology, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, GermanyMARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, GermanyMax Planck Institute for Marine Microbiology, Bremen, GermanyUltraslow spreading ridges account for one-third of the global mid-ocean ridges. Their impact on the diversity and connectivity of benthic deep-sea microbial assemblages is poorly understood, especially for hydrothermally inactive, magma-starved ridges. We investigated bacterial and archaeal diversity in sediments collected from an amagmatic segment (10°–17°E) of the Southwest Indian Ridge (SWIR) and in the adjacent northern and southern abyssal zones of similar water depths within one biogeochemical province of the Indian Ocean. Microbial diversity was determined by 16S ribosomal RNA (rRNA) gene sequencing. Our results show significant differences in microbial communities between stations outside and inside the SWIR, which were mostly explained by environmental selection. Community similarity correlated significantly with differences in chlorophyll a content and with the presence of upward porewater fluxes carrying reduced compounds (e.g., ammonia and sulfide), suggesting that trophic resource availability is a main driver for changes in microbial community composition. At the stations in the SWIR axial valley (3,655–4,448 m water depth), microbial communities were enriched in bacterial and archaeal taxa common in organic matter-rich subsurface sediments (e.g., SEEP-SRB1, Dehalococcoida, Atribacteria, and Woesearchaeota) and chemosynthetic environments (mainly Helicobacteraceae). The abyssal stations outside the SWIR communities (3,760–4,869 m water depth) were dominated by OM1 clade, JTB255, Planctomycetaceae, and Rhodospirillaceae. We conclude that ultraslow spreading ridges create a unique environmental setting in sedimented segments without distinct hydrothermal activity, and play an important role in shaping microbial communities and promoting diversity, but also in connectivity among deep-sea habitats.https://www.frontiersin.org/article/10.3389/fmicb.2019.00665/fullSouthwest Indian Ridgeseamountsdeep-seaconnectivitydiversitybacteria |
| spellingShingle | Gilda Varliero Gilda Varliero Christina Bienhold Christina Bienhold Florian Schmid Florian Schmid Antje Boetius Antje Boetius Antje Boetius Massimiliano Molari Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front Frontiers in Microbiology Southwest Indian Ridge seamounts deep-sea connectivity diversity bacteria |
| title | Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front |
| title_full | Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front |
| title_fullStr | Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front |
| title_full_unstemmed | Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front |
| title_short | Microbial Diversity and Connectivity in Deep-Sea Sediments of the South Atlantic Polar Front |
| title_sort | microbial diversity and connectivity in deep sea sediments of the south atlantic polar front |
| topic | Southwest Indian Ridge seamounts deep-sea connectivity diversity bacteria |
| url | https://www.frontiersin.org/article/10.3389/fmicb.2019.00665/full |
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