1
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Zaghloul EH, Abdel-Latif HH, Elsayis A, Hassan SWM. Production and characterization of novel marine black yeast's exopolysaccharide with potential antiradical and anticancer prospects. Microb Cell Fact 2024; 23:60. [PMID: 38388439 PMCID: PMC10882794 DOI: 10.1186/s12934-024-02332-1] [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: 11/09/2023] [Accepted: 02/12/2024] [Indexed: 02/24/2024] Open
Abstract
The marine black yeasts are characterized by the production of many novel protective substances. These compounds increase their physiological adaptation to multi-extreme environmental stress. Hence, the exopolysaccharide (EPS) producing marine black yeast SAHE was isolated in this study. It was molecularly identified as Hortaea werneckii (identity 98.5%) through ITS1 and ITS4 gene sequencing analysis. The physicochemical properties of the novel SAHE-EPS were investigated through FTIR, GC-MS, TGA, ESM, and EDX analysis, revealing its heteropolysaccharide nature. SAHE-EPS was found to be thermostable and mainly consists of sucrose, maltose, cellobiose, lactose, and galactose. Furthermore, it exhibited an amorphous texture and irregular porous surface structure. SAHE-EPS showed significant antiradical activity, as demonstrated by the DPPH radical scavenging assay, and the IC50 was recorded to be 984.9 μg/mL. In addition, SAHE-EPS exhibited outstanding anticancer activity toward the A549 human lung cancer cell line (IC50 = 22.9 μg/mL). Conversely, it demonstrates minimal cytotoxicity toward the WI-38 normal lung cell line (IC50 = 203 μg/mL), which implies its safety. This study represents the initial attempt to isolate and characterize the chemical properties of an EPS produced by the marine black yeast H. werneckii as a promising antiradical and anticancer agent.
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Affiliation(s)
- Eman H Zaghloul
- National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt.
| | | | - Asmaa Elsayis
- National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt
| | - Sahar W M Hassan
- National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt
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2
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Marques JA, Gafni A, Adler O, Levy O, Bar-Zeev E. Antiscalants used in the desalination industry impact the physiology of the coral Montipora capricornis. WATER RESEARCH 2023; 229:119411. [PMID: 36463678 DOI: 10.1016/j.watres.2022.119411] [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: 08/15/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Many coral reefs are found in arid and semi-arid regions that often face severe water scarcity and depend on seawater desalination for freshwater supply. Alongside freshwater production, desalination plants discharge brine waste into the sea. Brine includes various chemicals (e.g., antiscalants) that may harm the coastal environment. Although widely used, little is known about the ecotoxicological effects of antiscalants (AS) on hard corals. This study compared the impacts of polyphosphonate-based and polymer-based ASs on the coral Montipora capricornis. After two weeks of exposure, we determined the effects of AS on coral physiology, symbiotic microalgae, and associated bacteria, using various analytical approaches such as optical coherence tomography, pulse amplitude modulated fluorometry, and oxidative stress biomarkers. Both ASs reduced polyp activity (∼25%) and caused tissue damage (30% and 41% for polymer and polyphosphonate based AS, respectively). In addition, exposure to polyphosphonate-based AS decreased the abundance of endosymbiotic algae (39%) and upregulated the antioxidant capacity of the animal host (45%). The microalgal symbionts were under oxidative stress, with increased levels of antioxidant capacity and oxidative damage (a 2-fold increase compared to the control). Interestingly, exposure to AS enhanced the numbers of associated bacteria (∼40% compared to the control seawater) regardless of the AS type. Our results introduce new insights into the effects of brine on the physiology of hard corals, highlighting that choosing AS type must be examined according to the receiving ecosystem.
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Affiliation(s)
- Joseane A Marques
- Zuckerberg Institute for Water Research (ZIWR), Ben-Gurion University of the Negev, Sede Boker 84990, Israel; The Interuniversity Institute for Marine Sciences, Eilat 8810369, Israel.
| | - Almog Gafni
- Zuckerberg Institute for Water Research (ZIWR), Ben-Gurion University of the Negev, Sede Boker 84990, Israel
| | - Osher Adler
- Zuckerberg Institute for Water Research (ZIWR), Ben-Gurion University of the Negev, Sede Boker 84990, Israel
| | - Oren Levy
- Faculty of Life Sciences, The Mina and Everard Goodman, Bar-Ilan University, Ramat-Gan 5290002, Israel; The Interuniversity Institute for Marine Sciences, Eilat 8810369, Israel
| | - Edo Bar-Zeev
- Zuckerberg Institute for Water Research (ZIWR), Ben-Gurion University of the Negev, Sede Boker 84990, Israel.
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3
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Qi M, Zheng C, Wu W, Yu G, Wang P. Exopolysaccharides from Marine Microbes: Source, Structure and Application. Mar Drugs 2022; 20:md20080512. [PMID: 36005515 PMCID: PMC9409974 DOI: 10.3390/md20080512] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 12/03/2022] Open
Abstract
The unique living environment of marine microorganisms endows them with the potential to produce novel chemical compounds with various biological activities. Among them, the exopolysaccharides produced by marine microbes are an important factor for them to survive in these extreme environments. Up to now, exopolysaccharides from marine microbes, especially from extremophiles, have attracted more and more attention due to their structural complexity, biodegradability, biological activities, and biocompatibility. With the development of culture and separation methods, an increasing number of novel exopolysaccharides are being found and investigated. Here, the source, structure and biological activities of exopolysaccharides, as well as their potential applications in environmental restoration fields of the last decade are summarized, indicating the commercial potential of these versatile EPS in different areas, such as food, cosmetic, and biomedical industries, and also in environmental remediation.
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Affiliation(s)
- Mingxing Qi
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Caijuan Zheng
- Key Laboratory of Tropical Medicinal Resource Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, China
- Key Laboratory of Tropical Medicinal Plant Chemistry of Hainan Province, Haikou 571158, China
| | - Wenhui Wu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
- Correspondence: (W.W.); (G.Y.); (P.W.); Tel.: +86-021-61900388 (W.W.); +86-0532-8203-1609 (G.Y.); +86-021-61900388 (P.W.)
| | - Guangli Yu
- Key Laboratory of Marine Drugs, Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycoengineering, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266237, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Correspondence: (W.W.); (G.Y.); (P.W.); Tel.: +86-021-61900388 (W.W.); +86-0532-8203-1609 (G.Y.); +86-021-61900388 (P.W.)
| | - Peipei Wang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
- Correspondence: (W.W.); (G.Y.); (P.W.); Tel.: +86-021-61900388 (W.W.); +86-0532-8203-1609 (G.Y.); +86-021-61900388 (P.W.)
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4
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Riemann L, Rahav E, Passow U, Grossart HP, de Beer D, Klawonn I, Eichner M, Benavides M, Bar-Zeev E. Planktonic Aggregates as Hotspots for Heterotrophic Diazotrophy: The Plot Thickens. Front Microbiol 2022; 13:875050. [PMID: 35464923 PMCID: PMC9019601 DOI: 10.3389/fmicb.2022.875050] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 03/11/2022] [Indexed: 11/26/2022] Open
Abstract
Biological dinitrogen (N2) fixation is performed solely by specialized bacteria and archaea termed diazotrophs, introducing new reactive nitrogen into aquatic environments. Conventionally, phototrophic cyanobacteria are considered the major diazotrophs in aquatic environments. However, accumulating evidence indicates that diverse non-cyanobacterial diazotrophs (NCDs) inhabit a wide range of aquatic ecosystems, including temperate and polar latitudes, coastal environments and the deep ocean. NCDs are thus suspected to impact global nitrogen cycling decisively, yet their ecological and quantitative importance remain unknown. Here we review recent molecular and biogeochemical evidence demonstrating that pelagic NCDs inhabit and thrive especially on aggregates in diverse aquatic ecosystems. Aggregates are characterized by reduced-oxygen microzones, high C:N ratio (above Redfield) and high availability of labile carbon as compared to the ambient water. We argue that planktonic aggregates are important loci for energetically-expensive N2 fixation by NCDs and propose a conceptual framework for aggregate-associated N2 fixation. Future studies on aggregate-associated diazotrophy, using novel methodological approaches, are encouraged to address the ecological relevance of NCDs for nitrogen cycling in aquatic environments.
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Affiliation(s)
- Lasse Riemann
- Marine Biology Section, University of Copenhagen, Helsingør, Denmark
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Uta Passow
- Ocean Science Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Hans-Peter Grossart
- Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany.,Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Dirk de Beer
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Isabell Klawonn
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Meri Eichner
- Institute of Microbiology CAS, Centre ALGATECH, Třeboň, Czechia
| | - Mar Benavides
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France.,Turing Center for Living Systems, Aix-Marseille University, Marseille, France
| | - Edo Bar-Zeev
- The Jacob Blaustein Institutes for Desert Research, Zuckerberg Institute for Water Research (ZIWR), Ben-Gurion University of the Negev, Be'er Sheva, Israel
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5
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Ge Z, Li QP, Yang W, Liu X, Wu Z. Transparent exopolymer particle dynamics along a shelf-to-sea gradient and impacts on the regional carbon cycle. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:152117. [PMID: 34863747 DOI: 10.1016/j.scitotenv.2021.152117] [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: 09/12/2021] [Revised: 10/28/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
Transparent exopolymer particles (TEPs) have drawn extensive attention in recent decades due to their crucial role in the biogeochemical and ecological processes of the ocean. However, TEP distribution and fluxes are relatively less addressed in the shelf-seas, where its variability can be affected by not only biology but also complex physical dynamics. Here, we present a comprehensive study of TEP from the coast to the basin (12 sampling sites) of the northern South China Sea (NSCS). We found a large TEP variability from 0.6 to 78.6 μg Xeq. L-1 with higher levels in the coastal waters than the offshore epipelagic waters and the deep waters. In addition, the spatial distribution of TEP was significantly correlated to the cross-shelf change of temperature, salinity, and chlorophyll-a, revealing the complex physical-biogeochemical controls on TEP variability. We found the TEP dynamics nearshore largely influenced by the sedimentation and transportation of TEP-rich aggregates from the river plume. The contribution of TEP to particulate organic carbon (POC) increased gradually when approaching the shore from the sea, suggesting an elevated role of TEP in the coastal carbon cycle. Finally, a good correlation of particle-attached bacteria (PAB) with TEP but not POC revealed a preferential utilization of TEP by PAB. Thus, TEP may play an essential role in the recycling of carbon and nitrogen in the shelf-sea. These findings are crucial for understanding of the TEP dynamics under a changing environment and the associated impacts on the oceanic carbon cycle.
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Affiliation(s)
- Zaiming Ge
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qian P Li
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
| | - Weifeng Yang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Xin Liu
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Zhengchao Wu
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
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6
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Geisler E, Rahav E, Bar-Zeev E. Contribution of Heterotrophic Diazotrophs to N2 Fixation in a Eutrophic River: Free-Living vs. Aggregate-Associated. Front Microbiol 2022; 13:779820. [PMID: 35237246 PMCID: PMC8882987 DOI: 10.3389/fmicb.2022.779820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 01/19/2022] [Indexed: 12/19/2022] Open
Abstract
Recent studies have indicated that heterotrophic diazotrophs are highly diverse and fix N2 in aquatic environments with potentially adverse conditions for diazotrophy, such as oxic and rich in total nitrogen. In this study, we compared the activity and diversity of heterotrophic diazotrophs associated with aggregates (>12 μm) to free-living cells in the eutrophic Qishon River during the winter and summer seasons. Overall, measured heterotrophic N2 fixation rates in the Qishon River ranged between 2.6–3.5 nmol N L–1 d–1. Heterotrophic N2 fixation was mainly associated with aggregates in the summer samples (74 ± 24%), whereas during the winter the bulk diazotrophic activity was mostly ascribed to the free-living fraction (90 ± 6%). In addition, immunolabeled micrographs indicated the presence of aggregate-associated heterotrophic diazotrophs in both seasons, while phototrophic diazotrophs were also captured during the winter. The richness of free-living and aggregate-associated heterotrophic diazotrophs were overall similar, yet the evenness of the later was significantly smaller, suggesting that few of the species gained advantage from particle lifestyle. The differences in the activity, micro-localization and diversity of the diazotrophic community were mostly attributed to spatiotemporal changes in the ambient C:N ratios (total organic carbon, TOC: total nitrogen) and the TOC concentrations. Taken together, our results shed new light on the contribution of heterotrophic diazotroph associated with aggregates to total heterotrophic N2 fixation in oxic, highly eutrophic aquatic environments.
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Affiliation(s)
- Eyal Geisler
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker, Israel
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
- *Correspondence: Eyal Rahav,
| | - Edo Bar-Zeev
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker, Israel
- Edo Bar-Zeev,
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7
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Wu C, Fu L, Wang Y, Wan C. Real-time changes of the adsorption process and conformation of marine dissolved organic matters on the solid-liquid interface. CHEMOSPHERE 2022; 289:133140. [PMID: 34863728 DOI: 10.1016/j.chemosphere.2021.133140] [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: 09/27/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 06/13/2023]
Abstract
In this study, the adsorption characteristics of marine dissolved organic matters (MDOMs) on the solid-liquid interface in the coastal waters was investigated. The results showed that the organic macromolecules with adsorption ability in MDOMs are not rigid molecules. However, the macromolecules have viscoelasticity properties. At different dilution ratios, the MDOMs adsorption process includes rapid (0-200 s) and slow adsorption (200 s later) periods. MDOMs adsorption in the solid-liquid interface is a dynamic process in which adsorption and hydration occur simultaneously. MDOMs concentration is an important driving force for adsorption. The three macromolecules of acid polysaccharides, protein-like, and polycarboxylate-type humic acids in MDOMs are rich in functional groups and they have the ability to absorb to solid surface. Acidic polysaccharides exhibit a sustained adsorption ability, while the adsorption of other macromolecules occurred only in the initial rapid adsorption period. In addition, the acid polysaccharides show weak thixotropy during the adsorption process. It would cause the stretching of macromolecular structure of the adsorption layer, enhancing the hydration of the adsorption layer. The study shows the adsorption process of MDOMs at the solid-liquid interface and the structural characteristics of the adsorption layer. It can provide helpful information for the inhibition and removal of MDOMs pollution during the actual development of marine resources.
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Affiliation(s)
- Changyong Wu
- Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Liya Fu
- Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Yue Wang
- Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Chunli Wan
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
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8
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Gann ER, Kang Y, Dyhrman ST, Gobler CJ, Wilhelm SW. Metatranscriptome Library Preparation Influences Analyses of Viral Community Activity During a Brown Tide Bloom. Front Microbiol 2021; 12:664189. [PMID: 34135876 PMCID: PMC8200674 DOI: 10.3389/fmicb.2021.664189] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/16/2021] [Indexed: 11/13/2022] Open
Abstract
There is growing interest in the use of metatranscriptomics to study virus community dynamics. We used RNA samples collected from harmful brown tides caused by the eukaryotic alga Aureococcus anophagefferens within New York (United States) estuaries and in the process observed how preprocessing of libraries by either selection for polyadenylation or reduction in ribosomal RNA (rRNA) influenced virus community analyses. As expected, more reads mapped to the A. anophagefferens genome in polyadenylation-selected libraries compared to the rRNA-reduced libraries, with reads mapped in each sample correlating to one another regardless of preprocessing of libraries. Yet, this trend was not seen for reads mapping to the Aureococcus anophagefferens Virus (AaV), where significantly more reads (approximately two orders of magnitude) were mapped to the AaV genome in the rRNA-reduced libraries. In the rRNA-reduced libraries, there was a strong and significant correlation between reads mappings to AaV and A. anophagefferens. Overall, polyadenylation-selected libraries produced fewer viral contigs, fewer reads mapped to viral contigs, and different proportions across viral realms and families, compared to their rRNA-reduced pairs. This study provides evidence that libraries generated by rRNA reduction and not selected for polyadenylation are more appropriate for quantitative characterization of viral communities in aquatic ecosystems by metatranscriptomics.
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Affiliation(s)
- Eric R Gann
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Yoonja Kang
- Department of Ocean Integrated Science, School of Marine Technology, Chonnam National University, Yeosu, South Korea
| | - Sonya T Dyhrman
- Biology and Paleo Environment Division, Lamont-Doherty Earth Observatory, Columbia University, New York, NY, United States.,Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, United States
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
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9
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Eswaran R, Khandeparker L. Ecological relevance of high and low nucleic acid content bacteria in a monsoon influenced tropical estuary: Implications on the β-Glucosidase activity. ACTA OECOLOGICA 2021. [DOI: 10.1016/j.actao.2020.103697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Cai YM. Non-surface Attached Bacterial Aggregates: A Ubiquitous Third Lifestyle. Front Microbiol 2020; 11:557035. [PMID: 33343514 PMCID: PMC7746683 DOI: 10.3389/fmicb.2020.557035] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 11/13/2020] [Indexed: 01/03/2023] Open
Abstract
Bacteria are now generally believed to adopt two main lifestyles: planktonic individuals, or surface-attached biofilms. However, in recent years medical microbiologists started to stress that suspended bacterial aggregates are a major form of bacterial communities in chronic infection sites. Despite sharing many similarities with surface-attached biofilms and are thus generally defined as biofilm-like aggregates, these non-attached clumps of cells in vivo show much smaller sizes and different formation mechanisms. Furthermore, ex vivo clinical isolates were frequently reported to be less attached to abiotic surfaces when compared to standard type strains. While this third lifestyle is starting to draw heavy attention in clinical studies, it has a long history in natural and environmental sciences. For example, marine gel particles formed by bacteria attachment to phytoplankton exopolymers have been well documented in oceans; large river and lake snows loaded with bacterial aggregates are frequently found in freshwater systems; multispecies bacterial "flocs" have long been used in wastewater treatment. This review focuses on non-attached aggregates found in a variety of natural and clinical settings, as well as some recent technical developments facilitating aggregate research. The aim is to summarise the characteristics of different types of bacterial aggregates, bridging the knowledge gap, provoking new perspectives for researchers from different fields, and highlighting the importance of more research input in this third lifestyle of bacteria closely relevant to our daily life.
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Affiliation(s)
- Yu-Ming Cai
- National Biofilms Innovation Centre, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
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11
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Geisler E, Bogler A, Bar-Zeev E, Rahav E. Heterotrophic Nitrogen Fixation at the Hyper-Eutrophic Qishon River and Estuary System. Front Microbiol 2020; 11:1370. [PMID: 32670236 PMCID: PMC7326945 DOI: 10.3389/fmicb.2020.01370] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/27/2020] [Indexed: 12/04/2022] Open
Abstract
Planktonic heterotrophic diazotrophs (N2-fixers) are widely distributed in marine and freshwater systems, yet limited information is available on their activity, especially in environments with adverse conditions for diazotrophy (e.g., N-rich and oxygenated). Here, we followed the localization and activity of heterotrophic diazotrophs in the hyper-eutrophic N-rich Qishon River—an environment previously considered to be unfavorable for diazotrophy. Our results indicate high heterotrophic N2 fixation rates (up to 6.9 nmol N L–1 d–1), which were approximately three fold higher at an upstream location (freshwater) compared to an estuary (brackish) site. Further, active heterotrophic diazotrophs were capture associated with free-floating aggregates by a newly developed immunolocalization approach. These findings provide new insights on the activity of heterotrophic diazotrophs on aggregates in environments previously considered with adverse conditions for diazotrophy. Moreover, these new insights may be applicable to other aquatic regimes worldwide with similar N-rich/oxygenated conditions that should potentially inhibit N2 fixation.
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Affiliation(s)
- Eyal Geisler
- The Zuckerberg Institute for Water Research (ZIWR), The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Anne Bogler
- The Zuckerberg Institute for Water Research (ZIWR), The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Edo Bar-Zeev
- The Zuckerberg Institute for Water Research (ZIWR), The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
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12
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Sisma-Ventura G, Rahav E. DOP Stimulates Heterotrophic Bacterial Production in the Oligotrophic Southeastern Mediterranean Coastal Waters. Front Microbiol 2019; 10:1913. [PMID: 31474972 PMCID: PMC6706821 DOI: 10.3389/fmicb.2019.01913] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/05/2019] [Indexed: 11/13/2022] Open
Abstract
Phytoplankton and heterotrophic bacteria rely on a suite of inorganic and organic macronutrients to satisfy their cellular needs. Here, we explored the effect of dissolved inorganic phosphate (PO4) and several dissolved organic molecules containing phosphorus [ATP, glucose-6-phosphate, 2-aminoethylphosphonic acid, collectively referred to as dissolved organic phosphorus (DOP)], on the activity and biomass of autotrophic and heterotrophic microbial populations in the coastal water of the southeastern Mediterranean Sea (SEMS) during summertime. To this end, surface waters were supplemented with PO4, one of the different organic molecules, or PO4 + ATP, and measured the PO4 turnover time (Tt), alkaline phosphatase activity (APA), heterotrophic bacterial production (BP), primary production (PP), and the abundance of the different microbial components. Our results show that PO4 alone does not stimulate any significant change in most of the autotrophic or heterotrophic bacterial variables tested. ATP addition (alone or with PO4) triggers the strongest increase in primary and bacterial productivity or biomass. Heterotrophic bacterial abundance and BP respond faster than phytoplankton (24 h post addition) to the various additions of DOP or PO4 + ATP, followed by a recovery of primary productivity (48 h post addition). These observations suggest that both autotrophic and heterotrophic microbial communities compete for labile organic molecules containing P, such as ATP, to satisfy their cellular needs. It also suggests that SEMS coastal water heterotrophic bacteria are likely C and P co-limited.
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Affiliation(s)
- Guy Sisma-Ventura
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
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13
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Direct Detection of Heterotrophic Diazotrophs Associated with Planktonic Aggregates. Sci Rep 2019; 9:9288. [PMID: 31243322 PMCID: PMC6594930 DOI: 10.1038/s41598-019-45505-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/24/2019] [Indexed: 12/03/2022] Open
Abstract
N2 fixation by planktonic heterotrophic diazotrophs is more wide spread than previously thought, including environments considered “unfavorable” for diazotrophy. These environments include a substantial fraction of the aquatic biosphere such as eutrophic estuaries with high ambient nitrogen concentrations and oxidized aphotic water. Different studies suggested that heterotrophic diazotrophs associated with aggregates may promote N2 fixation in such environments. However, this association was never validated directly and relies mainly on indirect relationships and different statistical approaches. Here, we identified, for the first time, a direct link between active heterotrophic diazotrophs and aggregates that comprise polysaccharides. Our new staining method combines fluorescent tagging of active diazotrophs by nitrogenase-immunolabeling, polysaccharides staining by Alcian blue or concanavalin-A, and total bacteria via nucleic-acid staining. Concomitant to N2 fixation rates and bacterial activity, this new method provided specific localization of heterotrophic diazotrophs on artificial and natural aggregates. We postulate that the insights gained by this new visualization approach will have a broad significance for future research on the aquatic nitrogen cycle, including environments in which diazotrophy has traditionally been overlooked.
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Frank H, Fussmann KE, Rahav E, Bar Zeev E. Chronic effects of brine discharge form large-scale seawater reverse osmosis desalination facilities on benthic bacteria. WATER RESEARCH 2019; 151:478-487. [PMID: 30641463 DOI: 10.1016/j.watres.2018.12.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/15/2018] [Accepted: 12/08/2018] [Indexed: 06/09/2023]
Abstract
Seawater desalination facilities continuously discharge hyper-saline brine into the coastal environment which often flows as a concentrated plume over the seafloor, hence possibly impacting benthic microorganisms. Yet, the effects of brine discharge from desalination plants on benthic bacteria, key players in biodegradation of organic material and nutrient recycling is unknown. In this study, we tested the chronic (years) effects of brine discharge from three large-scale desalination facilities on the abundance, metabolic activity and community composition of benthic bacteria. To this end, four sampling campaigns were carried at the outfall areas of the Ashkelon, Sorek and Hadera desalination facilities. The effects of the brine were compared to corresponding reference stations which were not influenced by the brine (i.e., water temperature and salinity). Our sampling data indicate that bacterial abundance and activity that includes bacterial growth efficiency were 1.3-2.6-fold higher at the outfall area than the reference station. Concomitant analysis pointed out that the bacterial community structure at the brine discharge area was also different than the reference station, yet varied between each desalination facility. Our results demonstrate that the impact of brine effluent from desalination facilities on benthic bacteria are site-specific and localized (<1.4 Km2) around the discharge point. Namely, that the effects on benthic bacteria are prominent at the brine mixing zone and change according to the discharge method used to disperse the brine as well as local stressors (e.g., eutrophication and elevated water temperature). Our results contribute new insights on the effects of desalination-brine to benthic microbes, while providing scientifically-based aspects on the ecological impacts of brine dispersion for decision makers.
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Affiliation(s)
- Hila Frank
- Zuckerberg Institute for Water Research (ZIWR), The Jacob Blaustein Institutes for Desert Research (BIDR) Ben-Gurion University of the Negev, 84990, Israel; Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, 8030, Israel
| | - Katarina E Fussmann
- Zuckerberg Institute for Water Research (ZIWR), The Jacob Blaustein Institutes for Desert Research (BIDR) Ben-Gurion University of the Negev, 84990, Israel; Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, 8030, Israel
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, 8030, Israel.
| | - Edo Bar Zeev
- Zuckerberg Institute for Water Research (ZIWR), The Jacob Blaustein Institutes for Desert Research (BIDR) Ben-Gurion University of the Negev, 84990, Israel.
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Petersen KL, Paytan A, Rahav E, Levy O, Silverman J, Barzel O, Potts D, Bar-Zeev E. Impact of brine and antiscalants on reef-building corals in the Gulf of Aqaba - Potential effects from desalination plants. WATER RESEARCH 2018; 144:183-191. [PMID: 30029077 DOI: 10.1016/j.watres.2018.07.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/03/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
Seawater reverse osmosis (SWRO) is becoming an increasingly important source of potable water in arid and semi-arid regions worldwide. Discharge of brine-effluent from desalination facilities has been shown to significantly impact coastal marine ecosystems ranging from seagrass meadows to microbial communities. In this study, we examined the impacts of increased salinity (10% above ambient) and presence of antiscalants (0.2 mg L-1, polyphosphonate-based) on three reef-building coral species; Stylophora pistillata, Acropora tenuis and Pocillopora verrucosa, from the Gulf of Aqaba (northern Red-Sea). Our results indicate that the corals, as well as associated bacteria and algae, were significantly impaired by the elevated salinity and antiscalants, leading to partial bleaching. Specifically, the abundance of bacteria and symbiotic algae as well as calcification rates were typically lower (20-85%, 50-90% and 40-50%, respectively) following incubations with both amendments. However, the impact of desalination brine was often species-specific. Thus, we propose that the ecotoxicological criteria used for hard corals should be determined based on the sensitivity of key species in the community dominating the area affected by desalination discharge.
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Affiliation(s)
- Karen Lykkebo Petersen
- Department of Earth and Planetary Science, University of California Santa Cruz, CA, 95064, USA
| | - Adina Paytan
- Institute of Marine Science, University of California, Santa Cruz, CA, 95064, USA
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, Haifa, 31080, Israel
| | - Oren Levy
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Jacob Silverman
- Israel Oceanographic and Limnological Research, Haifa, 31080, Israel
| | - Oriya Barzel
- Israel Oceanographic and Limnological Research, Haifa, 31080, Israel; Institute of Earth Sciences, Edmond Safra Campus of Natural Sciences, Givat-Ram, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Donald Potts
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, CA, 95064, USA
| | - Edo Bar-Zeev
- Zuckerberg Institute for Water Research, Ben-Gurion University of the Negev, 84990, Israel.
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Phytoplankton and Bacterial Response to Desert Dust Deposition in the Coastal Waters of the Southeastern Mediterranean Sea: A Four-Year In Situ Survey. ATMOSPHERE 2018. [DOI: 10.3390/atmos9080305] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Atmospheric dust/aerosol deposition is an important source of external nutrients for the surface of the ocean. This study shows high-resolution observational data gathered in situ over a period of four years on bacterial and phytoplankton abundance and activity during typical background atmospheric conditions and during intense dust storm events in the low-nutrient, low-chlorophyll (LNLC) coastal waters of the southeastern Mediterranean Sea (SEMS). Chlorophyll a (an estimate for phytoplankton biomass) and bacterial abundance show moderate changes in response to dust deposition/events (−10% and +20%, respectively), while primary production, bacterial production, and N2 fixation rates were all significantly and positively affected by deposition (+25 to +40%; p < 0.05). The rapid changes in bacterial and/or phytoplankton rate parameters suggest that the released micro-/macronutrients from atmospheric deposition are tunneled directly in metabolic processes and, to a lesser extent, for biomass accumulation. The predicted expansion of LNLC areas in oceans in the future, and the projected increase in dust emission due to desertification, may affect the production of marine microbial communities in the surface of the ocean, yet only moderately affect their biomass or standing stock. Such alterations may impact carbon sequestration to the deep ocean.
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Rahav E, Raveh O, Hazan O, Gordon N, Kress N, Silverman J, Herut B. Impact of nutrient enrichment on productivity of coastal water along the SE Mediterranean shore of Israel - A bioassay approach. MARINE POLLUTION BULLETIN 2018; 127:559-567. [PMID: 29475698 DOI: 10.1016/j.marpolbul.2017.12.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 12/07/2017] [Accepted: 12/19/2017] [Indexed: 06/08/2023]
Abstract
The coastal waters of the southeastern Mediterranean-Sea (SEMS) are routinely enriched with naturally-occurring and anthropogenic land-based nutrient loads. These external inputs may affect autotrophic and heterotrophic microbial biomass and activity. Here, we conducted 13 microcosm bioassays with different additions of inorganic NO3-(N), PO4-(P) and Si(OH)4-(Si) in different seasons along the Mediterranean coast of Israel. Our results indicate that cyanobacteria are mainly N-limited, whereas N or Si (or both) limit pico-eukaryotes. Furthermore, the degree to which N affects phytoplankton depends on the ambient seawater's inorganic N and N:P characteristics. Heterotrophic bacteria displayed no response in all treatments, except when all nutrients were added simultaneously, suggesting a possible co-limitation by nutrients. These results contrast the N+P co-limitation of phytoplankton and the P-limitation of bacteria in the open waters of the SEMS. These observations enable the application for a better science-based environmental monitoring and policy implementation along the SEMS coast of Israel.
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Affiliation(s)
- Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel.
| | - Ofrat Raveh
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Or Hazan
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Nurit Gordon
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Nurit Kress
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Jacob Silverman
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Barak Herut
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
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18
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Hazan O, Silverman J, Sisma-Ventura G, Ozer T, Gertman I, Shoham-Frider E, Kress N, Rahav E. Mesopelagic Prokaryotes Alter Surface Phytoplankton Production during Simulated Deep Mixing Experiments in Eastern Mediterranean Sea Waters. FRONTIERS IN MARINE SCIENCE 2018. [PMID: 0 DOI: 10.3389/fmars.2018.00001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Rahav E, Giannetto MJ, Bar-Zeev E. Contribution of mono and polysaccharides to heterotrophic N2 fixation at the eastern Mediterranean coastline. Sci Rep 2016; 6:27858. [PMID: 27306501 PMCID: PMC4910064 DOI: 10.1038/srep27858] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/26/2016] [Indexed: 11/15/2022] Open
Abstract
N2 fixation should be a critical process in the nitrogen-poor surface water of the eastern Mediterranean Sea. Despite favorable conditions, diazotroph abundance and N2 fixation rates remains low for reasons yet explained. The main goal of this study was to investigate the limiting nutrients for diazotrophy in this oligotrophic environment. Hence, we conducted dedicated bottle-microcosms with eastern Mediterranean Sea water that were supplemented with mono and polysaccharides as well as inorganic nitrogen and phosphorous. Our results indicate that the diazotrophic community expressing nifH was primarily represented by heterotrophic Proteobacteria. N2 fixation and heterotrophic bacterial activity increased up-to tenfold following two days of dark incubations, once seawater was supplemented with organic carbon substrate in the form of glucose (monosaccharides) or gum-xanthan (polysaccharide surrogate). Furthermore, our results point that carbon-rich polysaccharides, such as transparent exopolymer particles, enhance heterotrophic N2 fixation, by forming microenvironments of intense metabolic activity, high carbon: nitrogen ratio, and possibly low O2 levels. The conclusions of this study indicate that diazotrophs in the eastern Mediterranean coast are primarily limited by organic carbon substrates, as possibly in many other marine regions.
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Affiliation(s)
- E. Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, 8030, Israel
| | - M. J. Giannetto
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA
| | - E. Bar-Zeev
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Midreshet Ben-Gurion, Israel
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Hønsvall BK, Altin D, Robertson LJ. Continuous harvesting of microalgae by new microfluidic technology for particle separation. BIORESOURCE TECHNOLOGY 2016; 200:360-365. [PMID: 26512859 DOI: 10.1016/j.biortech.2015.10.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/08/2015] [Accepted: 10/11/2015] [Indexed: 06/05/2023]
Abstract
A new microfluidic chip based on a trilobite structure, designed for continuously concentrating particles in moving fluids, was investigated as a pre-concentration method for microalgal harvesting. The chip has a 5-μm gap limit and was tested for concentrating the microalgae Rhodomonas baltica, Chaetoceros sp. and Thalassiosira weissflogii. The chip was able to concentrate rigid cells and to sort them according to size. However, optimization with respect to cell properties, such as size and flexibility, needs further work. Although no clogging of the chip was seen for R. baltica and Chaetoceros sp., production of exopolymers by T. weissflogii made harvesting challenging for this species. The Trilobite™ microfluidic chip appears to be a promising tool for pre-concentrating microalgae that are difficult to harvest due to their repelling properties or small size.
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Affiliation(s)
- Birgitte K Hønsvall
- Buskerud and Vestfold University College, Raveien 205, 3184 Borre, Norway; Trilobite Microsystems AS, Raveien 205, 3184 Borre, Norway.
| | | | - Lucy J Robertson
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences - Faculty of Veterinary Medicine, Adamstuen Campus, Oslo, Norway
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Raveh O, David N, Rilov G, Rahav E. The Temporal Dynamics of Coastal Phytoplankton and Bacterioplankton in the Eastern Mediterranean Sea. PLoS One 2015; 10:e0140690. [PMID: 26474399 PMCID: PMC4608699 DOI: 10.1371/journal.pone.0140690] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/28/2015] [Indexed: 11/18/2022] Open
Abstract
This study considers variability in phytoplankton and heterotrophic bacterial abundances and production rates, in one of the most oligotrophic marine regions in the world–the Levantine Basin. The temporal dynamics of these planktonic groups were studied in the coastal waters of the southeastern Mediterranean Sea approximately every two weeks for a total of two years. Heterotrophic bacteria were abundant mostly during late summer and midwinter, and were positively correlated with bacterial production and with N2 fixation. Based on size fractionating, picophytoplankton was abundant during the summer, whereas nano-microphytoplankton predominated during the winter and early spring, which were also evident in the size-fractionated primary production rates. Autotrophic abundance and production correlated negatively with temperature, but did not correlate with inorganic nutrients. Furthermore, a comparison of our results with results from the open Levantine Basin demonstrates that autotrophic and heterotrophic production, as well as N2 fixation rates, are considerably higher in the coastal habitat than in the open sea, while nutrient levels or cell abundance are not different. These findings have important ecological implications for food web dynamics and for biological carbon sequestration in this understudied region.
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Affiliation(s)
- Ofrat Raveh
- National Institute of Oceanography, Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Niv David
- National Institute of Oceanography, Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Gil Rilov
- National Institute of Oceanography, Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Eyal Rahav
- National Institute of Oceanography, Israel Oceanographic and Limnological Research, Haifa, Israel
- * E-mail:
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