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Cabrol L, Capo E, van Vliet DM, von Meijenfeldt FAB, Bertilsson S, Villanueva L, Sánchez-Andrea I, Björn E, G. Bravo A, Heimburger Boavida LE. Redox gradient shapes the abundance and diversity of mercury-methylating microorganisms along the water column of the Black Sea. mSystems 2023; 8:e0053723. [PMID: 37578240 PMCID: PMC10469668 DOI: 10.1128/msystems.00537-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 06/16/2023] [Indexed: 08/15/2023] Open
Abstract
In the global context of seawater deoxygenation triggered by climate change and anthropogenic activities, changes in redox gradients impacting biogeochemical transformations of pollutants, such as mercury, become more likely. Being the largest anoxic basin worldwide, with high concentrations of the potent neurotoxic methylmercury (MeHg), the Black Sea is an ideal natural laboratory to provide new insights about the link between dissolved oxygen concentration and hgcAB gene-carrying (hgc+) microorganisms involved in the formation of MeHg. We combined geochemical and microbial approaches to assess the effect of vertical redox gradients on abundance, diversity, and metabolic potential of hgc+ microorganisms in the Black Sea water column. The abundance of hgcA genes [congruently estimated by quantitative PCR (qPCR) and metagenomics] correlated with MeHg concentration, both maximal in the upper part of the anoxic water. Besides the predominant Desulfobacterales, hgc+ microorganisms belonged to a unique assemblage of diverse-previously underappreciated-anaerobic fermenters from Anaerolineales, Phycisphaerae (characteristic of the anoxic and sulfidic zone), Kiritimatiellales, and Bacteroidales (characteristic of the suboxic zone). The metabolic versatility of Desulfobacterota differed from strict sulfate reduction in the anoxic water to reduction of various electron acceptors in the suboxic water. Linking microbial activity and contaminant concentration in environmental studies is rare due to the complexity of biological pathways. In this study, we disentangle the role of oxygen in shaping the distribution of Hg-methylating microorganisms consistently with MeHg concentration, and we highlight their taxonomic and metabolic niche partitioning across redox gradients, improving the prediction of the response of marine communities to the expansion of oxygen-deficient zones. IMPORTANCE Methylmercury (MeHg) is a neurotoxin detected at high concentrations in certain marine ecosystems, posing a threat to human health. MeHg production is mainly mediated by hgcAB gene-carrying (hgc+) microorganisms. Oxygen is one of the main factors controlling Hg methylation; however, its effect on the diversity and ecology of hgc+ microorganisms remains unknown. Under the current context of seawater deoxygenation, mercury cycling is expected to be disturbed. Here, we show the strong effect of oxygen gradients on the distribution of potential Hg methylators. In addition, we show for the first time the significant contribution of a unique assemblage of potential fermenters from Anaerolineales, Phycisphaerae, and Kiritimatiellales to Hg methylation, stratified in different redox niches along the Black Sea gradient. Our results considerably expand the known taxonomic diversity and ecological niches prone to the formation of MeHg and contribute to better apprehend the consequences of oxygen depletion in seawater.
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Affiliation(s)
- Léa Cabrol
- Aix Marseille University, Univ. Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Marseille, France
- Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago, Chile
| | - Eric Capo
- Department of Marine Biology and Oceanography, Institute of Marine Sciences, CSIC, Barcelona, Spain
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Daan M. van Vliet
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, the Netherlands
- Wageningen Food and Biobased Research, Wageningen, the Netherlands
| | - F. A. Bastiaan von Meijenfeldt
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Texel, the Netherlands
| | - Stefan Bertilsson
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Laura Villanueva
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Texel, the Netherlands
- Faculty of Geosciences, Department of Earth Sciences, Utrecht University, Utrecht, the Netherlands
| | - Irene Sánchez-Andrea
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, the Netherlands
| | - Erik Björn
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Andrea G. Bravo
- Department of Marine Biology and Oceanography, Institute of Marine Sciences, CSIC, Barcelona, Spain
| | - Lars-Eric Heimburger Boavida
- Aix Marseille University, Univ. Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Marseille, France
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Melnik A, Silakov M, Mashukova O, Melnik L. Research into bioluminescence of the Black Sea ctenophores Pleurobrachia pileus O.F. Müller, 1776. LUMINESCENCE 2023. [PMID: 37259886 DOI: 10.1002/bio.4529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/02/2023]
Abstract
The work presents the findings of the laboratory and in situ studies of ctenophore Pleurobrachia pileus O.F. Müller, 1776 which have shown that this species has bioluminescent properties. These organisms were considered non-luminous before. P. pileus bioluminescence was studied on board RV Professor Vodyanitsky during its 116th voyage. Sampling live organisms was preceded by probing with the Salpa MA+ probe to register the daily maximum glow in redoxcline, which in this zone was recorded, as a rule, in the depth range of 60-70 m, where dense clusters of P. pileus were formed at that time. The samples of ctenophores were taken by a Bogorov-Rass plankton net. After the net was closed, it was lifted to the surface at a speed of 0.4-0.5 m·s-1 . It was shown that only at a temperature not exceeding 14°C, the P. pileus remained alive for 2-3 days. The data provided indicate that the temperature above 14°C is close to the maximum permissible for P. pileus, therefore, chemical and mechanical stimulation experiments were carried out at this temperature (14°C) to agitate ctenophores luminescence. Though, the nature of their signal was significantly different. The total percentage of luminous organisms from the entire catch was 32.43%, which unequivocally proves that P. pileus glows and makes a significant contribution to the intensity of the glow at great depths in redoxcline.
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Affiliation(s)
- Alexandr Melnik
- A.O.Kovalevsky Institute of Biology of the Southern Seas, Sevastopol, Russia
| | - Mikhail Silakov
- A.O.Kovalevsky Institute of Biology of the Southern Seas, Sevastopol, Russia
| | - Olga Mashukova
- A.O.Kovalevsky Institute of Biology of the Southern Seas, Sevastopol, Russia
| | - Lidia Melnik
- A.O.Kovalevsky Institute of Biology of the Southern Seas, Sevastopol, Russia
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Leberecht KM, Ritter SM, Lapp CJ, Klose L, Eschenröder J, Scholz C, Kühnel S, Stinnesbeck W, Kletzin A, Isenbeck-Schröter M, Gescher J. Microbially promoted calcite precipitation in the pelagic redoxcline: Elucidating the formation of the turbid layer. Geobiology 2022; 20:498-517. [PMID: 35514106 DOI: 10.1111/gbi.12492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 02/24/2022] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Large bell-shaped calcite formations called "Hells Bells" were discovered underwater in the stratified cenote El Zapote on the Yucatán Peninsula, Mexico. Together with these extraordinary speleothems, divers found a white, cloudy turbid layer into which some Hells Bells partially extend. Here, we address the central question if the formation of the turbid layer could be based on microbial activity, more specifically, on microbially induced calcite precipitation. Metagenomic and metatranscriptomic profiling of the microbial community in the turbid layer, which overlaps with the pelagic redoxcline in the cenote, revealed chemolithoautotrophic Hydrogenophilales and unclassified β-Proteobacteria as the metabolic key players. Bioinformatic and hydrogeochemical data suggest chemolithoautotrophic oxidation of sulfide to zero-valent sulfur catalyzed by denitrifying organisms due to oxygen deficiency. Incomplete sulfide oxidation via nitrate reduction and chemolithoautotrophy are both proton-consuming processes, which increase the pH in the redoxcline favoring authigenic calcite precipitation and may contribute to Hells Bells growth. The observed mechanism of microbially induced calcite precipitation is potentially applicable to many other stagnant sulfate-rich water bodies.
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Affiliation(s)
- Kerstin M Leberecht
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
| | - Simon M Ritter
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Christian J Lapp
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
| | - Lukas Klose
- Department of Physics & Earth Sciences, Jacobs University Bremen, Bremen, Germany
| | | | - Christian Scholz
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Sebastian Kühnel
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Wolfgang Stinnesbeck
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
| | - Arnulf Kletzin
- Department of Biology, Microbiology; Sulfur Biochemistry and Microbial Bioenergetics, Technical University of Darmstadt, Darmstadt, Germany
| | - Margot Isenbeck-Schröter
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
| | - Johannes Gescher
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
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Melnikov V, Melnik A, Mashukova O, Kapranov S, Melnik L. Bioluminescence of ctenophores near the boundary of oxygen-depleted waters at the redoxcline of the Black Sea. LUMINESCENCE 2021; 36:1063-1071. [PMID: 33600076 DOI: 10.1002/bio.4037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 11/05/2022]
Abstract
Vertical distribution of ctenophores near the boundary of oxygen-depleted waters of the Black Sea redoxcline was studied by use of video observations with real-time water sampling, horizontal MultiNet towing, and soundings using bathyphotometers with simultaneous vertical plankton net sampling. The results of the study showed for the first time that the daytime accumulation of ctenophores above the upper boundary of the suboxic zone changes the biophysical properties of the medium, causing an increase in the daytime intensity of bioluminescence near the redoxcline. The dynamics of this glow is in antiphase to that in the surface layers, where it is associated with the bioluminescence of phytoplankton. Therefore, in the deep-sea areas, two types of bioluminescence peaks differ in the light generation sources: the nighttime glow of phytoplankton in surface layers and the daytime glow of zooplankton in layers of oxygen-depleted waters at the redoxcline. The discovery of this new phenomenon allows the use of bioluminescent methods for the rapid assessment of the depth of the daytime zooplankton layers for the subsequent hauls of plankton nets. This significantly expands the possibilities of studying the structure and functioning of the pelagic ecosystem of the Black Sea and other marine basins with a redoxcline.
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Affiliation(s)
- Victor Melnikov
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (IBSS), Russia
| | - Alexandr Melnik
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (IBSS), Russia
| | - Olga Mashukova
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (IBSS), Russia
| | - Sergey Kapranov
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (IBSS), Russia
| | - Lidia Melnik
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (IBSS), Russia
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Louca S, Astor YM, Doebeli M, Taylor GT, Scranton MI. Microbial metabolite fluxes in a model marine anoxic ecosystem. Geobiology 2019; 17:628-642. [PMID: 31496030 DOI: 10.1111/gbi.12357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 04/11/2019] [Accepted: 06/23/2019] [Indexed: 06/10/2023]
Abstract
Permanently anoxic regions in the ocean are widespread and exhibit unique microbial metabolic activity exerting substantial influence on global elemental cycles and climate. Reconstructing microbial metabolic activity rates in these regions has been challenging, due to the technical difficulty of direct rate measurements. In Cariaco Basin, which is the largest permanently anoxic marine basin and an important model system for geobiology, long-term monitoring has yielded time series for the concentrations of biologically important compounds; however, the underlying metabolite fluxes remain poorly quantified. Here, we present a computational approach for reconstructing vertical fluxes and in situ net production/consumption rates from chemical concentration data, based on a 1-dimensional time-dependent diffusive transport model that includes adaptive penalization of overfitting. We use this approach to estimate spatiotemporally resolved fluxes of oxygen, nitrate, hydrogen sulfide, ammonium, methane, and phosphate within the sub-euphotic Cariaco Basin water column (depths 150-900 m, years 2001-2014) and to identify hotspots of microbial chemolithotrophic activity. Predictions of the fitted models are in excellent agreement with the data and substantially expand our knowledge of the geobiology in Cariaco Basin. In particular, we find that the diffusivity, and consequently fluxes of major reductants such as hydrogen sulfide, and methane, is about two orders of magnitude greater than previously estimated, thus resolving a long-standing apparent conundrum between electron donor fluxes and measured dark carbon assimilation rates.
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Affiliation(s)
- Stilianos Louca
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
- Department of Biology, University of Oregon, Eugene, OR, USA
| | - Yrene M Astor
- Estación de Investigaciones Marinas de Margarita, Fundación La Salle de Ciencias Naturales, Punta de Piedras, Venezuela
- Institute for Marine Remote Sensing, University of South Florida, Tampa, FL, USA
| | - Michael Doebeli
- Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Mathematics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gordon T Taylor
- School of Marine and Atmospheric Sciences, Stony Brook University, New York, NY, USA
| | - Mary I Scranton
- School of Marine and Atmospheric Sciences, Stony Brook University, New York, NY, USA
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Meyer D, Prien RD, Dellwig O, Waniek JJ, Schuffenhauer I, Donath J, Krüger S, Pallentin M, Schulz-Bull DE. A Multi-Pumping Flow System for In Situ Measurements of Dissolved Manganese in Aquatic Systems. Sensors (Basel) 2016; 16:s16122027. [PMID: 27916898 PMCID: PMC5191008 DOI: 10.3390/s16122027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 11/29/2022]
Abstract
A METals In Situ analyzer (METIS) has been used to determine dissolved manganese (II) concentrations in the subhalocline waters of the Gotland Deep (central Baltic Sea). High-resolution in situ measurements of total dissolved Mn were obtained in near real-time by spectrophotometry using 1-(2-pyridylazo)-2-naphthol (PAN). PAN is a complexing agent of dissolved Mn and forms a wine-red complex with a maximum absorbance at a wavelength of 562 nm. Results are presented together with ancillary temperature, salinity, and dissolved O2 data. Lab calibration of the analyzer was performed in a pressure testing tank. A detection limit of 77 nM was obtained. For validation purposes, discrete water samples were taken by using a pump-CTD system. Dissolved Mn in these samples was determined by an independent laboratory based method (inductively coupled plasma–optical emission spectrometry, ICP-OES). Mn measurements from both METIS and ICP-OES analysis were in good agreement. The results showed that the in situ analysis of dissolved Mn is a powerful technique reducing dependencies on heavy and expensive equipment (pump-CTD system, ICP-OES) and is also cost and time effective.
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Affiliation(s)
- David Meyer
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Ralf D Prien
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Olaf Dellwig
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Joanna J Waniek
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Ingo Schuffenhauer
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Jan Donath
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Siegfried Krüger
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Malte Pallentin
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
| | - Detlef E Schulz-Bull
- Leibniz Institute for Baltic Sea Research Warnemünde, Seestr. 15, 18119 Rostock, Germany.
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Glaubitz S, Abraham WR, Jost G, Labrenz M, Jürgens K. Pyruvate utilization by a chemolithoautotrophic epsilonproteobacterial key player of pelagic Baltic Sea redoxclines. FEMS Microbiol Ecol 2013; 87:770-9. [PMID: 24279499 DOI: 10.1111/1574-6941.12263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/14/2013] [Accepted: 11/20/2013] [Indexed: 11/27/2022] Open
Abstract
Pelagic redoxclines of the central Baltic Sea are dominated by the epsilonproteobacterial group Sulfurimonas GD17, considered to be the major driver of chemolithoautotrophic denitrification in this habitat. Autecological investigations of a recently isolated representative of this environmental group, Sulfurimonas gotlandica str. GD1(T), demonstrated that the bacterium grows best under sulfur-oxidizing, denitrifying conditions. However, in the presence of bicarbonate, this strain is able to use pyruvate as both an additional carbon source and an alternative electron donor. These observations suggested that the environmental group GD17 actively metabolizes organic substrates in situ. To examine this possibility, we used RNA-based stable isotope probing (RNA-SIP) on a natural redoxcline community provided with ¹³C-labeled pyruvate. While in this experiment, we were able to identify putative heterotrophic microorganisms, the uptake of ¹³C-pyruvate in GD17 nucleic acids could not be established. To resolve these contradictory findings, combined incorporation experiments with ¹⁴C- and ¹³C-labeled pyruvate were carried out in cells of strain GD1(T) cultivated under chemolithoautotrophic conditions, which favor pyruvate uptake rather than oxidation. An analysis of the labeled biomolecules revealed that pyruvate was mostly incorporated in cellular components such as amino acids, whose synthesis requires only minimal transformation. Carbon transfer into nucleic acids was not observed, explaining the inability of RNA-SIP to detect pyruvate incorporation by strain GD1(T) and the environmental group GD17. Together, these findings suggest that by integrating organic compounds such as pyruvate into cellular components S. gotlandica GD1(T) is able to replenish chemolithoautotrophic growth and thus ensure its survival in nutrient-limited habitats such as marine pelagic redoxclines.
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Affiliation(s)
- Sabine Glaubitz
- Section Biological Oceanography, Leibniz-Institute for Baltic Sea Research Warnemuende (IOW), Rostock, Germany
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