Changes in microbial (Bacteria and Archaea) plankton community structure after artificial dispersal in grazer-free microcosms

Microbes are considered to have a global distribution due to their high dispersal capabilities. However, our knowledge of the way geographically distant microbial communities assemble after dispersal in a new environment is limited. In this study, we examined whether communities would converge because similar taxa would be selected under the same environmental conditions, or would diverge because of initial community composition, after artificial dispersal. To this aim, a microcosm experiment was performed, in which the temporal changes in the composition and diversity of different prokaryoplankton assemblages from three distant geographic coastal areas (Banyuls-sur-Mer in northwest Mediterranean Sea, Pagasitikos Gulf in northeast Mediterranean and Woods Hole, MA, USA in the northwest Atlantic), were studied. Diversity was investigated using amplicon pyrosequencing of the V1-V3 hypervariable regions of the 16S rRNA. The three assemblages were grown separately in particle free and autoclaved Banyuls-sur-mer seawater at 18 °C in the dark. We found that the variability of prokaryoplankton community diversity (expressed as richness, evenness and dominance) as well as the composition were driven by patterns observed in Bacteria. Regarding community composition, similarities were found between treatments at family level. However, at the OTU level microbial communities from the three different original locations diverge rather than converge during incubation. It is suggested that slight differences in the composition of the initial prokaryoplankton communities, resulted in separate clusters the following days even when growth took place under identical abiotic conditions

Análisis de los sistemas de auditoría ‘SIRE’ y ‘CDI’ y sus prestaciones en relación a la accidentalidad de los buques cisterna que transportan materiales peligrosos

El principal objetivo de este trabajo consiste en analizar en profundidad las inspecciones vetting, las cuales se centran en las inspecciones a buques cisterna. esta propuesta de trabajo comparará los esquemas sire y cdi desde el punto de vista de la eficacia de sus evaluaciones en relación con la siniestralidad de los buques auditados. Se analizarán los parámetros estudiados y los incidentes sufridos por los buques implicados, así como la comparación de los índices de accidentes con los buques que no cuentan con estos regímenes de inspección, como los buques portacontenedores. Como conclusión del trabajo se presentarán los gráficos y estadísticas de la accidentalidad de estos sistemas identificando de esta manera posibles deficiencias. contendrá propuestas/sugerencias sobre cómo mejorar ambos sistemas de inspección vetting

Everything is not everywhere: can marine compartments shape phytoplankton assemblages?

The idea that ‘everything is everywhere, but the environment selects' has been seminal in microbial biogeography, and marine phytoplankton is one of the prototypical groups used to illustrate this. The typical argument has been that phytoplankton is ubiquitous, but that distinct assemblages form under environmental selection. It is well established that phytoplankton assemblages vary considerably between coastal ecosystems. However, the relative roles of compartmentalization of regional seas and site-specific environmental conditions in shaping assemblage structures have not been specifically examined. We collected data from coastal embayments that fall within two different water compartments within the same regional sea and are characterized by highly localized environmental pressures. We used principal coordinates of neighbour matrices (PCNM) and asymmetric eigenvector maps (AEM) models to partition the effects that spatial structures, environmental conditions and their overlap had on the variation in assemblage composition. Our models explained a high percentage of variation in assemblage composition (59–65%) and showed that spatial structure consistent with marine compartmentalization played a more important role than local environmental conditions. At least during the study period, surface currents connecting sites within the two compartments failed to generate sufficient dispersal to offset the impact of differences due to compartmentalization. In other words, our findings suggest that, even for a prototypical cosmopolitan group, everything is not everywhere

Increased contribution of parasites in microbial eukaryotic communities of different Aegean Sea coastal systems

Background-Aim: Protistan communities have a major contribution to biochemical processes and food webs in coastal ecosystems. However, related studies are scarce and usually limited in specific groups and/or sites. The present study examined the spatial structure of the entire protistan community in seven different gulfs and three different depths in a regional Mediterranean Sea, aiming to define taxa that are important for differences detected in the marine microbial network across the different gulfs studied as well as their trophic interactions. Methods: Protistan community structure analysis was based on the diversity of the V2–V3 hypervariable region of the 18S rRNA gene. Operational taxonomic units (OTUs) were identified using a 97% sequence identity threshold and were characterized based on their taxonomy, trophic role, abundance and niche specialization level. The differentially abundant, between gulfs, OTUs were considered for all depths and interactions amongst them were calculated, with statistic and network analysis. Results: It was shown that Dinophyceae, Bacillariophyta and Syndiniales were the most abundant groups, prevalent in all sites and depths. Gulfs separation was more striking at surface corroborating with changes in environmental factors, while it was less pronounced in higher depths. The study of differentially abundant, between gulfs, OTUs revealed that the strongest biotic interactions in all depths occurred between parasite species (mainly Syndiniales) and other trophic groups. Most of these species were generalists but not abundant highlighting the importance of rare species in protistan community assemblage. Conclusion: Overall this study revealed the emergence of parasites as important contributors in protistan network regulation regardless of depth

Acidification increases abundances of Vibrionales and Planctomycetia associated to a seaweed-grazer system: potential consequences for disease and prey digestion efficiency

Ocean acidification significantly affects marine organisms in several ways, with complex interactions. Seaweeds might benefit from rising CO2 through increased photosynthesis and carbon acquisition, with subsequent higher growth rates. However, changes in seaweed chemistry due to increased CO2 may change the nutritional quality of tissue for grazers. In addition, organisms live in close association with a diverse microbiota, which can also be influenced by environmental changes, with feedback effects. As gut microbiomes are often linked to diet, changes in seaweed characteristics and associated microbiome can affect the gut microbiome of the grazer, with possible fitness consequences. In this study, we experimentally investigated the effects of acidification on the microbiome of the invasive brown seaweed Sargassum muticum and a native isopod consumer Synisoma nadejda. Both were exposed to ambient CO2 conditions (380 ppm, pH 8.16) and an acidification treatment (1,000 ppm, pH 7.86) for three weeks. Microbiome diversity and composition were determined using high-throughput sequencing of the variable regions V5-7 of 16S rRNA. We anticipated that as a result of acidification, the seaweed-associated bacterial community would change, leading to further changes in the gut microbiome of grazers. However, no significant effects of elevated CO2 on the overall bacterial community structure and composition were revealed in the seaweed. In contrast, significant changes were observed in the bacterial community of the grazer gut. Although the bacterial community of S. muticum as whole did not change, Oceanospirillales and Vibrionales (mainly Pseudoalteromonas) significantly increased their abundance in acidified conditions. The former, which uses organic matter compounds as its main source, may have opportunistically taken advantage of the possible increase of the C/N ratio in the seaweed under acidified conditions. Pseudoalteromonas, commonly associated to diseased seaweeds, suggesting that acidification may facilitate opportunistic/pathogenic bacteria. In the gut of S. nadejda, the bacterial genus Planctomycetia increased abundance under elevated CO2. This shift might be associated to changes in food (S. muticum) quality under acidification. Planctomycetia are slow-acting decomposers of algal polymers that could be providing the isopod with an elevated algal digestion and availability of inorganic compounds to compensate the shifted C/N ratio under acidification in their food. In conclusion, our results indicate that even after only three weeks of acidified conditions, bacterial communities associated to ungrazed seaweed and to an isopod grazer show specific, differential shifts in associated bacterial community. These have potential consequences for seaweed health (as shown in corals) and isopod food digestion. The observed changes in the gut microbiome of the grazer seem to reflect changes in the seaweed chemistry rather than its microbial composition.Erasmus Mundus Doctoral Programme MARES on Marine Ecosystem Health Conservation [MARES_13_08]; FCT (Foundation for Science and Technology, Portugal) [SFRH/BPD/63703/2009, SFRH/BPD/107878/2015, SFRH/BPD/116774/2016]; EU SEAS-ERA project INVASIVES [SEAS-ERA/0001/2012]; [CCMAR/Multi/04326/2013

Methane-carbon flow into the benthic food web at cold seeps – a case study from the Costa Rica subduction zone

Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15:0 and C17:1ω6c with stable carbon isotope compositions as low as −53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other 13C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus

Comparison of the Norway lobster (Nephrops norvegicus) gut bacterial communities using 16S rDNA clone libraries and pyrosequencing

By comparing 16S rDNA cloning and 454 pyrosequencing in the Nephrops norvegicus midgut, several common bacterial OTUs were detected. However, when only one method is to be selected, it needs to be considered whether the revealing of rare OTUs or their accurate phylogenetic relationships is mostly preferred. (c) 2013 Elsevier Ltd. All rights reserved

Reuse of Solid Waste in Adsorption of the Textile Dye

AbstractThis work presents the study of the reuse of a regenerated spent bleaching earth (RSBE). The RSBE material was tested in the removal of a basic textile dye presents in aqueous solution. The effect of physicochemical parameters such as stirring speed, initial concentration, contact time and temperature have been invested and thermodynamic nature of the adsorption process was determined by calculating the ΔH°, ΔS° and ΔG° valuesThe results obtained show that the adsorption mechanism was described by the Langmuir model and the adsorption capacity, qmax (72.41 to 82.37mg.g-1), increases with temperature (20-50°C). The thermodynamic parameters show a presence of a strong affinity between two phases (liquid-solid) and an endothermic equilibrium adsorption process. However, the phenomenon of the adsorption kinetic follows the pseudo second order kinetic model

ANTIOXIDANT AND ANTI-INFLAMMATORY ACTIVITIES OF RUBUS FRUTICOSUS AND ZIZYPHUS VULGARIS METHANOL EXTRACTS

Objective: This report is an attempt to study the phenolic composition of Rubus fruticosus (RFE) and Zizyphus vulgaris (ZVE) methanol extracts and evaluate their antioxidant and anti-inflammatory effects in-vitro and in-vivo.Methods: Total phenolic and total flavonoids contents of extracts were determined by spectrophotometric methods. Phenolic compounds were identified by HPLC-TOF/MS. The antioxidant activities were evaluated in vitro using DPPH, ABTS and FRAP assays. The effect of RFE and ZVE on DNA cleavage induced by H2O2 UV-photolysis was also investigated. The antioxidant effect of RFE and ZVE was tested in vivo using the blood total antioxidant capacity test in mice. On the other hand, the anti-inflammatory activity was assessed in vivo using two models of acute inflammation ear edema and vascular permeability.Results: The phytochemical analysis of these extracts showed that RFE possesses higher polyphenolic and flavonoid content than ZVE. in the same way RFE exerted the highest antioxidant capacity with IC 50 value of 14 µg/ml in DPPH assay, 1.58 mmol of Trolox E/mg extract and 3.39 of mmol FesO4/mg extract in ABTS, and FRAP assay respectively. The studied extracts showed a concentration-dependent protective effect on DNA cleavage induced by H2O2 UV-photolysis. The daily oral administration of 200 mg/kg of RFE or ZVE during three weeks showed an improvement of the blood total antioxidant capacity; the HT50 values were151.45 min and 146.72 min for the groups treated with RFE and ZVE, respectively versus 122.5 min for the control group. The topical application of 2 mg/ear of RFE inhibited the croton oil-induced ear edema by 75.72%, while the inhibition exerted by ZVE was 64.24%. These inhibitions were higher than that of indomethacin, used as a reference. Moreover, the oral administration of 400 mg/kg of RFE inhibited significantly (33.57%) acetic acid induced vascular permeability in mice. However, this effect was lower than this of indomethacin. The inhibition effect exerted by ZVE was not significant.Conclusion: The results obtained in this investigation showed that RFE possesses strong antioxidant and anti-inflammatory potential in comparison with ZVE, which may be attributed to the presence of polyphenolic phytoconstituents