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Resultados 1721-1730 de 5,149
Characterisation of spatial variability in water quality in the Great Barrier Reef catchments using multivariate statistical analysis Texto completo
2018
Liu, S. | Ryu, D. | Webb, J.A. | Lintern, A. | Waters, D. | Guo, D. | Western, A.W.
Water quality monitoring is important to assess changes in inland and coastal water quality. The focus of this study was to improve understanding of the spatial component of spatial-temporal water quality dynamics, particularly the spatial variability in water quality and the association between this spatial variability and catchment characteristics. A dataset of nine water quality constituents collected from 32 monitoring sites over a 11-year period (2006–2016), across the Great Barrier Reef catchments (Queensland, Australia), were evaluated by multivariate techniques. Two clusters were identified, which were strongly associated with catchment characteristics. A two-step Principal Component Analysis/Factor Analysis revealed four groupings of constituents with similar spatial pattern and allowed the key catchment characteristics affecting water quality to be determined. These findings provide a more nuanced view of spatial variations in water quality compared with previous understanding and an improved basis for water quality management to protect nearshore marine ecosystem.
Mostrar más [+] Menos [-]Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast Texto completo
2018
Compa, Montserrat | Ventero, Ana | Iglesias, Magdalena | Deudero, Salud
Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast Texto completo
2018
Compa, Montserrat | Ventero, Ana | Iglesias, Magdalena | Deudero, Salud
The ingestion of microplastics and natural fibres (<5 mm) was assessed for two commercial fish species in the western Mediterranean Sea: Sardina pilchardus and Engraulis encrasicolus. Gastrointestinal tracts from 210 individuals from 14 stations were examined with 14.28–15.24% of the small pelagic fish S. pilchardus and E. encrasicolus having ingested microplastics and natural fibres. A latitudinal increase in condition index (Fulton's K) of S. pilchardus gave an indication that larger individuals with better physical condition are less likely to ingest microplastics and natural fibres. Fibres were the most frequent particle type (83%) and Fourier Transform Infrared spectroscopy (FT-IR) analysis indicated polyethylene terephthalate was the most common microplastics material (30%). Results from this study show that both microplastics and natural fibres of anthropogenic origin are common throughout the pelagic environment along the Spanish Mediterranean coast.
Mostrar más [+] Menos [-]Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast Texto completo
2018
Compa, Montserrat | Ventero, Ana | Iglesias, Magdalena | Deudero, Salud
The ingestion of microplastics and natural fibres (< 5 mm) was assessed for two commercial fish species in the western Mediterranean Sea: Sardina pilchardus and Engraulis encrasicolus. Gastrointestinal tracts from 210 individuals from 14 stations were examined with 14.28–15.24% of the small pelagic fish S. pilchardus and E. encrasicolus having ingested microplastics and natural fibres. A latitudinal increase in condition index (Fulton's K) of S. pilchardus gave an indication that larger individuals with better physical condition are less likely to ingest microplastics and natural fibres. Fibres were the most frequent particle type (83%) and Fourier Transform Infrared spectroscopy (FT-IR) analysis indicated polyethylene terephthalate was the most common microplastics material (30%). Results from this study show that both microplastics and natural fibres of anthropogenic origin are common throughout the pelagic environment along the Spanish Mediterranean coast | M. Compa is the recipient of a FPI Fellowship from Conselleria d'Innovació, Recerca i Turisme of the regional Government of the Balearic Islands co-financed by the European Social Fund as part of the FSE 2014–2020 operational program. This study was partially funded by Ajuts per dur a terme Accions Especials de Recerca i Desenvolupament 2015–2016 del Govern de les Illes Balears, Ref: 17/2015. Additional appreciation to Antonio Esteban for coordinating the sample collection and special thanks to Tamara Gajst, Tine Bizjak and Arto Koistinen from SIB Labs at the University of Finland. The MEDIAS surveys have been co-funded by the European Union through the European Maritime and Fisheries Fund (EMFF) within the National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy. In addition, this study was partially funded by the European Commission DG Environment project: “Support Mediterranean Member States towards coherent and Coordinated Implementation of the second phase of the MSFD – MEDCIS” with Grant no. 11.0661/2016/748067/SUB/ENV.C2. | Peer reviewed
Mostrar más [+] Menos [-]First assessment of the effectiveness of the international convention on the control of harmful anti-fouling systems on ships in Tunisia using imposex in Hexaplex trunculus as biomarker Texto completo
2018
Lahbib, Youssef | Abidli, Sami | Trigui-El Menif, Najoua
The global ban on the use of tributyltin (TBT) forced in September 2008 was ratified in Tunisia as late as June 2011. In this context, the present study aims to highlight the consequences of TBT contamination by monitoring 22 Tunisian sites before (2007) and after the ban (2012 and 2016) using as biomarker the occurrence of imposex in Hexaplex trunculus. From 2004 to 2016, complete recovery from imposex was reported in 11 sites. All average imposex indices calculated for each sampling year also decreased: imposex incidence from 61 to 27%, VDSI from 2 to 0.7, and RPLI from 15.7 to 1.6%. Ecological Quality Ratios (EQR) revealed that the sampling sites are in moderate to good ecological status. Overall, the present study confirms the effectiveness of the enacted legislation in reducing the impact of TBT pollution along the Tunisian coast.
Mostrar más [+] Menos [-]Intensive anthropogenic activities had affected Daya Bay in South China Sea since the 1980s: Evidence from heavy metal contaminations Texto completo
2018
Qu, Baoxiao | Song, Jinming | Yuan, Huamao | Li, Xuegang | Li, Ning | Duan, Liqin
Sediment geochemical characteristics were analyzed to assess how anthropogenic activities affected the Daya Bay, a subtropics bay adjacent to the most economically developed region of China. Vertical profiles of heavy metal contents and their enrichment factors indicated the development of Daya Bay environment in the past 100 years basically experienced three stages, which were closely consistent with the economic development. Before 1980s, the concentration of heavy metals was basically at the background level. Contamination of metals, particularly for Cr, Ni, Cu, Zn, Cd, and Pb, generally began in mid-1980s and became serious in 2000s. However, after late-2000s, the sediment quality had been radically improved. Heavy metals in nearshore sediment of Daya Bay were all closely related with import of anthropogenic and/or terrestrial material, whereas those in offshore were likely to be related with joint influence from the anthropogenic activities and the natural processes.
Mostrar más [+] Menos [-]Ingestion of marine debris by Wedge-tailed Shearwaters (Ardenna pacifica) on Lord Howe Island, Australia during 2005–2018 Texto completo
2018
Lavers, Jennifer L. | Hutton, Ian | Bond, Alexander L.
Annual rates of plastic production have been increasing rapidly since the 1950s. Inadequate or improper disposal of plastic products has contributed to a significant increase in plastic debris in the world's oceans and a corresponding increase in the number of species negatively affected by this debris. Here we investigate trends in the type, amount, and colour of ingested plastic over time, and determine whether ingested plastic contributes to reduced health of Wedge-tailed Shearwaters (Ardenna pacifica) on Lord Howe Island, Australia. The results show no clear influence of ingested plastic on body condition, while trends in the prevalence, number, and mass of plastic items ingested per bird during 2005 and 2013–2018 were more variable. There was some evidence adult birds are selecting plastic by colour. Future monitoring of this pan-tropical seabird would provide a unique opportunity to gather data from multiple sites, concurrently.
Mostrar más [+] Menos [-]Interactive effect of nitrogen source and high CO2 concentration on the growth of the dinoflagellate Alexandrium tamarense and its toxicity to zebrafish (Danio rerio) embryos Texto completo
2018
Guan, Wanchun | Si, Ranran | Li, Xi | Cai, Jingbo | Chen, Shaobo
Interactive effect of nitrogen source and high CO2 concentration on the growth of the dinoflagellate Alexandrium tamarense and its toxicity to zebrafish (Danio rerio) embryos Texto completo
2018
Guan, Wanchun | Si, Ranran | Li, Xi | Cai, Jingbo | Chen, Shaobo
The effects and interactive effects of different nitrogen (N) sources (ammonium, nitrate, and urea) and carbon dioxide (CO₂) concentrations were investigated on Alexandrium tamarense, a harmful marine dinoflagellate, by measuring its growth (μ), extracellular carbonic anhydrase (CA), and its toxicity to zebrafish (Danio rerio) embryo. The μ and CA were influenced more strongly by CO₂ concentrations rather than by N sources; significant effects of CO₂ on μ and CA were observed under low CO₂ concentration (LC) conditions compared to high CO₂ concentration (HC) conditions. The ammonium and nitrate media under LC conditions had the maximum μ and CA, which was inhibited under HC conditions. The embryotoxic effects were influenced more strongly by the N sources than by CO₂ concentrations, thus excluding the lower deformation in urea under HC conditions. Moreover, the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST), and catalase (CAT) were detected in normal (untreated) zebrafish embryos, and among them, the level of SOD was the highest. In summary, this study provides a clear insight for understanding the effects and interactive effects of N sources and CO₂ concentrations on the growth and toxicity of harmful dinoflagellates.
Mostrar más [+] Menos [-]Seawater carbonate chemistry and growth of the dinoflagellate Alexandrium tamarense and its toxicity to zebrafish (Danio rerio) embryos Texto completo
2018
Guan, WanChun | Si, Ranran | Li, Xi | Cai, Jingbo | Chen, Shaobo
The effects and interactive effects of different nitrogen (N) sources (ammonium, nitrate, and urea) and carbon dioxide (CO2) concentrations were investigated on Alexandrium tamarense, a harmful marine dinoflagellate, by measuring its growth (μ), extracellular carbonic anhydrase (CA), and its toxicity to zebrafish (Danio rerio) embryo. The μ and CA were influenced more strongly by CO2 concentrations rather than by N sources; significant effects of CO2 on μ and CA were observed under low CO2 concentration (LC) conditions compared to high CO2 concentration (HC) conditions. The ammonium and nitrate media under LC conditions had the maximum μ and CA, which was inhibited under HC conditions. The embryotoxic effects were influenced more strongly by the N sources than by CO2 concentrations, thus excluding the lower deformation in urea under HC conditions. Moreover, the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST), and catalase (CAT) were detected in normal (untreated) zebrafish embryos, and among them, the level of SOD was the highest. In summary, this study provides a clear insight for understanding the effects and interactive effects of N sources and CO2 concentrations on the growth and toxicity of harmful dinoflagellates.
Mostrar más [+] Menos [-]Classification of oil–particle interactions in aqueous environments: Aggregate types depending on state of oil and particle characteristics Texto completo
2018
Boglaienko, Daria | Tansel, Berrin
There are significant differences in the aggregation mechanisms and types of aggregates that form by oil-particle interactions in marine and laboratory environments depending on the state of oil (i.e., dissolved, emulsified, floating), size and type of particles involved (i.e., colloidal, granular, organic, inorganic), oil-particle interaction mechanisms, and settling/suspension characteristics. Distinct characteristics of oil-particle aggregates that form by interaction of granular particles with floating oil separate them from the well-known oil-colloidal particle aggregates (OcPA), which are sometimes called Pickering emulsions. Unlike OcPA, which involve emulsified oil (entrained oil droplets suspended in the water column) and colloidal particles, the oil-granular particle aggregates (OgPA) involve the floating oil and granular particles. Here, to clarify the differences and similarities between the two types of aggregates (OcPA and OgPA), we present classification of oil aggregates, drawing attention to important characteristics of OcPA, marine oil snow (MOS), and OgPA.
Mostrar más [+] Menos [-]Study of the oil interaction towards oil spill recovery skimmer material: Effect of the oil weathering and emulsification properties Texto completo
2018
Farooq, Umer | Taban, Ingrid C. | Daling, Per S.
Study of the oil interaction towards oil spill recovery skimmer material: Effect of the oil weathering and emulsification properties Texto completo
2018
Farooq, Umer | Taban, Ingrid C. | Daling, Per S.
The primary aim of this research was to identify the physicochemical properties of the oil and water-in-oil (W/O) emulsions used during a NOFO Oil-on-Water field trials that reduced the performance of the skimmers recovery efficacy during the trials. Extensive studies were performed at SINTEF laboratories with the residues of oil topped (i.e. evaporative loss of crude oil components by distillation process at large scale) for the field trial and compared it with different residues of oil topped by bench scale laboratory procedures. In order to obtain a sufficient stable W/O emulsion for the field trial, bunker fuel oil (IFO380) and various concentrations of an emulsifier (Paramul®) were also added to the residues of oil topped on large scale and investigated through interfacial tension, contact angle, droplet adhesion and “dip and withdraw” tests. The investigations revealed that the addition of an emulsifier lowered the interfacial tension of oil residues, which consequently reduced the adherence properties of the oil and emulsions to the surface of the skimmer material. Too high concentration of an emulsifier (>0,5%) also had a negative effect on the stability of W/O emulsion.
Mostrar más [+] Menos [-]Study of the oil interaction towards oil spill recovery skimmer material: Effect of the oil weathering and emulsification properties Texto completo
2018
Farooq, Umer | Taban, Ingrid Christina | Daling, Per Snorre
The primary aim of this research was to identify the physicochemical properties of the oil and water-in-oil (W/O) emulsions used during a NOFO Oil-on-Water field trials that reduced the performance of the skimmers recovery efficacy during the trials. Extensive studies were performed at SINTEF laboratories with the residues of oil topped (i.e. evaporative loss of crude oil components by distillation process at large scale) for the field trial and compared it with different residues of oil topped by bench scale laboratory procedures. In order to obtain a sufficient stable W/O emulsion for the field trial, bunker fuel oil (IFO380) and various concentrations of an emulsifier (Paramul®) were also added to the residues of oil topped on large scale and investigated through interfacial tension, contact angle, droplet adhesion and “dip and withdraw” tests. The investigations revealed that the addition of an emulsifier lowered the interfacial tension of oil residues, which consequently reduced the adherence properties of the oil and emulsions to the surface of the skimmer material. Too high concentration of an emulsifier (>0,5%) also had a negative effect on the stability of W/O emulsion. | Study of the oil interaction towards oil spill recovery skimmer material: Effect of the oil weathering and emulsification properties | acceptedVersion
Mostrar más [+] Menos [-]Phylogenetic characterization of culturable bacteria and fungi associated with tarballs from Betul beach, Goa, India Texto completo
2018
Tarballs are semisolid blobs of crude oil, normally formed due to weathering of crude-oil in the sea after any kind of oil spills. Microorganisms are believed to thrive on hydrocarbon-rich tarballs and possibly assist in biodegradation. The taxonomy of ecologically and economically important tarball-associated microbes, however, needs improvement as DNA-based identification and phylogenetic characterization have been scarcely incorporated into it. In this study, bacteria and fungi associated with tarballs from touristic Betul beach in Goa, India were isolated, followed by phylogenetic analyses of 16S rRNA gene and the ITS sequence-data to decipher their clustering patterns with closely-related taxa. The gene-sequence analyses identified phylogenetically diverse 20 bacterial genera belonging to the phyla Proteobacteria (14), Actinobacteria (3), Firmicutes (2) and Bacteroidetes (1), and 8 fungal genera belonging to the classes Eurotiomycetes (6), Sordariomycetes (1) and Leotiomycetes (1) associated with the Betul tarball samples. Future studies employing a polyphasic approach, including multigene sequence-data, are needed for species-level identification of culturable tarball-associated microbes. This paper also discusses potentials of tarball-associated microbes to degrade hydrocarbons.
Mostrar más [+] Menos [-]Elevated concentrations of naturally occurring radionuclides in heavy mineral-rich beach sands of Langkawi Island, Malaysia Texto completo
2018
Khandaker, Mayeen Uddin | Asaduzzaman, Khandoker | Sulaiman, Abdullah Fadil Bin | Bradley, D.A. | Isinkaye, Matthew Omoniyi
Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide ⁴⁰K and the natural-series indicator radionuclides ²²⁶Ra and ²³²Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of ²²⁶Ra, ²³²Th and ⁴⁰K from 451±9 to 2411±65Bqkg⁻¹ (mean of 1478Bqkg⁻¹); 232±4 to 1272±35Bqkg⁻¹ (mean of 718Bqkg⁻¹) and 61±6 to 136±7Bqkg⁻¹ (mean of 103Bqkg⁻¹) respectively. Conversely, in white sands the respective values for ²²⁶Ra and ²³²Th were appreciably lower, at 8.3±0.5 to 13.7±1.4Bqkg⁻¹ (mean of 9.8Bqkg⁻¹) and 4.5±0.7 to 9.4±1.0Bqkg⁻¹ (mean of 5.9Bqkg⁻¹); ⁴⁰K activities differed insubstantially from that in black sands, at 85±4 to 133±7Bqkg⁻¹ with a mean of 102Bqkg⁻¹. The mean activity concentrations of ²²⁶Ra and ²³²Th in black sands are comparable with that of high background areas elsewhere in the world. The heavy minerals content gives rise to elevated ²²⁶Ra and ²³²Th activity concentrations in all of black sand samples. Evaluation of the various radiological risk parameters points to values which in some cases could be in excess of recommendations providing for safe living and working. Statistical analysis examines correlations between the origins of the radionuclides, also identifying and classifying the radiological parameters. Present results may help to form an interest in rare-earth resources for the electronics industry, power generation and the viability of nuclear fuels cycle resources.
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