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Seasonal variation of bacterial communities in shellfish harvesting waters: Preliminary study before applying phage therapy
2015
Pereira, C. | Santos, L. | Silva, A.P. | Silva, Y.J. | Cunha, A. | Romalde, J.L. | Nunes, M.L. | Almeida, A.
The recurrent emergence of infections outbreaks associated with shellfish consumption is an important health problem, which results in substantial economic losses to the seafood industry. Even after depuration, shellfish is still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new efficient strategies to control the shellfish infection transmission. Phage therapy during the shellfish depuration is a promising approach, but its success depends on a detailed understanding of the dynamics of bacterial communities in the harvesting waters. This study intends to evaluate the seasonal dynamics of the overall bacterial communities, disease-causing bacterial populations and bacterial sanitary quality indicators in two authorized harvesting-zones at Ria de Aveiro.During the hot season, the total bacterial community presented high complexity and new prevalent populations of the main shellfish pathogenic bacteria emerged. These results indicate that the spring/summer season is a critical period during which phage therapy should be applied.
اظهر المزيد [+] اقل [-]Long-term functional changes in an estuarine fish assemblage
2015
Baptista, J. | Martinho, F. | Nyitrai, D. | Pardal, M.A. | Dolbeth, M.
The functional diversity of the fish assemblages of the Mondego estuary was studied for a discontinuous 30-year period (1988–2012). During this time, hydrological changes occurred due to man-induced alterations and weather extremes. These changes led to alterations in the structure and function of the fish community. Species richness and functional richness decreased over time and the fish community started to explore new micro-habitats and food resources. Before severe hydrological changes, the community was dominated by pelagic, detritivorous and species with wider salinity ranges. After, the community became dominated by demersal, benthic, piscivorous and marine species. During a drought, omnivorous became increasingly important, reflecting greater possibilities of using available feeding resources. We have also found an increase in sub-tropical species throughout the years, which might be related to gradual temperature increases at a global scale. This study also confirmed estuaries as extremely important for restocking several commercial species.
اظهر المزيد [+] اقل [-]Atmospheric particle number concentration and size distribution in a traffic–impacted area
2015
Schneider, Ismael Luis | Teixeira, Elba Calesso | Silva Oliveira, Luis Felipe | Wiegand, Flavio
This study measured ambient particle number concentrations (PNC) and the particle number distributions (PND) in the urban area of Porto Alegre, Rio Grande do Sul, Brazil. The samples were analyzed using a NanoScan model 3910 from TSI (diameters between 10 and 420 nm) and were taken from sites with high density of vehicular traffic, including two roadsides, two traffic intersections, one street canyon and one urban background. Association of meteorological variables (temperature, relative humidity, solar radiation, wind direction, and wind speed) on nanoparticle concentrations was examined. The results indicated PNC averages between 4.85×104 cm–3 and 1.80×105 cm–3 for locations affected by vehicular traffic, wherein highest concentrations were observed at sites corresponding to traffic intersections. In addition, all sites studied showed a trimodal average PND, with the modes centered at ~14 nm, ~30 nm, and ~105 nm. PND was dominated by nucleation (44.9%) and Aitken (42.0%) modes being representative at the studied sites of the pollution originating from urban traffic, except at the urban background. Meteorological parameters and synoptic meteorological conditions contributed to the variation in the results between the sampled days in the same location.
اظهر المزيد [+] اقل [-]Persistent organic pollutants and polycyclic aromatic hydrocarbons in mosses after fire at the Brazilian Antarctic Station
2015
Colabuono, Fernanda Imperatrice | Taniguchi, Satie | Cipro, Caio Vinícius Zecchin | da Silva, Josilene | Bícego, Márcia Caruso | Montone, Rosalinda Carmela
A fire at the Brazilian Antarctic Station on February 25th, 2012 led to the burning of material that produced organic pollutants. To evaluate the impact in the surrounding area, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs) were analyzed in moss samples collected in the vicinities of the station before and after the incident and compared to findings from previous studies in the same region. PCBs were on the same magnitude as that reported in previous studies, which could be associated to the global dispersion of these compounds and may not be related to the local fire. In contrast, concentrations of HCB and PAHs were higher than those reported in previous studies. No PBDEs were found above the method detection limit. Organic contaminant concentrations in mosses decreased a few months after the fire, which is an important characteristic when considering the use of mosses for monitoring recent exposure.
اظهر المزيد [+] اقل [-]Quantifying indicatively living phytoplankton cells in ballast water samples — recommendations for Port State Control
2015
Gollasch, Stephan | David, Matej | Francé, Janja | Mozetič, Patricija
Different phytoplankton analysis methods (pulse-amplitude modulated fluorometry (PAM) and microscopy) were compared in preparation for compliance monitoring and enforcement with ballast water discharge standards. The key objective was to practically evaluate the performance of different new methods and tools to identify indicatively living phytoplankton cells of the size <50μm in minimum dimension and ≥10μm in minimum dimension as addressed by the Ballast Water Performance Standard (Regulation D-2, International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004). Four different PAM instruments were selected for the tests based upon knowledge and experience gained in different ballast water sample processing studies. The measurements of the PAM instruments were compared with epifluorescence microscope algae cell counts using fluorescein diacetate as viability stain. It was concluded that PAM fluorometry is a suitable method for indicative phytoplankton analysis of ballast water and the most accurate PAM instruments were identified.
اظهر المزيد [+] اقل [-]Efficient dispersion of crude oil by blends of food-grade surfactants: Toward greener oil-spill treatments
2015
Riehm, David A. | Neilsen, John E. | Bothun, Geoffrey D. | John, Vijay T. | Raghavan, Srinivasa R. | McCormick, Alon V.
Effectiveness of oil spill dispersants containing lecithin/Tween 80 (L/T) blends in ethanol was measured as a function of L:T ratio, surfactant:solvent ratio, solvent composition, and dispersant:oil ratio (DOR) using baffled flask dispersion effectiveness tests. Optimal L:T ratios are between 60:40 and 80:20 (w/w); at higher L:T ratios, effectiveness is limited by high interfacial tension, while at lower L:T ratios, insufficient lecithin is present to form a well-packed monolayer at an oil–water interface. These optimal L:T ratios retain high effectiveness at low DOR: 80:20 (w/w) L:T dispersant is 89% effective at 1:25 DOR (v/v) and 77% effective at 1:100 DOR (v/v). Increasing surfactant:solvent ratio increases dispersant effectiveness even when DOR is proportionally reduced to keep total surfactant concentration dosed into the oil constant. Replacing some of the ethanol with octane or octanol also increases dispersant effectiveness, suggesting that ethanol's hydrophilicity lowers dispersant–oil miscibility, and that more hydrophobic solvents would increase effectiveness.
اظهر المزيد [+] اقل [-]Histopathological indices in sole (Solea solea) and hake (Merluccius merluccius) for implementation of the European Marine Strategy Framework Directive along the Basque continental shelf (SE Bay of Biscay)
2015
Cuevas, Nagore | Zorita, Izaskun | Costa, Pedro M. | Quincoces, Iñaki | Larreta, Joana | Franco, Javier
Sole and hake, together with sediments, were collected during two campaigns along the Basque continental shelf to study the utility of two existing histopathological indices for assessing the biological effects of contaminants to implement the European Marine Strategy Framework Directive. Hepatic and gonadal histopathology were measured, and metal and/or organic contaminants were determined in both liver and sediments. Sediments from the Basque continental shelf were found to be moderately impacted by metals but non-impacted by organic compounds. Metal bioaccumulation and histopathological lesions in liver were higher in sole than in hake, although non-specific and early non-neoplastic toxicopathic lesions were observed in both species. No gross alterations were recorded in gonad. The two histopathological indices applied were highly correlated in both organs but the lack of correlation between sediment contamination levels, bioaccumulation and histopathological indices suggests that other factors, rather than pollution alone, are responsible for the biological effects observed.
اظهر المزيد [+] اقل [-]Metallothionein, oxidative stress and trace metals in gills and liver of demersal and pelagic fish species from Kuwaits’ marine area
2015
Beg, M.U. | Al-Jandal, N. | Al-Subiai, S. | Karam, Q. | Husain, S. | Butt, S.A. | Ali, A. | Al-Hasan, E. | Al-Dufaileej, S. | Al-Husaini, M.
Two fish species yellowfin seabream (Acanthopagrus latus) and tonguesole (Cynoglossus arel) were collected from two locations in Kuwait’s territorial waters in non-reproductive periods and used as bio-indicator organism for the assessment of metals in the marine environment. Species variation in fish was observed; seabream contained high metal content and metallothionein in liver and gill tissues compared to tonguesole, especially from Kuwait Bay area. Oxidative injury was registered in the gills of both species, but in tonguesole liver was also involved. Consequently, antioxidant enzyme catalase was elevated in tonguesole enabling bottom dwelling fish to combat oxidative assault. The study provided information about the current status of metals in marine sediment and levels of metals accumulated in representative species along with oxidative damage in exposed tissues and the range of biomarker protein metallothionein and enzymes of antioxidant defence mechanism enhancing our understanding about the biological response to the existing marine environment in Kuwait.
اظهر المزيد [+] اقل [-]Tidal modulation of the hypoxia adjacent to the Yangtze Estuary in summer
2015
Chen, Xiaofeng | Shen, Zhenyao | Li, Yangyang | Yang, Ye
The influence of tide on the distribution of hypoxia adjacent to the Yangtze Estuary was investigated using a three-dimensional hydrodynamic eutrophication model. In the absence of tide, the hypoxic areal extent increased from 5226.75km2 in the base model run to 19,514.25km2, and it mainly occurred in the inner shelf region near the mouth of the Yangtze Estuary and in the inner part of Hangzhou Bay. During neap tide, the hypoxic areal extent further increased to cover 20,704.50km2. Hypoxia first appeared to the southeast of Hangzhou Bay. During the neap to spring tide transition, the hypoxic areal extent decreased to 2430.00km2 due to reduced stratification (2.65×10−3S–2) and the direction of the current. The hypoxic areal extent further decreased to 2319.75km2 during spring tide along with increased current and reduced stratification. Also, hypoxia mainly appeared in the submarine valley.
اظهر المزيد [+] اقل [-]Sequencing Batch Reactor for Wastewater Treatment: Recent Advances
2015
Dutta, Aparna | Sarkar, Sudipta
Sequencing batch reactors (SBRs), due to its operational flexibility and excellent process control possibilities, are being extensively used for the treatment of wastewater which nowadays is fast becoming contaminated with newer and more complex pollutants. It is also possible to include different expanding array of configurations and various operational modifications to meet the effluent limits which are also continuously getting upgraded. This article provides basic description of SBR process along with its functional and physical variants that lead to improved the removal of nutrients and emerging contaminants. The significance of selectors and various recent advancements in the application of SBR has been discussed along with the possibilities held by SBR process in the treatment of wastewater of different origins and composition to produce effluent of reusable quality.
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