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Thiagarajan V, Nah T, Xin X. Impacts of atmospheric particulate matter deposition on phytoplankton: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175280. [PMID: 39122032 DOI: 10.1016/j.scitotenv.2024.175280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 08/01/2024] [Accepted: 08/02/2024] [Indexed: 08/12/2024]
Abstract
In many rapidly urbanizing and industrializing countries, atmospheric pollution causes severe environmental problems and compromises the health of humans and ecosystems. Atmospheric emissions, which encompass gases and particulate matter, can be transported back to the earth's surface through atmospheric deposition. Atmospheric deposition supplies chemical species that can serve as nutrients and/or toxins to aquatic ecosystems, resulting in wide-ranging responses of aquatic organisms. Among the aquatic organisms, phytoplankton is the basis of the aquatic food web and is a key player in global primary production. Atmospheric deposition alters nutrient availability and thus influences phytoplankton species abundance and composition. This review provides a comprehensive overview of the physiological responses of phytoplankton resulting from the atmospheric deposition of trace metals, nitrogen-containing compounds, phosphorus-containing compounds, and sulfur-containing compounds in particulate matter into aquatic ecosystems. Knowledge gaps and critical areas for future studies are also discussed.
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Affiliation(s)
- Vignesh Thiagarajan
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong
| | - Theodora Nah
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong.
| | - Xiaying Xin
- Beaty Water Research Centre, Department of Civil Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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2
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Ghio AJ, Hilborn ED. Cyanobacterial blooms, iron, and environmental pollutants. Biometals 2024; 37:577-586. [PMID: 37910342 PMCID: PMC11209704 DOI: 10.1007/s10534-023-00553-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/14/2023] [Indexed: 11/03/2023]
Abstract
Iron determines the abundance and diversity of life and controls primary production in numerous aqueous environments. Over the past decades, the availability of this metal in natural waters has decreased. Iron deficiency can apply a selective pressure on microbial aquatic communities. Each aquatic organism has their individual requirements for iron and pathways for metal acquisition, despite all having access to the common pool of iron. Cyanobacteria, a photosynthesizing bacterium that can accumulate and form so-called 'algal blooms', have evolved strategies to thrive in such iron-deficient aqueous environments where they can outcompete other organisms in iron acquisition in diverse microbial communities. Metabolic pathways for iron acquisition employed by cyanobacteria allow it to compete successfully for this essential nutrient. By competing more effectively for requisite iron, cyanobacteria can displace other species and grow to dominate the microbial population in a bloom. Aquatic resources are damaged by a diverse number of environmental pollutants that can further decrease metal availability and result in a functional deficiency of available iron. Pollutants can also increase iron demand. A pollutant-exposed microbe is compelled to acquire further metal critical to its survival. Even in pollutant-impacted waters, cyanobacteria enjoy a competitive advantage and cyanobacterial dominance can be the result. We propose that cyanobacteria have a distinct competitive advantage over many other aquatic microbes in polluted, iron-poor environments.
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Affiliation(s)
- Andrew J Ghio
- US Environmental Protection Agency, Chapel Hill, NC, USA.
- Human Studies Facility, 104 Mason Farm Road, Chapel Hill, NC, 27514, USA.
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3
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Muller FLL, Tankéré-Muller SPC, Tang CH. Terrigenous humic substances regulate the concentrations of dissolved Fe and Cu (but not Al, Mn, Ni or Zn) in the Gaoping River plume. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167374. [PMID: 37758148 DOI: 10.1016/j.scitotenv.2023.167374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/17/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023]
Abstract
The small mountainous rivers of Oceania discharge a large fraction of their dissolved and particulate load of materials within a very small percentage of the time. As a result, the yearly inputs and physicochemical forms of dissolved metals exported to the ocean by these rivers are poorly quantified. We investigated the wet-season distribution patterns of metals and fluorescent organic substances in the surface waters of the Gaoping River plume, SW Taiwan, under both moderate (Sep 2020) and strong flow conditions (Aug 2021). The mixing behaviour of both soluble (<5 kDa) and colloidal (>5 kDa) metals and fluorescent components was examined over the salinity range 3.0-32.2 in 2020 and 5.8-31.1 in 2021. We detected two humic-like and one protein-like fluorescent components, the same on both surveys. The humic-like components, C1 and C3, originated from the Gaoping River and correlated strongly with Cu and Fe, respectively. Component C3 showed a greater enrichment relative to C1 in the colloidal (C3/C1 > 0.8) than in the soluble phase (C3/C1 = 0.4). The protein-like component, C2, came from both terrestrial and marine sources and displayed a more complex mixing behaviour than the other two. One striking result was that the effective zero-salinity concentrations of Fe (∼300 nM) and Cu (∼23 nM) did not change significantly in response to a 10-fold increase in river discharge between Sep 2020 and Aug 2021. Similarly to Fe and Cu, the distribution patterns of Components C1 and C3 did not change significantly between the moderate and the strong plume, and C3 and C1 correlated strongly with Fe and Cu, respectively. We conclude that subtropical mountainous rivers can provide soil-derived humic substances which facilitate and regulate the delivery of Fe and Cu to the ocean, provided mountain forests are preserved.
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Affiliation(s)
- François L L Muller
- Department of Oceanography, National Sun Yat-sen University, 70 Lienhai Road, Kaohsiung 80424, Taiwan.
| | | | - Chuan-Ho Tang
- National Museum of Marine Biology and Aquarium, 2 Houwan Road, Checheng, Pingtung 94450, Taiwan
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4
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Fourquez M, Janssen DJ, Conway TM, Cabanes D, Ellwood MJ, Sieber M, Trimborn S, Hassler C. Chasing iron bioavailability in the Southern Ocean: Insights from Phaeocystis antarctica and iron speciation. SCIENCE ADVANCES 2023; 9:eadf9696. [PMID: 37379397 DOI: 10.1126/sciadv.adf9696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 05/24/2023] [Indexed: 06/30/2023]
Abstract
Dissolved iron (dFe) availability limits the uptake of atmospheric CO2 by the Southern Ocean (SO) biological pump. Hence, any change in bioavailable dFe in this region can directly influence climate. On the basis of Fe uptake experiments with Phaeocystis antarctica, we show that the range of dFe bioavailability in natural samples is wider (<1 to ~200% compared to free inorganic Fe') than previously thought, with higher bioavailability found near glacial sources. The degree of bioavailability varied regardless of in situ dFe concentration and depth, challenging the consensus that sole dFe concentrations can be used to predict Fe uptake in modeling studies. Further, our data suggest a disproportionately major role of biologically mediated ligands and encourage revisiting the role of humic substances in influencing marine Fe biogeochemical cycling in the SO. Last, we describe a linkage between in situ dFe bioavailability and isotopic signatures that, we anticipate, will stimulate future research.
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Affiliation(s)
- Marion Fourquez
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UMR 110, Marseille 13288, France
- University of Geneva, Department F.-A. Forel for Environmental and Aquatic Sciences, Geneva 1211, Switzerland
| | - David J Janssen
- Department Surface Waters, Eawag-Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Tim M Conway
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701, USA
| | - Damien Cabanes
- University of Geneva, Department F.-A. Forel for Environmental and Aquatic Sciences, Geneva 1211, Switzerland
| | - Michael J Ellwood
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
- Australian Centre for Excellence in Antarctic Science, Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | - Matthias Sieber
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701, USA
- Institute of Geochemistry and Petrology, ETH Zürich, Zürich, Switzerland
| | - Scarlett Trimborn
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven 27570, Germany
| | - Christel Hassler
- University of Geneva, Department F.-A. Forel for Environmental and Aquatic Sciences, Geneva 1211, Switzerland
- Institute of Earth Sciences, University of Lausanne, Lausanne 1015, Switzerland
- School of Architecture, Civil, and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Sion 1951, Switzerland
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5
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Xu F, Wang Z, Chen Y, Luo Y, Luo Z. Enhancing arsenate metabolism in Microcystis aeruginosa and relieving risks of arsenite and microcystins by nano-Fe 2O 3 under dissolved organic phosphorus conditions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 330:121801. [PMID: 37169240 DOI: 10.1016/j.envpol.2023.121801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 05/13/2023]
Abstract
Little information is available on how nano-Fe2O3 substituted iron ions as a possible iron source impacting on algal growth and arsenate (As(V)) metabolism under dissolved organic phosphorus (DOP) (D-glucose-6-phosphate (GP)) conditions. We investigated the growth of Microcystis aeruginosa and As(V) metabolism together with their metabolites in As(V) aquatic environments with nano-Fe2O3 and GP as the sole iron and P sources, respectively. Results showed that nano-Fe2O3 showed inhibitory effects on M. aeruginosa growth and microcystin (MCs) release under GP conditions in As(V) polluted water. There was little influence on As species changes in GP media under different nano-Fe2O3 concentrations except for obvious total As (TAs) removal in 100 mg L-1 nano-Fe2O3 levels. As(V) metabolism dominated with As(V) biotransformation in algal cells was facilitated and arsenite (As(III)) releasing risk was relieved clearly by nano-Fe2O3 under GP conditions. The dissolved organic matter (DOM) in media exhibited more fatty acid analogs containing -CO, -CH2 =CH2, and -CH functional groups with increasing nano-Fe2O3 concentrations, but the fluorescent analogs were relatively reduced especially for the fluorescent DOM dominated by aromatic protein-like tryptophan which was significantly inhibited by nano-Fe2O3. Thus, As methylation that was facilitated in M. aeruginosa by nano-Fe2O3 in GP environments also caused more organic substances to release that absorb infrared spectra while reducing the release risks of As(III) and MCs as well as protein-containing tryptophan fractions. From 1H-NMR analysis, this might be caused by the increased metabolites of aromatic compounds, organic acid/amino acid, and carbohydrates/glucose in algal cells. The findings are vital for a better understanding of nano-Fe2O3 role-playing in As bioremediation by microalgae and the subsequent potential aquatic ecological risks.
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Affiliation(s)
- Feng Xu
- College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Key Laboratory of Modern, Separation and Analysis Science and Technology, Key Laboratory of Pollution Monitoring and Control, Zhangzhou, 363000, China
| | - Zhenhong Wang
- College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Key Laboratory of Modern, Separation and Analysis Science and Technology, Key Laboratory of Pollution Monitoring and Control, Zhangzhou, 363000, China.
| | - Yan Chen
- College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Key Laboratory of Modern, Separation and Analysis Science and Technology, Key Laboratory of Pollution Monitoring and Control, Zhangzhou, 363000, China
| | - Yinchai Luo
- College of Chemical Engineering, Huaqiao University, Xiamen, 361021, China
| | - Zhuanxi Luo
- College of Chemical Engineering, Huaqiao University, Xiamen, 361021, China
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6
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Sukekava CF, Andrade CFFD, Niencheski LFH, de Souza MS, Laglera LM. Macronutrients, iron and humic substances summer cycling over the extended continental shelf of the South Brazil Bight. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 865:161182. [PMID: 36584442 DOI: 10.1016/j.scitotenv.2022.161182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/10/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
We surveyed macronutrients and dissolved iron (DFe) concentrations and speciation in a transect over the shelf of the South Brazil Bight (SBB) at Santa Marta Grande Cape (SE Brazil) during a coastal downwelling episode. Driven by dominant NE winds, coastal downwelling is a common feature during the austral summer and force after water convergence, with contribution of internal wave breaking at the shelf edge, upwelling of macronutrients into the nutrient-depleted waters of the southbound Brazil Current at ~100 km from the coastline. As a result, we found a plume of high turbidity that reached the euphotic layer, a deepening of the silicate, nitrate, and phosphate isolines over the shelf and a bulging of the nitrate and phosphate isolines over the shelf edge and the slope. Our first measurements of DFe concentration and speciation in the area revealed that against prior findings in other coastal areas, macronutrients, DFe, and iron ligand cycles were disentangled. Higher DFe concentrations were often found at the surface indicating aerial deposition. Secondary DFe maxima over the sediment-water interface and in the upwelled plume indicated DFe fluxes from the sediment and from resuspended instable colloids. Iron ligand concentrations were higher than DFe concentrations in most stations with a clear land-to-ocean gradient. Subtraction of HS iron ligands revealed that except in upwelled water, the bulk of surface ligands was the result of local biological processes. The analysis of the concentrations of Fe-HS complexes showed that the contribution of HS to DFe was dominant in upwelled waters, significant in waters close to the coast, but nearly negligible in the rest of the studied area. We hypothesize that the injection of iron-humic complexes into the euphotic layer during summer upwelling episodes is the key to understanding the persistent high chlorophyll meanders found over the shelf edge of the SBB coast.
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Affiliation(s)
- Camila Fiaux Sukekava
- Instituto de Oceanografia, Fundação Universidade Federal do Rio Grande, Rio Grande 96203900, Brazil; Departamento de Química, Universidad de las Islas Baleares, Palma, Balearic Islands 07122, Spain.
| | | | | | - Marcio Silva de Souza
- Instituto de Oceanografia, Fundação Universidade Federal do Rio Grande, Rio Grande 96203900, Brazil
| | - Luis M Laglera
- Departamento de Química, Universidad de las Islas Baleares, Palma, Balearic Islands 07122, Spain
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West CP, Morales AC, Ryan J, Misovich MV, Hettiyadura APS, Rivera-Adorno F, Tomlin JM, Darmody A, Linn BN, Lin P, Laskin A. Molecular investigation of the multi-phase photochemistry of Fe(III)-citrate in aqueous solution. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:190-213. [PMID: 35634912 DOI: 10.1039/d1em00503k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Iron (Fe) is ubiquitous in nature and found as FeII or FeIII in minerals or as dissolved ions Fe2+ or Fe3+ in aqueous systems. The interactions of soluble Fe have important implications for fresh water and marine biogeochemical cycles, which have impacts on global terrestrial and atmospheric environments. Upon dissolution of FeIII into natural aquatic systems, organic carboxylic acids efficiently chelate FeIII to form [FeIII-carboxylate]2+ complexes that undergo a wide range of photochemistry-induced radical reactions. The chemical composition and photochemical transformations of these mixtures are largely unknown, making it challenging to estimate their environmental impact. To investigate the photochemical process of FeIII-carboxylates at the molecular level, we conduct a comprehensive experimental study employing UV-visible spectroscopy, liquid chromatography coupled to photodiode array and high-resolution mass spectrometry detection, and oil immersion flow microscopy. In this study, aqueous solutions of FeIII-citrate were photolyzed under 365 nm light in an experimental setup with an apparent quantum yield of (φ) ∼0.02, followed by chemical analyses of reacted mixtures withdrawn at increment time intervals of the experiment. The apparent photochemical reaction kinetics of Fe3+-citrates (aq) were expressed as two generalized consecutive reactions of with the experimental rate constants of j1 ∼ 0.12 min-1 and j2 ∼ 0.05 min-1, respectively. Molecular characterization results indicate that R and I consist of both water-soluble organic and Fe-organic species, while P compounds are a mixture of water-soluble and colloidal materials. The latter were identified as Fe-carbonaceous colloids formed at long photolysis times. The carbonaceous content of these colloids was identified as unsaturated organic species with low oxygen content and carbon with a reduced oxidation state, indicative of their plausible radical recombination mechanism under oxygen-deprived conditions typical for the extensively photolyzed mixtures. Based on the molecular characterization results, we discuss the comprehensive reaction mechanism of FeIII-citrate photochemistry and report on the formation of previously unexplored colloidal reaction products, which may contribute to atmospheric and terrestrial light-absorbing materials in aquatic environments.
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Affiliation(s)
- Christopher P West
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Ana C Morales
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Jackson Ryan
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Maria V Misovich
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | | | | | - Jay M Tomlin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Andrew Darmody
- Department of Aeronautics and Aerospace Engineering, Purdue University, West Lafayette, IN, USA
| | - Brittany N Linn
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Peng Lin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
- Department of Earth, Atmospheric & Planetary Sciences, Purdue University, West Lafayette, IN, USA
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8
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Kazamia E, Mach J, McQuaid JB, Gao X, Coale TH, Malych R, Camadro J, Lesuisse E, Allen AE, Bowler C, Sutak R. In vivo localization of iron starvation induced proteins under variable iron supplementation regimes in Phaeodactylum tricornutum. PLANT DIRECT 2022; 6:e472. [PMID: 36582220 PMCID: PMC9792268 DOI: 10.1002/pld3.472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/03/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
UNLABELLED The model pennate diatom Phaeodactylum tricornutum is able to assimilate a range of iron sources. It therefore provides a platform to study different mechanisms of iron processing concomitantly in the same cell. In this study, we follow the localization of three iron starvation induced proteins (ISIPs) in vivo, driven by their native promoters and tagged by fluorophores in an engineered line of P. tricornutum. We find that the localization patterns of ISIPs are dynamic and variable depending on the overall iron status of the cell and the source of iron it is exposed to. Notwithstanding, a shared destination of the three ISIPs both under ferric iron and siderophore-bound iron supplementation is a globular compartment in the vicinity of the chloroplast. In a proteomic analysis, we identify that the cell engages endocytosis machinery involved in the vesicular trafficking as a response to siderophore molecules, even when these are not bound to iron. Our results suggest that there may be a direct vesicle traffic connection between the diatom cell membrane and the periplastidial compartment (PPC) that co-opts clathrin-mediated endocytosis and the "cytoplasm to vacuole" (Cvt) pathway, for proteins involved in iron assimilation. Proteomics data are available via ProteomeXchange with identifier PXD021172. HIGHLIGHT The marine diatom P. tricornutum engages a vesicular network to traffic siderophores and phytotransferrin from the cell membrane directly to a putative iron processing site in the vicinity of the chloroplast.
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Affiliation(s)
- Elena Kazamia
- Institut de Biologie de l'ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERMUniversité PSLParisFrance
| | - Jan Mach
- Department of Parasitology, Faculty of ScienceCharles UniversityVestecCzech Republic
| | - Jeffrey B. McQuaid
- Microbial and Environmental GenomicsJ. Craig Venter InstituteLa JollaCaliforniaUSA
- The Alfred Wegener InstituteHelmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - Xia Gao
- Institut de Biologie de l'ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERMUniversité PSLParisFrance
| | - Tyler H. Coale
- Scripps Institution of Oceanography, Integrative Oceanography DivisionUniversity of California, San DiegoLa JollaCaliforniaUSA
| | - Ronald Malych
- Department of Parasitology, Faculty of ScienceCharles UniversityVestecCzech Republic
| | | | | | - Andrew E. Allen
- Microbial and Environmental GenomicsJ. Craig Venter InstituteLa JollaCaliforniaUSA
- Scripps Institution of Oceanography, Integrative Oceanography DivisionUniversity of California, San DiegoLa JollaCaliforniaUSA
| | - Chris Bowler
- Institut de Biologie de l'ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERMUniversité PSLParisFrance
| | - Robert Sutak
- Department of Parasitology, Faculty of ScienceCharles UniversityVestecCzech Republic
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9
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Facey JA, Violi JP, King JJ, Sarowar C, Apte SC, Mitrovic SM. The Influence of Micronutrient Trace Metals on Microcystis aeruginosa Growth and Toxin Production. Toxins (Basel) 2022; 14:toxins14110812. [PMID: 36422986 PMCID: PMC9694995 DOI: 10.3390/toxins14110812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Microcystis aeruginosa is a widespread cyanobacteria capable of producing hepatotoxic microcystins. Understanding the environmental factors that influence its growth and toxin production is essential to managing the negative effects on freshwater systems. Some micronutrients are important cofactors in cyanobacterial proteins and can influence cyanobacterial growth when availability is limited. However, micronutrient requirements are often species specific, and can be influenced by substitution between metals or by luxury uptake. In this study, M. aeruginosa was grown in modified growth media that individually excluded some micronutrients (cobalt, copper, iron, manganese, molybdenum) to assess the effect on growth, toxin production, cell morphology and iron accumulation. M. aeruginosa growth was limited when iron, cobalt and manganese were excluded from the growth media, whereas the exclusion of copper and molybdenum had no effect on growth. Intracellular microcystin-LR concentrations were variable and were at times elevated in treatments undergoing growth limitation by cobalt. Intracellular iron was notably higher in treatments grown in cobalt-deplete media compared to other treatments possibly due to inhibition or competition for transporters, or due to irons role in detoxifying reactive oxygen species (ROS).
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Affiliation(s)
- Jordan A. Facey
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2000, Australia
- Correspondence:
| | - Jake P. Violi
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2000, Australia
| | - Josh J. King
- CSIRO Land and Water, Lucas Heights, Sydney, NSW 2234, Australia
| | - Chowdhury Sarowar
- Prince of Wales Clinical School, University of New South Wales, Kensington, NSW 2052, Australia
| | - Simon C. Apte
- CSIRO Land and Water, Lucas Heights, Sydney, NSW 2234, Australia
| | - Simon M. Mitrovic
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2000, Australia
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10
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Fourquez M, Strzepek RF, Ellwood MJ, Hassler C, Cabanes D, Eggins S, Pearce I, Deppeler S, Trull TW, Boyd PW, Bressac M. Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy. Microorganisms 2022; 10:microorganisms10081655. [PMID: 36014073 PMCID: PMC9413495 DOI: 10.3390/microorganisms10081655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
In the Subantarctic sector of the Southern Ocean, vertical entrainment of iron (Fe) triggers the seasonal productivity cycle but diminishing physical supply during the spring to summer transition forces microbial assemblages to rapidly acclimate. Here, we tested how phytoplankton and bacteria within an isolated eddy respond to different dissolved Fe (DFe)/ligand inputs. We used three treatments: one that mimicked the entrainment of new DFe (Fe-NEW), another in which DFe was supplied from bacterial regeneration of particles (Fe-REG), and a control with no addition of DFe (Fe-NO). After 6 days, 3.5 (Fe-NO, Fe-NEW) to 5-fold (Fe-REG) increases in Chlorophyll a were observed. These responses of the phytoplankton community were best explained by the differences between the treatments in the amount of DFe recycled during the incubation (Fe-REG, 15% recycled c.f. 40% Fe-NEW, 60% Fe-NO). This additional recycling was more likely mediated by bacteria. By day 6, bacterial production was comparable between Fe-NO and Fe-NEW but was approximately two-fold higher in Fe-REG. A preferential response of phytoplankton (haptophyte-dominated) relative to high nucleic acid (HNA) bacteria was also found in the Fe-REG treatment while the relative proportion of diatoms increased faster in the Fe-NEW and Fe-NO treatments. Comparisons between light and dark incubations further confirmed the competition between picophytoplankton and HNA for DFe. Overall, our results demonstrate great versatility by microorganisms to use different Fe sources that results in highly efficient Fe recycling within surface waters. This study also encourages future research to further investigate the interactions between functional groups of microbes (e.g. HNA and cyanobacteria) to better constraint modeling in Fe and carbon biogeochemical cycles.
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Affiliation(s)
- Marion Fourquez
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UMR 110, 13288 Marseille, France
- Correspondence:
| | - Robert F. Strzepek
- Australian Antarctic Program Partnership (AAPP), Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
| | - Michael J. Ellwood
- Research School of Earth Sciences, Australian National University, Canberra 2601, Australia
| | - Christel Hassler
- Marine and Lake Biogeochemistry, Department F.-A. Forel, University of Geneva, 1205 Geneva, Switzerland
- Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland
| | - Damien Cabanes
- Marine and Lake Biogeochemistry, Department F.-A. Forel, University of Geneva, 1205 Geneva, Switzerland
| | - Sam Eggins
- Research School of Earth Sciences, Australian National University, Canberra 2601, Australia
| | - Imojen Pearce
- Australian Antarctic Division (AAD), Kingston 7050, Australia
| | - Stacy Deppeler
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- National Institute of Water and Atmospheric Research, Wellington 6021, New Zealand
| | - Thomas W. Trull
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
- Climate Science Centre, Oceans and Atmosphere, Commonwealth Scientific and Industrial Research Organisation, Hobart 7004, Australia
| | - Philip W. Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
| | - Matthieu Bressac
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Laboratoire d’Océanographie de Villefranche, Sorbonne Université, CNRS, 06230 Villefranche-sur-Mer, France
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11
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Kong L, Price NM. Light Stimulates Copper-Limited Growth of an Oceanic Diatom by Increasing Cellular Copper(II) Reduction─A Rate-Determining Step in Copper Uptake. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9103-9111. [PMID: 35549243 DOI: 10.1021/acs.est.2c01479] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Uptake of Cu by Thalassiosira oceanica requires that Cu(II) is reduced to Cu(I) prior to transport across the cell membrane. The reduction step is mediated biochemically by cellular reductases active with a broad range of Cu chemical species. Here, we report on the cellular Cu(II) reduction and Cu(I) uptake of a diatom under saturating and subsaturating irradiance. An increase in growth irradiance, from 50 to 400 μmol photons m-2 s-1, increased the rate of extracellular Cu(II) reduction and steady-state Cu uptake. Under these conditions, Cu-limited cells acquired Cu more efficiently and maintained faster rates of growth than Cu-limited cells in low light. Pseudo-first-order reaction rate constants were about 70-fold faster for Cu(I) uptake than for Cu(II) reduction so that reduction was the rate-determining step in Cu acquisition. Accordingly, steady-state Cu uptake rates predicted from the reduction rate constants agreed well with measured rates of Cu uptake obtained from cultures growing at low nanomolar Cu concentrations. Transcript abundance of putative Cu(II) reductases followed a similar pattern to cupric reductase activity, increasing in Cu-limited cells and with increasing growth irradiance. The results are significant in showing Cu(II) reduction as the rate-determining step in Cu uptake: they suggest that biologically mediated Cu(II) reduction may be an important part of the Cu cycle in surface waters of the open sea.
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Affiliation(s)
- Liangliang Kong
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada
- College of Marine Life Science, Ocean University of China, Qingdao 266001, Shandong, China
| | - Neil M Price
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada
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12
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Wang B, Chen M, Zheng M, Qiu Y. The biological uptake of dissolved iron in the changing Daya Bay, South China Sea: Effect of pH and DO. MARINE POLLUTION BULLETIN 2022; 178:113635. [PMID: 35421641 DOI: 10.1016/j.marpolbul.2022.113635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
The oceanic acidification and coastal hypoxia have potential to enhance biological uptake of dissolved iron (Fe) by phytoplankton. In this study, the Fe uptake rate (FeUR) in Daya Bay was significantly negatively correlated with pH and dissolved oxygen (DO) (r = -0.81 and -0.73, respectively, p < 0.001). In addition, binary regression (FeUR = -1.45 × pH - 0.10 × DO + 13.64) also indicated that both pH and DO played key roles in FeUR variations. As pH and DO decreased, Fe uptake by phytoplankton was promoted, and the contribution of nano-phytoplankton to Fe uptake increased significantly, while that of pico-FeUR decreased. These will result in the phytoplankton community to be miniaturized and Fe requirement of phytoplankton goes higher, thereby leading changes of phytoplankton composition and coastal ecosystem. This study helps to understand how Fe could affect the coastal ecosystem under the increasing anthropogenic influences.
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Affiliation(s)
- Bo Wang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, China
| | - Min Chen
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
| | - Minfang Zheng
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Yusheng Qiu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
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13
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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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14
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Wang H, Fan Y, Zhou M, Wang W, Li X, Wang Y. Function of Fe(III)-minerals in the enhancement of anammox performance exploiting integrated network and metagenomics analyses. WATER RESEARCH 2022; 210:117998. [PMID: 34968878 DOI: 10.1016/j.watres.2021.117998] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 12/06/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
Iron is a recognized physiological requirement for microorganisms but, for anaerobic ammonium oxidation (anammox) bacteria, its role extends well beyond that of a nutritional necessity. In this study, the function of two typical Fe(III)-minerals (ferrihydrite and magnetite) in anammox processes was evaluated in the absence/presence of Fe(II) by integrated network and metagenomics analyses. Results showed that Fe-(III) minerals addition increased the activity of cellular processes and pathways associated with granule formation, enabling the peak values of particle size to increase by 144% and 115%, respectively. Notably, ferrihydrite (5 mM) enhanced nitrogen removal by 4.8% and 4.1%, respectively, in the short-term and long-term absence of Fe(II). Ferrihydrite also promoted the retention of anammox bacteria affiliated with phylum Planctomycetes in the reactor, contributing to an 11% higher abundance with ferrihydrite amendment when compared with the control (without iron additions) in the short-term absence of Fe(II). Network-based analyses revealed that ferrihydrite facilitated the microbial community to form densely clustered and complex topologies to improve resistance to environmental disturbance (i.e., Fe(II) deficiency), and effectively increased the underlying cooperation and facilitation in the community. Metagenomic analysis revealed that there was limited promotion of anammox central metabolism by the extra addition of Fe(III)-minerals in the presence of Fe(II), highlighting the poor utilization of Fe(III)-minerals by anammox bacteria under Fe(II) sufficiency. This study deepens our understanding of the function of Fe(III)-minerals in anammox systems at the community and functional level, and provides a fundamental basis for developing Fe-based anammox enhancement technologies.
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Affiliation(s)
- Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P R China
| | - Yufei Fan
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P R China
| | - Mingda Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P R China
| | - Weigang Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P R China
| | - Xiang Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P R China.
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15
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Wu Z, Aharonovich D, Roth-Rosenberg D, Weissberg O, Luzzatto-Knaan T, Vogts A, Zoccarato L, Eigemann F, Grossart HP, Voss M, Follows MJ, Sher D. Single-cell measurements and modelling reveal substantial organic carbon acquisition by Prochlorococcus. Nat Microbiol 2022; 7:2068-2077. [PMID: 36329198 PMCID: PMC9712107 DOI: 10.1038/s41564-022-01250-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 09/13/2022] [Indexed: 11/06/2022]
Abstract
Marine phytoplankton are responsible for about half of the photosynthesis on Earth. Many are mixotrophs, combining photosynthesis with heterotrophic assimilation of organic carbon, but the relative contribution of these two lifestyles is unclear. Here single-cell measurements reveal that Prochlorococcus at the base of the photic zone in the Eastern Mediterranean Sea obtain only ~20% of carbon required for growth by photosynthesis. This is supported by laboratory-calibrated calculations based on photo-physiology parameters and compared with in situ growth rates. Agent-based simulations show that mixotrophic cells could grow tens of metres deeper than obligate photo-autotrophs, deepening the nutricline by ~20 m. Time series from the North Atlantic and North Pacific indicate that, during thermal stratification, on average 8-10% of the Prochlorococcus cells live without enough light to sustain obligate photo-autotrophic populations. Together, these results suggest that mixotrophy underpins the ecological success of a large fraction of the global Prochlorococcus population and its collective genetic diversity.
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Affiliation(s)
- Zhen Wu
- grid.116068.80000 0001 2341 2786Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Dikla Aharonovich
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Dalit Roth-Rosenberg
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Osnat Weissberg
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Tal Luzzatto-Knaan
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Angela Vogts
- grid.423940.80000 0001 2188 0463Leibniz-Institute for Baltic Sea Research, Warnemuende, Germany
| | - Luca Zoccarato
- grid.419247.d0000 0001 2108 8097Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany
| | - Falk Eigemann
- grid.423940.80000 0001 2188 0463Leibniz-Institute for Baltic Sea Research, Warnemuende, Germany
| | - Hans-Peter Grossart
- grid.419247.d0000 0001 2108 8097Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany ,grid.11348.3f0000 0001 0942 1117Institute of Biochemistry and Biology, Potsdam University, Potsdam, Germany
| | - Maren Voss
- grid.423940.80000 0001 2188 0463Leibniz-Institute for Baltic Sea Research, Warnemuende, Germany
| | - Michael J. Follows
- grid.116068.80000 0001 2341 2786Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Daniel Sher
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
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16
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Malych R, Stopka P, Mach J, Kotabová E, Prášil O, Sutak R. Flow cytometry-based study of model marine microalgal consortia revealed an ecological advantage of siderophore utilization by the dinoflagellate Amphidinium carterae. Comput Struct Biotechnol J 2021; 20:287-295. [PMID: 35024100 PMCID: PMC8718654 DOI: 10.1016/j.csbj.2021.12.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/09/2022] Open
Abstract
Investigations of phytoplankton responses to iron stress in seawater are complicated by the fact that iron concentrations do not necessarily reflect bioavailability. Most studies to date have been based on single species or field samples and are problematic to interpret. Here, we report results from an experimental cocultivation model system that enabled us to evaluate interspecific competition as a function of iron content and form, and to study the effect of nutritional conditions on the proteomic profiles of individual species. Our study revealed that the dinoflagellate Amphidinium carterae was able to utilize iron from a hydroxamate siderophore, a strategy that could provide an ecological advantage in environments where siderophores present an important source of iron. Additionally, proteomic analysis allowed us to identify a potential candidate protein involved in iron acquisition from hydroxamate siderophores, a strategy that is largely unknown in eukaryotic phytoplankton.
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Key Words
- (s)PLS-DA, (sparse) partial least squares discriminant analysis
- AUC, area under curve
- Amphidinium carterae
- AtpE, ATP synthase
- BCS, bathocuproinedisulfonic acid disodium salt
- CREG1, cellular repressor of E1A stimulated genes 1
- DFOB, desferrioxamine B
- EDTA, ethylenediaminetetraacetic acid
- ENT, enterobactin
- FACS, fluorescence-activated cell sorting
- FBAI, fructose-bisphosphate aldolase I
- FBAII, fructose-bisphosphate aldolase II
- FBP1, putative ferrichrome-binding protein
- FOB, ferrioxamine B
- Flow cytometry
- ISIP, iron starvation induced protein
- Iron
- LHCX, light-harvesting complex subunits
- LL, long-term iron limitation
- LR, iron enrichment
- Marine microalgae
- NBD, nitrobenz-2-oxa-1,3-diazole
- NPQ, nonphotochemical quenching
- PAGE, polyacrylamide gel electrophoresis
- PSI, photosystem I
- PSII, photosystem II
- PetA, cytochrome b6/f
- Proteomics
- PsaC, photosystem I iron-sulfur center
- PsaD, photosystem I reaction center subunit II
- PsaE, photosystem I reaction center subunit IV
- PsaL, photosystem I reaction center subunit XI
- PsbC, photosystem II CP43 reaction center protein
- PsbV, cytochrome c-550
- RR, long-term iron sufficiency
- SOD1, superoxide dismutase [Cu-Zn]
- Siderophores
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Affiliation(s)
- Ronald Malych
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech
| | - Pavel Stopka
- Department of Zoology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech
| | - Jan Mach
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech
| | - Eva Kotabová
- Institute of Microbiology, Academy of Sciences, Centrum Algatech, Trebon, Czech
| | - Ondřej Prášil
- Institute of Microbiology, Academy of Sciences, Centrum Algatech, Trebon, Czech
| | - Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech
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17
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Shaked Y, Twining BS, Tagliabue A, Maldonado MT. Probing the Bioavailability of Dissolved Iron to Marine Eukaryotic Phytoplankton Using In Situ Single Cell Iron Quotas. GLOBAL BIOGEOCHEMICAL CYCLES 2021; 35:e2021GB006979. [PMID: 35865367 PMCID: PMC9286392 DOI: 10.1029/2021gb006979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/09/2021] [Accepted: 06/29/2021] [Indexed: 05/08/2023]
Abstract
We present a new approach for quantifying the bioavailability of dissolved iron (dFe) to oceanic phytoplankton. Bioavailability is defined using an uptake rate constant (kin-app) computed by combining data on: (a) Fe content of individual in situ phytoplankton cells; (b) concurrently determined seawater dFe concentrations; and (c) growth rates estimated from the PISCES model. We examined 930 phytoplankton cells, collected between 2002 and 2016 from 45 surface stations during 11 research cruises. This approach is only valid for cells that have upregulated their high-affinity Fe uptake system, so data were screened, yielding 560 single cell k in-app values from 31 low-Fe stations. We normalized k in-app to cell surface area (S.A.) to account for cell-size differences. The resulting bioavailability proxy (k in-app/S.A.) varies among cells, but all values are within bioavailability limits predicted from defined Fe complexes. In situ dFe bioavailability is higher than model Fe-siderophore complexes and often approaches that of highly available inorganic Fe'. Station averaged k in-app/S.A. are also variable but show no systematic changes across location, temperature, dFe, and phytoplankton taxa. Given the relative consistency of k in-app/S.A. among stations (ca. five-fold variation), we computed a grand-averaged dFe availability, which upon normalization to cell carbon (C) yields k in-app/C of 42,200 ± 11,000 L mol C-1 d-1. We utilize k in-app/C to calculate dFe uptake rates and residence times in low Fe oceanic regions. Finally, we demonstrate the applicability of k in-app/C for constraining Fe uptake rates in earth system models, such as those predicting climate mediated changes in net primary production in the Fe-limited Equatorial Pacific.
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Affiliation(s)
- Yeala Shaked
- Freddy and Nadine Herrmann Institute of Earth SciencesHebrew UniversityJerusalemIsrael
- Interuniversity Institute for Marine SciencesEilatIsrael
| | | | | | - Maria T. Maldonado
- Department of Earth, Ocean and Atmospheric SciencesUniversity of British ColumbiaVancouverCanada
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18
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McCain JSP, Tagliabue A, Susko E, Achterberg EP, Allen AE, Bertrand EM. Cellular costs underpin micronutrient limitation in phytoplankton. SCIENCE ADVANCES 2021; 7:7/32/eabg6501. [PMID: 34362734 PMCID: PMC8346223 DOI: 10.1126/sciadv.abg6501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/22/2021] [Indexed: 05/08/2023]
Abstract
Micronutrients control phytoplankton growth in the ocean, influencing carbon export and fisheries. It is currently unclear how micronutrient scarcity affects cellular processes and how interdependence across micronutrients arises. We show that proximate causes of micronutrient growth limitation and interdependence are governed by cumulative cellular costs of acquiring and using micronutrients. Using a mechanistic proteomic allocation model of a polar diatom focused on iron and manganese, we demonstrate how cellular processes fundamentally underpin micronutrient limitation, and how they interact and compensate for each other to shape cellular elemental stoichiometry and resource interdependence. We coupled our model with metaproteomic and environmental data, yielding an approach for estimating biogeochemical metrics, including taxon-specific growth rates. Our results show that cumulative cellular costs govern how environmental conditions modify phytoplankton growth.
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Affiliation(s)
- J Scott P McCain
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Edward Susko
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Eric P Achterberg
- GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany
| | - Andrew E Allen
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, CA 92037, USA
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA
| | - Erin M Bertrand
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
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19
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Krachler R, Krachler RF. Northern High-Latitude Organic Soils As a Vital Source of River-Borne Dissolved Iron to the Ocean. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9672-9690. [PMID: 34251212 DOI: 10.1021/acs.est.1c01439] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Organic soils in the Arctic-boreal region produce small aquatic humic ligands (SAHLs), a category of naturally occurring complexing agents for iron. Every year, large amounts of SAHLs-loaded with iron mobilized in river basins-reach the oceans via river runoff. Recent studies have shown that a fraction of SAHLs belong to the group of strong iron-binding ligands in the ocean. That means, their Fe(III) complexes withstand dissociation even under the conditions of extremely high dilution in the open ocean. Fe(III)-loaded SAHLs are prone to UV-photoinduced ligand-to-metal charge-transfer which leads to disintegration of the complex and, as a consequence, to enhanced concentrations of bioavailable dissolved Fe(II) in sunlit upper water layers. On the other hand, in water depths below the penetration depth of UV, the Fe(III)-loaded SAHLs are fairly resistant to degradation which makes them ideally suited as long-lived molecular transport vehicles for river-derived iron in ocean currents. At locations where SAHLs are present in excess, they can bind to iron originating from various sources. For example, SAHLs were proposed to contribute substantially to the stabilization of hydrothermal iron in deep North Atlantic waters. Recent discoveries have shown that SAHLs, supplied by the Arctic Great Rivers, greatly improve dissolved iron concentrations in the Arctic Ocean and the North Atlantic Ocean. In these regions, SAHLs play a critical role in relieving iron limitation of phytoplankton, thereby supporting the oceanic sink for anthropogenic CO2. The present Critical Review describes the most recent findings and highlights future research directions.
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Affiliation(s)
- Regina Krachler
- Institute of Inorganic Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; http://anorg-chemie.univie.ac.at
| | - Rudolf F Krachler
- Institute of Inorganic Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; http://anorg-chemie.univie.ac.at
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20
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Böckmann S, Koch F, Meyer B, Pausch F, Iversen M, Driscoll R, Laglera LM, Hassler C, Trimborn S. Salp fecal pellets release more bioavailable iron to Southern Ocean phytoplankton than krill fecal pellets. Curr Biol 2021; 31:2737-2746.e3. [DOI: 10.1016/j.cub.2021.02.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 12/29/2022]
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21
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Iron transport in cyanobacteria - from molecules to communities. Trends Microbiol 2021; 30:229-240. [PMID: 34175176 DOI: 10.1016/j.tim.2021.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 11/22/2022]
Abstract
Iron is an essential micronutrient for the ecologically important photoautotrophic cyanobacteria which are found across diverse aquatic environments. Low concentrations and poor bioavailability of certain iron species exert a strong control on cyanobacterial growth, affecting ecosystem structure and biogeochemical cycling. Here, we review the iron-acquisition pathways cyanobacteria utilize for overcoming these challenges. As the molecular details of cyanobacterial iron transport are being uncovered, an overall scheme of how cyanobacteria handle and exploit this scarce and redox-active micronutrient is emerging. Importantly, the range of biological solutions used by cyanobacteria to increase iron fluxes goes beyond transport and includes behavioral traits of colonial cyanobacteria and intricate cyanobacteria-bacteria interactions.
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22
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Li B, Zhang X, Deng J, Cheng Y, Chen Z, Qin B, Tefsen B, Wells M. A new perspective of copper-iron effects on bloom-forming algae in a highly impacted environment. WATER RESEARCH 2021; 195:116889. [PMID: 33735628 DOI: 10.1016/j.watres.2021.116889] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/23/2020] [Accepted: 01/31/2021] [Indexed: 06/12/2023]
Abstract
Relatively little work has been done on the role of micronutrients in influencing development and progression of harmful algal blooms, yet micronutrients are ineluctably required for growth. Relatively small changes in micronutrient status have wide-ranging consequences. Here, we report results from mesocosm experiments with Microcystis and Desmodesmus spp., in mono- and mixed-cultures, to probe questions of how copper, iron, and copper-iron amendments affect growth, short-term assemblage progression, and production of siderophore, chalkophore, and microcystin in lake water from a large, hypereutrophic lake (Taihu, China). Our approach offers an entirely new perspective to understanding micronutrient dynamics in aqueous environments, as this is the first work to systematically screen for chalkophores and siderophores separately, as a function of copper/iron amendment, and using community trajectory analysis. Singular findings are summarized as follows: 1) unlike lab-based studies, in our work we observe neither dramatic copper-modulation of iron demand, nor evidence of an iron-protective effect from copper toxicity. 2) The interplay between chalkophore/siderophore production supports a concept model wherein Microcystis spp. varies behavior to individually and uniquely manage copper/iron requirements in a phased manner. In being able to specifically screen for chalkophores, we observe a previously unreported link between chalkophore and microcystin production that may relate to iron-limitation. 3) Regarding harmful algal bloom (HAB) persistance, the lake water itself influences mesocosm changes; differentiated effects for iron regarding growth indicators and/or reduction of Fe-limitation stress were found at an HAB-free field station (Xukou Bay), likely a consequence of low bioavailability of iron in this station as compared to HAB-impacted stations (half the initial dissolved iron concentration, persisting throughout experiments). The low dissolved iron accompanies more intense chalkophore/siderophore community trajectories.
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Affiliation(s)
- Boling Li
- Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool L69 7ZX, United Kingdom; Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China
| | - Xiaokai Zhang
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Jianming Deng
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yili Cheng
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China
| | - Zheng Chen
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China
| | - Boqiang Qin
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Boris Tefsen
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China; Ronin Institute, Montclair, NJ 07043, United States.
| | - Mona Wells
- Environmental Sciences, Hawkes Bay Regional Council, Napier 4110, New Zealand.
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23
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Shafiee RT, Diver PJ, Snow JT, Zhang Q, Rickaby REM. Marine ammonia-oxidising archaea and bacteria occupy distinct iron and copper niches. ISME COMMUNICATIONS 2021; 1:1. [PMID: 37938628 PMCID: PMC9723733 DOI: 10.1038/s43705-021-00001-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/11/2020] [Accepted: 01/06/2021] [Indexed: 12/22/2022]
Abstract
Ammonia oxidation by archaea and bacteria (AOA and AOB), is the first step of nitrification in the oceans. As AOA have an ammonium affinity 200-fold higher than AOB isolates, the chemical niche allowing AOB to persist in the oligotrophic ocean remains unclear. Here we show that marine isolates, Nitrosopumilus maritimus strain SCM1 (AOA) and Nitrosococcus oceani strain C-107 (AOB) have contrasting physiologies in response to the trace metals iron (Fe) and copper (Cu), holding potential implications for their niche separation in the oceans. A greater affinity for unchelated Fe may allow AOB to inhabit shallower, euphotic waters where ammonium supply is high, but competition for Fe is rife. In contrast to AOB, AOA isolates have a greater affinity and toxicity threshold for unchelated Cu providing additional explanation to the greater success of AOA in the marine environment where Cu availability can be highly variable. Using comparative genomics, we predict that the proteomic and metal transport basis giving rise to contrasting physiologies in isolates is widespread across phylogenetically diverse marine AOA and AOB that are not yet available in pure culture. Our results develop the testable hypothesis that ammonia oxidation may be limited by Cu in large tracts of the open ocean and suggest a relatively earlier emergence of AOB than AOA when considered in the context of evolving trace metal availabilities over geologic time.
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Affiliation(s)
- Roxana T Shafiee
- Department of Earth Sciences, University of Oxford, Oxfordshire, UK.
| | - Poppy J Diver
- Department of Earth Sciences, University of Oxford, Oxfordshire, UK
| | - Joseph T Snow
- Department of Earth Sciences, University of Oxford, Oxfordshire, UK
| | - Qiong Zhang
- Department of Earth Sciences, University of Oxford, Oxfordshire, UK
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24
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Gao X, Bowler C, Kazamia E. Iron metabolism strategies in diatoms. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2165-2180. [PMID: 33693565 PMCID: PMC7966952 DOI: 10.1093/jxb/eraa575] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 03/03/2021] [Indexed: 05/28/2023]
Abstract
Diatoms are one of the most successful group of photosynthetic eukaryotes in the contemporary ocean. They are ubiquitously distributed and are the most abundant primary producers in polar waters. Equally remarkable is their ability to tolerate iron deprivation and respond to periodic iron fertilization. Despite their relatively large cell sizes, diatoms tolerate iron limitation and frequently dominate iron-stimulated phytoplankton blooms, both natural and artificial. Here, we review the main iron use strategies of diatoms, including their ability to assimilate and store a range of iron sources, and the adaptations of their photosynthetic machinery and architecture to iron deprivation. Our synthesis relies on published literature and is complemented by a search of 82 diatom transcriptomes, including information collected from seven representatives of the most abundant diatom genera in the world's oceans.
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Affiliation(s)
- Xia Gao
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Chris Bowler
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Elena Kazamia
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
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25
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Blanco-Ameijeiras S, Cabanes DJE, Cable RN, Trimborn S, Jacquet S, Wiegmann S, Völkner C, Lelchat F, Bracher A, Duhaime MB, Hassler CS. Exopolymeric Substances Control Microbial Community Structure and Function by Contributing to both C and Fe Nutrition in Fe-Limited Southern Ocean Provinces. Microorganisms 2020; 8:E1980. [PMID: 33322799 PMCID: PMC7763086 DOI: 10.3390/microorganisms8121980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/02/2020] [Accepted: 12/05/2020] [Indexed: 11/23/2022] Open
Abstract
Organic ligands such as exopolymeric substances (EPS) are known to form complexes with iron (Fe) and modulate phytoplankton growth. However, the effect of organic ligands on bacterial and viral communities remains largely unknown. Here, we assessed how Fe associated with organic ligands influences phytoplankton, microbial, and viral abundances and their diversity in the Southern Ocean. While the particulate organic carbon (POC) was modulated by Fe chemistry and bioavailability in the Drake Passage, the abundance and diversity of microbes and viruses were not governed by Fe bioavailability. Only following amendments with bacterial EPS did bacterial abundances increase, while phenotypic alpha diversity of bacterial and viral communities decreased. The latter was accompanied by significantly enhanced POC, pointing toward the relief of C limitation or other drivers of the microbial loop. Based on the literature and our findings, we propose a conceptual framework by which EPS may affect phytoplankton, bacteria, and viruses. Given the importance of the Southern Ocean for Earth's climate as well as the prevalence of viruses and their increasingly recognized impact on marine biogeochemistry and C cycling; the role of microbe-virus interactions on primary productivity in the Southern Ocean needs urgent attention.
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Affiliation(s)
- Sonia Blanco-Ameijeiras
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva—Faculty of Science, Boulevard Carl-Vogt 66, 1211 Geneva, Switzerland; (S.B.-A.); (D.J.E.C.); (F.L.); (C.S.H.)
| | - Damien J. E. Cabanes
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva—Faculty of Science, Boulevard Carl-Vogt 66, 1211 Geneva, Switzerland; (S.B.-A.); (D.J.E.C.); (F.L.); (C.S.H.)
| | - Rachel N. Cable
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; (R.N.C.); (M.B.D.)
| | - Scarlett Trimborn
- Sections Ecological Chemistry and Physical Oceanography, Alfred Wegener Institute—Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany; (S.W.); (C.V.); (A.B.)
- Department Marine Botany, University of Bremen, Leobener Strasse NW2-A, 28359 Bremen, Germany
| | - Stéphan Jacquet
- INRAE, UMR CARRTEL, Université Savoie Mont-Blanc, 75bis Avenue de Corzent, 74200 Thonon-les-Bains, France ;
| | - Sonja Wiegmann
- Sections Ecological Chemistry and Physical Oceanography, Alfred Wegener Institute—Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany; (S.W.); (C.V.); (A.B.)
| | - Christian Völkner
- Sections Ecological Chemistry and Physical Oceanography, Alfred Wegener Institute—Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany; (S.W.); (C.V.); (A.B.)
| | - Florian Lelchat
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva—Faculty of Science, Boulevard Carl-Vogt 66, 1211 Geneva, Switzerland; (S.B.-A.); (D.J.E.C.); (F.L.); (C.S.H.)
- Leo Viridis, 245 rue René Descartes, 29280 Plouzané, Bretagne, France
| | - Astrid Bracher
- Sections Ecological Chemistry and Physical Oceanography, Alfred Wegener Institute—Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany; (S.W.); (C.V.); (A.B.)
- Institute of Environmental Physics, University Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Melissa B. Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; (R.N.C.); (M.B.D.)
| | - Christel S. Hassler
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva—Faculty of Science, Boulevard Carl-Vogt 66, 1211 Geneva, Switzerland; (S.B.-A.); (D.J.E.C.); (F.L.); (C.S.H.)
- Swiss Polar Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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26
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Hunnestad AV, Vogel AIM, Armstrong E, Digernes MG, Ardelan MV, Hohmann-Marriott MF. From the Ocean to the Lab-Assessing Iron Limitation in Cyanobacteria: An Interface Paper. Microorganisms 2020; 8:E1889. [PMID: 33260337 PMCID: PMC7760322 DOI: 10.3390/microorganisms8121889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/22/2022] Open
Abstract
Iron is an essential, yet scarce, nutrient in marine environments. Phytoplankton, and especially cyanobacteria, have developed a wide range of mechanisms to acquire iron and maintain their iron-rich photosynthetic machinery. Iron limitation studies often utilize either oceanographic methods to understand large scale processes, or laboratory-based, molecular experiments to identify underlying molecular mechanisms on a cellular level. Here, we aim to highlight the benefits of both approaches to encourage interdisciplinary understanding of the effects of iron limitation on cyanobacteria with a focus on avoiding pitfalls in the initial phases of collaboration. In particular, we discuss the use of trace metal clean methods in combination with sterile techniques, and the challenges faced when a new collaboration is set up to combine interdisciplinary techniques. Methods necessary for producing reliable data, such as High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS), Flow Injection Analysis Chemiluminescence (FIA-CL), and 77K fluorescence emission spectroscopy are discussed and evaluated and a technical manual, including the preparation of the artificial seawater medium Aquil, cleaning procedures, and a sampling scheme for an iron limitation experiment is included. This paper provides a reference point for researchers to implement different techniques into interdisciplinary iron studies that span cyanobacteria physiology, molecular biology, and biogeochemistry.
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Affiliation(s)
- Annie Vera Hunnestad
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.V.H.); (M.G.D.)
| | - Anne Ilse Maria Vogel
- PhotoSynLab, Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.I.M.V.); (M.F.H.-M.)
| | - Evelyn Armstrong
- NIWA/University of Otago Research Centre for Oceanography, Department of Chemistry, University of Otago, 9054 Dunedin, New Zealand;
| | - Maria Guadalupe Digernes
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.V.H.); (M.G.D.)
| | - Murat Van Ardelan
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.V.H.); (M.G.D.)
| | - Martin Frank Hohmann-Marriott
- PhotoSynLab, Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.I.M.V.); (M.F.H.-M.)
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27
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Qiu GW, Jiang HB, Lis H, Li ZK, Deng B, Shang JL, Sun CY, Keren N, Qiu BS. A unique porin meditates iron-selective transport through cyanobacterial outer membranes. Environ Microbiol 2020; 23:376-390. [PMID: 33196124 DOI: 10.1111/1462-2920.15324] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 11/02/2020] [Accepted: 11/12/2020] [Indexed: 10/23/2022]
Abstract
Cyanobacteria are globally important primary producers and nitrogen fixers with high iron demands. Low ambient dissolved iron concentrations in many aquatic environments mean that these organisms must maintain sufficient and selective transport of iron into the cell. However, the nature of iron transport pathways through the cyanobacterial outer membrane remains obscure. Here we present multiple lines of experimental evidence that collectively support the existence of a novel class of substrate-selective iron porin, Slr1908, in the outer membrane of the cyanobacterium Synechocystis sp. PCC 6803. Elemental composition analysis and short-term iron uptake assays with mutants in Slr1908 reveal that this protein is primarily involved in inorganic iron uptake and contributes less to the accumulation of other metals. Homologues of Slr1908 are widely distributed in both freshwater and marine cyanobacteria, most notably in unicellular marine diazotrophs. Complementary experiments with a homologue of Slr1908 in Synechococcus sp. PCC 7002 restored the phenotype of Synechocystis knockdown mutants, showing that this siderophore producing species also possesses a porin with a similar function in Fe transport. The involvement of a substrate-selective porins in iron uptake may allow cyanobacteria to tightly control iron flux into the cell, particularly in environments where iron concentrations fluctuate.
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Affiliation(s)
- Guo-Wei Qiu
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Hai-Bo Jiang
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Hagar Lis
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Zheng-Ke Li
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Bin Deng
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Jin-Long Shang
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Chuan-Yu Sun
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Nir Keren
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Bao-Sheng Qiu
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
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28
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Sutak R, Camadro JM, Lesuisse E. Iron Uptake Mechanisms in Marine Phytoplankton. Front Microbiol 2020; 11:566691. [PMID: 33250865 PMCID: PMC7676907 DOI: 10.3389/fmicb.2020.566691] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/19/2020] [Indexed: 12/20/2022] Open
Abstract
Oceanic phytoplankton species have highly efficient mechanisms of iron acquisition, as they can take up iron from environments in which it is present at subnanomolar concentrations. In eukaryotes, three main models were proposed for iron transport into the cells by first studying the kinetics of iron uptake in different algal species and then, more recently, by using modern biological techniques on the model diatom Phaeodactylum tricornutum. In the first model, the rate of uptake is dependent on the concentration of unchelated Fe species, and is thus limited thermodynamically. Iron is transported by endocytosis after carbonate-dependent binding of Fe(III)' (inorganic soluble ferric species) to phytotransferrin at the cell surface. In this strategy the cells are able to take up iron from very low iron concentration. In an alternative model, kinetically limited for iron acquisition, the extracellular reduction of all iron species (including Fe') is a prerequisite for iron acquisition. This strategy allows the cells to take up iron from a great variety of ferric species. In a third model, hydroxamate siderophores can be transported by endocytosis (dependent on ISIP1) after binding to the FBP1 protein, and iron is released from the siderophores by FRE2-dependent reduction. In prokaryotes, one mechanism of iron uptake is based on the use of siderophores excreted by the cells. Iron-loaded siderophores are transported across the cell outer membrane via a TonB-dependent transporter (TBDT), and are then transported into the cells by an ABC transporter. Open ocean cyanobacteria do not excrete siderophores but can probably use siderophores produced by other organisms. In an alternative model, inorganic ferric species are transported through the outer membrane by TBDT or by porins, and are taken up by the ABC transporter system FutABC. Alternatively, ferric iron of the periplasmic space can be reduced by the alternative respiratory terminal oxidase (ARTO) and the ferrous ions can be transported by divalent metal transporters (FeoB or ZIP). After reoxidation, iron can be taken up by the high-affinity permease Ftr1.
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Affiliation(s)
- Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czechia
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29
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Mausz MA, Segovia M, Larsen A, Berger SA, Egge JK, Pohnert G. High CO 2 concentration and iron availability determine the metabolic inventory in an Emiliania huxleyi-dominated phytoplankton community. Environ Microbiol 2020; 22:3863-3882. [PMID: 32656913 DOI: 10.1111/1462-2920.15160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/08/2020] [Indexed: 11/27/2022]
Abstract
Ocean acidification (OA), a consequence of anthropogenic carbon dioxide (CO2 ) emissions, strongly impacts marine ecosystems. OA also influences iron (Fe) solubility, affecting biogeochemical and ecological processes. We investigated the interactive effects of CO2 and Fe availability on the metabolome response of a natural phytoplankton community. Using mesocosms we exposed phytoplankton to ambient (390 μatm) or future CO2 levels predicted for the year 2100 (900 μatm), combined with ambient (4.5 nM) or high (12 nM) dissolved iron (dFe). By integrating over the whole phytoplankton community, we assigned functional changes based on altered metabolite concentrations. Our study revealed the complexity of phytoplankton metabolism. Metabolic profiles showed three stages in response to treatments and phytoplankton dynamics. Metabolome changes were related to the plankton group contributing respective metabolites, explaining bloom decline and community succession. CO2 and Fe affected metabolic profiles. Most saccharides, fatty acids, amino acids and many sterols significantly correlated with the high dFe treatment at ambient pCO2 . High CO2 lowered the abundance of many metabolites irrespective of Fe. However, sugar alcohols accumulated, indicating potential stress. We demonstrate that not only altered species composition but also changes in the metabolic landscape affecting the plankton community may change as a consequence of future high-CO2 oceans.
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Affiliation(s)
- Michaela A Mausz
- Department for Bioorganic Analytics, Friedrich Schiller University Jena, Lessingstr. 8, Jena, 07743, Germany.,Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Beutenbergstr. 11a, Jena, 07745, Germany.,School of Life Sciences, The University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, United Kingdom
| | - María Segovia
- Department of Ecology, Faculty of Sciences, University of Málaga, Bulevar Louis Pasteur s/n, Málaga, 29071, Spain
| | - Aud Larsen
- NORCE Norwegian Research Centre AS, Nygårdsgaten 112, Bergen, 5038, Norway.,Department of Biology, University of Bergen, Thormøhlensgaten 53A/B, Bergen, 5020, Norway
| | - Stella A Berger
- Department of Biology, University of Bergen, Thormøhlensgaten 53A/B, Bergen, 5020, Norway.,Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, Stechlin, 16775, Germany
| | - Jorun K Egge
- Department of Biology, University of Bergen, Thormøhlensgaten 53A/B, Bergen, 5020, Norway
| | - Georg Pohnert
- Department for Bioorganic Analytics, Friedrich Schiller University Jena, Lessingstr. 8, Jena, 07743, Germany
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30
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Kolodny Y, Zer H, Propper M, Yochelis S, Paltiel Y, Keren N. Marine cyanobacteria tune energy transfer efficiency in their light‐harvesting antennae by modifying pigment coupling. FEBS J 2020; 288:980-994. [DOI: 10.1111/febs.15371] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/24/2020] [Accepted: 05/15/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Yuval Kolodny
- Applied Physics Department The Hebrew University of Jerusalem Jerusalem Israel
- The Center for Nanoscience and Nanotechnology The Hebrew University of Jerusalem Jerusalem Israel
| | - Hagit Zer
- Department of Plant and Environmental Sciences The Alexander Silberman Institute of Life Sciences The Hebrew University of Jerusalem Jerusalem Israel
| | - Mor Propper
- Department of Plant and Environmental Sciences The Alexander Silberman Institute of Life Sciences The Hebrew University of Jerusalem Jerusalem Israel
| | - Shira Yochelis
- Applied Physics Department The Hebrew University of Jerusalem Jerusalem Israel
- The Center for Nanoscience and Nanotechnology The Hebrew University of Jerusalem Jerusalem Israel
| | - Yossi Paltiel
- Applied Physics Department The Hebrew University of Jerusalem Jerusalem Israel
- The Center for Nanoscience and Nanotechnology The Hebrew University of Jerusalem Jerusalem Israel
| | - Nir Keren
- Department of Plant and Environmental Sciences The Alexander Silberman Institute of Life Sciences The Hebrew University of Jerusalem Jerusalem Israel
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31
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Wang B, Chen M, Zheng M, Qiu Y. Responses of Two Coastal Algae (Skeletonema costatum and Chlorella vulgaris) to Changes in Light and Iron Levels 1. JOURNAL OF PHYCOLOGY 2020; 56:618-629. [PMID: 31965566 DOI: 10.1111/jpy.12972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Iron (Fe) is essential for phytoplankton growth and photosynthesis, and is proposed to be an important factor regulating algal blooms under replete major nutrients in coastal environments. Here, Skeletonema costatum, a typical red-tide diatom species, and Chlorella vulgaris, a widely distributed Chlorella, were chosen to examine carbon fixation and Fe uptake by coastal algae under dark and light conditions with different Fe levels. The cellular carbon fixation and intracellular Fe uptake were measured via 14 C and 55 Fe tracer assay, respectively. Cell growth, cell size, and chlorophyll-α concentration were measured to investigate the algal physiological variation in different treatments. Our results showed that cellular Fe uptake proceeds under dark and the uptake rates were comparable to or even higher than those in the light for both algal species. Fe requirements per unit carbon fixation were also higher in the dark resulting in higher Fe: C ratios. During the experimental period, high Fe addition significantly enhanced cellular carbon fixation and Fe uptake. Compared to C. vulgaris, S. costatum was the common dominant bloom species because of its lower Fe demand but higher Fe uptake rate. This study provides some of the first measurements of Fe quotas in coastal phytoplankton cells, and implies that light and Fe concentrations may influence the phytoplankton community succession when blooms occur in coastal ecosystems.
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Affiliation(s)
- Bo Wang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Min Chen
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Minfang Zheng
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Yusheng Qiu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
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32
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Sanvito F, Monticelli D. Fast iron speciation in seawater by catalytic Competitive Ligand Equilibration-Cathodic Stripping Voltammetry with tenfold sample size reduction. Anal Chim Acta 2020; 1113:9-17. [PMID: 32340671 DOI: 10.1016/j.aca.2020.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/19/2020] [Accepted: 04/02/2020] [Indexed: 11/17/2022]
Abstract
Iron speciation analysis in seawater is a fundamental step to understand the cycling of this element in oceanic waters, in view of its central role in regulating primary productivity and its connection to global planetary cycles. At present, analytical procedures are the bottleneck for speciation analysis, in term of both time and sample size requirement. Here we present a novel instrumental configuration for the speciation analysis of iron by the Competitive Ligand Equilibration - Cathodic Stripping Voltammetry (CLE-CSV) procedure. The new system features a 1 mL microcell and a silver wire pseudoreference enabling a tenfold reduction of the sample volume. 2,3-dihydroxynaphthalene was used as the complexing ligand and atmospheric oxygen as the catalytic enhancer because they ensured the best analytical performances in terms of detection capabilities. The side reaction coefficient for the FeDHN complex αFe'DHN was calibrated against EDTA and an average value of 9.25 for logK'Fe'DHN was calculated. The method was successfully validated in UV digested seawater using diethylenetriaminepentaacetic acid (DTPA), which has known stability constant for iron. The method was lastly applied to six samples from the Ross Sea water column (Antarctica), demonstrating its fit for purpose for the detection of trace amounts of iron ligands in seawater. Thanks to the employed instrumental configuration and the high sensitivity, the proposed method achieved a tenfold reduction in sample size, a tenfold increase in sensitivity compared with other methods employing DHN and halved the analysis time with respect to the fastest method reported in the literature. Half an hour is enough to measure a 12 point titration, making the analysis of at least three titrations per day feasible. It is expected that the application of this procedure will foster the sample throughput, thanks to the reduced analysis time, and make possible the analysis of limitedly available and challenging samples, like porewater and vent fluids via the tenfold reduction in sample size.
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Affiliation(s)
- F Sanvito
- Università degli Studi dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Via Valleggio 11, 22100, Como, Italy
| | - D Monticelli
- Università degli Studi dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Via Valleggio 11, 22100, Como, Italy.
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Koedooder C, Van Geersdaële R, Guéneuguès A, Bouget FY, Obernosterer I, Blain S. The interplay between iron limitation, light and carbon in the proteorhodopsin-containing Photobacterium angustum S14. FEMS Microbiol Ecol 2020; 96:5847691. [DOI: 10.1093/femsec/fiaa103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 05/25/2020] [Indexed: 01/01/2023] Open
Abstract
ABSTRACTIron (Fe) limitation is known to affect heterotrophic bacteria within the respiratory electron transport chain, therefore strongly impacting the overall intracellular energy production. We investigated whether the gene expression pattern of the light-sensitive proton pump, proteorhodopsin (PR), is influenced by varying light, carbon and Fe concentrations in the marine bacterium Photobacterium angustum S14 and whether PR can alleviate the physiological processes associated with Fe starvation. Our results show that the gene expression of PR increases as cells enter the stationary phase, irrespective of Fe-replete or Fe-limiting conditions. This upregulation is coupled to a reduction in cell size, indicating that PR gene regulation is associated with a specific starvation-stress response. We provide experimental evidence that PR gene expression does not result in an increased growth rate, cell abundance, enhanced survival or ATP concentration within the cell in either Fe-replete or Fe-limiting conditions. However, independent of PR gene expression, the presence of light did influence bacterial growth rates and maximum cell abundances under varying Fe regimes. Our observations support previous results indicating that PR phototrophy seems to play an important role within the stationary phase for several members of the Vibrionaceae family, but that the exact role of PR in Fe limitation remains to be further explored.
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Affiliation(s)
- Coco Koedooder
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/mer, France
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rémy Van Geersdaële
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/mer, France
| | - Audrey Guéneuguès
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/mer, France
| | - François-Yves Bouget
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/mer, France
| | - Ingrid Obernosterer
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/mer, France
| | - Stéphane Blain
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/mer, France
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Shaked Y, Buck KN, Mellett T, Maldonado MT. Insights into the bioavailability of oceanic dissolved Fe from phytoplankton uptake kinetics. THE ISME JOURNAL 2020; 14:1182-1193. [PMID: 32024947 PMCID: PMC7174416 DOI: 10.1038/s41396-020-0597-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 01/12/2020] [Accepted: 01/21/2020] [Indexed: 12/05/2022]
Abstract
Phytoplankton growth in large parts of the world ocean is limited by low availability of dissolved iron (dFe), restricting oceanic uptake of atmospheric CO2. The bioavailability of dFe in seawater is however difficult to appraise since it is bound by a variety of poorly characterized organic ligands. Here, we propose a new approach for evaluating seawater dFe bioavailability based on its uptake rate constant by Fe-limited cultured phytoplankton. We utilized seven phytoplankton species of diverse classes, sizes, and provenances to probe for dFe bioavailability in 12 seawater samples from several ocean basins and depths. All tested phytoplankton acquired organically bound Fe in any given sample at similar rates (after normalizing to cellular surface area), confirming that multiple, Fe-limited phytoplankton species can be used to probe dFe bioavailability in seawater. These phytoplankton-based uptake rate constants allowed us to compare water types, and obtain a grand average estimate of seawater dFe bioavailability. Among water types, dFe bioavailability varied by approximately four-fold, and did not clearly correlate with Fe concentrations or any of the measured Fe speciation parameters. Compared with well-studied Fe complexes, seawater dFe is more available than model siderophore Fe, but less available than inorganic Fe. Exposure of seawater to sunlight, however, significantly enhanced dFe bioavailability. The rate constants established in this work, not only facilitate comparison between water types, but also allow calculation of Fe uptake rates by phytoplankton in the ocean based on measured dFe concentrations. The approach established and verified in this study, opens a new way for determining dFe bioavailability in samples across the ocean, and enables modeling of in situ Fe uptake rates by phytoplankton using dFe concentrations from GEOTRACES datasets.
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Affiliation(s)
- Yeala Shaked
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel.
- Interuniversity Institute for Marine Sciences, Eilat, Israel.
| | - Kristen N Buck
- College of Marine Science, University of South Florida, Tampa, FL, USA
| | - Travis Mellett
- College of Marine Science, University of South Florida, Tampa, FL, USA
| | - Maria T Maldonado
- Earth, Ocean and Atmospheric Sciences Department, University of British Columbia, Vancouver, BC, Canada
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Anderson RF. GEOTRACES: Accelerating Research on the Marine Biogeochemical Cycles of Trace Elements and Their Isotopes. ANNUAL REVIEW OF MARINE SCIENCE 2020; 12:49-85. [PMID: 31337253 DOI: 10.1146/annurev-marine-010318-095123] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The biogeochemical cycles of trace elements and their isotopes (TEIs) constitute an active area of oceanographic research due to their role as essential nutrients for marine organisms and their use as tracers of oceanographic processes. Selected TEIs also provide diagnostic information about the physical, geological, and chemical processes that supply or remove solutes in the ocean. Many of these same TEIs provide information about ocean conditions in the past, as their imprint on marine sediments can be interpreted to reflect changes in ocean circulation, biological productivity, the ocean carbon cycle, and more. Other TEIs have been introduced as the result of human activities and are considered contaminants. The development and implementation of contamination-free methods for collecting and analyzing samples for TEIs revolutionized marine chemistry, revealing trace element distributions with oceanographically consistent features and new insights about the processes regulating them. Despite these advances, the volume and geographic coverage of high-quality TEI data by the end of the twentieth century were insufficient to constrain their global biogeochemical cycles. To accelerate progress in this field of research, marine geochemists developed a coordinated international effort to systematically study the marine biogeochemical cycles of TEIs-the GEOTRACES program. Following a decade of planning and implementation, GEOTRACES launched its main field effort in 2010. This review, roughly midway through the field program, summarizes the steps involved in designing the program, its management structure, and selected findings.
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Affiliation(s)
- Robert F Anderson
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA;
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Abstract
Diatoms can access inorganic iron with remarkable efficiency, but this process is contingent on carbonate ion concentration. As ocean acidification reduces carbonate concentration, inorganic iron uptake may be discouraged in favor of carbonate-independent uptake. We report details of an iron assimilation process that needs no carbonate but requires exogenous compounds produced by cooccurring organisms. We show this process to be critical for diatom growth at high siderophore concentrations, but ineffective at acquiring iron from low-affinity organic chelators or lithogenic particulates. Understanding the caveats associated with iron source preference in diatoms will help predict the impacts of climate change on microbial community structure in high-nitrate low-chlorophyll ecosystems. Iron uptake by diatoms is a biochemical process with global biogeochemical implications. In large regions of the surface ocean diatoms are both responsible for the majority of primary production and frequently experiencing iron limitation of growth. The strategies used by these phytoplankton to extract iron from seawater constrain carbon flux into higher trophic levels and sequestration into sediments. In this study we use reverse genetic techniques to target putative iron-acquisition genes in the model pennate diatom Phaeodactylum tricornutum. We describe components of a reduction-dependent siderophore acquisition pathway that relies on a bacterial-derived receptor protein and provides a viable alternative to inorganic iron uptake under certain conditions. This form of iron uptake entails a close association between diatoms and siderophore-producing organisms during low-iron conditions. Homologs of these proteins are found distributed across diatom lineages, suggesting the significance of siderophore utilization by diatoms in the marine environment. Evaluation of specific proteins enables us to confirm independent iron-acquisition pathways in diatoms and characterize their preferred substrates. These findings refine our mechanistic understanding of the multiple iron-uptake systems used by diatoms and help us better predict the influence of iron speciation on taxa-specific iron bioavailability.
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Shafiee RT, Snow JT, Zhang Q, Rickaby REM. Iron requirements and uptake strategies of the globally abundant marine ammonia-oxidising archaeon, Nitrosopumilus maritimus SCM1. THE ISME JOURNAL 2019; 13:2295-2305. [PMID: 31076641 PMCID: PMC6776035 DOI: 10.1038/s41396-019-0434-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/04/2019] [Accepted: 04/15/2019] [Indexed: 01/08/2023]
Abstract
Ammonia-oxidising archaea (AOA) mediate the rate-limiting step of nitrification, the central component of the marine nitrogen cycle that converts ammonia to nitrite then nitrate. Competition with phytoplankton for ammonium and light inhibition are considered to restrict AOA activity to below the photic zone, but observations of surface nitrification now demand a further understanding of the factors driving AOA distribution and activity. Pico- to nanomolar concentrations of iron (Fe) limit the growth of microorganisms in a significant portion of the world's surface oceans, yet there is no examination of the role of Fe in AOA growth despite the process of ammonia oxidation being considered to rely on the micronutrient. Here we investigate the Fe requirements and Fe uptake strategies of the Nitrosopumilus maritimus strain SCM1, a strain representative of globally abundant marine AOA. Using trace metal clean culturing techniques, we found that N. maritimus growth is determined by Fe availability, displaying a free inorganic Fe (Fe') half saturation constant 1-2 orders of magnitude greater for cell growth than numerous marine phytoplankton and heterotrophic bacterial species driven by a reduced affinity for Fe'. In addition, we discovered that whilst unable to produce siderophores to enhance access to Fe, N. maritimus is able to use the exogenous siderophore desferrioxamine B (DFB), likely through a reductive uptake pathway analogous to that demonstrated in phytoplankton. Our work suggests AOA growth in surface waters may be Fe limited and advances our understanding of AOA physiology on the cellular and mechanistic levels with implications for ecosystem dynamics and the biogeochemical N-cycle.
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Affiliation(s)
- Roxana T Shafiee
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK.
| | - Joseph T Snow
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK
| | - Qiong Zhang
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK
| | - Rosalind E M Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK
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Debeljak P, Toulza E, Beier S, Blain S, Obernosterer I. Microbial iron metabolism as revealed by gene expression profiles in contrasted Southern Ocean regimes. Environ Microbiol 2019; 21:2360-2374. [PMID: 30958628 PMCID: PMC6618146 DOI: 10.1111/1462-2920.14621] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/18/2019] [Accepted: 04/01/2019] [Indexed: 11/28/2022]
Abstract
Iron (Fe) is a limiting nutrient in large regions of the ocean, but the strategies of prokaryotes to cope with this micronutrient are poorly known. Using a gene-specific approach from metatranscriptomics data, we investigated seven Fe-related metabolic pathways in microbial communities from high nutrient low chlorophyll and naturally Fe-fertilized waters in the Southern Ocean. We observed major differences in the contribution of prokaryotic groups at different taxonomic levels to transcripts encoding Fe-uptake mechanisms, intracellular Fe storage and replacement and Fe-related pathways in the tricarboxylic acid (TCA) cycle. The composition of the prokaryotic communities contributing to the transcripts of a given Fe-related pathway was overall independent of the in situ Fe supply, indicating that microbial taxa utilize distinct Fe-related metabolic processes. Only a few prokaryotic groups contributed to the transcripts of more than one Fe-uptake mechanism, suggesting limited metabolic versatility. Taxa-specific expression of individual genes varied among prokaryotic groups and was substantially higher for all inspected genes in Fe-limited as compared to naturally fertilized waters, indicating the link between transcriptional state and Fe regime. Different metabolic strategies regarding low Fe concentrations in the Southern Ocean are discussed for two abundant prokaryotic groups, Pelagibacteraceae and Flavobacteriaceae.
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Affiliation(s)
- Pavla Debeljak
- Sorbonne UniversitéCNRS, Laboratoire d'Océanographie Microbienne, LOMICF‐66650 Banyuls/merFrance
- Department of Limnology and Bio‐OceanographyUniversity of Vienna, A‐1090ViennaAustria
| | - Eve Toulza
- Université Perpignan Via DomitiaIHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, F‐66860PerpignanFrance
| | - Sara Beier
- Leibniz Institute for Baltic Sea ResearchWarnemündeGermany
| | - Stephane Blain
- Sorbonne UniversitéCNRS, Laboratoire d'Océanographie Microbienne, LOMICF‐66650 Banyuls/merFrance
| | - Ingrid Obernosterer
- Sorbonne UniversitéCNRS, Laboratoire d'Océanographie Microbienne, LOMICF‐66650 Banyuls/merFrance
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Blanco-Ameijeiras S, Cabanes DJE, Hassler CS. Towards the development of a new generation of whole-cell bioreporters to sense iron bioavailability in oceanic systems-learning from the case of Synechococcus sp. PCC7002 iron bioreporter. J Appl Microbiol 2019; 127:1291-1304. [PMID: 30970168 DOI: 10.1111/jam.14277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 02/17/2019] [Accepted: 04/04/2019] [Indexed: 12/24/2022]
Abstract
Whole-cell bioreporters are genetically modified micro-organisms designed to sense bioavailable forms of nutrients or toxic compounds in aquatic systems. As they represent the most promising cost-efficient tools available for such purpose, engineering and use of bioreporters is rapidly growing in association with wide applicability. Bioreporters are urgently needed to determine phytoplankton iron (Fe) limitation, which has been reported in up to 30% of the ocean, with consequences affecting Earth's global carbon cycle and climate. This study presents a critical evaluation and optimization of the only Cyanobacteria bioreporter available to sense Fe limitation in marine systems (Synechococcus sp. PCC7002). The nonmonotonic biphasic dose-response curve between the bioreporters' signal and Fe bioavailability impairs an appropriate data interpretation, highlighting the need for new carefully designed bioreporters. Here, limitations under low Fe concentrations were related to cellular energy stress, nonlinear expression of the targeted promoter and siderophore expression. Furthermore, we provide critical standard criteria for the development of new Fe bioreporters. Finally, based on gene expression data under a range of marine Fe concentrations, we propose novel sensor genes for the development of new Cyanobacteria Fe bioreporters for distinct marine regions.
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Affiliation(s)
- S Blanco-Ameijeiras
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - D J E Cabanes
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - C S Hassler
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Geneva, Switzerland
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Menacherry SPM, Kim K, Lee W, Choi CH, Choi W. Ligand-Specific Dissolution of Iron Oxides in Frozen Solutions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13766-13773. [PMID: 30395706 DOI: 10.1021/acs.est.8b04484] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The freezing-enhanced dissolution of iron oxides by various ligands has been recently proposed as a new mechanism that may influence the supply of bioavailable iron in frozen environments. The ligand-induced dissolution of iron oxides is sensitively affected by the kind and concentration of ligands, pH, and kind of iron oxides. While most ligands are thought to be freeze-concentrated in the ice grain boundary region along with iron oxides to enhance the iron dissolution, this study found that some ligands, such as ascorbic acid, suppress the iron dissolution in frozen solution relative to that in aqueous solution. Such ligands are proposed to be preferentially incorporated in the ice lattice bulk and not freeze-concentrated in the liquid-like grain boundary. The experimental analysis estimated that the ionized forms of ligands (e.g., iodide ions) are hardly present in the ice bulk region (<3%) and enhance the iron dissolution in frozen solution (relative to that in aqueous solution), whereas some neutral ligands (e.g., undissociated ascorbic acid) are significantly trapped in the ice bulk (>50%) and suppress the iron dissolution compared to the aqueous counterpart. The present results reveal that the ligand-induced dissolution of iron oxide in frozen solution is not always enhanced relative to aqueous solution but depends upon the kind of ligand and experimental conditions.
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Affiliation(s)
- Sunil Paul M Menacherry
- Division of Environmental Science and Engineering , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
| | - Kitae Kim
- Korea Polar Research Institute (KOPRI) , Incheon 21990 , Korea
| | - Woojin Lee
- Department of Civil and Environmental Engineering , Nazarbayev University , Astana 010000 , Kazakhstan
| | - Cheol Ho Choi
- Department of Chemistry , Kyungpook National University , Daegu 41566 , Korea
| | - Wonyong Choi
- Division of Environmental Science and Engineering , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
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Outer Membrane Iron Uptake Pathways in the Model Cyanobacterium Synechocystis sp. Strain PCC 6803. Appl Environ Microbiol 2018; 84:AEM.01512-18. [PMID: 30076192 DOI: 10.1128/aem.01512-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 07/21/2018] [Indexed: 02/01/2023] Open
Abstract
Cyanobacteria are foundational drivers of global nutrient cycling, with high intracellular iron (Fe) requirements. Fe is found at extremely low concentrations in aquatic systems, however, and the ways in which cyanobacteria take up Fe are largely unknown, especially the initial step in Fe transport across the outer membrane. Here, we identified one TonB protein and four TonB-dependent transporters (TBDTs) of the energy-requiring Fe acquisition system and six porins of the passive diffusion Fe uptake system in the model cyanobacterium Synechocystis sp. strain PCC 6803. The results experimentally demonstrated that TBDTs not only participated in organic ferri-siderophore uptake but also in inorganic free Fe (Fe') acquisition. 55Fe uptake rate measurements showed that a TBDT quadruple mutant acquired Fe at a lower rate than the wild type and lost nearly all ability to take up ferri-siderophores, indicating that TBDTs are critical for siderophore uptake. However, the mutant retained the ability to take up Fe' at 42% of the wild-type Fe' uptake rate, suggesting additional pathways of Fe' acquisition besides TBDTs, likely by porins. Mutations in four of the six porin-encoding genes produced a low-Fe-sensitive phenotype, while a mutation in all six genes was lethal to cell survival. These diverse outer membrane Fe uptake pathways reflect cyanobacterial evolution and adaptation under a range of Fe regimes across aquatic systems.IMPORTANCE Cyanobacteria are globally important primary producers and contribute about 25% of global CO2 fixation. Low Fe bioavailability in surface waters is thought to limit the primary productivity in as much as 40% of the global ocean. The Fe acquisition strategies that cyanobacteria have evolved to overcome Fe deficiency remain poorly characterized. We experimentally characterized the key players and the cooperative work mode of two Fe uptake pathways, including an active uptake pathway and a passive diffusion pathway in the model cyanobacterium Synechocystis sp. PCC 6803. Our finding proved that cyanobacteria use ferri-siderophore transporters to take up Fe', and they shed light on the adaptive mechanisms of cyanobacteria to cope with widespread Fe deficiency across aquatic environments.
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Obando S. TA, Babykin MM, Zinchenko VV. A Cluster of Five Genes Essential for the Utilization of Dihydroxamate Xenosiderophores in Synechocystis sp. PCC 6803. Curr Microbiol 2018; 75:1165-1173. [DOI: 10.1007/s00284-018-1505-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/03/2018] [Indexed: 10/16/2022]
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Müller MN, Krabbenhöft A, Vollstaedt H, Brandini FP, Eisenhauer A. Stable isotope fractionation of strontium in coccolithophore calcite: Influence of temperature and carbonate chemistry. GEOBIOLOGY 2018; 16:297-306. [PMID: 29431278 DOI: 10.1111/gbi.12276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
Marine calcifying eukaryotic phytoplankton (coccolithophores) is a major contributor to the pelagic production of CaCO3 and plays an important role in the biogeochemical cycles of C, Ca and other divalent cations present in the crystal structure of calcite. The geochemical signature of coccolithophore calcite is used as palaeoproxy to reconstruct past environmental conditions and to understand the underlying physiological mechanisms (vital effects) and precipitation kinetics. Here, we present the stable Sr isotope fractionation between seawater and calcite (Δ88/86 Sr) of laboratory cultured coccolithophores in individual dependence of temperature and seawater carbonate chemistry. Coccolithophores were cultured within a temperature and a pCO2 range from 10 to 25°C and from 175 to 1,240 μatm, respectively. Both environmental drivers induced a significant linear increase in coccolith stable Sr isotope fractionation. The temperature correlation at constant pCO2 for Emiliania huxleyi and Coccolithus braarudii is expressed as Δ88/86 Sr = -7.611 × 10-3 T + 0.0061. The relation of Δ88/86 Sr to pCO2 was tested in Emiliania huxleyi at 10 and 20°C and resulted in Δ88/86 Sr = -5.394 × 10-5 pCO2 - 0.0920 and Δ88/86 Sr = -5.742 × 10-5 pCO2 - 0.1351, respectively. No consistent relationship was found between coccolith Δ88/86 Sr and cellular physiology impeding a direct application of fossil coccolith Δ88/86 Sr as coccolithophore productivity proxy. An overall significant correlation was detected between the elemental distribution coefficient (DSr ) and Δ88/86 Sr similar to inorganic calcite with a physiologically induced offset. Our observations indicate (i) that temperature and pCO2 induce specific effects on coccolith Δ88/86 Sr values and (ii) that strontium elemental ratios and stable isotope fractionation are mainly controlled by precipitation kinetics when embedded into the crystal lattice and subject to vital effects during the transmembrane transport from seawater to the site of calcification. These results provide an important step to develop a coccolith Δ88/86 Sr palaeoproxy complementing the existing toolbox of palaeoceanography.
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Affiliation(s)
- M N Müller
- Department of Oceanography, Federal University of Recife, Cidade Universitária, Recife, PE, Brazil
- Oceanographic Institute at the University of São Paulo, São Paulo, SP, Brazil
| | - A Krabbenhöft
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - H Vollstaedt
- Institute of Geological Science, University of Bern, Bern, Switzerland
| | - F P Brandini
- Oceanographic Institute at the University of São Paulo, São Paulo, SP, Brazil
| | - A Eisenhauer
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
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McQuaid JB, Kustka AB, Oborník M, Horák A, McCrow JP, Karas BJ, Zheng H, Kindeberg T, Andersson AJ, Barbeau KA, Allen AE. Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms. Nature 2018. [DOI: 10.1038/nature25982] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Mustoe GE. Biogenic Weathering: Solubilization of Iron from Minerals by Epilithic Freshwater Algae and Cyanobacteria. Microorganisms 2018; 6:microorganisms6010008. [PMID: 29342973 PMCID: PMC5874622 DOI: 10.3390/microorganisms6010008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 12/29/2017] [Accepted: 01/09/2018] [Indexed: 12/23/2022] Open
Abstract
A sandstone outcrop exposed to freshwater seepage supports a diverse assemblage of photosynthetic microbes. Dominant taxa are two cyanophytes (Oscillatoria sp., Rivularia sp.) and a unicellular green alga (Palmellococcus sp.). Less abundant taxa include a filamentous green alga, Microspora, and the desmid Cosmarium. Biologic activity is evidenced by measured levels of chlorophyll and lipids. Bioassay methods confirm the ability of these microbes to dissolve and metabolize Fe from ferruginous minerals. Chromatographic analysis reveals citric acid as the likely chelating agent; this low molecular weight organic acid is detectable in interstitial fluid in the sandstone, measured as 0.0756 mg/mL. Bioassays using a model organism, Synechoccus elongates strain UTEX 650, show that Fe availability varies among different ferruginous minerals. In decreasing order of Fe availability: magnetite > limonite > biotite > siderite > hematite. Biotite was selected for detailed study because it is the most abundant iron-bearing mineral in the sandstone. SEM images support the microbiologic evidence, showing weathering of biotite compared to relatively undamaged grains of other silicate minerals.
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Affiliation(s)
- George E Mustoe
- Geology Department, Western Washington University, Bellingham, WA 98225, USA.
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Moreno CM, Lin Y, Davies S, Monbureau E, Cassar N, Marchetti A. Examination of gene repertoires and physiological responses to iron and light limitation in Southern Ocean diatoms. Polar Biol 2017. [DOI: 10.1007/s00300-017-2228-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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47
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Babykin MM, Obando TSA, Zinchenko VV. TonB-Dependent Utilization of Dihydroxamate Xenosiderophores in Synechocystis sp. PCC 6803. Curr Microbiol 2017; 75:117-123. [PMID: 28900692 DOI: 10.1007/s00284-017-1355-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/06/2017] [Indexed: 01/04/2023]
Abstract
In Gram-negative bacteria, transport of ferric siderophores through outer membrane is a complex process that requires specific outer membrane transporters and energy-transducing TonB-ExbB-ExbD system in the cytoplasmic membrane. The genome of the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 encodes all putative components of the siderophore-mediated iron uptake system. So far, there has been no experimental evidence for the existence of such a pathway in this organism. On the contrary, its reductive iron uptake pathway has been studied in detail. We demonstrate that Synechocystis sp. PCC 6803 is capable of using dihydroxamate xenosiderophores, either ferric schizokinen (FeSK) or a siderophore of the filamentous cyanobacterium Anabaena variabilis ATCC 29413 (SAV), as the sole source of iron. Inactivation of the tonB gene or the exbB1-exbD1 gene cluster resulted in an inability to utilize these siderophores. At the same time, the inactivation of the feoB gene encoding FeoB plasma membrane ferrous iron transporter, or one of the futB or futC genes encoding permease and ATPase subunit of FutABC ferric iron transporter, did not impair the ability of cells to utilize FeSK or SAV as the sole source of iron for growth. Our data suggest that cyanobacterium Synechocystis sp. PCC 6803 is capable of acquiring iron-siderophore complexes in a TonB-dependent manner without iron reduction in the periplasm.
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Affiliation(s)
- Michael M Babykin
- International Biotechnological Centre, Moscow State University, Moscow, Russian Federation, 119991
| | - Tobias S A Obando
- Department of Genetics, Moscow State University, Moscow, Russian Federation, 119991
| | - Vladislav V Zinchenko
- Department of Genetics, Moscow State University, Moscow, Russian Federation, 119991.
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48
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Intraspecific variability in Phaeocystis antarctica's response to iron and light stress. PLoS One 2017; 12:e0179751. [PMID: 28692685 PMCID: PMC5503234 DOI: 10.1371/journal.pone.0179751] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 06/02/2017] [Indexed: 12/13/2022] Open
Abstract
Phaeocystis antarctica is an abundant phytoplankton species in the Southern Ocean, where growth is frequently limited by iron and light. Being able to grow under low iron conditions is essential to the species’ success, but there have been hints that this ability differs among clones. Here, we compare the growth, cell size and chlorophyll a concentrations of four P. antarctica clones cultured under different iron and light conditions. Iron was provided either as unchelated iron (Fe′) or bound to the bacterial siderophore desferrioxamine B, representing, respectively, the most and least bioavailable forms of iron which phytoplankton encounter in the marine environment. The growth rate data demonstrate that the clones vary in their ability to grow using organically bound iron, and that this ability is not related to their ability to grow at low inorganic iron concentrations. These results are consistent at low and high light. Physiologically, only three of the four clones shrink or decrease the concentration of chlorophyll a in response to iron limitation, and only one clone decreases colony formation. Together, our data show that P. antarctica clones 1) respond to the same degree of iron limitation using different acclimation strategies, and 2) vary in their ability to grow under the same external iron and light conditions. This physiological diversity is surprisingly large for isolates of a single phytoplankton species.
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49
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Tagliabue A, Bowie AR, Boyd PW, Buck KN, Johnson KS, Saito MA. The integral role of iron in ocean biogeochemistry. Nature 2017; 543:51-59. [PMID: 28252066 DOI: 10.1038/nature21058] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 12/06/2016] [Indexed: 11/09/2022]
Abstract
The micronutrient iron is now recognized to be important in regulating the magnitude and dynamics of ocean primary productivity, making it an integral component of the ocean's biogeochemical cycles. In this Review, we discuss how a recent increase in observational data for this trace metal has challenged the prevailing view of the ocean iron cycle. Instead of focusing on dust as the major iron source and emphasizing iron's tight biogeochemical coupling to major nutrients, a more complex and diverse picture of the sources of iron, its cycling processes and intricate linkages with the ocean carbon and nitrogen cycles has emerged.
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Affiliation(s)
- Alessandro Tagliabue
- Department of Earth Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - Andrew R Bowie
- Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems Co-operative Research Centre, University of Tasmania, Hobart, Australia
| | - Philip W Boyd
- Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems Co-operative Research Centre, University of Tasmania, Hobart, Australia
| | | | | | - Mak A Saito
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
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50
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Shoenfelt EM, Sun J, Winckler G, Kaplan MR, Borunda AL, Farrell KR, Moreno PI, Gaiero DM, Recasens C, Sambrotto RN, Bostick BC. High particulate iron(II) content in glacially sourced dusts enhances productivity of a model diatom. SCIENCE ADVANCES 2017; 3:e1700314. [PMID: 28691098 PMCID: PMC5482553 DOI: 10.1126/sciadv.1700314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/08/2017] [Indexed: 05/31/2023]
Abstract
Little is known about the bioavailability of iron (Fe) in natural dusts and the impact of dust mineralogy on Fe utilization by photosynthetic organisms. Variation in the supply of bioavailable Fe to the ocean has the potential to influence the global carbon cycle by modulating primary production in the Southern Ocean. Much of the dust deposited across the Southern Ocean is sourced from South America, particularly Patagonia, where the waxing and waning of past and present glaciers generate fresh glaciogenic material that contrasts with aged and chemically weathered nonglaciogenic sediments. We show that these two potential sources of modern-day dust are mineralogically distinct, where glaciogenic dust sources contain mostly Fe(II)-rich primary silicate minerals, and nearby nonglaciogenic dust sources contain mostly Fe(III)-rich oxyhydroxide and Fe(III) silicate weathering products. In laboratory culture experiments, Phaeodactylum tricornutum, a well-studied coastal model diatom, grows more rapidly, and with higher photosynthetic efficiency, with input of glaciogenic particulates compared to that of nonglaciogenic particulates due to these differences in Fe mineralogy. Monod nutrient accessibility models fit to our data suggest that particulate Fe(II) content, rather than abiotic solubility, controls the Fe bioavailability in our Fe fertilization experiments. Thus, it is possible for this diatom to access particulate Fe in dusts by another mechanism besides uptake of unchelated Fe (Fe') dissolved from particles into the bulk solution. If this capability is widespread in the Southern Ocean, then dusts deposited to the Southern Ocean in cold glacial periods are likely more bioavailable than those deposited in warm interglacial periods.
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Affiliation(s)
- Elizabeth M Shoenfelt
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - Jing Sun
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - Gisela Winckler
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - Michael R Kaplan
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
| | - Alejandra L Borunda
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - Kayla R Farrell
- Department of Environmental Science, Barnard College at Columbia University, New York, NY 10027, USA
| | - Patricio I Moreno
- Department of Ecological Sciences, University of Chile, Av. Libertador Bernardo O'Higgins 1058, Santiago, Chile
| | - Diego M Gaiero
- Center for Earth Science Research, National University of Córdoba, Av. Haya de la Torre s/n, Córdoba, Argentina
| | - Cristina Recasens
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
| | - Raymond N Sambrotto
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
| | - Benjamin C Bostick
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, NY 10964, USA
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