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Lory C, Van Wambeke F, Fourquez M, Barani A, Guieu C, Tilliette C, Marie D, Nunige S, Berman-Frank I, Bonnet S. Assessing the contribution of diazotrophs to microbial Fe uptake using a group specific approach in the Western Tropical South Pacific Ocean. ISME COMMUNICATIONS 2022; 2:41. [PMID: 37938297 PMCID: PMC9723570 DOI: 10.1038/s43705-022-00122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/26/2022] [Accepted: 04/07/2022] [Indexed: 04/27/2023]
Abstract
Diazotrophs are often limited by iron (Fe) availability in the oligotrophic ocean. The Western Tropical South Pacific (WTSP) ocean has been suggested as an intense N2 fixation area due to Fe fertilizations through shallow hydrothermal activity. Yet, the Fe demand of diazotrophs in their natural habitat, where they cohabit with other microbial organisms also requiring Fe, remains unknown. Here we develop and apply a method consisting of coupling 55Fe uptake experiments with cell-sorting by flow cytometry, and provide group-specific rates of in situ Fe uptake by the microbial community in the WTSP, in addition to bulk and size fractionation rates. We reveal that the diazotrophs Crocosphaera watsonii and Trichodesmium contribute substantially to the bulk in situ Fe uptake (~33% on average over the studied area), despite being numerically less abundant compared to the rest of the planktonic community. Trichodesmium had the highest cell-specific Fe uptake rates, followed by C. watsonii, picoeukaryotes, Prochlorococcus, Synechococcus and finally heterotrophic bacteria. Calculated Fe:C quotas were higher (by 2 to 52-fold) for both studied diazotrophs compared to those of the non-diazotrophic plankton, reflecting their high intrinsic Fe demand. This translates into a diazotroph biogeographical distribution that appears to be influenced by ambient dissolved Fe concentrations in the WTSP. Despite having low cell-specific uptake rates, Prochlorococcus and heterotrophic bacteria were largely the main contributors to the bulk Fe uptake (~23% and ~12%, respectively). Overall, this group-specific approach increases our ability to examine the ecophysiological role of functional groups, including those of less abundant and/or less active microbes.
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Affiliation(s)
- C Lory
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France.
| | - F Van Wambeke
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - M Fourquez
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - A Barani
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - C Guieu
- Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France
| | - C Tilliette
- Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France
| | - D Marie
- Sorbonne Université, CNRS, Station Biologique de Roscoff, Roscoff, France
| | - S Nunige
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - I Berman-Frank
- Department of Marine Biology, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - S Bonnet
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France.
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Benavides M, Arístegui J. Untreated sewage outfalls do not promote Trichodesmium blooms in the coasts of the Canary Islands. Sci Rep 2020; 10:18386. [PMID: 33110228 PMCID: PMC7591472 DOI: 10.1038/s41598-020-75447-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 09/30/2020] [Indexed: 11/10/2022] Open
Abstract
During the summer of 2017, recurrent extensive blooms of the diazotrophic cyanobacterium Trichodesmium invaded the beaches and coastal waters of the Canary Islands, causing great social alarm. Some local media and public sectors ascribed, without any strong scientific evidence, the origin and reactivation of these blooms to untreated sewage outfalls distributed along the coasts. In order to test whether sewage outfalls could have any influence on the metabolic activity of Trichodesmium, we performed 13C and 15N2 uptake experiments with colonies experiencing three different bloom development stages, incubated both with clear seawater and sewage water from an outfall south of Gran Canaria island. Our results showed that sewage outfalls did not promote any increase in dinitrogen (N2) fixation in Trichodesmium, supporting the hypothesis that decaying blooms were generated offshore and transported shoreward by local currents and winds, accumulating mostly leeward of the islands. The combination of unusually warm seawater temperatures, enhanced and sustained stratification of the upper water column and recurrent dust deposition events would have favored the development of the Trichodesmium blooms, which lasted for at least four months.
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Affiliation(s)
- Mar Benavides
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Javier Arístegui
- Instituto de Oceanografía y Cambio Global, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain.
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Hou S, López-Pérez M, Pfreundt U, Belkin N, Stüber K, Huettel B, Reinhardt R, Berman-Frank I, Rodriguez-Valera F, Hess WR. Benefit from decline: the primary transcriptome of Alteromonas macleodii str. Te101 during Trichodesmium demise. ISME JOURNAL 2018; 12:981-996. [PMID: 29335641 PMCID: PMC5864184 DOI: 10.1038/s41396-017-0034-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 11/20/2017] [Accepted: 11/26/2017] [Indexed: 12/21/2022]
Abstract
Interactions between co-existing microorganisms deeply affect the physiology of the involved organisms and, ultimately, the function of the ecosystem as a whole. Copiotrophic Alteromonas are marine gammaproteobacteria that thrive during the late stages of phytoplankton blooms in the marine environment and in laboratory co-cultures with cyanobacteria such as Trichodesmium. The response of this heterotroph to the sometimes rapid and transient changes in nutrient supply when the phototroph crashes is not well understood. Here, we isolated and sequenced the strain Alteromonas macleodii str. Te101 from a laboratory culture of Trichodesmium erythraeum IMS101, yielding a chromosome of 4.63 Mb and a single plasmid of 237 kb. Increasing salinities to ≥43 ppt inhibited the growth of Trichodesmium but stimulated growth of the associated Alteromonas. We characterized the transcriptomic responses of both microorganisms and identified the complement of active transcriptional start sites in Alteromonas at single-nucleotide resolution. In replicate cultures, a similar set of genes became activated in Alteromonas when growth rates of Trichodesmium declined and mortality was high. The parallel activation of fliA, rpoS and of flagellar assembly and growth-related genes indicated that Alteromonas might have increased cell motility, growth, and multiple biosynthetic activities. Genes with the highest expression in the data set were three small RNAs (Aln1a-c) that were identified as analogs of the small RNAs CsrB-C in E. coli or RsmX-Z in pathogenic bacteria. Together with the carbon storage protein A (CsrA) homolog Te101_05290, these RNAs likely control the expression of numerous genes in responding to changes in the environment.
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Affiliation(s)
- Shengwei Hou
- Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Mario López-Pérez
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Apartado 18, San Juan, 03550, Alicante, Spain
| | - Ulrike Pfreundt
- Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany.,ETH Zürich, Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, Stefano-Franscini-Platz 5, CH-8093, Zürich, Switzerland
| | - Natalia Belkin
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900, Israel
| | - Kurt Stüber
- Max Planck-Genome-Centre Cologne, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
| | - Bruno Huettel
- Max Planck-Genome-Centre Cologne, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
| | - Richard Reinhardt
- Max Planck-Genome-Centre Cologne, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
| | - Ilana Berman-Frank
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900, Israel
| | - Francisco Rodriguez-Valera
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Apartado 18, San Juan, 03550, Alicante, Spain
| | - Wolfgang R Hess
- Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany. .,Freiburg Institute for Advanced Studies, University of Freiburg, Albertstr. 19, D-79104, Freiburg, Germany.
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Pfreundt U, Spungin D, Hou S, Voß B, Berman-Frank I, Hess WR. Genome of a giant bacteriophage from a decaying Trichodesmium bloom. Mar Genomics 2017; 33:21-25. [PMID: 28237778 DOI: 10.1016/j.margen.2017.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 01/31/2017] [Accepted: 02/04/2017] [Indexed: 10/20/2022]
Abstract
De-novo assembly of a metagenomic dataset obtained from a decaying cyanobacterial Trichodesmium bloom from the New Caledonian lagoon resulted in a complete giant phage genome of 257,908bp, obtained independently with multiple assembly tools. Noteworthy, gammaproteobacteria were an abundant fraction in the sequenced samples. Mapping of the raw reads with 99% accuracy to the giant phage genome resulted in an average coverage of 262X. The closest sequenced relatives, albeit still distant, are the Pseudomonas phages PaBG from Lake Baikal and Lu11 isolated from a soil sample from the Philippines. The phage reported here might belong to the same family within the Myoviridae as PaBG and Lu11 and would thus be its first marine member, indicating a more widespread occurrence of this group. We named this phage NCTB (New Caledonia Trichodesmium Bloom) after its origin.
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Affiliation(s)
- Ulrike Pfreundt
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Dina Spungin
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Shengwei Hou
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Björn Voß
- Computational Biology, Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| | - Ilana Berman-Frank
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
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Carreto JI, Carignan MO. Mycosporine-like amino acids: relevant secondary metabolites. Chemical and ecological aspects. Mar Drugs 2011; 9:387-446. [PMID: 21556168 PMCID: PMC3083659 DOI: 10.3390/md9030387] [Citation(s) in RCA: 260] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 02/18/2011] [Accepted: 03/09/2011] [Indexed: 01/09/2023] Open
Abstract
Taxonomically diverse marine, freshwater and terrestrial organisms have evolved the capacity to synthesize, accumulate and metabolize a variety of UV-absorbing substances called mycosporine-like amino acids (MAAs) as part of an overall strategy to diminish the direct and indirect damaging effects of environmental ultraviolet radiation (UVR). Whereas the enzymatic machinery to synthesize MAAs was probably inherited from cyanobacteria ancestors via the endosymbionts hypothesis, metazoans lack this biochemical pathway, but can acquire and metabolize these compounds by trophic transference, symbiotic or bacterial association. In this review we describe the structure and physicochemical properties of MAAs, including the recently discovered compounds and the modern methods used for their isolation and identification, updating previous reviews. On this basis, we review the metabolism and distribution of this unique class of metabolites among marine organism.
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Affiliation(s)
- Jose I. Carreto
- National Institute for Fisheries Research and Development (INIDEP), Paseo Victoria Ocampo Street No. 1, North Pier, B7602HSA, Mar del Plata, Argentina; E-Mail:
| | - Mario O. Carignan
- National Institute for Fisheries Research and Development (INIDEP), Paseo Victoria Ocampo Street No. 1, North Pier, B7602HSA, Mar del Plata, Argentina; E-Mail:
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Rodier M, Le Borgne R. Population and trophic dynamics of Trichodesmium thiebautii in the SE lagoon of New Caledonia. Comparison with T. erythraeum in the SW lagoon. MARINE POLLUTION BULLETIN 2010; 61:349-359. [PMID: 20638692 DOI: 10.1016/j.marpolbul.2010.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
While Trichodesmium erythraeum is prevalent in the semi-closed SW lagoon of New Caledonia, T. thiebautii is dominant in the more open SE lagoon. This led to the comparison of the two species from the results of two high-frequency surveys focused on T. erythraeum (Rodier and Le Borgne, 2008) and T. thiebautii (the present paper). (1) Environmental conditions and triggers of the blooms are the same: calm weather and/or temperature >26 degrees C, and temporary nutrient inputs are required for both; (2) growth rates under favorable conditions are similar (0.14-0.27 d(-1)) but (3) T. thiebautii has lower net ascent rates along the water column during blooming events, due to distinct buoyancy capacities and the resulting vertical distributions; (4) carbon and dinitrogen fixation rates are not significantly different and contribution of Trichodesmium spp. represent less than 35% and 5% of the total phytoplankton carbon and nitrogen requirements, respectively. It is concluded the two species can be mixed in ecological studies, except for their vertical distributions during the bloom periods.
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Affiliation(s)
- Martine Rodier
- Centre IRD de Nouméa, UMR LOPB Université de la Méditerranée, CNRS, IRD, BP A5, 98848 Nouméa Cédex, New Caledonia.
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Abstract
After the successful Coastal Zone Color Scanner (CZCS, 1978-1986) demonstration that quantitative estimations of geophysical variables such as chlorophyll a and diffuse attenuation coefficient could be derived from top of the atmosphere radiances, a number of international missions with ocean color capabilities were launched beginning in the late 1990s. Most notable were those with global data acquisition capabilities, i.e., the Ocean Color and Temperature Sensor (OCTS,Japan, 1996-1997), the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, United States, 1997-present), two Moderate Resolution Imaging Spectroradiometers (MODIS, United States, Terra/2000-present and Aqua/2002-present), the Global Imager (GLI, Japan, 2002-2003), and the Medium Resolution Imaging Spectrometer (MERIS, European Space Agency, 2002-present). These missions have provided data of exceptional quality and continuity, allowing for scientific inquiries into a wide variety of marine research topics not possible with the CZCS. This review focuses on the scientific advances made over the past decade using these data sets.
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Affiliation(s)
- Charles R McClain
- Oceans Branch, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
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Gross L, Frouin R, Dupouy C, André JM, Thiria S. Reducing variability that is due to secondary pigments in the retrieval of chlorophyll a concentration from marine reflectance: a case study in the western equatorial Pacific Ocean. APPLIED OPTICS 2004; 43:4041-4054. [PMID: 15285096 DOI: 10.1364/ao.43.004041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A neural network is developed to retrieve chlorophyll a concentration from marine reflectance by use of the five visible spectral bands of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The network, dedicated to the western equatorial Pacific Ocean, is calibrated with synthetic data that vary in terms of atmospheric content, solar zenith angle, and secondary pigments. Pigment variability is based on in situ data collected in the study region and is introduced through nonlinear modeling of phytoplankton absorption as a function of chlorophyll a, b, and c and photosynthetic and photoprotectant carotenoids. Tests performed on simulated yet realistic data show that chlorophyll a retrievals are substantially improved by use of the neural network instead of classical algorithms, which are sensitive to spectrally uncorrelated effects. The methodology is general, i.e., is applicable to regions other than the western equatorial Pacific Ocean.
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Affiliation(s)
- Lydwine Gross
- Scripps Institution of Oceanography, California Space Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0221, USA.
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Radenac MH, Menkes C, Vialard J, Moulin C, Dandonneau Y, Delcroix T, Dupouy C, Stoens A, Deschamps PY. Modeled and observed impacts of the 1997-1998 El Niño on nitrate and new production in the equatorial Pacific. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jc000546] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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