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Brown S, Lloyd CC, Giljan G, Ghobrial S, Amann R, Arnosti C. Pulsed inputs of high molecular weight organic matter shift the mechanisms of substrate utilisation in marine bacterial communities. Environ Microbiol 2024; 26:e16580. [PMID: 38254313 DOI: 10.1111/1462-2920.16580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024]
Abstract
Heterotrophic bacteria hydrolyze high molecular weight (HMW) organic matter extracellularly prior to uptake, resulting in diffusive loss of hydrolysis products. An alternative 'selfish' uptake mechanism that minimises this loss has recently been found to be common in the ocean. We investigated how HMW organic matter addition affects these two processing mechanisms in surface and bottom waters at three stations in the North Atlantic Ocean. A pulse of HMW organic matter increased cell numbers, as well as the rate and spectrum of extracellular enzymatic activities at both depths. The effects on selfish uptake were more differentiated: in Gulf Stream surface waters and productive surface waters south of Newfoundland, selfish uptake of structurally simple polysaccharides increased upon HMW organic matter addition. The number of selfish bacteria taking up structurally complex polysaccharides, however, was largely unchanged. In contrast, in the oligotrophic North Atlantic gyre, despite high external hydrolysis rates, the number of selfish bacteria was unchanged, irrespective of polysaccharide structure. In deep bottom waters (> 4000 m), structurally complex substrates were processed only by selfish bacteria. Mechanisms of substrate processing-and the extent to which hydrolysis products are released to the external environment-depend on substrate structural complexity and the resident bacterial community.
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Affiliation(s)
- Sarah Brown
- Environment, Ecology, and Energy Program, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - C Chad Lloyd
- Department of Earth, Marine and Environmental Sciences, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Greta Giljan
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sherif Ghobrial
- Department of Earth, Marine and Environmental Sciences, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Carol Arnosti
- Department of Earth, Marine and Environmental Sciences, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
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2
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Thiele S, Vader A, Thomson S, Saubrekka K, Petelenz E, Müller O, Bratbak G, Øvreås L. Seasonality of the bacterial and archaeal community composition of the Northern Barents Sea. Front Microbiol 2023; 14:1213718. [PMID: 37485507 PMCID: PMC10360405 DOI: 10.3389/fmicb.2023.1213718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/15/2023] [Indexed: 07/25/2023] Open
Abstract
The Barents Sea is a transition zone between the Atlantic and the Arctic Ocean. The ecosystem in this region is highly variable, and a seasonal baseline of biological factors is needed to monitor the effects of global warming. In this study, we report the results from the investigations of the bacterial and archaeal community in late winter, spring, summer, and early winter along a transect through the northern Barents Sea into the Arctic Ocean east of Svalbard using 16S rRNA metabarcoding. Winter samples were dominated by members of the SAR11 clade and a community of nitrifiers, namely Cand. Nitrosopumilus and LS-NOB (Nitrospinia), suggest a prevalence of chemoautotrophic metabolisms. During spring and summer, members of the Gammaproteobacteria (mainly members of the SAR92 and OM60(NOR5) clades, Nitrincolaceae) and Bacteroidia (mainly Polaribacter, Formosa, and members of the NS9 marine group), which followed a succession based on their utilization of different phytoplankton-derived carbon sources, prevailed. Our results indicate that Arctic marine bacterial and archaeal communities switch from carbon cycling in spring and summer to nitrogen cycling in winter and provide a seasonal baseline to study the changes in these processes in response to the effects of climate change.
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Affiliation(s)
- Stefan Thiele
- Department of Biological Science, University of Bergen, Bergen, Norway
- Bjerknes Centre for Climate Research, Bergen, Norway
| | - Anna Vader
- University Center in Svalbard (UNIS), Longyearbyen, Norway
| | - Stuart Thomson
- University Center in Svalbard (UNIS), Longyearbyen, Norway
| | | | - Elzbieta Petelenz
- Department of Biological Science, University of Bergen, Bergen, Norway
| | - Oliver Müller
- Department of Biological Science, University of Bergen, Bergen, Norway
| | - Gunnar Bratbak
- Department of Biological Science, University of Bergen, Bergen, Norway
| | - Lise Øvreås
- Department of Biological Science, University of Bergen, Bergen, Norway
- University Center in Svalbard (UNIS), Longyearbyen, Norway
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3
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Sun CC, Zhao WJ, Yue WZ, Cheng H, Sun FL, Wang YT, Wu ML, Engel A, Wang YS. Polymeric carbohydrates utilization separates microbiomes into niches: insights into the diversity of microbial carbohydrate-active enzymes in the inner shelf of the Pearl River Estuary, China. Front Microbiol 2023; 14:1180321. [PMID: 37425997 PMCID: PMC10322874 DOI: 10.3389/fmicb.2023.1180321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/31/2023] [Indexed: 07/11/2023] Open
Abstract
Polymeric carbohydrates are abundant and their recycling by microbes is a key process of the ocean carbon cycle. A deeper analysis of carbohydrate-active enzymes (CAZymes) can offer a window into the mechanisms of microbial communities to degrade carbohydrates in the ocean. In this study, metagenomic genes encoding microbial CAZymes and sugar transporter systems were predicted to assess the microbial glycan niches and functional potentials of glycan utilization in the inner shelf of the Pearl River Estuary (PRE). The CAZymes gene compositions were significantly different between in free-living (0.2-3 μm, FL) and particle-associated (>3 μm, PA) bacteria of the water column and between water and surface sediments, reflecting glycan niche separation on size fraction and selective degradation in depth. Proteobacteria and Bacteroidota had the highest abundance and glycan niche width of CAZymes genes, respectively. At the genus level, Alteromonas (Gammaproteobacteria) exhibited the greatest abundance and glycan niche width of CAZymes genes and were marked by a high abundance of periplasmic transporter protein TonB and members of the major facilitator superfamily (MFS). The increasing contribution of genes encoding CAZymes and transporters for Alteromonas in bottom water contrasted to surface water and their metabolism are tightly related with particulate carbohydrates (pectin, alginate, starch, lignin-cellulose, chitin, and peptidoglycan) rather than on the utilization of ambient-water DOC. Candidatus Pelagibacter (Alphaproteobacteria) had a narrow glycan niche and was primarily preferred for nitrogen-containing carbohydrates, while their abundant sugar ABC (ATP binding cassette) transporter supported the scavenging mode for carbohydrate assimilation. Planctomycetota, Verrucomicrobiota, and Bacteroidota had similar potential glycan niches in the consumption of the main component of transparent exopolymer particles (sulfated fucose and rhamnose containing polysaccharide and sulfated-N-glycan), developing considerable niche overlap among these taxa. The most abundant CAZymes and transporter genes as well as the widest glycan niche in the abundant bacterial taxa implied their potential key roles on the organic carbon utilization, and the high degree of glycan niches separation and polysaccharide composition importantly influenced bacterial communities in the coastal waters of PRE. These findings expand the current understanding of the organic carbon biotransformation, underlying the size-fractionated glycan niche separation near the estuarine system.
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Affiliation(s)
- Cui-Ci Sun
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China
| | - Wen-Jie Zhao
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wei-Zhong Yue
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Hao Cheng
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Fu-Lin Sun
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China
| | - Yu-Tu Wang
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China
| | - Mei-Lin Wu
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Anja Engel
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - You-Shao Wang
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China
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4
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Dionisi HM, Lozada M, Campos E. Diversity of GH51 α-L-arabinofuranosidase homolog sequences from subantarctic intertidal sediments. Biologia (Bratisl) 2023. [DOI: 10.1007/s11756-023-01382-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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5
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Giljan G, Brown S, Lloyd CC, Ghobrial S, Amann R, Arnosti C. Selfish bacteria are active throughout the water column of the ocean. ISME COMMUNICATIONS 2023; 3:11. [PMID: 36739317 PMCID: PMC9899235 DOI: 10.1038/s43705-023-00219-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/22/2023] [Accepted: 01/26/2023] [Indexed: 02/06/2023]
Abstract
Heterotrophic bacteria in the ocean invest carbon, nitrogen, and energy in extracellular enzymes to hydrolyze large substrates to smaller sizes suitable for uptake. Since hydrolysis products produced outside of a cell may be lost to diffusion, the return on this investment is uncertain. Selfish bacteria change the odds in their favor by binding, partially hydrolyzing, and transporting polysaccharides into the periplasmic space without loss of hydrolysis products. We expected selfish bacteria to be most common in the upper ocean, where phytoplankton produce abundant fresh organic matter, including complex polysaccharides. We, therefore, sampled water in the western North Atlantic Ocean at four depths from three stations differing in physiochemical conditions; these stations and depths also differed considerably in microbial community composition. To our surprise, we found that selfish bacteria are common throughout the water column of the ocean, including at depths greater than 5500 m. Selfish uptake as a strategy thus appears to be geographically-and phylogenetically-widespread. Since processing and uptake of polysaccharides require enzymes that are highly sensitive to substrate structure, the activities of these bacteria might not be reflected by measurements relying on uptake only of low molecular weight substrates. Moreover, even at the bottom of the ocean, the supply of structurally-intact polysaccharides, and therefore the return on enzymatic investment, must be sufficient to maintain these organisms.
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Affiliation(s)
- Greta Giljan
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sarah Brown
- Environment, Ecology, and Energy Program, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA
| | - C Chad Lloyd
- Department of Earth, Marine, and Environmental Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA
| | - Sherif Ghobrial
- Department of Earth, Marine, and Environmental Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Carol Arnosti
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
- Department of Earth, Marine, and Environmental Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA.
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6
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Bligh M, Nguyen N, Buck-Wiese H, Vidal-Melgosa S, Hehemann JH. Structures and functions of algal glycans shape their capacity to sequester carbon in the ocean. Curr Opin Chem Biol 2022; 71:102204. [PMID: 36155346 DOI: 10.1016/j.cbpa.2022.102204] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 01/27/2023]
Abstract
Algae synthesise structurally complex glycans to build a protective barrier, the extracellular matrix. One function of matrix glycans is to slow down microorganisms that try to enzymatically enter living algae and degrade and convert their organic carbon back to carbon dioxide. We propose that matrix glycans lock up carbon in the ocean by controlling degradation of organic carbon by bacteria and other microbes not only while algae are alive, but also after death. Data revised in this review shows accumulation of algal glycans in the ocean underscoring the challenge bacteria and other microbes face to breach the glycan barrier with carbohydrate active enzymes. Briefly we also update on methods required to certify the uncertain magnitude and unknown molecular causes of glycan-controlled carbon sequestration in a changing ocean.
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Affiliation(s)
- Margot Bligh
- Max Planck Institute for Marine Microbiology, Bremen, Germany; University of Bremen, MARUM Centre for Marine Environmental Sciences Bremen, Germany
| | - Nguyen Nguyen
- Max Planck Institute for Marine Microbiology, Bremen, Germany; University of Bremen, MARUM Centre for Marine Environmental Sciences Bremen, Germany
| | - Hagen Buck-Wiese
- Max Planck Institute for Marine Microbiology, Bremen, Germany; University of Bremen, MARUM Centre for Marine Environmental Sciences Bremen, Germany
| | - Silvia Vidal-Melgosa
- Max Planck Institute for Marine Microbiology, Bremen, Germany; University of Bremen, MARUM Centre for Marine Environmental Sciences Bremen, Germany
| | - Jan-Hendrik Hehemann
- Max Planck Institute for Marine Microbiology, Bremen, Germany; University of Bremen, MARUM Centre for Marine Environmental Sciences Bremen, Germany.
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7
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Thiele S, Storesund JE, Fernández-Méndez M, Assmy P, Øvreås L. A Winter-to-Summer Transition of Bacterial and Archaeal Communities in Arctic Sea Ice. Microorganisms 2022; 10:1618. [PMID: 36014036 PMCID: PMC9414599 DOI: 10.3390/microorganisms10081618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/21/2022] [Accepted: 07/28/2022] [Indexed: 12/02/2022] Open
Abstract
The Arctic is warming 2-3 times faster than the global average, leading to a decrease in Arctic sea ice extent, thickness, and associated changes in sea ice structure. These changes impact sea ice habitat properties and the ice-associated ecosystems. Sea-ice algal blooms provide various algal-derived carbon sources for the bacterial and archaeal communities within the sea ice. Here, we detail the transition of these communities from winter through spring to early summer during the Norwegian young sea ICE (N-ICE2015) expedition. The winter community was dominated by the archaeon Candidatus Nitrosopumilus and bacteria belonging to the Gammaproteobacteria (Colwellia, Kangiellaceae, and Nitrinocolaceae), indicating that nitrogen-based metabolisms, particularly ammonia oxidation to nitrite by Cand. Nitrosopumilus was prevalent. At the onset of the vernal sea-ice algae bloom, the community shifted to the dominance of Gammaproteobacteria (Kangiellaceae, Nitrinocolaceae) and Bacteroidia (Polaribacter), while Cand. Nitrosopumilus almost disappeared. The bioinformatically predicted carbohydrate-active enzymes increased during spring and summer, indicating that sea-ice algae-derived carbon sources are a strong driver of bacterial and archaeal community succession in Arctic sea ice during the change of seasons. This implies a succession from a nitrogen metabolism-based winter community to an algal-derived carbon metabolism-based spring/ summer community.
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Affiliation(s)
- Stefan Thiele
- Department of Biological Science, University of Bergen, Thormøhlensgate 53 A/B, 5020 Bergen, Norway
- Bjerknes Centre for Climate Research, Jahnebakken 5, 5007 Bergen, Norway
| | | | - Mar Fernández-Méndez
- Norwegian Polar Institute, Fram Centre, Hjalmar Johansens Gate 14, 9296 Tromsø, Norway
- Biological Oceanography, GEOMAR Helmholtz Centre of Ocean Research, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Philipp Assmy
- Norwegian Polar Institute, Fram Centre, Hjalmar Johansens Gate 14, 9296 Tromsø, Norway
| | - Lise Øvreås
- Department of Biological Science, University of Bergen, Thormøhlensgate 53 A/B, 5020 Bergen, Norway
- Bjerknes Centre for Climate Research, Jahnebakken 5, 5007 Bergen, Norway
- Department of Arctic Biology, University Center in Svalbard, UNIS, 9171 Longyearbyen, Norway
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8
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Manna V, Zoccarato L, Banchi E, Arnosti C, Grossart H, Celussi M. Linking lifestyle and foraging strategies of marine bacteria: selfish behaviour of particle-attached bacteria in the northern Adriatic Sea. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:549-558. [PMID: 35362215 PMCID: PMC9546125 DOI: 10.1111/1758-2229.13059] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/13/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
Microbe-mediated enzymatic hydrolysis of organic matter entails the production of hydrolysate, the recovery of which may be more or less efficient. The selfish uptake mechanism, recently discovered, allows microbes to hydrolyze polysaccharides and take up large oligomers, which are then degraded in the periplasmic space. By minimizing the hydrolysate loss, selfish behaviour may be profitable for free-living cells dwelling in a patchy substrate landscape. However, selfish uptake seems to be tailored to algal-derived polysaccharides, abundant in organic particles, suggesting that particle-attached microbes may use this strategy. We tracked selfish polysaccharides uptake in surface microbial communities of the northeastern Mediterranean Sea, linking the occurrence of this processing mode with microbial lifestyle. Additionally, we set up fluorescently labelled polysaccharides incubations supplying phytodetritus to investigate a 'pioneer' scenario for particle-attached microbes. Under both conditions, selfish behaviour was almost exclusively carried out by particle-attached microbes, suggesting that this mechanism may represent an advantage in the race for particle exploitation. Our findings shed light on the selfish potential of particle-attached microbes, suggesting multifaceted foraging strategies exerted by particle colonizers.
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Affiliation(s)
- Vincenzo Manna
- National Institute of Oceanography and Applied Geophysics – OGSDepartment of OceanographyTriesteItaly
| | - Luca Zoccarato
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB)Department of Experimental LimnologyZur alten Fischerhuette 2, D‐16775 StechlinGermany
| | - Elisa Banchi
- National Institute of Oceanography and Applied Geophysics – OGSDepartment of OceanographyTriesteItaly
| | - Carol Arnosti
- University of North Carolina – Chapel HillDepartment of Earth, Marine, and Environmental SciencesChapel HillNC27599USA
| | - Hans‐Peter Grossart
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB)Department of Experimental LimnologyZur alten Fischerhuette 2, D‐16775 StechlinGermany
- Potsdam UniversityInstitute for Biochemistry and BiologyMaulbeeralle 2, D‐14469 PotsdamGermany
| | - Mauro Celussi
- National Institute of Oceanography and Applied Geophysics – OGSDepartment of OceanographyTriesteItaly
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9
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Giljan G, Arnosti C, Kirstein IV, Amann R, Fuchs BM. Strong seasonal differences of bacterial polysaccharide utilization in the North Seas over an annual cycle. Environ Microbiol 2022; 24:2333-2347. [PMID: 35384240 DOI: 10.1111/1462-2920.15997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/26/2022] [Accepted: 04/02/2022] [Indexed: 11/29/2022]
Abstract
Marine heterotrophic bacteria contribute considerably to global carbon cycling, in part by utilizing phytoplankton-derived polysaccharides. The patterns and rates of two different polysaccharide utilization modes - extracellular hydrolysis and selfish uptake - have previously been found to change during spring phytoplankton bloom events. Here we investigated seasonal changes in bacterial utilization of three polysaccharides, laminarin, xylan, and chondroitin sulfate. Strong seasonal differences were apparent in mode and speed of polysaccharide utilization, as well as in bacterial community compositions. Compared to the winter month of February, during the spring bloom in May, polysaccharide utilization was detected earlier in the incubations and a higher portion of all bacteria took up laminarin selfishly. Highest polysaccharide utilization was measured in June and September, mediated by bacterial communities that were significantly different from spring assemblages. Extensive selfish laminarin uptake, for example, was detectible within a few hours in June, while extracellular hydrolysis of chondroitin was dominant in September. In addition to the well-known Bacteroidota and Gammaproteobacteria clades, the numerically minor verrucomicrobial clade Pedosphaeraceae could be identified as a rapid laminarin utilizer. In summary, polysaccharide utilization proved highly variable over the seasons, both in mode and speed, and also by the bacterial clades involved. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Greta Giljan
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Carol Arnosti
- Department of Marine Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA
| | - Inga V Kirstein
- Alfred-Wegner-Institute Helmholtz-Center for Polar and Marine Research, Biological Station Helgoland, Helgoland, Germany
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Bernhard M Fuchs
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
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10
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Liu S, Longnecker K, Kujawinski EB, Vergin K, Bolaños LM, Giovannoni SJ, Parsons R, Opalk K, Halewood E, Hansell DA, Johnson R, Curry R, Carlson CA. Linkages Among Dissolved Organic Matter Export, Dissolved Metabolites, and Associated Microbial Community Structure Response in the Northwestern Sargasso Sea on a Seasonal Scale. Front Microbiol 2022; 13:833252. [PMID: 35350629 PMCID: PMC8957919 DOI: 10.3389/fmicb.2022.833252] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/31/2022] [Indexed: 01/04/2023] Open
Abstract
Deep convective mixing of dissolved and suspended organic matter from the surface to depth can represent an important export pathway of the biological carbon pump. The seasonally oligotrophic Sargasso Sea experiences annual winter convective mixing to as deep as 300 m, providing a unique model system to examine dissolved organic matter (DOM) export and its subsequent compositional transformation by microbial oxidation. We analyzed biogeochemical and microbial parameters collected from the northwestern Sargasso Sea, including bulk dissolved organic carbon (DOC), total dissolved amino acids (TDAA), dissolved metabolites, bacterial abundance and production, and bacterial community structure, to assess the fate and compositional transformation of DOM by microbes on a seasonal time-scale in 2016–2017. DOM dynamics at the Bermuda Atlantic Time-series Study site followed a general annual trend of DOC accumulation in the surface during stratified periods followed by downward flux during winter convective mixing. Changes in the amino acid concentrations and compositions provide useful indices of diagenetic alteration of DOM. TDAA concentrations and degradation indices increased in the mesopelagic zone during mixing, indicating the export of a relatively less diagenetically altered (i.e., more labile) DOM. During periods of deep mixing, a unique subset of dissolved metabolites, such as amino acids, vitamins, and benzoic acids, was produced or lost. DOM export and compositional change were accompanied by mesopelagic bacterial growth and response of specific bacterial lineages in the SAR11, SAR202, and SAR86 clades, Acidimicrobiales, and Flavobacteria, during and shortly following deep mixing. Complementary DOM biogeochemistry and microbial measurements revealed seasonal changes in DOM composition and diagenetic state, highlighting microbial alteration of the quantity and quality of DOM in the ocean.
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Affiliation(s)
- Shuting Liu
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Krista Longnecker
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Elizabeth B Kujawinski
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Kevin Vergin
- Microbial DNA Analytics, Phoenix, OR, United States
| | - Luis M Bolaños
- School of Biosciences, University of Exeter, Exeter, United Kingdom.,Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Stephen J Giovannoni
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Rachel Parsons
- Bermuda Institute of Ocean Sciences, Saint George's, Bermuda
| | - Keri Opalk
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Elisa Halewood
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Dennis A Hansell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Rod Johnson
- Bermuda Institute of Ocean Sciences, Saint George's, Bermuda
| | - Ruth Curry
- Bermuda Institute of Ocean Sciences, Saint George's, Bermuda
| | - Craig A Carlson
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
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11
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Müller O, Seuthe L, Pree B, Bratbak G, Larsen A, Paulsen ML. How Microbial Food Web Interactions Shape the Arctic Ocean Bacterial Community Revealed by Size Fractionation Experiments. Microorganisms 2021; 9:2378. [PMID: 34835503 PMCID: PMC8617753 DOI: 10.3390/microorganisms9112378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
In the Arctic, seasonal changes are substantial, and as a result, the marine bacterial community composition and functions differ greatly between the dark winter and light-intensive summer. While light availability is, overall, the external driver of the seasonal changes, several internal biological interactions structure the bacterial community during shorter timescales. These include specific phytoplankton-bacteria associations, viral infections and other top-down controls. Here, we uncover these microbial interactions and their effects on the bacterial community composition during a full annual cycle by manipulating the microbial food web using size fractionation. The most profound community changes were detected during the spring, with 'mutualistic phytoplankton'-Gammaproteobacteria interactions dominating in the pre-bloom phase and 'substrate-dependent phytoplankton'-Flavobacteria interactions during blooming conditions. Bacterivores had an overall limited effect on the bacterial community composition most of the year. However, in the late summer, grazing was the main factor shaping the community composition and transferring carbon to higher trophic levels. Identifying these small-scale interactions improves our understanding of the Arctic marine microbial food web and its dynamics.
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Affiliation(s)
- Oliver Müller
- Department of Biological Sciences, University of Bergen, 5006 Bergen, Norway; (B.P.); (G.B.)
| | - Lena Seuthe
- Department of Arctic and Marine Biology, UiT—The Arctic University of Norway, 9037 Tromsø, Norway;
| | - Bernadette Pree
- Department of Biological Sciences, University of Bergen, 5006 Bergen, Norway; (B.P.); (G.B.)
| | - Gunnar Bratbak
- Department of Biological Sciences, University of Bergen, 5006 Bergen, Norway; (B.P.); (G.B.)
| | - Aud Larsen
- Molecular Ecology Group, NORCE, 5008 Bergen, Norway;
| | - Maria Lund Paulsen
- Arctic Research Center, Department of Ecoscience, Aarhus University, 8600 Silkeborg, Denmark;
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12
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Kieft B, Li Z, Bryson S, Hettich RL, Pan C, Mayali X, Mueller RS. Phytoplankton exudates and lysates support distinct microbial consortia with specialized metabolic and ecophysiological traits. Proc Natl Acad Sci U S A 2021; 118:e2101178118. [PMID: 34620710 PMCID: PMC8521717 DOI: 10.1073/pnas.2101178118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2021] [Indexed: 11/18/2022] Open
Abstract
Blooms of marine phytoplankton fix complex pools of dissolved organic matter (DOM) that are thought to be partitioned among hundreds of heterotrophic microbes at the base of the food web. While the relationship between microbial consumers and phytoplankton DOM is a key component of marine carbon cycling, microbial loop metabolism is largely understood from model organisms and substrates. Here, we took an untargeted approach to measure and analyze partitioning of four distinct phytoplankton-derived DOM pools among heterotrophic populations in a natural microbial community using a combination of ecogenomics, stable isotope probing (SIP), and proteomics. Each 13C-labeled exudate or lysate from a diatom or a picocyanobacterium was preferentially assimilated by different heterotrophic taxa with specialized metabolic and physiological adaptations. Bacteroidetes populations, with their unique high-molecular-weight transporters, were superior competitors for DOM derived from diatom cell lysis, rapidly increasing growth rates and ribosomal protein expression to produce new relatively high C:N biomass. Proteobacteria responses varied, with relatively low levels of assimilation by Gammaproteobacteria populations, while copiotrophic Alphaproteobacteria such as the Roseobacter clade, with their diverse array of ABC- and TRAP-type transporters to scavenge monomers and nitrogen-rich metabolites, accounted for nearly all cyanobacteria exudate assimilation and produced new relatively low C:N biomass. Carbon assimilation rates calculated from SIP data show that exudate and lysate from two common marine phytoplankton are being used by taxonomically distinct sets of heterotrophic populations with unique metabolic adaptations, providing a deeper mechanistic understanding of consumer succession and carbon use during marine bloom events.
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Affiliation(s)
- Brandon Kieft
- Department of Microbiology, Oregon State University, Corvallis, OR 97331;
| | - Zhou Li
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996
| | - Samuel Bryson
- Department of Microbiology, Oregon State University, Corvallis, OR 97331
- Department of Civil & Environmental Engineering, The University of Washington, Seattle, WA 98195
| | - Robert L Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830
| | - Chongle Pan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996
- Department of Microbiology and Plant Microbiology, University of Oklahoma, Norman, OK 73019
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Ryan S Mueller
- Department of Microbiology, Oregon State University, Corvallis, OR 97331;
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13
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Verrucomicrobiota are specialist consumers of sulfated methyl pentoses during diatom blooms. ISME JOURNAL 2021; 16:630-641. [PMID: 34493810 PMCID: PMC8857213 DOI: 10.1038/s41396-021-01105-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 12/11/2022]
Abstract
Marine algae annually sequester petagrams of carbon dioxide into polysaccharides, which are a central metabolic fuel for marine carbon cycling. Diatom microalgae produce sulfated polysaccharides containing methyl pentoses that are challenging to degrade for bacteria compared to other monomers, implicating these sugars as a potential carbon sink. Free-living bacteria occurring in phytoplankton blooms that specialise on consuming microalgal sugars, containing fucose and rhamnose remain unknown. Here, genomic and proteomic data indicate that small, coccoid, free-living Verrucomicrobiota specialise in fucose and rhamnose consumption during spring algal blooms in the North Sea. Verrucomicrobiota cell abundance was coupled with the algae bloom onset and accounted for up to 8% of the bacterioplankton. Glycoside hydrolases, sulfatases, and bacterial microcompartments, critical proteins for the consumption of fucosylated and sulfated polysaccharides, were actively expressed during consecutive spring bloom events. These specialised pathways were assigned to novel and discrete candidate species of the Akkermansiaceae and Puniceicoccaceae families, which we here describe as Candidatus Mariakkermansia forsetii and Candidatus Fucivorax forsetii. Moreover, our results suggest specialised metabolic pathways could determine the fate of complex polysaccharides consumed during algae blooms. Thus the sequestration of phytoplankton organic matter via methyl pentose sugars likely depend on the activity of specialised Verrucomicrobiota populations.
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14
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Baetge N, Behrenfeld MJ, Fox J, Halsey KH, Mojica KDA, Novoa A, Stephens BM, Carlson CA. The Seasonal Flux and Fate of Dissolved Organic Carbon Through Bacterioplankton in the Western North Atlantic. Front Microbiol 2021; 12:669883. [PMID: 34220753 PMCID: PMC8249739 DOI: 10.3389/fmicb.2021.669883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
The oceans teem with heterotrophic bacterioplankton that play an appreciable role in the uptake of dissolved organic carbon (DOC) derived from phytoplankton net primary production (NPP). As such, bacterioplankton carbon demand (BCD), or gross heterotrophic production, represents a major carbon pathway that influences the seasonal accumulation of DOC in the surface ocean and, subsequently, the potential vertical or horizontal export of seasonally accumulated DOC. Here, we examine the contributions of bacterioplankton and DOM to ecological and biogeochemical carbon flow pathways, including those of the microbial loop and the biological carbon pump, in the Western North Atlantic Ocean (∼39-54°N along ∼40°W) over a composite annual phytoplankton bloom cycle. Combining field observations with data collected from corresponding DOC remineralization experiments, we estimate the efficiency at which bacterioplankton utilize DOC, demonstrate seasonality in the fraction of NPP that supports BCD, and provide evidence for shifts in the bioavailability and persistence of the seasonally accumulated DOC. Our results indicate that while the portion of DOC flux through bacterioplankton relative to NPP increased as seasons transitioned from high to low productivity, there was a fraction of the DOM production that accumulated and persisted. This persistent DOM is potentially an important pool of organic carbon available for export to the deep ocean via convective mixing, thus representing an important export term of the biological carbon pump.
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Affiliation(s)
- Nicholas Baetge
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Michael J. Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - James Fox
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Kimberly H. Halsey
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Kristina D. A. Mojica
- Division of Marine Science, School of Ocean Science and Engineering, The University of Southern Mississippi, John C. Stennis Space Center, Hattiesburg, MS, United States
| | - Anai Novoa
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Brandon M. Stephens
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Craig A. Carlson
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
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15
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Changing expression patterns of TonB-dependent transporters suggest shifts in polysaccharide consumption over the course of a spring phytoplankton bloom. ISME JOURNAL 2021; 15:2336-2350. [PMID: 33649555 PMCID: PMC8319329 DOI: 10.1038/s41396-021-00928-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 01/27/2021] [Accepted: 02/04/2021] [Indexed: 02/02/2023]
Abstract
Algal blooms produce large quantities of organic matter that is subsequently remineralised by bacterial heterotrophs. Polysaccharide is a primary component of algal biomass. It has been hypothesised that individual bacterial heterotrophic niches during algal blooms are in part determined by the available polysaccharide substrates present. Measurement of the expression of TonB-dependent transporters, often specific for polysaccharide uptake, might serve as a proxy for assessing bacterial polysaccharide consumption over time. To investigate this, we present here high-resolution metaproteomic and metagenomic datasets from bacterioplankton of the 2016 spring phytoplankton bloom at Helgoland island in the southern North Sea, and expression profiles of TonB-dependent transporters during the bloom, which demonstrate the importance of both the Gammaproteobacteria and the Bacteroidetes as degraders of algal polysaccharide. TonB-dependent transporters were the most highly expressed protein class, split approximately evenly between the Gammaproteobacteria and Bacteroidetes, and totalling on average 16.7% of all detected proteins during the bloom. About 93% of these were predicted to take up organic matter, and for about 12% of the TonB-dependent transporters, we predicted a specific target polysaccharide class. Most significantly, we observed a change in substrate specificities of the expressed transporters over time, which was not reflected in the corresponding metagenomic data. From this, we conclude that algal cell wall-related compounds containing fucose, mannose, and xylose were mostly utilised in later bloom stages, whereas glucose-based algal and bacterial storage molecules including laminarin, glycogen, and starch were used throughout. Quantification of transporters could therefore be key for understanding marine carbon cycling.
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16
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Klassen L, Reintjes G, Tingley JP, Jones DR, Hehemann JH, Smith AD, Schwinghamer TD, Arnosti C, Jin L, Alexander TW, Amundsen C, Thomas D, Amann R, McAllister TA, Abbott DW. Quantifying fluorescent glycan uptake to elucidate strain-level variability in foraging behaviors of rumen bacteria. MICROBIOME 2021; 9:23. [PMID: 33482928 PMCID: PMC7825182 DOI: 10.1186/s40168-020-00975-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 12/07/2020] [Indexed: 05/03/2023]
Abstract
Gut microbiomes, such as the microbial community that colonizes the rumen, have vast catabolic potential and play a vital role in host health and nutrition. By expanding our understanding of metabolic pathways in these ecosystems, we will garner foundational information for manipulating microbiome structure and function to influence host physiology. Currently, our knowledge of metabolic pathways relies heavily on inferences derived from metagenomics or culturing bacteria in vitro. However, novel approaches targeting specific cell physiologies can illuminate the functional potential encoded within microbial (meta)genomes to provide accurate assessments of metabolic abilities. Using fluorescently labeled polysaccharides, we visualized carbohydrate metabolism performed by single bacterial cells in a complex rumen sample, enabling a rapid assessment of their metabolic phenotype. Specifically, we identified bovine-adapted strains of Bacteroides thetaiotaomicron that metabolized yeast mannan in the rumen microbiome ex vivo and discerned the mechanistic differences between two distinct carbohydrate foraging behaviors, referred to as "medium grower" and "high grower." Using comparative whole-genome sequencing, RNA-seq, and carbohydrate-active enzyme fingerprinting, we could elucidate the strain-level variability in carbohydrate utilization systems of the two foraging behaviors to help predict individual strategies of nutrient acquisition. Here, we present a multi-faceted study using complimentary next-generation physiology and "omics" approaches to characterize microbial adaptation to a prebiotic in the rumen ecosystem. Video abstract.
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Affiliation(s)
- Leeann Klassen
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada
| | - Greta Reintjes
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
- Max Planck Institute for Marine Microbiology, 28359, Bremen, Germany
| | - Jeffrey P Tingley
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Darryl R Jones
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Jan-Hendrik Hehemann
- Max Planck Institute for Marine Microbiology, 28359, Bremen, Germany
- Center for Marine Environmental Sciences, University of Bremen (MARUM), 28359, Bremen, Germany
| | - Adam D Smith
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Timothy D Schwinghamer
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Carol Arnosti
- Department of Marine Sciences, University of North Carolina, Chapel Hill, 27599-3300, NC, USA
| | - Long Jin
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Trevor W Alexander
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Carolyn Amundsen
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Dallas Thomas
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, 28359, Bremen, Germany
| | - Tim A McAllister
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - D Wade Abbott
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403-1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada.
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada.
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17
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Arnosti C, Wietz M, Brinkhoff T, Hehemann JH, Probandt D, Zeugner L, Amann R. The Biogeochemistry of Marine Polysaccharides: Sources, Inventories, and Bacterial Drivers of the Carbohydrate Cycle. ANNUAL REVIEW OF MARINE SCIENCE 2021; 13:81-108. [PMID: 32726567 DOI: 10.1146/annurev-marine-032020-012810] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Polysaccharides are major components of macroalgal and phytoplankton biomass and constitute a large fraction of the organic matter produced and degraded in the ocean. Until recently, however, our knowledge of marine polysaccharides was limited due to their great structural complexity, the correspondingly complicated enzymatic machinery used by microbial communities to degrade them, and a lack of readily applied means to isolate andcharacterize polysaccharides in detail. Advances in carbohydrate chemistry, bioinformatics, molecular ecology, and microbiology have led to new insights into the structures of polysaccharides, the means by which they are degraded by bacteria, and the ecology of polysaccharide production and decomposition. Here, we survey current knowledge, discuss recent advances, and present a new conceptual model linking polysaccharide structural complexity and abundance to microbially driven mechanisms of polysaccharide processing. We conclude by highlighting specific future research foci that will shed light on this central but poorly characterized component of the marine carbon cycle.
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Affiliation(s)
- C Arnosti
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
| | - M Wietz
- HGF MPG Joint Research Group for Deep-Sea Ecology and Technology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany, and Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - T Brinkhoff
- Institute for the Chemistry and Biology of the Marine Environment, University of Oldenburg, 26111 Oldenburg, Germany
| | - J-H Hehemann
- MARUM MPG Bridge Group Marine Glycobiology, Center for Marine Environmental Sciences (MARUM), University of Bremen, and Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - D Probandt
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - L Zeugner
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - R Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
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18
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Reintjes G, Fuchs BM, Amann R, Arnosti C. Extensive Microbial Processing of Polysaccharides in the South Pacific Gyre via Selfish Uptake and Extracellular Hydrolysis. Front Microbiol 2020; 11:583158. [PMID: 33391202 PMCID: PMC7775370 DOI: 10.3389/fmicb.2020.583158] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/25/2020] [Indexed: 11/13/2022] Open
Abstract
Primary productivity occurs throughout the deep euphotic zone of the oligotrophic South Pacific Gyre (SPG), fueled largely by the regeneration of nutrients and thus recycling of organic matter. We investigated the heterotrophic capabilities of the SPG's bacterial communities by examining their ability to process polysaccharides, an important component of marine organic matter. We focused on the initial step of organic matter degradation by measuring the activities of extracellular enzymes that hydrolyze six different polysaccharides to smaller sizes. This process can occur by two distinct mechanisms: "selfish uptake," in which initial hydrolysis is coupled to transport of large polysaccharide fragments into the periplasmic space of bacteria, with little to no loss of hydrolysis products to the external environment, and "external hydrolysis," in which low molecular weight (LMW) hydrolysis products are produced in the external environment. Given the oligotrophic nature of the SPG, we did not expect high enzymatic activity; however, we found that all six polysaccharides were hydrolyzed externally and taken up selfishly in the central SPG, observations that may be linked to a comparatively high abundance of diatoms at the depth and location sampled (75 m). At the edge of the gyre and close to the center of the gyre, four of six polysaccharides were externally hydrolyzed, and a lower fraction of the bacterial community showed selfish uptake. One polysaccharide (fucoidan) was selfishly taken up without measurable external hydrolysis at two stations. Additional incubations of central gyre water from depths of 1,250 and 2,800 m with laminarin (an abundant polysaccharide in the ocean) led to extreme growth of opportunistic bacteria (Alteromonas), as tracked by cell counts and next generation sequencing of the bacterial communities. These Alteromonas appear to concurrently selfishly take up laminarin and release LMW hydrolysis products. Overall, extracellular enzyme activities in the SPG were similar to activities in non-oligotrophic regions, and a considerable fraction of the community was capable of selfish uptake at all three stations. A diverse set of bacteria responded to and are potentially important for the recycling of organic matter in the SPG.
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Affiliation(s)
- Greta Reintjes
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Bernhard M. Fuchs
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Carol Arnosti
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
- Department of Marine Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, United States
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19
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Varela MM, Rodríguez-Ramos T, Guerrero-Feijóo E, Nieto-Cid M. Changes in Activity and Community Composition Shape Bacterial Responses to Size-Fractionated Marine DOM. Front Microbiol 2020; 11:586148. [PMID: 33329457 PMCID: PMC7714726 DOI: 10.3389/fmicb.2020.586148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/30/2020] [Indexed: 12/21/2022] Open
Abstract
To study the response of bacteria to different size-fractions of naturally occurring dissolved organic matter (DOM), a natural prokaryotic community from North Atlantic mesopelagic waters (1000 m depth) was isolated and grown in (i) 0.1-μm filtered seawater (CONTROL), (ii) the low-molecular-weight (<1 kDa) DOM fraction (L-DOM), and (iii) the recombination of high- (>1 kDa) and low-molecular-weight DOM fractions (H + L-DOM), to test the potential effect of ultrafiltration on breaking the DOM size continuum. Prokaryotic abundance and leucine incorporation were consistently higher in the H + L-DOM niche than in the L-DOM and CONTROL treatments, suggesting a different interaction with each DOM fraction and the disruption of the structural DOM continuum by ultrafiltration, respectively. Rhodobacterales (Alphaproteobacteria) and Flavobacteriales (Bacteroidetes) were particularly enriched in L-DOM and closely related to the colored DOM (CDOM) fraction, indicating the tight link between these groups and changes in DOM aromaticity. Conversely, some other taxa that were rare or undetectable in the original bacterial community were enriched in the H + L-DOM treatment (e.g., Alteromonadales belonging to Gammaproteobacteria), highlighting the role of the rare biosphere as a seed bank of diversity against ecosystem disturbance. The relationship between the fluorescence of protein-like CDOM and community composition of populations in the H + L-DOM treatment suggested their preference for labile DOM. Conversely, the communities growing on the L-DOM niche were coupled to humic-like CDOM, which may indicate their ability to degrade more reworked DOM and/or the generation of refractory substrates (as by-products of the respiration processes). Most importantly, L- and/or H + L-DOM treatments stimulated the growth of unique bacterial amplicon sequence variants (ASVs), suggesting the potential of environmental selection (i.e., changes in DOM composition and availability), particularly in the light of climate change scenarios. Taken together, our results suggest that different size-fractions of DOM induced niche-specialization and differentiation of mesopelagic bacterial communities.
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Affiliation(s)
- Marta M Varela
- Centro Oceanográfico de A Coruña, Instituto Español de Oceanografía (IEO), A Coruña, Spain
| | - Tamara Rodríguez-Ramos
- Centro Oceanográfico de A Coruña, Instituto Español de Oceanografía (IEO), A Coruña, Spain
| | - Elisa Guerrero-Feijóo
- Centro Oceanográfico de A Coruña, Instituto Español de Oceanografía (IEO), A Coruña, Spain
| | - Mar Nieto-Cid
- Centro Oceanográfico de A Coruña, Instituto Español de Oceanografía (IEO), A Coruña, Spain.,Laboratorio de Geoquímica Orgánica, Instituto de Investigaciones Marinas (CSIC), Vigo, Spain
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20
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Alejandre-Colomo C, Viver T, Urdiain M, Francis B, Harder J, Kämpfer P, Amann R, Rosselló-Móra R. Taxonomic study of nine new Winogradskyella species occurring in the shallow waters of Helgoland Roads, North Sea. Proposal of Winogradskyella schleiferi sp. nov., Winogradskyella costae sp. nov., Winogradskyella helgolandensis sp. nov., Winogradskyella vidalii sp. nov., Winogradskyella forsetii sp. nov., Winogradskyella ludwigii sp. nov., Winogradskyella ursingii sp. nov., Winogradskyella wichelsiae sp. nov., and Candidatus "Winogradskyella atlantica" sp. nov. Syst Appl Microbiol 2020; 43:126128. [PMID: 32977081 DOI: 10.1016/j.syapm.2020.126128] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/21/2020] [Accepted: 07/21/2020] [Indexed: 11/18/2022]
Abstract
Evaluation of bacterial succession with cultivation-dependent strategies during a spring phytoplankton bloom in the North Sea led to the isolation of 41 strains that affiliated with the genus Winogradskyella. Fifteen of the strains were selected for a taxonomic study after discarding clonal cultures. A thorough phylogenetic, genomic and phenotypic analysis of the isolates indicated that they represented eight new species that coexisted in North Sea waters. Molecular data revealed the existence of an as yet uncultivated novel species recurrently binned from the North Sea metagenomes. The metagenome-assembled genomes (MAGs) of this new Winogradskyella were used to classify it as a new Candidatus species. This study represented a new example of the use of the tandem approach of whole cell mass spectrometry linked to 16S rRNA gene sequencing in order to facilitate the discovery of new taxa by high-throughput cultivation, which increases the probability of finding more than a single isolate for new species. In addition, we demonstrated the reasons for classifying MAGs representing recurrently retrieved heterotrophic species that evade cultivation even after an important high-throughput effort. The taxonomic study resulted in the classification of eight new species and one new Candidatus species of the genus Winogradskyella for which we propose the names W. schleiferi sp. nov., W. costae sp. nov., W. helgolandensis sp. nov., W. vidalii sp. nov., W. forsetii sp. nov., W. ludwigii sp. nov., W. ursingii sp. nov., W. wichelsiae sp. nov., and Candidatus "W. atlantica" sp. nov.
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Affiliation(s)
- Carlota Alejandre-Colomo
- Marine Microbiology Group, Department of Animal and Microbial Diversity, Mediterranean Institute for Advanced Studies (IMEDEA, UIB-CSIC), 07190 Esporles, Illes Balears, Spain
| | - Tomeu Viver
- Marine Microbiology Group, Department of Animal and Microbial Diversity, Mediterranean Institute for Advanced Studies (IMEDEA, UIB-CSIC), 07190 Esporles, Illes Balears, Spain
| | - Mercedes Urdiain
- Marine Microbiology Group, Department of Animal and Microbial Diversity, Mediterranean Institute for Advanced Studies (IMEDEA, UIB-CSIC), 07190 Esporles, Illes Balears, Spain
| | - Ben Francis
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany
| | - Jens Harder
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany
| | - Peter Kämpfer
- Institut für Angewandte Mikrobiologie, Justus Liebig Universität Giessen, IFZ-Heinrich-Buff-Ring, Giessen, Germany
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany
| | - Ramon Rosselló-Móra
- Marine Microbiology Group, Department of Animal and Microbial Diversity, Mediterranean Institute for Advanced Studies (IMEDEA, UIB-CSIC), 07190 Esporles, Illes Balears, Spain.
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21
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Grieb A, Francis TB, Krüger K, Orellana LH, Amann R, Fuchs BM. Candidatus Abditibacter, a novel genus within the Cryomorphaceae, thriving in the North Sea. Syst Appl Microbiol 2020; 43:126088. [PMID: 32690198 DOI: 10.1016/j.syapm.2020.126088] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/22/2020] [Accepted: 04/22/2020] [Indexed: 11/25/2022]
Abstract
Coastal phytoplankton blooms are frequently followed by successive blooms of heterotrophic bacterial clades. The class Flavobacteriia within the Bacteroidetes has been shown to play an important role in the degradation of high molecular weight substrates that become available in the later stages of such blooms. One of the flavobacterial clades repeatedly observed over the course of several years during phytoplankton blooms off the coast of Helgoland, North Sea, is Vis6. This genus-level clade belongs to the family Cryomorphaceae and has been resistant to cultivation to date. Based on metagenome assembled genomes, comparative 16S rRNA gene sequence analyses and fluorescence in situ hybridization, we here propose a novel candidate genus Abditibacter, comprising three novel species Candidatus Abditibacter vernus, Candidatus Abditibacter forsetii and Candidatus Abditibacter autumni. While the small genomes of the three novel photoheterotrophic species encode highly similar gene repertoires, including genes for degradation of proteins and algal storage polysaccharides such as laminarin, two of them - Ca. A. vernus and Ca. A. forsetii - seem to have a preference for spring blooms, while Ca. A. autumni almost exclusively occurs in late summer and autumn.
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Affiliation(s)
- Anissa Grieb
- Max Planck Institute for Marine Microbiology, Celsiusstr.1, 28359 Bremen, Germany
| | - T Ben Francis
- Max Planck Institute for Marine Microbiology, Celsiusstr.1, 28359 Bremen, Germany
| | - Karen Krüger
- Max Planck Institute for Marine Microbiology, Celsiusstr.1, 28359 Bremen, Germany
| | - Luis H Orellana
- Max Planck Institute for Marine Microbiology, Celsiusstr.1, 28359 Bremen, Germany
| | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, Celsiusstr.1, 28359 Bremen, Germany
| | - Bernhard M Fuchs
- Max Planck Institute for Marine Microbiology, Celsiusstr.1, 28359 Bremen, Germany
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