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Qi R, Xue N, Zhou X, Zhao L, Song W, Yang Y. Distinct Composition and Assembly Processes of Bacterial Communities in a River from the Arid Area: Ecotypes or Habitat Types? MICROBIAL ECOLOGY 2022; 84:769-779. [PMID: 34686898 DOI: 10.1007/s00248-021-01902-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 10/14/2021] [Indexed: 06/13/2023]
Abstract
The composition, function, and assembly mechanism of the bacterial community are the focus of microbial ecology. Unsupervised machine learning may be a better way to understand the characteristics of bacterial metacommunities compared to the empirical habitat types. In this study, the composition, potential function, and assembly mechanism of the bacterial community in the arid river were analysed. The Dirichlet multinomial mixture method recognised four ecotypes across the three habitats (biofilm, water, and sediment). The bacterial communities in water are more sensitive to human activities. Bacterial diversity and richness in water decreased as the intensity of human activities increased from the region of water II to water I. Significant differences in the composition and potential function profile of bacterial communities between water ecotypes were also observed, such as higher relative abundance in the taxonomic composition of Firmicutes and potential function of plastic degradation in water I than those in water II. Habitat filtering may play a more critical role in the assembly of bacterial communities in the river biofilm, while stochastic processes dominate the assembly process of bacterial communities in water and sediment. In water I, salinity and mean annual precipitation were the main drivers shaping the biogeography of taxonomic structure, while mean annual temperature, total organic carbon, and ammonium nitrogen were the main environmental factors influencing the taxonomic structure in water II. These results would provide conceptual frameworks about choosing habitat types or ecotypes for the research of microbial communities among different niches in the aquatic environment.
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Affiliation(s)
- Ran Qi
- Institute of Geological Survey, China University of Geosciences, Wuhan, 430074, China
- Command Center of Integrated Survey of Natural Resources, China Geological Survey, Beijing, 100055, China
| | - Nana Xue
- College of Resources and Environment, Xinjiang Agricultural University, Urumqi, 830052, China
| | - Xiaobin Zhou
- Xinjiang Laboratory of Environmental Pollution and Ecological Remediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Li Zhao
- Xinjiang Laboratory of Environmental Pollution and Ecological Remediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
| | - Wenjuan Song
- Xinjiang Laboratory of Environmental Pollution and Ecological Remediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.
- University of Chinese Academy of Science, Beijing, 100049, China.
| | - Yuyi Yang
- University of Chinese Academy of Science, Beijing, 100049, China
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
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2
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Rosero-López D, Todd Walter M, Flecker AS, De Bièvre B, Osorio R, González-Zeas D, Cauvy-Fraunié S, Dangles O. A whole-ecosystem experiment reveals flow-induced shifts in a stream community. Commun Biol 2022; 5:420. [PMID: 35513491 PMCID: PMC9072309 DOI: 10.1038/s42003-022-03345-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/10/2022] [Indexed: 12/30/2022] Open
Abstract
The growing threat of abrupt and irreversible changes to the functioning of freshwater ecosystems compels robust measures of tipping point thresholds. To determine benthic cyanobacteria regime shifts in a potable water supply system in the tropical Andes, we conducted a whole ecosystem-scale experiment in which we systematically diverted 20 to 90% of streamflow and measured ecological responses. Benthic cyanobacteria greatly increased with a 60% flow reduction and this tipping point was related to water temperature and nitrate concentration increases, both known to boost algal productivity. We supplemented our experiment with a regional survey collecting > 1450 flow-benthic algal measurements at streams varying in water abstraction levels. We confirmed the tipping point flow value, albeit at a slightly lower threshold (40-50%). A global literature review broadly confirmed our results with a mean tipping point at 58% of flow reduction. Our study provides robust in situ demonstrations of regime shift thresholds in running waters with potentially strong implications for environmental flows management.
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Affiliation(s)
- Daniela Rosero-López
- Soil and Water Lab, Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA. .,Universidad San Francisco de Quito USFQ, Instituto Biósfera, Laboratorio de Ecología Acuática, Calle Diego de Robles y Pampite, Quito, Ecuador.
| | - M Todd Walter
- Soil and Water Lab, Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA
| | - Alexander S Flecker
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | | | - Rafael Osorio
- Gerencia de Ambiente e Hidrología, Empresa Pública de Agua Potable y Saneamiento EPMAPS, Quito, Ecuador
| | - Dunia González-Zeas
- Université de Montpellier, Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université Paul Valéry Montpellier, EPHE, IRD, Montpellier, France
| | | | - Olivier Dangles
- Université de Montpellier, Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université Paul Valéry Montpellier, EPHE, IRD, Montpellier, France
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3
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Almela P, Velázquez D, Rico E, Justel A, Quesada A. Marine Vertebrates Impact the Bacterial Community Composition and Food Webs of Antarctic Microbial Mats. Front Microbiol 2022; 13:841175. [PMID: 35464973 PMCID: PMC9023888 DOI: 10.3389/fmicb.2022.841175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/28/2022] [Indexed: 01/04/2023] Open
Abstract
The biological activity of marine vertebrates represents an input of nutrients for Antarctic terrestrial biota, with relevant consequences for the entire ecosystem. Even though microbial mats assemble most of the biological diversity of the non-marine Antarctica, the effects of the local macrofauna on these microecosystems remain understudied. Using 16S rRNA gene sequencing, 13C and 15N stable isotopes, and by characterizing the P and N-derived nutrient levels, we evaluated the effects of penguins and other marine vertebrates on four microbial mats located along the Antarctic Peninsula. Our results show that P concentrations, C/N and N/P ratios, and δ15N values of "penguin-impacted" microbial mats were significantly higher than values obtained for "macrofauna-free" sample. Nutrients derived from penguin colonies and other marine vertebrates altered the trophic interactions of communities within microbial mats, as well as the relative abundance and trophic position of meiofaunal groups. Twenty-nine bacterial families from eight different phyla significantly changed with the presence of penguins, with inorganic nitrogen (NH4 + and NO3 -) and δ15N appearing as key factors in driving bacterial community composition. An apparent change in richness, diversity, and dominance of prokaryotes was also related to penguin-derived nutrients, affecting N utilization strategies of microbial mats and relating oligotrophic systems to communities with a higher metabolic versatility. The interdisciplinary approach of this study makes these results advance our understanding of interactions and composition of communities inhabiting microbial mats from Antarctica, revealing how they are deeply associated with marine animals.
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Affiliation(s)
- Pablo Almela
- Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
| | - David Velázquez
- Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Eugenio Rico
- Department of Ecology, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Ana Justel
- UC3M-Santander Big Data Institute (IBiDat), Universidad Carlos III de Madrid, Madrid, Spain
- Department of Mathematics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio Quesada
- Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
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Tee HS, Wood SA, Bouma-Gregson K, Lear G, Handley KM. Genome Streamlining, Plasticity, and Metabolic Versatility Distinguish Co-occurring Toxic and Nontoxic Cyanobacterial Strains of Microcoleus. mBio 2021; 12:e0223521. [PMID: 34700377 PMCID: PMC8546630 DOI: 10.1128/mbio.02235-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/20/2021] [Indexed: 01/21/2023] Open
Abstract
Harmful cyanobacterial bloom occurrences have increased worldwide due to climate change and eutrophication, causing nuisance and animal deaths. Species from the benthic cyanobacterial genus Microcoleus are ubiquitous and form thick mats in freshwater systems, such as rivers, that are sometimes toxic due to the production of potent neurotoxins (anatoxins). Anatoxin-producing (toxic) strains typically coexist with non-anatoxin-producing (nontoxic) strains in mats, although the reason for this is unclear. To determine the genetic mechanisms differentiating toxic and nontoxic Microcoleus, we sequenced and assembled genomes from 11 cultures and compared these to another 31 Microcoleus genomes. Average nucleotide identities (ANI) indicate that toxic and nontoxic strains are distinct species (ANI, <95%), and only 6% of genes are shared across all 42 genomes, suggesting a high level of genetic divergence among Microcoleus strains. Comparative genomics showed substantial genome streamlining in toxic strains and a potential dependency on external sources for thiamine and sucrose. Toxic and nontoxic strains are further differentiated by an additional set of putative nitrate transporter (nitrogen uptake) and cyanophycin (carbon and nitrogen storage) genes, respectively. These genes likely confer distinct competitive advantages based on nutrient availability and suggest nontoxic strains are more robust to nutrient fluctuations. Nontoxic strains also possess twice as many transposable elements, potentially facilitating greater genetic adaptation to environmental changes. Our results offer insights into the divergent evolution of Microcoleus strains and the potential for cooperative and competitive interactions that contribute to the co-occurrence of toxic and nontoxic species within mats. IMPORTANCE Microcoleus autumnalis, and closely related Microcoleus species, compose a geographically widespread group of freshwater benthic cyanobacteria. Canine deaths due to anatoxin-a poisoning, following exposure to toxic proliferations, have been reported globally. While Microcoleus proliferations are on the rise, the mechanisms underpinning competition between, or coexistence of, toxic and nontoxic strains are unknown. This study identifies substantial genetic differences between anatoxin-producing and non-anatoxin-producing strains, pointing to reduced metabolic flexibility in toxic strains, and potential dependence on cohabiting nontoxic strains. Results provide insights into the metabolic and evolutionary differences between toxic and nontoxic Microcoleus, which may assist in predicting and managing aquatic proliferations.
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Affiliation(s)
- Hwee Sze Tee
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | | | - Keith Bouma-Gregson
- U.S. Geological Survey, California Water Science Center, Sacramento, California, USA
| | - Gavin Lear
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Kim M. Handley
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
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Wood SA, Kelly L, Bouma-Gregson K, Humbert JF, Laughinghouse HD, Lazorchak J, McAllister T, McQueen A, Pokrzywinski K, Puddick J, Quiblier C, Reitz LA, Ryan K, Vadeboncoeur Y, Zastepa A, Davis TW. Toxic benthic freshwater cyanobacterial proliferations: Challenges and solutions for enhancing knowledge and improving monitoring and mitigation. FRESHWATER BIOLOGY 2020; 65:1824-1842. [PMID: 34970014 PMCID: PMC8715960 DOI: 10.1111/fwb.13532] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
1. This review summarises knowledge on the ecology, toxin production, and impacts of toxic freshwater benthic cyanobacterial proliferations. It documents monitoring, management, and sampling strategies, and explores mitigation options. 2. Toxic proliferations of freshwater benthic cyanobacteria (taxa that grow attached to substrates) occur in streams, rivers, lakes, and thermal and meltwater ponds, and have been reported in 19 countries. Anatoxin- and microcystin-containing mats are most commonly reported (eight and 10 countries, respectively). 3. Studies exploring factors that promote toxic benthic cyanobacterial proliferations are limited to a few species and habitats. There is a hierarchy of importance in environmental and biological factors that regulate proliferations with variables such as flow (rivers), fine sediment deposition, nutrients, associated microbes, and grazing identified as key drivers. Regulating factors differ among colonisation, expansion, and dispersal phases. 4. New -omics-based approaches are providing novel insights into the physiological attributes of benthic cyanobacteria and the role of associated microorganisms in facilitating their proliferation. 5. Proliferations are commonly comprised of both toxic and non-toxic strains, and the relative proportion of these is the key factor contributing to the overall toxin content of each mat. 6. While these events are becoming more commonly reported globally, we currently lack standardised approaches to detect, monitor, and manage this emerging health issue. To solve these critical gaps, global collaborations are needed to facilitate the rapid transfer of knowledge and promote the development of standardised techniques that can be applied to diverse habitats and species, and ultimately lead to improved management.
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Affiliation(s)
| | | | - Keith Bouma-Gregson
- Office of Information Management and Analysis, California State Water Resources Control Board, Sacramento, California, United States of America
| | | | - H Dail Laughinghouse
- Fort Lauderdale Research and Education Center, University of Florida, Florida, USA
| | - James Lazorchak
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Monitoring and Modeling, Cincinnati, Ohio, United States of America
| | - Tara McAllister
- Te Pūnaha Matatini Centre of Research Excellence for Complex Systems, University of Auckland, Auckland, New Zealand
| | - Andrew McQueen
- Environmental Risk Assessment Branch, US Army Corps of Engineers, Engineering Research & Development Center, Vicksburg, Mississippi, United States of America
| | - Katyee Pokrzywinski
- Environmental Risk Assessment Branch, US Army Corps of Engineers, Engineering Research & Development Center, Vicksburg, Mississippi, United States of America
| | | | | | - Laura A Reitz
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Ken Ryan
- School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - Yvonne Vadeboncoeur
- Department of Biological Sciences, Wright State University, Ohio, United States of America
| | - Arthur Zastepa
- Environment and Climate Change Canada, Canada Centre for Inland Waters, Ontario, Canada
| | - Timothy W Davis
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
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6
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Tee HS, Waite D, Payne L, Middleditch M, Wood S, Handley KM. Tools for successful proliferation: diverse strategies of nutrient acquisition by a benthic cyanobacterium. THE ISME JOURNAL 2020; 14:2164-2178. [PMID: 32424245 PMCID: PMC7367855 DOI: 10.1038/s41396-020-0676-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 04/23/2020] [Accepted: 05/01/2020] [Indexed: 12/28/2022]
Abstract
Freshwater cyanobacterial blooms have increased worldwide, channeling organic carbon into these systems, and threatening animal health through the production of cyanotoxins. Both toxic and nontoxic Microcoleus proliferations usually occur when there are moderate concentrations of dissolved inorganic nitrogen, but when phosphorus is scarce. In order to understand how Microcoleus establishes thick biofilms (or mats) on riverbeds under phosphorus-limiting conditions, we collected Microcoleus-dominated biofilms over a 19-day proliferation event for proteogenomics. A single pair of nitrogen-dependent Microcoleus species were consistently present in relatively high abundance, although each followed a unique metabolic trajectory. Neither possessed anatoxin gene clusters, and only very low concentrations of anatoxins (~2 µg kg-1) were detected, likely originating from rarer Microcoleus species also present. Proteome allocations were dominated by photosynthesizing cyanobacteria and diatoms, and data indicate biomass was actively recycled by Bacteroidetes and Myxococcales. Microcoleus likely acquired nutrients throughout the proliferation event by uptake of nitrate, urea, and inorganic and organic phosphorus. Both species also harbored genes that could be used for inorganic phosphate solubilization with pyrroloquinoline quinone cofactors produced by cohabiting Proteobacteria. Results indicate that Microcoleus are equipped with diverse mechanisms for nitrogen and phosphorus acquisition, enabling them to proliferate and out-compete others in low-phosphorus waters.
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Affiliation(s)
- H S Tee
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - D Waite
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - L Payne
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - M Middleditch
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - S Wood
- Cawthron Institute, Nelson, New Zealand
| | - K M Handley
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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Thomson-Laing G, Puddick J, Laroche O, Fulton S, Steiner K, Heath MW, Wood SA. Broad and Fine Scale Variability in Bacterial Diversity and Cyanotoxin Quotas in Benthic Cyanobacterial Mats. Front Microbiol 2020; 11:129. [PMID: 32117151 PMCID: PMC7017413 DOI: 10.3389/fmicb.2020.00129] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 01/21/2020] [Indexed: 11/13/2022] Open
Abstract
Benthic proliferations of Microcoleus autumnalis (basionym Phormidium autumnale) and closely related taxa are being reported with increasing frequency in streams and rivers worldwide. This species commonly produces the potent neurotoxin anatoxin, and exposure to this has resulted in animal fatalities and human health concerns. Bacterial communities within cyanobacterial assemblages can facilitate processes such as nutrient cycling and are posited to influence cyanobacterial growth and function. However, there is limited knowledge on spatial variability of bacterial communities associated with benthic cyanobacteria and anatoxin content and quotas. In this study, M. autumnalis-dominated mat samples were collected from six sites in two New Zealand streams. Associated bacterial communities were characterized using 16S rRNA metabarcoding, anatoxin content by liquid chromatography-mass spectrometry and anaC copies using droplet digital PCR. Bacterial assemblages differed significantly when amplicon sequence variants were compared between streams and most sites within streams. These differences were associated with conductivity, DRP, DIN, temperature, anatoxin concentration, and quota. Despite the differences in bacterial community composition; at phyla, class and order levels there was high similarity across spatial scales, with Bacteroidetes (ca. 67%) and Proteobacteria (ca. 25%) dominant. There was significant variability in total anatoxin concentrations between sites in both streams (p < 0.001). When the data were converted to anatoxin quotas variability was reduced, suggesting that the relative abundance of toxic genotypes is a key driver of total anatoxin concentrations in mats. This study demonstrates the complexity of microbial communities within M. autumnalis-dominated mats and highlights their likely important role in within-mat nutrient cycling processes.
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Affiliation(s)
| | | | - Olivier Laroche
- Cawthron Institute, Nelson, New Zealand.,Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | | | | | - Mark W Heath
- Greater Wellington Reginal Council, Wellington, New Zealand
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Vogt JC, Abed RMM, Albach DC, Palinska KA. Latitudinal gradient of cyanobacterial diversity in tidal flats. PLoS One 2019; 14:e0224444. [PMID: 31721816 PMCID: PMC6853291 DOI: 10.1371/journal.pone.0224444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 10/14/2019] [Indexed: 11/18/2022] Open
Abstract
Latitudinal diversity gradients are well-known for plants and animals, but only recently similar patterns have been described for some specific microbial communities in distinct habitats. Although microbial diversity is well-investigated worldwide, most of the studies are spatially too restricted to allow general statements about global diversity patterns. Additionally, methodological differences make it hard and often impossible to compare several studies. This study investigated the cyanobacterial diversity in tidal flats along geographical and ecological gradients based on high-throughput sequencing of 16S rRNA gene fragments (Illumina MiSeq) and environmental data on a large spatial scale from the subtropics to the Arctic. Latitude and strongly correlated environmental parameters (e.g. temperature) were identified as important drivers of cyanobacterial diversity on global scale resulting in a latitudinal diversity gradient similar to that known from plants and animals. Other non-correlated parameters (e.g. grain size) were shown to be more important on local scales, although no consistent pattern occurred across different locations. Among a total number of 989 operational taxonomic units (OTUs) only one cosmopolitan (classified as Coleofasciculus chthonoplastes), but many location-specific and putative endemic ones (78%) were detected. High proportions of rare members of the community (up to 86%) were found in all samples. Phylogenetic beta diversity was shown to be influenced by the developmental stage of the mat community becoming increasingly similar with increasing stabilization.
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Affiliation(s)
- Janina C Vogt
- Institute for Biology and Environmental Science (IBU), Biodiversity and Evolution of Plants, Carl-von-Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Raeid M M Abed
- Biology Department, College of Science, Sultan Qaboos University, Al Khoud, Muscat, Sultanate of Oman
| | - Dirk C Albach
- Institute for Biology and Environmental Science (IBU), Biodiversity and Evolution of Plants, Carl-von-Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Katarzyna A Palinska
- Department of Marine Biology and Ecology, Institute of Oceanography, University of Gdansk, al. Marszałka Józefa Piłsudskiego 46, Gdynia, Poland
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Echenique-Subiabre I, Tenon M, Humbert JF, Quiblier C. Spatial and Temporal Variability in the Development and Potential Toxicity of Phormidium Biofilms in the Tarn River, France. Toxins (Basel) 2018; 10:toxins10100418. [PMID: 30336603 PMCID: PMC6215143 DOI: 10.3390/toxins10100418] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 09/24/2018] [Accepted: 10/09/2018] [Indexed: 11/29/2022] Open
Abstract
Proliferation of Phormidium biofilms in rivers is becoming a worldwide sanitation problem for humans and animals, due to the ability of these bacteria to produce anatoxins. To better understand the environmental conditions that favor the development of Phormidium biofilms and the production of anatoxins, we monitored the formation of these biofilms and their toxins for two years in the Tarn River, biofilms from which are known to have caused the deaths of multiple dogs. As previously observed in New Zealand, Phormidium biofilm development occurred in riffle areas. The coverage of these biofilms at the bottom of the river exhibited strong spatial and temporal variations, but was positively correlated with water temperature and depth. Anatoxin-a was detected in less than 50% of the biofilms. The concentrations of these toxins in the biofilms exhibited high spatiotemporal variability, with the highest concentrations being recorded at the end of the summer period at the upstream sampling sites. These findings suggest that the maturity of the biofilms, combined with the local environmental conditions, have an impact on the production of anatoxin, making risk assessment for these benthic proliferations challenging.
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Affiliation(s)
- Isidora Echenique-Subiabre
- INRA, Sorbonne University, iEES Paris, 4 Place Jussieu, 75252 Paris CEDEX, France.
- Unité Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum National d'Histoire Naturelle, CNRS, Case 39, 57 rue Cuvier, 75005 Paris, France.
| | - Maxime Tenon
- Unité Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum National d'Histoire Naturelle, CNRS, Case 39, 57 rue Cuvier, 75005 Paris, France.
| | | | - Catherine Quiblier
- Unité Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum National d'Histoire Naturelle, CNRS, Case 39, 57 rue Cuvier, 75005 Paris, France.
- Department Sciences du Vivant, Paris Diderot University, 5 rue T. Mann, 75013 Paris, France.
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