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Resultados 1081-1090 de 4,029
Trace elements in striped dolphins (Stenella coeruleoalba) from the Eastern Mediterranean: A 10-years perspective
2016
Shoham-Frider, Efrat | Goffman, Oz | Harlavan, Yehudit | Kress, Nurit | Morick, Danny | Roditi-Elasar, Mia | Shefer, Edna | Kerem, Dan
Concentrations of Hg, Se, Cd, Cu, Zn, Fe, Mn and As, in kidney, liver, muscle and blubber from 7 specimens of Stenella coeruleoalba, stranded along the Israeli Mediterranean coast (IMC) from 2006 to 2011 (2011-series) were determined and compared to previous data on S. coeruleoalba from the IMC (2001-series). No differences were observed in essential and toxic elements concentrations, between the two series, except for hepatic Mn which was higher in the latter. Hg/Se molar ratios in blubber, kidney and liver increased linearly with log Hg concentrations, while muscle was more heterogenic in this respect. Means (±SD) of hepatic Hg concentrations (134±89 and 181±200mgkg−1, from the 2011 and 2001 series, respectively) were similar to that found in 2007–2009 specimens from Spain, possibly reflecting the relatively high natural background levels of mercury in the Mediterranean Sea.
Mostrar más [+] Menos [-]Photodegradation of PAHs in passive water samplers
2016
Allan, Ian J. | Christensen, Guttorm | Bæk, Kine | Evenset, Anita
Losses of deuterated polycyclic aromatic hydrocarbons (PAHs) used as performance reference compounds (PRCs) in semipermeable membrane devices deployed at fifteen coastal sampling sites near Harstad harbour in Northern Norway were used to investigate photodegradation of these photosensitive compounds. Unusual PRC dissipation profiles, especially for samplers exposed <5m below the water surface are indicative of photodegradation. A strong correlation between loss rates for d12-chrysene and d12-benzo[e]pyrene with consistently higher losses of the latter was found. The observed photodegradation rates may be sufficiently high to impact PAH masses absorbed by a factor of two. This study demonstrates that photodegradation during exposure of passive water samplers needs to be taken into account, particularly with deployments close to the water surface, when using SPMD canisters, or when sampling in the Arctic.
Mostrar más [+] Menos [-]Effect of abalone farming on seawater movement and benthic foraminiferal assemblage of Zostera marina in the inner bay of Wando, South Korea
2016
Lee, Yeon Gyu | Choi, Yang Ho | Jeong, Da Un | Lee, Jung Sick | Kim, Yong-wan | Park, Jung Jun | Choi, Jae Ung
Tidal current survey as well as geochemical and benthic foraminiferal analyses of sediment cores were conducted in an abalone farm and a Zostera bed to understand the degree to which the abalone farm facilities installed along a channel in a shallow sea affect the benthic environment and ecology. In the abalone farm, Ammonia beccarii-Pseudoparrella naraensis-Elphidium somaense-Rosalina globularis-Trochammina hadai and P. naraensis-E. somaense-A. beccarii-T. hadai assemblages appeared owing to an increase in the total nitrogen content from the biodeposits. The Zostera bed consisted of A. beccarii-P. naraensis-Buccella frigida-T. hadai assemblage owing to the gradual expansion of a brackish shallow-water environment by the rapidly decreasing current speed, and it may have flourished. Moreover, the total sulfur, Zn, Cr, and Cu contents in the sediments decreased remarkably more than those of the pre-abalone farming did, caused by the vigorous activity of Zostera marina physiology.
Mostrar más [+] Menos [-]Optimisation for assay of fluorescein diacetate hydrolytic activity as a sensitive tool to evaluate impacts of pollutants and nutrients on microbial activity in coastal sediments
2016
Jiang, Shan | Huang, Jing | Lu, Haoliang | Liu, Jingchun | Yan, Chongling
Fluorescein diacetate (FDA) assay has been widely applied in coastal research to quantify microbial activity in sediments. However, the present FDA assay procedures embodied in sediment studies potentially include operational errors since the protocol was established for studies of terrestrial soil. In the present study, we optimised the procedure of FDA assay using sandy and cohesive sediments to improve experiential sensitivity and reproducibility. The optimised method describes quantitative measurement of the fluorescein produced when 1.0g of fresh sediment is incubated with 50mM phosphate buffer solution (pH: 7.3) and glass beads (2g) at 35°C for 1h under a rotation of 50rpm. The covariation coefficient of the optimised method ranged from 1.9% to 3.8% and the method sensitivity ranged from 0.25 to 1.57. The improved protocol provides a more reliable measurement of the FDA hydrolysis rate over a wide range of sediments compared to the original method.
Mostrar más [+] Menos [-]Bioassessment of water quality status using a potential bioindicator based on functional groups of planktonic ciliates in marine ecosystems
2016
Xu, Henglong | Yong, Jiang | Xu, Guangjian
The feasibility of a potential ecological indicator based on functional groups of planktonic ciliates for bioassessment of water quality status were studied in a bay, northern Yellow Sea. Samples were biweekly collected at five stations with different water quality status during a 1-year period. The multivariate approach based on “bootstrap-average” analysis was used to summarize the spatial variation in functional structure of the samples. The functional patterns represented a significant spatial variability, and were significantly correlated with the changes of nutrients (mainly nitrate nitrogen, NO3-N), alone or in combination with dissolve oxygen and salinity among five stations. The functional diversity represented a clear spatial variation among five stations, and was found to be significantly related to the nutrient NO3-N. According to the results, we suggest that the ecological parameter based on functional groups of planktonic ciliates may be used as a potential bioindicator of water quality status in marine ecosystems.
Mostrar más [+] Menos [-]Bacterial inoculants for enhanced seed germination of Spartina densiflora: Implications for restoration of metal polluted areas
2016
Paredes-Páliz, Karina I. | Pajuelo, Eloísa | Doukkali, Bouchra | Caviedes, Miguel Ángel | Rodríguez-Llorente, Ignacio D. | Mateos-Naranjo, Enrique
The design of effective phytoremediation programs is severely hindered by poor seed germination on metal polluted soils. The possibility that inoculation with plant growth promoting rhizobacteria (PGPR) could help overcoming this problem is hypothesized. Our aim was investigating the role of PGPR in Spartina densiflora seed germination on sediments with different physicochemical characteristics and metal pollution degrees. Gram negative Pantoea agglomerans RSO6 and RSO7, and gram positive Bacillus aryabhattai RSO25, together with the consortium of the three strains, were used for independent inoculation experiments. The presence of metals (As, Cu, Pb and Zn) in sediments reduced seed germination by 80%. Inoculation with Bacillus aryabhattai RSO25 or Pantoea agglomerans RSO6 and RSO7 enhanced up to 2.5 fold the germination rate of S. densiflora in polluted sediments regarding non-inoculated controls. Moreover, the germination process was accelerated and the germination period was extended. The consortium did not achieve further improvements in seed germination.
Mostrar más [+] Menos [-]Tracking pollutant characteristics during haze events at background site Zhongmu, Henan Province, China
2016
Yu, Fei | Yan, Qishe | Jiang, Nan | Su, Fangcheng | Zhang, Leishi | Yin, Shasha | Li, Yang | Zhang, Ruiqin | Chen, Liangfu
Recently, China has faced a large scale air pollution problem not only in urban but also in rural areas. To better understand the occurrence of haze events and properties of particulate matter (PM) in rural area, continuous monitoring of PM and its related characteristics is necessary. Consequently, in this study, a comprehensive observation was performed at a rural site of Zhongmu, Henan Province. The meteorological parameters, physical and chemical properties including number and mass concentration, size resolved and water soluble ions were measured. During the observation period, the highest hourly mass concentration of PM2.5 obtained from Electrical Low Pressure Impactor plus (ELPI+) was 560 μg/m3 on January 5, 2015. The Hybrid Single-Particle Lagrangian Integrated Trajectory model shows that the most polluted day (January 5) was under the influence of static stability meteorological conditions and greatly influenced by the surrounding regional (within 200 km). During new particle formation stage, higher number concentration in nucleation mode (<30 nm) was found. Through the measurement of water-soluble inorganic ions, it was found that Ca2+ was the highest water-soluble inorganic ions in the coarse fraction (PM2.1–10) while SO42−, NO3− and NH4+ were the three major species in the fine fraction (PM2.1). Furthermore, the ratio of [NH4+]/(2[SO42−] + [NO3−]) was higher in fine particulate and [NH4+]/[SO42−] was more than 2 in fine particulate, indicating the presence of both (NH4)2SO4 and NH4NO3 in fine particulate during haze days. The regional transport and to some extent local dust were responsible for haze formation in the observed site.
Mostrar más [+] Menos [-]The influence of substrate material on ascidian larval settlement
2016
Chase, Anna L. | Dijkstra, Jennifer A. | Harris, Larry G.
Submerged man-made structures present novel habitat for marine organisms and often host communities that differ from those on natural substrates. Although many factors are known to contribute to these differences, few studies have directly examined the influence of substrate material on organism settlement. We quantified larval substrate preferences of two species of ascidians, Ciona intestinalis (cryptogenic, formerly C. intestinalis type B) and Botrylloides violaceus (non-native), on commonly occurring natural (granite) and man-made (concrete, high-density polyethylene, PVC) marine materials in laboratory trials. Larvae exhibited species-specific settlement preferences, but generally settled more often than expected by chance on concrete and HDPE. Variation in settlement between materials may reflect preferences for rougher substrates, or may result from the influence of leached chemicals on ascidian settlement. These findings indicate that an experimental plate material can influence larval behavior and may help us understand how substrate features may contribute to differences in settlement in the field.
Mostrar más [+] Menos [-]Determination of PM2.5 and polycyclic aromatic hydrocarbons from incense burning emission at shrine for health risk assessment
2016
Bootdee, Susira | Chantara, Somporn | Prapamontol, Tippawan
This study aims to determine fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) bounded with PM2.5 emitted from incense burning at shrine to assess human health risk. The PM2.5 samples were collected by a mini volume air sampler during special occasions and normal period at a shrine located in the city center of Chiang Mai, Thailand. The samples were analyzed for 16-PAHs by GC–MS. The descending order of 8- and 24-hrs PM2.5 concentrations (μg/m3) were 625 ± 147 and 406 ± 159 (Chinese New Year) > 184 ± 85 and 133 ± 71 (other special occasions) > 100 ± 35 and 50 ± 20 (normal period). Their concentrations in each occasion were significantly different due to number of visitors and amount of incense being burned. Total PAHs concentrations (ng/m3) for 8- and 24-hrs in descending order were 90 ± 41 and 45 ± 29 (Chinese New Year), 71 ± 30 and 30 ± 12 (other special occasions) and 25 ± 15 and 14 ± 9 (normal periods). Correlation between PM2.5 and total PAHs concentrations was relatively strong. In addition, PM2.5 concentrations were highly correlated (r = 0.618) with carcinogenic PAHs (c-PAHs) indicated that carcinogenic compounds were dominant in particulate PAHs and generated from incense burning. The values of toxicity equivalent concentration (TEQ) indicate human health risk from PAHs inhalation. According to European guideline, it should be less than1 ng/m3 in ambient air. During Chinese New Year, they were relatively high (32 ± 27 ng/m3 (8 h) and 10 ± 4 ng/m3 (24 h)). Moreover, the isometric ratio analysis revealed that emission from incense burning was the main source of PM2.5 and PM2.5-bound PAHs.
Mostrar más [+] Menos [-]Sea surface microplastics in Slovenian part of the Northern Adriatic
2016
Gajšt, Tamara | Bizjak, Tine | Palatinus, Andreja | Liubartseva, Svitlana | Kržan, Andrej
Plastics are the most common material of marine litter and have become a global pollution concern. They are persistent in the environment where they gradually degrade into increasingly smaller particles–microplastics (MP). Our study presents results of sea-surface monitoring for MP in the Slovenian part of the Trieste Bay in the Northern Adriatic Sea. In 17 trawls conducted over a 20-month period we found a high average concentration of 406×103MPparticles/km2. Over 80% of the particles were identified as polyethylene. The significant variability of MP concentrations obtained on different sampling dates is explained by use of surface current maps and a recently developed Markov chain marine litter distribution model for the Adriatic Sea.
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