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High thresholds for avoidance of sonar by free-ranging long-finned pilot whales (Globicephala melas) Texte intégral
2014
Antunes, R. | Kvadsheim, P.H. | Lam, F.P.A. | Tyack, P.L. | Thomas, L. | Wensveen, P.J. | Miller, P.J.O.
The potential effects of exposing marine mammals to military sonar is a current concern. Dose–response relationships are useful for predicting potential environmental impacts of specific operations. To reveal behavioral response thresholds of exposure to sonar, we conducted 18 exposure/control approaches to 6 long-finned pilot whales. Source level and proximity of sonar transmitting one of two frequency bands (1–2kHz and 6–7kHz) were increased during exposure sessions. The 2-dimensional movement tracks were analyzed using a changepoint method to identify the avoidance response thresholds which were used to estimate dose–response relationships. No support for an effect of sonar frequency or previous exposures on the probability of response was found. Estimated response thresholds at which 50% of population show avoidance (SPLmax=170dB re 1μPa, SELcum=173dB re 1μPa2s) were higher than previously found for other cetaceans. The US Navy currently uses a generic dose–response relationship to predict the responses of cetaceans to naval active sonar, which has been found to underestimate behavioural impacts on killer whales and beaked whales. The navy curve appears to match more closely our results with long-finned pilot whales, though it might underestimate the probability of avoidance for pilot-whales at long distances from sonar sources.
Afficher plus [+] Moins [-]The discrepancy in concentration of metals (Cu, Pb and Zn) in oyster tissue (Saccostrea glomerata) and ambient bottom sediment (Sydney estuary, Australia) Texte intégral
2014
Birch, G.F. | Melwani, A. | Lee, J. H. | Apostolatos, C.
The current study aimed to examine the relationship between metals in sediments and metal bioaccumulation in oyster tissue in a highly-modified estuary (Sydney estuary, Australia). While extensive metal contamination was observed in surficial sediments, suspended particulate matter and oyster tissue, a significant relationship between these media could not be established. No relationship was determined between sediment quality guidelines and oyster size or weight, nor with human consumption levels for metals in oyster tissue. Moreover, oyster tissue metal concentrations varied greatly at a single locality over temporal scales of years. Oyster tissue at all 19 study sites exceeded consumptions levels for Cu. Bioaccumulation of metals in oyster tissue is a useful dynamic indicator of anthropogenic influence within estuaries, however oysters cannot be used in Sydney estuary as a valid biomonitor due to overriding internal regulation (homoestasis) by the animal, or by external natural (sediment resuspension) and anthropogenic (sewer/stormwater discharges) pressures, or both.
Afficher plus [+] Moins [-]Accumulation of trace metals in grey mangrove Avicennia marina fine nutritive roots: The role of rhizosphere processes Texte intégral
2014
Chaudhuri, Punarbasu | Nath, Bibhash | Birch, Gavin
Mangrove sediment has long been recognized as being important in restricting the mobility of contaminants in estuarine environments. To investigate the role of rhizosphere processes in the accumulation of trace metals in mangrove fine nutritive roots, the mangrove sediments and associated fine nutritive roots are collected from five major embayments of Sydney estuary (Australia) for geochemical studies. In this estuary Avicennia marina sediments are accumulating large quantities of trace metals due to presence of abundant fine sediment (<62.5μm) and organic matter as well as anthropogenic input. Accumulation of trace metals in fine nutritive roots responds to total sediment chemistry mainly due to rhizosphere sediment geochemical processes resulting in a strong linear correlation between metal concentrations in fine nutritive roots vs. total and bio-available contents in sediments. Accumulation of trace metals in fine nutritive roots is almost always exceeds rhizosphere total sediment metal concentrations.
Afficher plus [+] Moins [-]Salinity fluctuation of the brine discharge affects growth and survival of the seagrass Cymodocea nodosa Texte intégral
2014
Garrote-Moreno, A. | Fernández-Torquemada, Y. | Sánchez-Lizaso, J.L.
Salinity fluctuation of the brine discharge affects growth and survival of the seagrass Cymodocea nodosa Texte intégral
2014
Garrote-Moreno, A. | Fernández-Torquemada, Y. | Sánchez-Lizaso, J.L.
The increase of seawater desalination plants may affect seagrasses as a result of its hypersaline effluents. There are some studies on the salinity tolerance of seagrasses under controlled laboratory conditions, but few have been done in situ. To this end, Cymodocea nodosa shoots were placed during one month at four localities: two close to a brine discharge; and the other two not affected by the discharge, and this experiment was repeated four times. The results obtained showed a decrease in growth and an increased mortality at the localities affected by the brine discharge. An increase was detected in the percentage of horizontal shoots in respect to vertical shoots at the impacted localities. It is probably that not only the average salinity, but also the constant salinity fluctuations and slightly higher temperatures associated with the brine that may have caused physiological stress thus reducing C. nodosa growth and survival.
Afficher plus [+] Moins [-]Salinity fluctuation of the brine discharge affects growth and survival of the seagrass Cymodocea nodosa Texte intégral
2014
Garrote-Moreno, Aurora | Fernández-Torquemada, Yolanda | Sánchez-Lizaso, José Luis | Fernández-Torquemada, Yolanda | Sánchez-Lizaso, José Luis | Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada | Biología Marina | Recursos Hídricos y Desarrollo Sostenible
The increase of seawater desalination plants may affect seagrasses as a result of its hypersaline effluents. There are some studies on the salinity tolerance of seagrasses under controlled laboratory conditions, but few have been done in situ. To this end, Cymodocea nodosa shoots were placed during one month at four localities: two close to a brine discharge; and the other two not affected by the discharge, and this experiment was repeated four times. The results obtained showed a decrease in growth and an increased mortality at the localities affected by the brine discharge. An increase was detected in the percentage of horizontal shoots in respect to vertical shoots at the impacted localities. It is probably that not only the average salinity, but also the constant salinity fluctuations and slightly higher temperatures associated with the brine that may have caused physiological stress thus reducing C. nodosa growth and survival. | This research was financed by a grant of University of Alicante and by an ACUAMED contract.
Afficher plus [+] Moins [-]Coral reef baselines: How much macroalgae is natural? Texte intégral
2014
Bruno, John F. | Precht, William F. | Vroom, Peter S. | Aronson, Richard B.
Identifying the baseline or natural state of an ecosystem is a critical step in effective conservation and restoration. Like most marine ecosystems, coral reefs are being degraded by human activities: corals and fish have declined in abundance and seaweeds, or macroalgae, have become more prevalent. The challenge for resource managers is to reverse these trends, but by how much? Based on surveys of Caribbean reefs in the 1970s, some reef scientists believe that the average cover of seaweed was very low in the natural state: perhaps less than 3%. On the other hand, evidence from remote Pacific reefs, ecological theory, and impacts of over-harvesting in other systems all suggest that, historically, macroalgal biomass may have been higher than assumed. Uncertainties about the natural state of coral reefs illustrate the difficulty of determining the baseline condition of even well studied systems.
Afficher plus [+] Moins [-]T-PAH contamination in Mediterranean mussels (Mytilus galloprovincialis, Lamarck, 1819) at various stations of the Turkish Straits System Texte intégral
2014
Balcıoğlu, Esra Billur | Aksu, Abdullah | Balkıs, Nuray | Öztürk, Bayram
Mussels (Mytilus galloprovincialis) from the Turkish Straits Systems were analyzed for sixteen parent polycyclic aromatic hydrocarbon (PAH) contents by high performance liquid chromatography (HPLC). This marine organism was selected because of its multitude, wide distribution, being bio indicator for the pollution and consumption by humans. Total PAH concentrations ranged from 1.2 to 589μgg−1 in Istanbul Strait, 0.94–36.4μgg−1 in Marmara Sea and 0.4–47.9μgg−1 in Çanakkale Strait during the samplings. According to the results Istanbul and Çanakkale Straits are more polluted than the Marmara Sea.
Afficher plus [+] Moins [-]Distribution and sources of polycyclic aromatic hydrocarbons in the surface sediments of Gorgan Bay, Caspian Sea Texte intégral
2014
Araghi, Peyman Eghtesadi | Bastami, Kazem Darvish | Rahmanpoor, Shirin
The level and source of 16 polycyclic aromatic hydrocarbons (PAHs) were investigated in the surface sediments from the Gorgan Bay, Caspian Sea. The sum of 16 PAHs (ΣPAH16) concentrations varied from 107.87 to 516.18ngg−1dry weight, with average value of 270.96±150.47ngg−1dry weight. Ecological risk assessment of PAHs, indicated that adverse biological effects caused by acenaphthene, naphthalene, fluoranthene and Pyrene occasionally and frequently may take place in the sediments of Gorgan Bay. PAHs source identification demonstrated that the PAHs come from mixed and pyrogenic origin.
Afficher plus [+] Moins [-]Spatial variation, environmental assessment and source identification of heavy metals in sediments of the Yangtze River Estuary Texte intégral
2014
Wang, Jiawei | Liu, Ruimin | Zhang, Peipei | Yu, Wenwen | Shen, Zhenyao | Feng, Chenghong
In order to analyze the spatial distribution patterns, pollution sources and ecological risks of heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn), 30 sediment samples were taken from in the Yangtze River Estuary (YRE). The results indicated that the contamination ranking of heavy metals was As>Cr>Cd>Ni>Mn>Pb>Zn>Cu. In the various areas, the pollution magnitude decreased as follows: adjacent sea>river mouth>inner-region. Compared to data published for other regions, the YRE data indicated that the sediment was not severely contaminated by heavy metals. In the YRE, natural and anthropogenic inputs dominated the distribution patterns of the heavy metals. Beyond that, the hydrodynamic conditions, such as the Taiwan warm current, coastal current and Yangtze diluted water, also caused distribution variations in the study areas.
Afficher plus [+] Moins [-]From a millennium base line to 2012: Beach litter changes in Wales Texte intégral
2014
Williams, A.T. | Randerson, P. | Alharbi, O.A.
Forty-five beaches at 41 bathing area locations in Wales were analysed for litter in 2000 and 2012, via a standard seven category checklist. Fourteen resorts, 2 urban, 11 village, 15 rural 3 remote, were graded, A to D. A grade beach numbers changed from 5 to19; B, 27 to 24; C, 9 to 2; D, 4 to 0, many beaches maintaining their current status. Assuming trend continuance within the next 12years, the A:B grade ratio would approach equilibrium of 44:56, with no grade C or D beaches. Recreational litter was ubiquitous; fishing materials prevalent along Cardigan Bay. New water treatment plant investment reduced sewage related debris. Despite apparent increased awareness of beach litter, improving visitor behaviour through information/education should be a future priority. Removing a few gross items could improve beach grades at little cost to local authorities and benefits to the Welsh economy.
Afficher plus [+] Moins [-]Comparison of number, surface area and volume distributions of particles emitted from a multipoint port fuel injection car and a gasoline direct injection car Texte intégral
2014
Lv, Gang | Song, Chong–lin | Pan, Suo–zhu | Gao, Jun–hua | Cao, Xiao–feng
A chassis dynamometer study was conducted to compare the characteristics of particle emissions from a port fuel injection (PFI) and a gasoline direct injection (GDI) car, both of which comply with Euro 4 exhaust emission standards. Experiments were carried out over the New European Driving Cycle (NEDC), the ECE–15 segments, the period from 0 to 49 s within the NEDC procedure (FSE) and the Extra Urban Driving Cycle segment. Exhaust particles were characterized in terms of the particle number, surface area, volume and size distributions between 30nm and 1μm. Under the NEDC, the GDI car had particle emissions weighted by particle number, surface area and volume that were 56–2 739% higher than the emissions from the PFI car in the range of particle size measured, and the particle number, volume and surface area emissions per km for the GDI car are respectively 5.3, 9.0 and 14.6 times higher than those for the PFI car. Among the testing conditions employed, the highest concentrations of average particle number, surface area and volume were found in the FSE, and the particle number, surface area and volume for the GDI car were respectively 9.5, 33.2 and 39.8 times higher than those for the PFI car. Moreover, the peak of the particle size distributions for the PFI car was toward a smaller size, while that for the GDI was toward a larger size, indicating that particles emitted by the PFI car are much smaller than those emitted by the GDI car.
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