Spatial and temporal dynamics of virioplankton in a high - mountain tropical reservoir, El Neusa (Cundinamarca, Colombia) (original) (raw)
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PANGAEA, 2021
This data set includes water column nitrate+nitrite and phosphate concentrations and ancillary CTD variables from the deep-water region in the southern Gulf of Mexico (GoM). These measurements were used to estimate water mass fractions using an Optimum Multi-parameter analysis that requires semiconservative parameters (NO and PO4* parameters) calculated with nitrate+nitrite, phosphate and dissolved oxygen concentrations. Water samples were collected with a rosette equipped with 12 20-L Niskin bottles during the XIXIMI-5 oceanographic cruise that took place during June 10–25, 2016. The southern region of the GoM (20–26º N, 86–97º W) comprises the deep-waters of the GoM, including the continental slope and abyssal plain. A total of 35 stations were sampled on board R/V Justo Sierra of the National Autonomous University of Mexico. Data columns include sampling Date/Time stamp in ISO format, Longitude, Latitude, Depth, Pressure, temperature and salinity from CTD. The CTD sensors were previously calibrated by the manufacturer, and the accuracy of the measurements was ± 0.001 ºC for temperature, ± 0.002 for salinity, and 2% for DO. Data from the DO sensor were calibrated with data from the Niskin bottle samples, analyzed with the microWinkler method. The accuracy and precision of the microWinkler method were 0.1% and ~ 1.3 µmol/kg, respectively. Nitrate+nitrite and phosphate analyses were performed with a SEAL-AA3-HR auto-analyzer (SEAL Analytical Ltd., Norderstedt, Germany), following the guidelines described in the GO-SHIP Repeat Hydrography Manual. Accuracy and precision were estimated with measurements of certified reference material (CRM) for nutrients (Lots CD and CC; Kanso Co. Ltd., Osaka, Japan). The Ocean Data Standards from the UNESCO were used to assign Quality Flags (QF) for nutrients. The limits of detection (3 SD, n = 11) for nitrate+nitrite and phosphate were 0.037 and 0.028 µmol/kg, respectively. The mean values obtained for nitrate+nitrite from the CD and CC lots were 5.514±0.012 µmol/kg and 30.958±0.047 µmol/kg, respectively. The sum of the certified values for nitrate and nitrate from the CD and CC lots is 5.516±0.050 µmol/kg and 30.996±0.240 µmol/kg, respectively. The mean values obtained for phosphate from the CD and CC lots were 0.447±0.010 µmol/kg and 2.092±0.012 µmol/kg, respectively. The certified values for phosphate from the CD and CC lots is 0.446±0.008 µmol/kg and 2.080±0.019 µmol/kg, respectively. This research has been funded by the Mexican National Council for Science and Technology - Mexican Ministry of Energy - Hydrocarbon Fund, project 201441. This is a contribution of the Gulf of Mexico Research Consortium (CIGoM, http://www.cigom.info). We acknowledge PEMEX's specific request to the Hydrocarbon Fund to address the environmental effects of oil spills in the Gulf of Mexico. Project: Implementación de redes de observación oceanográficas (físicas, geoquímicas, y ecológicas) para la generación de escenarios ante posibles contingencias relacionadas a la exploración y producción de hidrocarburos en aguas profundas del Golfo de México.
Viral and microbial community dynamics in four aquatic environments
The ISME Journal, 2010
The species composition and metabolic potential of microbial and viral communities are predictable and stable for most ecosystems. This apparent stability contradicts theoretical models as well as the viral-microbial dynamics observed in simple ecosystems, both of which show Kill-the-Winner behavior causing cycling of the dominant taxa. Microbial and viral metagenomes were obtained from four human-controlled aquatic environments at various time points separated by one day to 41 year. These environments were maintained within narrow geochemical bounds and had characteristic species composition and metabolic potentials at all time points. However, underlying this stability were rapid changes at the fine-grained level of viral genotypes and microbial strains. These results suggest a model wherein functionally redundant microbial and viral taxa are cycling at the level of viral genotypes and virus-sensitive microbial strains. Microbial taxa, viral taxa, and metabolic function persist over time in stable ecosystems and both communities fluctuate in a Kill-the-Winner manner at the level of viral genotypes and microbial strains.
Viral abundance in aquatic systems: a comparison between marine and fresh waters
Marine ecology progress series. Oldendorf, 1995
In order to investigate the factors controlling viral abundance, 22 lakes In Quebec were surveyed. We measured viral and bacterial abundance, bacterial production, chlorophyll a, total phosphorus and DOC (dissolved organic carbon) concentrations. Regression models built with these data were compared to models based on literature data, which to date have been collected largely from marine sites Positive empirical relationships were found between viral abundance and (1) chlorophyll a concentrations, (2) bacterial abundances, (3) bacterial production, and (4) total phosphorus concentration. There was little to no trend in the virus-to-bacteria ratio with increasing trophy. Analysis of covariance revealed significant differences between relations in marine and freshwater systems. The virusto-bacteria ratio was significantly higher in freshwater (mode = 22.5) than marine environments (mode = 2.51, and there were significantly more bacteria per unit chlorophyll in our freshwater samples. We suggest that this difference is related to the increased dependence of freshwater bacteria on allochthonous material relative to marine systems, as well as the increased relative importance of photosynthetic cyanobacteria in lakes. KEY WORDS: Virus Bacteria. Chlorophyll a. Bacterial production. Marine. Freshwater. Empirical relationsh~ps O Inter-Research 1995 Resale of full article not permittea
Viruses as regulators of nutrient cycles in aquatic environments
2000
ABSTRACT Viruses are abundant and dynamic members of marine environments. The persistence of viral communities in aquatic systems requires the daily destruction of a significant proportion of the bacterial and phytoplankton populations. While the destruction of host cells by viruses has several implications, one of the most important effects may be the role viruses play as regulators of nutrient cycles.
Virus-Bacterium Coupling Driven by both Turbidity and Hydrodynamics in an Amazonian Floodplain Lake
Applied and Environmental Microbiology, 2010
The importance of viruses in aquatic ecosystem functioning has been widely described. However, few studies have examined tropical aquatic ecosystems. Here, we evaluated for the first time viruses and their relationship with other planktonic communities in an Amazonian freshwater ecosystem. Coupling between viruses and bacteria was studied, focusing both on hydrologic dynamics and anthropogenic forced turbidity in the system (Lake Batata). Samples were taken during four hydrologic seasons at both natural and impacted sites to count virus-like particles (VLP) and bacteria. In parallel, virus-infected bacteria were identified and quantified by transmission electron microscopy (TEM). Viral abundance ranged from 0.5 ؋ 10 7 ؎ 0.2 ؋ 10 7 VLP ml ؊1 (high-water season, impacted site) to 1.7 ؋ 10 7 ؎ 0.4 ؋ 10 7 VLP ml ؊1 (low-water season, natural site). These data were strongly correlated with the bacterial abundance (r 2 ؍ 0.84; P < 0.05), which ranged from 1.0 ؋ 10 6 ؎ 0.5 ؋ 10 6 cells ml ؊1 (high water, impacted site) to 3.4 ؋ 10 6 ؎ 0.7 ؋ 10 6 cells ml ؊1 (low water, natural site). Moreover, the viral abundance was weakly correlated with chlorophyll a, suggesting that most viruses were bacteriophages. TEM quantitative analyses revealed that the frequency of visibly infected cells was 20%, with 10 ؎ 3 phages per cell section. In general, we found a low virus-bacterium ratio (<7). Both the close coupling between the viral and bacterial abundances and the low virus-bacterium ratio suggest that viral abundance tends to be driven by the reduction of hosts for viral infection. Our results demonstrate that viruses are controlled by biological substrates, whereas in addition to grazing, bacteria are regulated by physical processes caused by turbidity, which affect underwater light distribution and dissolved organic carbon availability.
Metabolic and biogeochemical consequences of viral infection in aquatic ecosystems
Nature Reviews Microbiology, 2019
Ecosystems are controlled by 'bottom-up' (resources) and 'top-down' (predation) forces. Viral infection is now recognized as a ubiquitous top-down control of microbial growth across ecosystems but, at the same time, cell death by viral predation influences, and is influenced by , resource availability. In this Review , we discuss recent advances in understanding the biogeochemical impact of viruses, focusing on how metabolic reprogramming of host cells during lytic viral infection alters the flow of energy and nutrients in aquatic ecosystems. Our synthesis revealed several emerging themes. First, viral infection transforms host metabolism, in part through virus-encoded metabolic genes; the functions performed by these genes appear to alleviate energetic and biosynthetic bottlenecks to viral production. Second, viral infection depends on the physiological state of the host cell and on environmental conditions, which are challenging to replicate in the laboratory. Last, metabolic reprogramming of infected cells and viral lysis alter nutrient cycling and carbon export in the oceans, although the net impacts remain uncertain. This Review highlights the need for understanding viral infection dynamics in realistic physiological and environmental contexts to better predict their biogeochemical consequences.
RIA Almeida et al 2001 Microbial Ecology 42 (vírus)
The bacterioplankton density in Ria de Aveiro, a shallow estuarine ecosystem, varied in the broad range of 1.9-10.6 × 10 9 cells L −1 . The range of values was about 2 times higher in brackish water than in marine water. At high tide bacterial abundance was 2-3 times lower than at low tide. The overall variation in virioplankton was in the range of 2.4-25.0 × 10 10 particles L −1 . Brackish water was about 2 times richer in viral particles than the marine water. Near low tide the virioplankton was 2-3 times higher that at high tide. Viral density followed the pattern of bacterial abundance (it explained 40% of virioplankton variation). The viruses to bacterium ratio varied, throughout tidal cycles, by a factor of about 10 establishing the range 4.7-55.6 (average 17.6). This ratio was rather similar in the two estuarine zones. We compared the effects of infection and predation on the control of bacterioplankton size in the two zones of the estuary. The approach to this question was conducted in experimental microcosms, set up in six combinations of plankton variables affecting the presence/ absence of predators, virus-to-bacterium ratio (10-fold increase), virus-to-bacterium distance (2.2fold increase), and bacterial growth rate. The results showed that predation was similar, in a percent basis, in marine (69%) and brackish water (73%). Viral infection was, however, higher in brackish water (59%) than in the marine water (36%). We conclude that the bacterioplankton along the salinity gradient evolves under biological pressures that are in different balance in the marine and brackish water zones. The effect of viral lysis on bacterial communities with enhanced growth (after yeast extract addition) was masked even when the initial ratio was 10-fold greater than in the natural samples. The high density of the virioplankton did not preclude the large and rapid increase in bacterial density. We suggest that the dynamics of the equilibrium between bacteria and viruses in the environment is driven to higher numerical levels during periods of intensive bacterial growth.
Ecological Role of Viruses in Aquatic Ecosystems
Encyclopedia of Life Sciences, 2001
Over two decades of research have indicated that viruses play crucial roles in aquatic food webs as active constituents of the microbial loop and in the population ecology of both prokaryotic and eukaryotic microorganisms. Over the past 5 years, there has been a sharp increase in reported aquatic virus research, notably in the areas of freshwater viral ecology, viruses of eukaryotic microorganisms and viral genetic diversity. Recent studies of the interactions between viral infection, bacterivory and grazing have demonstrated the complex dynamics of viral infection within aquatic ecosystems. These reports have helped solidify our understanding of the environmental controls on viral abundance, impacts of viral infection upon host community structure and have elucidated new roles of viruses in biogeochemical cyclessuch as photosystem gene expression. Previously unrecognised groups of viruses (ribonucleic acid viruses and single-stranded deoxyribonucleic acid viruses) have also been revealed as diverse and active components of marine virioplankton assemblages.
Temporal variation in freshwater viral and bacterial community composition
2007
1. The goal of this study conducted in three lakes differing in nutrient content and size was to assess the temporal variation in viral community composition and possible co-variation with compositional changes in bacterial communities. 2. The viral community composition differed among lakes and changed over the season. Changes could also be detected on short-time scales, i.e. over a few days. These changes were comparable in magnitude to the changes detected between months or seasons. 3. The most important environmental factors co-varying with viral community composition, as determined by multivariate analysis, differed over the year and among lakes. Temperature and concentrations of dissolved organic carbon (DOC), total phosphorus and soluble reactive phosphorus were the most important factors. 4. Bacterial community composition also varied over the season and among lakes. The most important factors co-varying with bacterial community composition, as determined by multivariate analysis, were also temperature and DOC concentration. 5. Correlation between viral and bacterial community composition was weak and appeared to be a result of an indirect connection rather than a direct relationship between bacteria and viruses.
Deep Sea Research Part I: Oceanographic Research Papers, 2007
Viruses are hypothesized to maintain diversity in microbial assemblages by regulating the abundance of dominant competitors and thereby allowing less-dominant competitors to persist in assemblages; however, there have been few empirical data sets to support this idea. In this study, we examined the relationship between the ratio of viral abundance to bacterial abundance, viral production, and the relative richness and diversity of bacterial assemblage fingerprints, in samples taken from geographically widespread locations (North Pacific gyre, the Amazon River plume and adjacent North Atlantic gyre, Gulf of Mexico, Southern California Bight and Arafura-Coral Seas) which are oligo-to mesotrophic. Bacterial assemblage richness and diversity as measured by automated rRNA intergenic spacer (ARISA) fingerprinting were significantly and positively correlated with the ratio of virus abundance to bacteria abundance (VBR) and to the rate of virus production only in the oligotrophic North Pacific gyre. ARISA fingerprint richness/diversity were not significantly correlated to viral parameters when assessed across all samples in surface waters, suggesting there is not a singular global quantitative relationship between viral pressure and host diversity within well evolved host/virus systems in different geographic locations in plankton. In sediments off Southern California, viral parameters significantly and negatively correlated with ARISA diversity, suggesting strong viral interactions in this habitat. To examine covariation of viral parameters and the relative abundance and diversity of rarer bacterial taxa (i.e., less-dominant competitor), the richness and diversity of diazotroph communities was measured using terminal restriction fragment length polymorphism (TRFLP) of a portion (nifH) of the nitrogenase gene. The richness and diversity of diazotrophic communities were significantly and negatively correlated with viral parameters across all locations. Since diazotrophs include many opportunistic taxa (e.g. Vibrionaceae), and because these bacteria may be more susceptible to viral attack due to enhanced resource uptake abilities and potentially rapid localized growth, it is possible that this negative effect was due to enhanced viral lysis. Consequently, virus infection may have positive effects upon bacterioplankton diversity in the oligotrophic ocean, by regulating the abundance of dominant competitors, and allowing rarer taxa to coexist; however, some rarer taxa (such as diazotrophs) may be more susceptible to viral attack due to opportunistic lifestyles.