1
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Cheng H, Medina JS, Zhou J, Pinho EM, Meng R, Wang L, He Q, Morán XA, Hong PY. Predicting Anaerobic Membrane Bioreactor Performance Using Flow-Cytometry-Derived High and Low Nucleic Acid Content Cells. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:2360-2372. [PMID: 38261758 PMCID: PMC10851436 DOI: 10.1021/acs.est.3c07702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/25/2024]
Abstract
Having a tool to monitor the microbial abundances rapidly and to utilize the data to predict the reactor performance would facilitate the operation of an anaerobic membrane bioreactor (AnMBR). This study aims to achieve the aforementioned scenario by developing a linear regression model that incorporates a time-lagging mode. The model uses low nucleic acid (LNA) cell numbers and the ratio of high nucleic acid (HNA) to LNA cells as an input data set. First, the model was trained using data sets obtained from a 35 L pilot-scale AnMBR. The model was able to predict the chemical oxygen demand (COD) removal efficiency and methane production 3.5 days in advance. Subsequent validation of the model using flow cytometry (FCM)-derived data (at time t - 3.5 days) obtained from another biologically independent reactor did not exhibit any substantial difference between predicted and actual measurements of reactor performance at time t. Further cell sorting, 16S rRNA gene sequencing, and correlation analysis partly attributed this accurate prediction to HNA genera (e.g., Anaerovibrio and unclassified Bacteroidales) and LNA genera (e.g., Achromobacter, Ochrobactrum, and unclassified Anaerolineae). In summary, our findings suggest that HNA and LNA cell routine enumeration, along with the trained model, can derive a fast approach to predict the AnMBR performance.
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Affiliation(s)
- Hong Cheng
- Key
Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry
of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, People’s
Republic of China
- Environmental
Science and Engineering Program, Biological and Environmental Sciences
& Engineering Division (BESE), King
Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Julie Sanchez Medina
- Environmental
Science and Engineering Program, Biological and Environmental Sciences
& Engineering Division (BESE), King
Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Water
Desalination and Reuse Center (WDRC), Biological and Environmental
Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Jianqiang Zhou
- Environmental
Science and Engineering Program, Biological and Environmental Sciences
& Engineering Division (BESE), King
Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- State
Power Investment Corporation Research Institute, Beijing 102209, People’s Republic of China
| | - Eduardo Machado Pinho
- Environmental
Science and Engineering Program, Biological and Environmental Sciences
& Engineering Division (BESE), King
Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Department
of Bioengineering, Faculty of Engineering, University of Porto, 4099-002 Porto, Portugal
| | - Rui Meng
- Lawrence
Berkeley National Laboratory, Berkeley, California 94301, United States
- Amazon,
Incorporated, Palo Alto, California 94301, United States
| | - Liuwei Wang
- Systems
Medicine of Infectious Disease (P5), Robert
Koch Institute, 13353 Berlin, Germany
- Department
of Mathematics and Computer Science, Freie
Universität Berlin, 10117 Berlin, Germany
| | - Qiang He
- Key
Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry
of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, People’s
Republic of China
| | - Xosé Anxelu
G. Morán
- Red
Sea Research Center, Biological and Environmental Science & Engineering
Division, King Abdullah University of Science
and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Pei-Ying Hong
- Environmental
Science and Engineering Program, Biological and Environmental Sciences
& Engineering Division (BESE), King
Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Water
Desalination and Reuse Center (WDRC), Biological and Environmental
Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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2
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Sabbagh EI, Calleja ML, Daffonchio D, Morán XAG. Seasonality of top-down control of bacterioplankton at two central Red Sea sites with different trophic status. Environ Microbiol 2023; 25:2002-2019. [PMID: 37286523 DOI: 10.1111/1462-2920.16439] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 05/22/2023] [Indexed: 06/09/2023]
Abstract
The role of bottom-up (nutrient availability) and top-down (grazers and viruses mortality) controls on tropical bacterioplankton have been rarely investigated simultaneously from a seasonal perspective. We have assessed them through monthly samplings over 2 years in inshore and offshore waters of the central Red Sea differing in trophic status. Flow cytometric analysis allowed us to distinguish five groups of heterotrophic bacteria based on physiological properties (nucleic acid content, membrane integrity and active respiration), three groups of cyanobacteria (two populations of Synechococcus and Prochlorococcus), heterotrophic nanoflagellates (HNFs) and three groups of viruses based on nucleic acid content. The dynamics of bacterioplankton and their top-down controls varied with season and location, being more pronounced in inshore waters. HNFs abundances showed a strong preference for larger prey inshore (r = -0.62 to -0.59, p = 0.001-0.002). Positive relationships between viruses and heterotrophic bacterioplankton abundances were more marked inshore (r = 0.67, p < 0.001) than offshore (r = 0.44, p = 0.03). The negative correlation between HNFs and viruses abundances (r = -0.47, p = 0.02) in shallow waters indicates a persistent seasonal switch between protistan grazing and viral lysis that maintains the low bacterioplankton stocks in the central Red Sea area.
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Affiliation(s)
- Eman I Sabbagh
- Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Maria Ll Calleja
- Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Department of Climate Geochemistry, Max Plank Institute for Chemistry (MPIC), Mainz, Germany
| | - Daniele Daffonchio
- Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Xosé Anxelu G Morán
- Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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3
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Hasanin G, Mosquera AM, Emwas AH, Altmann T, Das R, Buijs PJ, Vrouwenvelder JS, Gonzalez-Gil G. The microbial growth potential of antiscalants used in seawater desalination. WATER RESEARCH 2023; 233:119802. [PMID: 36871379 DOI: 10.1016/j.watres.2023.119802] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/10/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
20 years since the first report on the biofouling potential of chemicals used for scale control, still, antiscalants with high bacterial growth potential are used in practice. Evaluating the bacterial growth potential of commercially available antiscalants is therefore essential for a rational selection of these chemicals. Previous antiscalant growth potential tests were conducted in drinking water or seawater inoculated with model bacterial species which do not represent natural bacterial communities. To reflect better on the conditions of desalination systems, we investigated the bacterial growth potential of eight different antiscalants in natural seawater and an autochthonous bacterial population as inoculum. The antiscalants differed strongly in their bacterial growth potential varying from ≤ 1 to 6 μg easily biodegradable C equivalents/mg antiscalant. The six phosphonate-based antiscalants investigated showed a broad range of growth potential, which depended on their chemical composition, whilst the biopolymer and the synthetic carboxylated polymers-based antiscalants showed limited or no significant bacterial growth. Moreover, nuclear magnetic resonance (NMR) scans enabled antiscalant fingerprinting, identifying components and contaminants, providing a rapid and sensitive characterization, and opening opportunities for rational selection of antiscalants for biofouling control.
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Affiliation(s)
- Ghadeer Hasanin
- Biological and Environmental Science and Engineering Division (BESE), Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Ana Maria Mosquera
- Biological and Environmental Science and Engineering Division (BESE), Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Abdul-Hamid Emwas
- Advanced Nanofabrication Imaging and Characterization, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Thomas Altmann
- Innovation and New Technology, ACWA Power, 41st Floor, The One Tower, Barsha Heights, Sheikh Zayed Road, Dubai, United Arab Emirates
| | - Ratul Das
- Innovation and New Technology, ACWA Power, 41st Floor, The One Tower, Barsha Heights, Sheikh Zayed Road, Dubai, United Arab Emirates.
| | - Paulus J Buijs
- Biological and Environmental Science and Engineering Division (BESE), Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Johannes S Vrouwenvelder
- Biological and Environmental Science and Engineering Division (BESE), Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Graciela Gonzalez-Gil
- Biological and Environmental Science and Engineering Division (BESE), Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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4
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Labban A, Shibl AA, Calleja ML, Hong PY, Morán XAG. Growth dynamics and transcriptional responses of a Red Sea Prochlorococcus strain to varying temperatures. Environ Microbiol 2022; 25:1007-1021. [PMID: 36567447 DOI: 10.1111/1462-2920.16326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 12/11/2022] [Indexed: 12/27/2022]
Abstract
Prochlorococcus play a crucial role in the ocean's biogeochemical cycling, but it remains controversial how they will respond to global warming. Here we assessed the response to temperature (22-30°C) of the growth dynamics and gene expression profiles of a Red Sea Prochlorococcus strain (RSP50) in a non-axenic culture. Both the specific growth rate (0.55-0.80 day-1 ) and cell size (0.04-0.07 μm3 ) of Prochlorococcus increased significantly with temperature. The primary production released extracellularly ranged from 20% to 34%, with humic-like fluorescent compounds increasing up to fivefold as Prochlorococcus reached its maximum abundance. At 30°C, genes involved in carbon fixation such as CsoS2 and CsoS3 and photosynthetic electron transport including PTOX were downregulated, suggesting a cellular homeostasis and energy saving mechanism response. In contrast, PTOX was found upregulated at 22°C and 24°C. Similar results were found for transaldolase, related to carbon metabolism, and citrate synthase, an important enzyme in the TCA cycle. Our data suggest that in spite of the currently warm temperatures of the Red Sea, Prochlorococcus can modulate its gene expression profiles to permit growth at temperatures lower than its optimum temperature (28°C) but is unable to cope with temperatures exceeding 30°C.
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Affiliation(s)
- Abbrar Labban
- Marine Science, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia.,Environmental Science and Engineering, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Ahmed A Shibl
- Genetic Heritage Group, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.,Public Health Research Center, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Maria Ll Calleja
- Climate Geochemistry Department, Max Plank Institute for Chemistry, Mainz, Germany
| | - Pei-Ying Hong
- Environmental Science and Engineering, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Xosé Anxelu G Morán
- Marine Science, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia.,Centro Oceanográfico de Gijón/Xixón, Instituto Español de Oceanografía (IEO-CSIC), Gijón/Xixón, Spain
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5
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Wang T, Li J, Jing H, Qin S. Picocyanobacterial Synechococcus in marine ecosystem: Insights from genetic diversity, global distribution, and potential function. MARINE ENVIRONMENTAL RESEARCH 2022; 177:105622. [PMID: 35429822 DOI: 10.1016/j.marenvres.2022.105622] [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: 01/28/2022] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Marine Synechococcus, a main group of picocyanobacteria, has been ubiquitously observed across the global oceans. Synechococcus exhibits high phylogenetical and phenotypical diversity, and horizontal gene transfer makes its genetic evolution much more intricate. With the development of measurement technologies and analysis methods, the genomic information and niche partition of each Synechococcus lineage tend to be precisely described, but the global analysis is still lacking. Therefore, it is necessary to summarize existing studies and integrate published data to gain a comprehensive understanding of Synechococcus on genetic variation, niche division, and potential functions. In this review, the maximum likelihood trees are constructed based on existing sequence data, including both phylogenetic and pigmentary gene markers. The global distribution characteristics of abundance, lineages, and pigment types are concluded through pooled analysis of more than 700 samples obtained from approximately 50 scientific research cruises. The potential functions of Synechococcus are explored in element cycles and biological interactions. Future work on Synechococcus is suggested to focus on not only elucidating the nature of Synechococcus biodiversity but also demonstrating its interactions with the ecosystem by combining bioinformatics and macroscopic isotope-labeled environmental parameters.
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Affiliation(s)
- Ting Wang
- Key Laboratory of Coastal Biology and Biological Resource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264000, China; CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jialin Li
- Key Laboratory of Coastal Biology and Biological Resource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264000, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China.
| | - Hongmei Jing
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Song Qin
- Key Laboratory of Coastal Biology and Biological Resource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264000, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
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6
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Brewin RJW, Dall’Olmo G, Gittings J, Sun X, Lange PK, Raitsos DE, Bouman HA, Hoteit I, Aiken J, Sathyendranath S. A Conceptual Approach to Partitioning a Vertical Profile of Phytoplankton Biomass Into Contributions From Two Communities. JOURNAL OF GEOPHYSICAL RESEARCH. OCEANS 2022; 127:e2021JC018195. [PMID: 35859661 PMCID: PMC9285788 DOI: 10.1029/2021jc018195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/18/2022] [Accepted: 03/16/2022] [Indexed: 06/15/2023]
Abstract
We describe an approach to partition a vertical profile of chlorophyll-a concentration into contributions from two communities of phytoplankton: one (community 1) that resides principally in the turbulent mixed-layer of the upper ocean and is observable through satellite visible radiometry; the other (community 2) residing below the mixed-layer, in a stably stratified environment, hidden from the eyes of the satellite. The approach is tuned to a time-series of profiles from a Biogeochemical-Argo float in the northern Red Sea, selected as its location transitions from a deep mixed layer in winter (characteristic of vertically well-mixed systems) to a shallow mixed layer in the summer with a deep chlorophyll-a maximum (characteristic of vertically stratified systems). The approach is extended to reproduce profiles of particle backscattering, by deriving the chlorophyll-specific backscattering coefficients of the two communities and a background coefficient assumed to be dominated by non-algal particles in the region. Analysis of the float data reveals contrasting phenology of the two communities, with community 1 blooming in winter and 2 in summer, community 1 negatively correlated with epipelagic stratification, and 2 positively correlated. We observe a dynamic chlorophyll-specific backscattering coefficient for community 1 (stable for community 2), positively correlated with light in the mixed-layer, suggesting seasonal changes in photoacclimation and/or taxonomic composition within community 1. The approach has the potential for monitoring vertical changes in epipelagic biogeography and for combining satellite and ocean robotic data to yield a three-dimensional view of phytoplankton distribution.
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Affiliation(s)
- Robert J. W. Brewin
- Centre for Geography and Environmental ScienceCollege of Life and Environmental SciencesUniversity of ExeterCornwallUK
| | - Giorgio Dall’Olmo
- Plymouth Marine LaboratoryPlymouthUK
- National Centre for Earth ObservationPlymouth Marine LaboratoryPlymouthUK
| | - John Gittings
- Program of Earth Science and EngineeringKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
- Department of BiologyNational and Kapodistrian University of AthensAthensGreece
| | - Xuerong Sun
- Centre for Geography and Environmental ScienceCollege of Life and Environmental SciencesUniversity of ExeterCornwallUK
- State Key Laboratory of Estuarine and Coastal ResearchEast China Normal UniversityShanghaiChina
| | - Priscila K. Lange
- Departamento de MeteorologiaUniversidade Federal do Rio de Janeiro (UFRJ)Rio de JaneiroBrazil
- Blue Marble Space Institute of Science (BMSIS)SeattleWAUSA
| | | | | | - Ibrahim Hoteit
- Program of Earth Science and EngineeringKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
| | - Jim Aiken
- Plymouth Marine LaboratoryPlymouthUK
| | - Shubha Sathyendranath
- Plymouth Marine LaboratoryPlymouthUK
- National Centre for Earth ObservationPlymouth Marine LaboratoryPlymouthUK
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7
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Morán XAG, García FC, Røstad A, Silva L, Al-Otaibi N, Irigoien X, Calleja ML. Diel dynamics of dissolved organic matter and heterotrophic prokaryotes reveal enhanced growth at the ocean's mesopelagic fish layer during daytime. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 804:150098. [PMID: 34508930 DOI: 10.1016/j.scitotenv.2021.150098] [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: 05/28/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Contrary to epipelagic waters, where biogeochemical processes closely follow the light and dark periods, little is known about diel cycles in the ocean's mesopelagic realm. Here, we monitored the dynamics of dissolved organic matter (DOM) and planktonic heterotrophic prokaryotes every 2 h for one day at 0 and 550 m (a depth occupied by vertically migrating fishes during light hours) in oligotrophic waters of the central Red Sea. We additionally performed predator-free seawater incubations of samples collected from the same site both at midnight and at noon. Comparable in situ variability in microbial biomass and dissolved organic carbon concentration suggests a diel supply of fresh DOM in both layers. The presence of fishes in the mesopelagic zone during daytime likely promoted a sustained, longer growth of larger prokaryotic cells. The specific growth rates were consistently higher in the noon experiments from both depths (surface: 0.34 vs. 0.18 d-1, mesopelagic: 0.16 vs. 0.09 d-1). Heterotrophic prokaryotes in the mesopelagic layer were also more efficient at converting extant DOM into new biomass. These results suggest that the ocean's twilight zone receives a consistent diurnal supply of labile DOM from the diel vertical migration of fishes, enabling an unexpectedly active community of heterotrophic prokaryotes.
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Affiliation(s)
- Xosé Anxelu G Morán
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Science & Engineering Division, 23955-6900 Thuwal, Saudi Arabia.
| | - Francisca C García
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Science & Engineering Division, 23955-6900 Thuwal, Saudi Arabia; Environment and Sustainability Institute, University of Exeter, TR10 9FE Penryn, United Kingdom
| | - Anders Røstad
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Science & Engineering Division, 23955-6900 Thuwal, Saudi Arabia
| | - Luis Silva
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Science & Engineering Division, 23955-6900 Thuwal, Saudi Arabia
| | - Najwa Al-Otaibi
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Science & Engineering Division, 23955-6900 Thuwal, Saudi Arabia; Department of Biology, College of Science, Taif University, Al-Hawiya 888, Saudi Arabia
| | | | - Maria Ll Calleja
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Science & Engineering Division, 23955-6900 Thuwal, Saudi Arabia; Max Planck Institute for Chemistry, 55128 Mainz, Germany
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8
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Silva L, Calleja ML, Huete-Stauffer TM, Ivetic S, Ansari MI, Viegas M, Morán XAG. Heterotrophic Bacterioplankton Growth and Physiological Properties in Red Sea Tropical Shallow Ecosystems With Different Dissolved Organic Matter Sources. Front Microbiol 2022; 12:784325. [PMID: 35046913 PMCID: PMC8762102 DOI: 10.3389/fmicb.2021.784325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/06/2021] [Indexed: 11/21/2022] Open
Abstract
Despite the key role of heterotrophic bacterioplankton in the biogeochemistry of tropical coastal waters, their dynamics have been poorly investigated in relation to the different dissolved organic matter (DOM) pools usually available. In this study we conducted four seasonal incubations of unfiltered and predator-free seawater (Community and Filtered treatment, respectively) at three Red Sea coastal sites characterized by different dominant DOM sources: Seagrass, Mangrove, and Phytoplankton. Bacterial abundance, growth and physiological status were assessed by flow cytometry and community composition by 16S rRNA gene amplicons. The Seagrass site showed the highest initial abundances (6.93 ± 0.30 × 105 cells mL-1), coincident with maximum DOC concentrations (>100 μmol C L-1), while growth rates peaked at the Mangrove site (1.11 ± 0.09 d-1) and were consistently higher in the Filtered treatment. The ratio between the Filtered and Community maximum bacterial abundance (a proxy for top-down control by protistan grazers) showed minimum values at the Seagrass site (1.05 ± 0.05) and maximum at the Phytoplankton site (1.24 ± 0.30), suggesting protistan grazing was higher in open waters, especially in the first half of the year. Since the Mangrove and Seagrass sites shared a similar bacterial diversity, the unexpected lack of bacterial response to predators removal at the latter site should be explained by differences in DOM characteristics. Nitrogen-rich DOM and fluorescent protein-like components were significantly associated with enhanced specific growth rates along the inshore-offshore gradient. Our study confirms the hypotheses that top-down factors control bacterial standing stocks while specific growth rates are bottom-up controlled in representative Red Sea shallow, oligotrophic ecosystems.
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Affiliation(s)
- Luis Silva
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Maria Ll. Calleja
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Department of Climate Geochemistry, Max Planck Institute for Chemistry, Mainz, Germany
| | - Tamara M. Huete-Stauffer
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Snjezana Ivetic
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Mohd I. Ansari
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Department of Biosciences, Integral University, Lucknow, India
| | - Miguel Viegas
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Xosé Anxelu G. Morán
- Division of Biological and Environmental Sciences and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Centro Oceanográfico de Gijón/Xixón (IEO, CSIC), Gijón, Spain
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9
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Dunne A, Carvalho S, Morán XAG, Calleja ML, Jones B. Localized effects of offshore aquaculture on water quality in a tropical sea. MARINE POLLUTION BULLETIN 2021; 171:112732. [PMID: 34330001 DOI: 10.1016/j.marpolbul.2021.112732] [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: 12/17/2020] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Aquaculture production has increased steadily in many tropical countries over the past few decades, although impact assessments have been frequently neglected. We investigated the impacts of an offshore barramundi fish farm on water quality in the southern-central Red Sea, a traditionally understudied tropical, oligotrophic, and semi-enclosed basin. Inorganic nutrients, particulate matter, chlorophyll-a, and heterotrophic bacteria were measured periodically over 8 months around the farm. Water down-current from the farm had, on average, more heterotrophic bacteria and chlorophyll-a than up-current (11% and 34% higher, respectively). Ratios of dissolved inorganic nitrogen:phosphorus down-current from the farm were lower than ratios up-current (mean 9.8 vs 16.0, respectively). Phosphate, inorganic nitrogen, and particulate matter showed patterns of enrichment associated with the farm after a fish feeding event. Strategies such as feed optimization and considering hydrodynamics in site selection may improve water quality for future fish farms in Saudi Arabia and other tropical countries.
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Affiliation(s)
- Aislinn Dunne
- King Abdullah University of Science and Technology, Red Sea Research Center, Thuwal 23955-6900, Saudi Arabia.
| | - Susana Carvalho
- King Abdullah University of Science and Technology, Red Sea Research Center, Thuwal 23955-6900, Saudi Arabia
| | - Xosé Anxelu G Morán
- King Abdullah University of Science and Technology, Red Sea Research Center, Thuwal 23955-6900, Saudi Arabia; Centro Oceanográfico de Gijón/Xixón (IEO, CSIC), Avda. Príncipe de Asturias 70 bis, 33212 Gijón/Xixón, Spain
| | - Maria Ll Calleja
- Department of Climate Geochemistry, Max Planck Institute for Chemistry (MPIC), Hahn-Meitner-Weg 1, 55128 Mainz, Germany
| | - Burton Jones
- King Abdullah University of Science and Technology, Red Sea Research Center, Thuwal 23955-6900, Saudi Arabia
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10
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Significance of Viral Activity for Regulating Heterotrophic Prokaryote Community Dynamics along a Meridional Gradient of Stratification in the Northeast Atlantic Ocean. Viruses 2020; 12:v12111293. [PMID: 33198110 PMCID: PMC7696675 DOI: 10.3390/v12111293] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 11/17/2022] Open
Abstract
How microbial populations interact influences the availability and flux of organic carbon in the ocean. Understanding how these interactions vary over broad spatial scales is therefore a fundamental aim of microbial oceanography. In this study, we assessed variations in the abundances, production, virus and grazing induced mortality of heterotrophic prokaryotes during summer along a meridional gradient in stratification in the North Atlantic Ocean. Heterotrophic prokaryote abundance and activity varied with phytoplankton biomass, while the relative distribution of prokaryotic subpopulations (ratio of high nucleic acid fluorescent (HNA) and low nucleic acid fluorescent (LNA) cells) was significantly correlated to phytoplankton mortality mode (i.e., viral lysis to grazing rate ratio). Virus-mediate morality was the primary loss process regulating the heterotrophic prokaryotic communities (average 55% of the total mortality), which may be attributed to the strong top-down regulation of the bacterivorous protozoans. Host availability, encounter rate, and HNA:LNA were important factors regulating viral dynamics. Conversely, the abundance and activity of bacterivorous protozoans were largely regulated by temperature and turbulence. The ratio of total microbial mediated mortality to total available prokaryote carbon reveals that over the latitudinal gradient the heterotrophic prokaryote community gradually moved from a near steady state system regulated by high turnover in subtropical region to net heterotrophic production in the temperate region.
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Morán XAG, Baltar F, Carreira C, Lønborg C. Responses of physiological groups of tropical heterotrophic bacteria to temperature and dissolved organic matter additions: food matters more than warming. Environ Microbiol 2020; 22:1930-1943. [PMID: 32249543 PMCID: PMC7384166 DOI: 10.1111/1462-2920.15007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/09/2020] [Accepted: 03/07/2020] [Indexed: 12/18/2022]
Abstract
Compared to higher latitudes, tropical heterotrophic bacteria may be less responsive to warming because of strong bottom‐up control. In order to separate both drivers, we determined the growth responses of bacterial physiological groups to temperature after adding dissolved organic matter (DOM) from mangroves, seagrasses and glucose to natural seawater from the Great Barrier Reef. Low (LNA) and high (HNA) nucleic acid content, membrane‐intact (Live) and membrane‐damaged (Dead) plus actively respiring (CTC+) cells were monitored for 4 days. Specific growth rates of the whole community were significantly higher (1.9 day‐1) in the mangrove treatment relative to the rest (0.2–0.4 day‐1) at in situ temperature and their temperature dependence, estimated as activation energy, was also consistently higher. Strong bottom‐up control was suggested in the other treatments. Cell size depended more on DOM than temperature. Mangrove DOM resulted in significantly higher contributions of Live, HNA and CTC+ cells to total abundance, while the seagrass leachate reduced Live cells below 50%. Warming significantly decreased Live and CTC+ cells contributions in most treatments. Our results suggest that only in the presence of highly labile compounds, such as mangroves DOM, can we anticipate increases in heterotrophic bacteria biomass in response to warming in tropical regions.
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Affiliation(s)
- Xosé Anxelu G Morán
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center (RSRC), Thuwal, 23955-6900, Saudi Arabia
| | - Federico Baltar
- Department of Functional and Evolutionary Ecology, University of Vienna, 1090, Althanstraße 14, Vienna, Austria.,Department of Marine Science, University of Otago, Dunedin, 9054, New Zealand.,NIWA/University of Otago Research Centre for Oceanography, Dunedin, 9054, New Zealand
| | - Cátia Carreira
- Departamento de Biologia and CESAM, Universidade de Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
| | - Christian Lønborg
- Australian Institute of Marine Science, Townsville, Queensland, 4810, Australia
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