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  1. Article ; Online: Corrigendum

    Alba Filella / Lasse Riemann / France Van Wambeke / Elvira Pulido-Villena / Angela Vogts / Sophie Bonnet / Olivier Grosso / Julia M. Diaz / Solange Duhamel / Mar Benavides

    Frontiers in Marine Science, Vol

    Contrasting roles of DOP as a source of phosphorus and energy for marine diazotrophs

    2023  Volume 10

    Keywords nitrogen fixation ; Trichodesmium ; Crocosphaera ; polyphosphate ; phosphoanhydride ; phosphoester ; Science ; Q ; General. Including nature conservation ; geographical distribution ; QH1-199.5
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article: Extensive nitrification and active ammonia oxidizers in two contrasting coastal systems of the Baltic Sea

    Happel, Elisabeth / Ines Bartl / Lasse Riemann / Maren Voss

    Environmental microbiology. 2018 Aug., v. 20, no. 8

    2018  

    Abstract: Nitrification is important in nitrogen (N) cycling of aquatic environments, but knowledge about its regulation and importance is sparse. Here we examined nitrification and ammonia oxidizers in the Baltic Sea. We investigated two sites with different ... ...

    Abstract Nitrification is important in nitrogen (N) cycling of aquatic environments, but knowledge about its regulation and importance is sparse. Here we examined nitrification and ammonia oxidizers in the Baltic Sea. We investigated two sites with different catchment characteristics (agricultural and forest), the Bay of Gdánsk (south) and the Öre Estuary (north), and measured pelagic nitrification rates and abundance, composition and expression of ammonia monooxygenase (amoA) genes. Highest nitrification rates were found in the nutrient rich Bay of Gdańsk. Interestingly, abundances of ammonia‐oxidizing archaea (AOA) and bacteria (AOB) were orders of magnitude lower than reported from other sites. Although AOA were most abundant at both sites, the highest expression levels were from AOB. Interestingly, few AOA and AOB taxa dominated amoA gene expression, with a Nitrosomarinus related phylotype showing widespread expression. AOA and AOB communities differed between sites and depths, respectively, with the composition in rivers being distinct. A storm event, causing an even depth distribution of nitrification and particles in the Bay of Gdańsk, indicated that the presence of particles stimulate nitrification. The study highlights coastal regions as dynamic sites of extensive pelagic nitrification, which may affect local food web dynamics and loss of N mediated by denitrification.
    Keywords ammonia ; ammonia monooxygenase ; aquatic environment ; Archaea ; bacteria ; coasts ; denitrification ; estuaries ; food webs ; forests ; gene expression ; genes ; nitrification ; nitrogen ; nitrogen cycle ; oxidants ; phylotype ; rivers ; storms ; watersheds ; Baltic Sea
    Language English
    Dates of publication 2018-08
    Size p. 2913-2926.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 2020213-1
    ISSN 1462-2920 ; 1462-2912
    ISSN (online) 1462-2920
    ISSN 1462-2912
    DOI 10.1111/1462-2920.14293
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Deep Into Oceanic N2 Fixation

    Mar Benavides / Sophie Bonnet / Ilana Berman-Frank / Lasse Riemann

    Frontiers in Marine Science, Vol

    2018  Volume 5

    Keywords nitrogen budget ; mesopelagic ; non-cyanobacterial diazotrophs ; nifH gene ; aphotic layer ; Science ; Q ; General. Including nature conservation ; geographical distribution ; QH1-199.5
    Language English
    Publishing date 2018-04-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Filtration via Conventional Glass Fiber Filters in 15N2 Tracer Assays Fails to Capture All Nitrogen-Fixing Prokaryotes

    Deniz Bombar / Ryan W. Paerl / Ruth Anderson / Lasse Riemann

    Frontiers in Marine Science, Vol

    2018  Volume 5

    Abstract: Biological dinitrogen fixation (BNF) represents a major input of reduced nitrogen (N) to the oceans. Accurate direct measurements of BNF rates are crucial for reliably determining the biogeochemical significance of diazotrophy at local and global scales. ...

    Abstract Biological dinitrogen fixation (BNF) represents a major input of reduced nitrogen (N) to the oceans. Accurate direct measurements of BNF rates are crucial for reliably determining the biogeochemical significance of diazotrophy at local and global scales. Traditionally, borosilicate glass fiber filters (GF/F, Whatman) with a nominal pore size of 0.7 μm are used to collect suspended particles by filtration after incubations with added 15N2 tracer. We carried out BNF experiments in the Baltic Sea, Danish coastal waters, and the Pacific Ocean comparing the retentive characteristics of precombusted GF/F filters with newer Advantec glass fiber filters which have a smaller nominal pore size of 0.3 μm. Where BNF was detected, rates were nearly always higher, and sometimes even exclusively detectable, when using Advantec filters. In the majority of samples across tested habitats, significantly more cells were lost to GF/F filtrate (average = 51%, range = 10–70% of cells) than to Advantec filtrate (average = 40%, range = 10–54%). Using Illumina sequencing of nitrogenase (nifH) gene amplicons, we show that diazotroph communities can markedly differ between bulk water and filtrates from GF/F and Advantec filtrations, suggesting that different diazotrophs can pass through the filter types. In order to reduce the potential underestimations of BNF due to filtration loss of diazotrophs, we recommend using Advantec filters or alternatively silver membranes with 0.2 μm pore size, especially in waters expected to be inhabited by relatively small, unicellular diazotrophs.
    Keywords oceanic nitrogen fixation ; diazotrophs ; cyanobacteria ; glass fiber filter ; bias ; filtration ; Science ; Q ; General. Including nature conservation ; geographical distribution ; QH1-199.5
    Subject code 620
    Language English
    Publishing date 2018-01-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: A quantitative model of nitrogen fixation in the presence of ammonium.

    Keisuke Inomura / Jason Bragg / Lasse Riemann / Michael J Follows

    PLoS ONE, Vol 13, Iss 11, p e

    2018  Volume 0208282

    Abstract: Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory ... ...

    Abstract Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models.
    Keywords Medicine ; R ; Science ; Q
    Subject code 551
    Language English
    Publishing date 2018-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Quantifying nitrogen fixation by heterotrophic bacteria in sinking marine particles

    Subhendu Chakraborty / Ken H. Andersen / André W. Visser / Keisuke Inomura / Michael J. Follows / Lasse Riemann

    Nature Communications, Vol 12, Iss 1, Pp 1-

    2021  Volume 14

    Abstract: N2 fixation by heterotrophic bacteria has recently been found to take place on sinking marine particles, but an understanding of its regulation and importance is lacking. Here the authors develop a trait-based model for this N2 fixation, finding that ... ...

    Abstract N2 fixation by heterotrophic bacteria has recently been found to take place on sinking marine particles, but an understanding of its regulation and importance is lacking. Here the authors develop a trait-based model for this N2 fixation, finding that this once overlooked process could have global importance.
    Keywords Science ; Q
    Language English
    Publishing date 2021-07-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Contrasting Roles of DOP as a Source of Phosphorus and Energy for Marine Diazotrophs

    Alba Filella / Lasse Riemann / France Van Wambeke / Elvira Pulido-Villena / Angela Vogts / Sophie Bonnet / Olivier Grosso / Julia M. Diaz / Solange Duhamel / Mar Benavides

    Frontiers in Marine Science, Vol

    2022  Volume 9

    Abstract: The oceanic dissolved organic phosphorus (DOP) pool is mainly composed of P-esters and, to a lesser extent, equally abundant phosphonate and P-anhydride molecules. In phosphate-limited ocean regions, diazotrophs are thought to rely on DOP compounds as an ...

    Abstract The oceanic dissolved organic phosphorus (DOP) pool is mainly composed of P-esters and, to a lesser extent, equally abundant phosphonate and P-anhydride molecules. In phosphate-limited ocean regions, diazotrophs are thought to rely on DOP compounds as an alternative source of phosphorus (P). While both P-esters and phosphonates effectively promote dinitrogen (N2) fixation, the role of P-anhydrides for diazotrophs is unknown. Here we explore the effect of P-anhydrides on N2 fixation at two stations with contrasting biogeochemical conditions: one located in the Tonga trench volcanic arc region (“volcano,” with low phosphate and high iron concentrations), and the other in the South Pacific Gyre (“gyre,” with moderate phosphate and low iron). We incubated surface seawater with AMP (P-ester), ATP (P-ester and P-anhydride), or 3polyP (P-anhydride) and determined cell-specific N2 fixation rates, nifH gene abundance, and transcription in Crocosphaera and Trichodesmium. Trichodesmium did not respond to any DOP compounds added, suggesting that they were not P-limited at the volcano station and were outcompeted by the low iron conditions at the gyre station. Conversely, Crocosphaera were numerous at both stations and their specific N2 fixation rates were stimulated by AMP at the volcano station and slightly by 3polyP at both stations. Heterotrophic bacteria responded to ATP and 3polyP additions similarly at both stations, despite the contrasting phosphate and iron availability. The use of 3polyP by Crocosphaera and heterotrophic bacteria at both low and moderate phosphate concentrations suggests that this compound, in addition to being a source of P, can be used to acquire energy for which both groups compete. P-anhydrides may thus leverage energy restrictions to diazotrophs in the future stratified and nutrient-impoverished ocean.
    Keywords nitrogen fixation ; Trichodesmium ; Crocosphaera ; polyphosphate ; phosphoanhydride ; phosphoester ; Science ; Q ; General. Including nature conservation ; geographical distribution ; QH1-199.5
    Subject code 551
    Language English
    Publishing date 2022-07-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article: Marine Non-Cyanobacterial Diazotrophs: Moving beyond Molecular Detection

    Bombar, Deniz / Lasse Riemann / Ryan W. Paerl

    Trends in microbiology. 2016 Nov., v. 24, no. 11

    2016  

    Abstract: The nitrogen input through biological N2 fixation is essential for life in vast areas of the global ocean. The belief is that cyanobacteria are the only relevant N2-fixing (diazotrophic) organisms. It has, however, now become evident that non- ... ...

    Abstract The nitrogen input through biological N2 fixation is essential for life in vast areas of the global ocean. The belief is that cyanobacteria are the only relevant N2-fixing (diazotrophic) organisms. It has, however, now become evident that non-cyanobacterial diazotrophs, bacteria and archaea with ecologies fundamentally distinct from those of cyanobacteria, are widespread and occasionally fix N2 at significant rates. The documentation of a globally relevant nitrogen input from these diazotrophs would constitute a new paradigm for research on oceanic nitrogen cycling. Here we highlight the need for combining rate measurements and molecular analyses of field samples with cultivation studies in order to clarify the ecology of non-cyanobacteria and their contribution to marine N2 fixation on local and global scales.
    Keywords Archaea ; Cyanobacteria ; ecology ; nitrogen ; nitrogen fixation ; nitrogen-fixing bacteria ; oceans
    Language English
    Dates of publication 2016-11
    Size p. 916-927.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1158963-2
    ISSN 1878-4380 ; 0966-842X
    ISSN (online) 1878-4380
    ISSN 0966-842X
    DOI 10.1016/j.tim.2016.07.002
    Database NAL-Catalogue (AGRICOLA)

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  9. Article ; Online: Molecular and functional ecology of aquatic microbial symbionts

    Hans-PeterGrossart / LasseRiemann / KamW.Tang

    Frontiers in Microbiology, Vol

    2013  Volume 4

    Keywords Archaea ; Bacteria ; Fungi ; Microbial Interactions ; Parasites ; Zooplankton ; adaptation ; evolution ; algae ; corals ; Microbial metabolism ; ascidians ; biodiversity-ecosystem functioning ; ciliate-bacteria interaction ; Microbial Symbionts ; Photsynthesis ; Microhabitats ; Microbiology ; QR1-502 ; Science ; Q
    Language English
    Publishing date 2013-03-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article: Summer comes to the Southern Ocean: how phytoplankton shape bacterioplankton communities far into the deep dark sea

    Richert, Inga / Patricia L. Yager / Julie Dinasquet / Ramiro Logares / Lasse Riemann / Annelie Wendeberg / Stefan Bertilsson / Douglas G. Scofield

    Ecosphere. 2019 Mar., v. 10, no. 3

    2019  

    Abstract: During austral spring and summer, the coastal Antarctic experiences a sharp increase in primary production and a steepening of biotic and abiotic gradients that result from increased solar radiation and retreating sea ice. In one of the largest ... ...

    Abstract During austral spring and summer, the coastal Antarctic experiences a sharp increase in primary production and a steepening of biotic and abiotic gradients that result from increased solar radiation and retreating sea ice. In one of the largest seasonally ice‐free regions, the Amundsen Sea Polynya, pelagic samples were collected from 15 sites during a massive Phaeocystis antarctica bloom in 2010/2011. Along with a suite of other biotic and abiotic measurements, bacterioplankton were collected and analyzed for community structure by pyrosequencing of the 16S rRNA gene. The aims were to identify patterns in diversity and composition of heterotrophic bacterioplankton and to test mechanistic hypotheses for explaining these differences along variations in depth, water mass, phytoplankton biomass, and organic and inorganic nutrients. The overall goal was to clarify the relationship between primary producers and bacterioplankton community structure in the Southern Ocean. Results suggested that both epipelagic and mesopelagic bacterioplankton communities were structured by phytoplankton blooming in the euphotic zone. As chlorophyll a (chl‐a) increased in surface waters, the abundance of surface bacterioplankton increased, but their diversity decreased. Similarity in bacterioplankton community composition between surface‐water sites increased as the bloom progressed, suggesting that algal blooms may homogenize surface‐water bacterioplankton communities at larger spatial scales. Below the euphotic zone, the opposite relationship was found. Mesopelagic bacterioplankton diversity increased with increasing chl‐a in the overlying surface waters. This shift may be promoted by several factors including local increase in organic and inorganic nutrients from particles sinking out of the euphotic zone, an increase in niche differentiation associated with the particle flux, interactions with deep‐dwelling macrozooplankton, and release from competition with primary producers. Additional multivariate analyses of bacterioplankton community structure and nutrient concentrations revealed distinct depth horizons, with bacterioplankton communities having maximum alpha and beta diversity just below the euphotic zone, while nutrient composition gradually homogenized with increasing depth. Our results provide evidence for bloom‐driven (bottom‐up) control of bacterioplankton community diversity in the coastal Southern Ocean and suggest mechanisms whereby surface processes can shape the diversity of bacterioplankton communities at great depth.
    Keywords Phaeocystis ; algal blooms ; bacterioplankton ; biomass ; chlorophyll ; community structure ; ecological differentiation ; euphotic zone ; genes ; ice ; multivariate analysis ; nutrient content ; nutrients ; phytoplankton ; primary productivity ; ribosomal RNA ; sequence analysis ; solar radiation ; species diversity ; spring ; summer ; surface water ; trophic relationships ; zooplankton ; Antarctic region
    Language English
    Dates of publication 2019-03
    Size p. e02641.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 2572257-8
    ISSN 2150-8925
    ISSN 2150-8925
    DOI 10.1002/ecs2.2641
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