Уточнить поиск
Результаты 1451-1460 из 4,291
Italy introduces pre and post operation monitoring phases for offshore seismic exploration activities
2017
Fossati, C. | Mussi, B. | Tizzi, R. | Pavan, G. | Pace, D.S.
Concern is growing that marine fauna can be affected by noise such as naval sonar, pile driving or geophysical surveys, among others. Literature reports a variety of animal reactions to human noise (from apparently null or negligible to strong). However, conclusive results on its effects on marine mammals at individual and population level are still lacking. In 2015, the Italian Environmental Impact Assessment Commission mandated seismic operators apply a standard scientific protocol comparing marine mammal presence before, during, and after offshore seismic survey. For 60days before and after the survey, marine mammals are monitored using visual and acoustic methods. One or more acoustic autonomous recorders, depending on area size, must also be deployed throughout the three phases for continuous monitoring. Consistent data gathered from many surveys will enable robust statistical analysis of results. Diffusion of this monitoring method internationally would improve the study of far-reaching, intense, low frequency noise.
Показать больше [+] Меньше [-]Fine sediments suppress detritivory on coral reefs
2017
Tebbett, Sterling B. | Goatley, Christopher H.R. | Bellwood, David R.
Increasing sediment inputs are recognised as an important factor leading to coral reef degradation. However, the role of sediments in ecological processes is poorly understood. This study used paired-choice trials to quantify the effects of sediment grain size and chemical composition on feeding by the abundant detritivorous reef fish, Ctenochaetus striatus. The size of sediments from algal turfs were also compared to those ingested by reef-dwelling C. striatus. Algal turfs containing coarser sediments were preferred by C. striatus, while sediment composition (reefal carbonates vs. riverine silicates) had little effect. On the reef, C. striatus ingested finer sediments than those present in algal turfs. C. striatus appears to prefer algal turfs with coarser sediments as this facilitates ingestion of fine detrital particles, while finer sediments prevent selective feeding on detritus. These findings suggest that fine sediments from terrestrial runoff or dredging may be detrimental to feeding by detritivorous species.
Показать больше [+] Меньше [-]Sub-lethal effects of a glyphosate-based commercial formulation and adjuvants on juvenile oysters (Crassostrea gigas) exposed for 35days
2017
Séguin, Alexis | Mottier, Antoine | Perron, Carole | Lebel, Jean Marc | Serpentini, Antoine | Costil, Katherine
Glyphosate-based herbicides include active matter and adjuvants (e.g. polyethoxylated tallow amines, POEAs). In addition to a previous investigation on the effect of glyphosate on oysters, the aim of the present study was to investigate the effects of sub-chronic exposures (35days) to three concentrations (0.1, 1 and 100μgL−1) of Roundup Express® (REX) and POEAs on oysters belonging to the same age group. Low mortality rates were calculated, and only few significant differences (i.e. shell length) between exposure conditions were observed at a given date. However, when comparing the biomarker's temporal variations, some different patterns (e.g. condition index, reproduction, parameters of oxidative stress) were observed depending on the molecules and concentrations. These results suggest that a longer exposure to an environmental concentration (0.1μgL−1) of REX and POEAs could induce harmful effects on oysters.
Показать больше [+] Меньше [-]Recent findings on phenoloxidases in bivalves
2017
Luna-Acosta, A. | Breitwieser, Marine | Renault, T. | Thomas-Guyon, H.
The production of melanin is a complex process involving biochemical cascades, such as the pro-phenoloxidase (proPO) system, and enzymes, such as phenoloxidases (POs). Different studies have shown a strong correlation between the decrease in PO activities and the occurrence of diseases in bivalve invertebrates, leading to mortalities in the host. Results of these studies suggest that POs could play a fundamental role in defense mechanisms in bivalves. This article reviews the fundamental knowledge on the proPO system in bivalves and the methods used to assess PO activities. Finally, this is the first report on the major findings of laboratory and field studies that indicate that a type of PO in bivalves, the laccase enzyme, is inducible and involved in the 1) immune 2) antioxidant and 3) detoxification roles in bivalves, and might be an ecological potential biomarker of environmental stress.
Показать больше [+] Меньше [-]Impact of Mine Waste Leachates on Aquatic Environment: A Review
2017
Jain, Manish Kumar | Das, Arpita
The economic development of a country is mainly dependent on important industrial activities such as mining. Because of mining operations, huge quantities of solid wastes especially, overburden and rejects, are generated. As these are not valuable to the owners of the mine, they may be inappropriately disposed of into the environment, posing severe threat to the environment, particularly affecting both surface and ground water quality. Most mine waste-related environmental degradation is associated with leaching of contaminants from overburden dumps and acid mine drainage. Leachates originating from mine waste overburden dumps may have the potential to contaminate the surrounding water resources, especially ground water. The present paper envisages the harmful effect of mine waste leachates on the environment and how it creates possible hazard to aquatic life. This paper also reviews the strategies for improvements in existing mine waste management along with the suitable measures to combat the overall problem.
Показать больше [+] Меньше [-]Comparison of organochlorine and PAHs residues in terns eggs from two natural protected areas in the Gulf of Mexico
2017
Vallarino, Adriana | Rendon von Osten, Jaime
Persistent organic pollutants (POPs) are dispersed all over the world while polycyclic aromatic hydrocarbons (PAHs) are released into the environment from pyrogenic and petrogenic sources and are not very mobile or persistent. The aim of this study was to identify POPs and PAHs from eggs of Least and Sooty Terns nesting in two protected marine areas with different anthropogenic impacts in the southern Gulf of Mexico. ΣHCHs were higher in Terminos in 2010 and higher in Alacranes in 2011. ΣDienes and ΣDDTs were higher in 2011 in both study sites. ΣEndosulfan was higher in Terminos than in Alacranes in both years. ΣDienes, ΣDDT and ΣHeptachlor were the highest in both species both years. Acenaphtylene and Fluoranthene were higher in Terminos while Pyrene was higher in Alacranes. No differences were present within species between years. In 2011 PAHs in eggs could have reflected the BP oil spill input.
Показать больше [+] Меньше [-]Potential bioavailability assessment, source apportionment and ecological risk of heavy metals in the sediment of Brisbane River estuary, Australia
2017
Duodu, Godfred Odame | Goonetilleke, Ashantha | Ayoko, G. A. (Godwin A.)
A weak acid extraction was used to mobilize the loosely bound metals in estuary sediment samples. More than 30% of Ag, As, Ca, Cd, Co, Cu, Hg, Mn Ni, Pb and Zn were leached from the sediment showing that these metals are significantly present in the bioavailable form. PCA/APCS identified three sources of the metals, namely: lithogenic accounting for 72%, shipping related contributing 15% and traffic related representing 13% of the total load. Application of pollution index (PI) and modified pollution index (MPI) revealed that the sediment range from unpolluted to heavily polluted while ecological risk index (RI) classifies the sediment as posing low ecological risk modified ecological risk index (MRI) suggests considerable to very high ecological risk. To provide holistic insights into the ecological risks posed by metals, enrichment factor, MPI and MRI are recommended for the assessment of sediment in complex environments such as estuaries.
Показать больше [+] Меньше [-]Negative Binomial regression model for analysis of the relationship between hospitalization and air pollution
2017
Ardiles, Leda G. | Tadano, Yara S. | Costa, Silvano | Urbina, Viviana | Capucim, Maurício N. | da Silva, Iara | Braga, Alfésio | Martins, Jorge A. | Martins, Leila D.
Air pollution is currently one of the major environmental risk to human health in the world. Several studies link health to air pollution through the Poisson regression model. However, this study showed that the best method is the regression model with Negative Binomial distribution. The analysis was made based on daily data for the period between 2010 and 2014 regarding hospitalizations due to circulatory and respiratory diseases, stratified by age due to the concentration of air pollutants: CO, PM10, NO2, SO2 and O3 and meteorological variables. The results with Negative Binomial distribution model indicate, for interquartile range (IQR), that CO is a risk factor (1.00259–1.19688, 95% CI) for circulatory diseases in the elderly (aged over 64) and for respiratory diseases in the population aged 10–19 years old, while NO2 is a risk factor for the population in the range of 20–64 years (1.00313–1.25827, 95% CI) in the city of Araucaria. In Curitiba, air pollutants presenting a risk factor for respiratory diseases were PM10 (RR = 1.05322) in the range of 0–9 years old, CO and O3 (RR = 1.05047) in the range of 20–64 years old, and CO for the elderly. It could be verified that exposure to air pollutants is harmful to health even when their concentrations are below the standards set out in legislation. Additionally, the city of Araucaria presented the highest number of hospital admissions, which may be associated with the large number of industries and lower human development index in the city.
Показать больше [+] Меньше [-]Management of plastic wastes at Brazilian ports and diagnosis of their generation
2017
Neffa Gobbi, Clarice | Lourenço Sanches, Vânia Maria | Acordi Vasques Pacheco, Elen Beatriz | de Oliveira Cavalcanti Guimarães, Maria José | Freitas, Marcos Aurélio Vasconcelos de
This study evaluated the management of plastic wastes at 20 Brazilian maritime ports, from three sources: vessels, leased and non-leased areas. The data were obtained from documents on port wastes organized in a relational database with defined protocols (closed form). Analysis of the spreadsheets prepared and field visits revealed that the main bottleneck in managing plastic wastes at ports is their segregation. In general, more material is segregated and sent for recycling from leased areas than non-leased ones (administered by the government). This relatively better performance in managing the wastes generated in leased areas is probably due to the need for private operators to comply with the international standards such as the Code of Environmental Practice to satisfy the international market.
Показать больше [+] Меньше [-]Microplastic contamination of intertidal sediments of Scapa Flow, Orkney: A first assessment
2017
Blumenröder, J. | Sechet, P. | Kakkonen, J.E. | Hartl, M.G.J.
The concentration of microplastic particles and fibres was determined in the intertidal sediments at selected sites in Scapa Flow, Orkney, using a super-saturated NaCl flotation technique to extract the plastic and FT-IR spectroscopy to determine the polymer types. Mean concentrations were 730 and 2300kg−1 sediment (DW), respectively. Detailed spatial and quantitative analysis revealed that their distribution was a function of proximity to populated areas and associated wastewater effluent, industrial installations, degree of shore exposure and complex tidal flow patterns. Sediment samples from Orkney showed similar levels of microplastic contamination as in two highly populate industrialized mainland UK areas, The Clyde and the Firth of Forth. It was concluded that relative remoteness and a comparative small island population are not predictors of lower microplastic pollution. Furthermore, a larger concerted effort across Scotland and the UK is required to establish a baseline microplastic database for the evaluation of future policy measures.
Показать больше [+] Меньше [-]