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Effects of the construction of Scroby Sands offshore wind farm on the prey base of Little tern Sternula albifrons at its most important UK colony Texte intégral
2011
Perrow, Martin R. | Gilroy, James J. | Skeate, Eleanor R. | Tomlinson, Mark L.
Despite widespread interest in the impacts of wind farms upon birds, few researchers have examined the potential for indirect or trophic (predator–prey) effects. Using surface trawls, we monitored prey abundance before and after construction of a 30 turbine offshore wind farm sited close to an internationally important colony of Little terns. Observations confirmed that young-of-the-year clupeids dominated chick diet, which trawl samples suggested were mainly herring. Multivariate modelling indicated a significant reduction in herring abundance from 2004 onwards that could not be explained by environmental factors. Intensely noisy monopile installation during the winter spawning period was suggested to be responsible. Reduced prey abundance corresponded with a significant decline in Little tern foraging success. Unprecedented egg abandonment and lack of chick hatching tentatively suggested a colony-scale response in some years. We urge a precautionary approach to the timing and duration of pile-driving activity supported with long-term targeted monitoring of sensitive receptors.
Afficher plus [+] Moins [-]Total mercury in sediments and in Brazilian Ariidae catfish from two estuaries under different anthropogenic influence Texte intégral
2011
Azevedo, Juliana S. | Braga, Elisabete S. | Favaro, Deborah T. | Perretti, Adriana R. | Rezende, Carlos Eduardo | Souza, Cristina Maria M.
Santos-São Vicente estuary, located in São Paulo State, Brazil, has a history of contamination by inorganic chemicals such as mercury (Hg). In the 1980s the Cubatão was considered one of the most polluted sites in the world as a consequence of the intense industrial activities located in the city close to the estuary. To provide data and evaluate the local biota, total mercury (THg) contents were determined in sediments and in fish, Cathorops spixii, from different areas of the Santos-São Vicente estuary. For comparison, samples were also collected in a non-polluted system with similar hydrochemistry characteristics, the Cananeia estuary. The water characteristics and THg levels in sediment and fish samples confirmed a high human influence in the Santos-São Vicente estuary. The lowest THg values, observed in Cananeia, were evidence of low anthropogenic influence. High values observed in Santos-São Vicente show the necessity for a monitoring program.
Afficher plus [+] Moins [-]The combined effects of oxygen availability and salinity on physiological responses and scope for growth in the green-lipped mussel Perna viridis Texte intégral
2011
Wang, Youji | Hu, Menghong | Wong, Wai Hing | Shin, Paul K.S. | Cheung, Siu Gin
Mussels were maintained for 4weeks under different combinations of dissolved oxygen concentration (1.5, 3.0 and 6.0mgO₂l⁻¹) and salinity (15, 20, 25 and 30) in a 3×4 factorial design experiment. Clearance rate (CR), absorption efficiency (AE), respiration rate (RR) and scope for growth (SFG) decreased with decreasing salinity and dissolved oxygen concentration (DO), while excretion rate (ER) increased with decreasing salinity and increasing DO. The O:N ratio was <10 at salinities of 15 and 20, irrespective of DO levels. SFG was negative in most of the treatments, except for those under 6.0mgO₂l⁻¹ or at a salinity of 30 when DO was lower. The results may help explain the distribution pattern of Perna viridis in Hong Kong waters and provide guidelines for mussel culture site selection.
Afficher plus [+] Moins [-]Metal (Al, Fe, Mn and Cu) distributions and origins of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Marmara Sea and the coast of Istanbul, Turkey Texte intégral
2011
Taşkın, Ö.S. | Aksu, A. | Balkıs, N.
In this study, total metal (Al, Fe, Mn and Cu) and PAHs analyses have been done in the surface sediments. Sediment samples have been collected from seven parts of the Marmara Sea and the coast of Istanbul during 2009. Total Al, Fe, Mn and Cu contents vary between 1.8% and 5.4%; 1.1% and 2.8%; 122 and 259μgg⁻¹; 27 and 416μgg⁻¹, respectively. EF and CF values of Fe and Mn are lower than 1.5 and 1, respectively, in all the stations. Total PAH contents range between 135 and 6009ngg⁻¹ in the surface sediments. The origin of PAHs has been found pyrolitic according to the Phe/Ant ratio in the all stations. Contrastingly, at K0, MKC and MY1 Stations, PAH origins have been observed petrogenic according to the Flu/Pyr ratio.
Afficher plus [+] Moins [-]Do long lived seabirds reduce the negative effects of acute pollution on adult survival by skipping breeding? A study with European storm petrels (Hydrobates pelagicus) during the “Prestige” oil-spill Texte intégral
2011
Zabala, Jabi | Zuberogoitia, Iñigo | Martínez-Climent, Jose Antonio | Etxezarreta, Jon
We estimated the survival probability of breeding European storm petrels before, during and after a severe oil-spill. We hypothesized that petrels might have deserted the breeding colony to maximize their own survival probability and we expected no major change on adult survival probabilities as a consequence of the spill. We used an information-theoretical approach and multi-model inference to assess the strength of the evidence in favour of different hypotheses. Evidence contained in the data clearly supported the non-effect of the spill on adult survival hypothesis while punctual impact of the spill on survival and expanded (3years) impact alternatives received less support. The effect size of the spill on averaged survival estimates was negligible in every case. We suggest that petrels minimized the impact of acute pollution by not investing in reproduction. We suggest that short-medium term management actions after oil-spills and similar catastrophes should focus on ecosystem restoration.
Afficher plus [+] Moins [-]Bioindicative potential of shell abnormalities occurring in the clam Macoma balthica (L.) from the Baltic Sea Texte intégral
2011
Smolarz, Katarzyna | Bradtke, Katarzyna
This study reports the occurrence of shell deformities in the Baltic clam Macoma balthica from the Northern Baltic Sea (Trösa Archipelago, Sweden). The functional significance and the bioindicative potential of observed exoskeleton’ anomalies was assessed using a suite of physiological and morphological biomarkers. Analyzed shell deformations (SD) included damages of the dorsal margin visible as shell excavations, destruction of the beak, umbo and hinge ligament and decreased shell’ transparency. Deformed clams exhibited worse physiological conditions and increased frequency of micronuclei. Skewed sex ratio towards male domination was observed in all studied populations. Spatial differences in the occurrence of deformed clams are reported, with more than 50% of deformed clams inhabiting polluted locations and 8% the reference station. These results are encouraging for the use of described SDs as initial and cost effective indicators of environmental health.
Afficher plus [+] Moins [-]Matrix-bound phosphine in sediments from Lake Illawarra, New South Wales, Australia Texte intégral
2011
Song, Xiuxian | Morrison, R.J. | Feng, Zhihua | Liu, Dongyan | Harrison, J.J. | Yu, Zhiming
Matrix-bound phosphine (MBP) has been measured in sediment from two cores in Lake Illawarra on the south east coast of Australia. The sediments were also dated in the upper layers. MBP concentrations found range from 142 to 1813ngkg⁻¹, dw (dry weight of sediment) with some values being amongst the highest ever measured. Values of MBP in deeper sediments were higher than for near surface samples, but the patterns with depth were not consistent. Strong correlations were noted between MBP and organic phosphorus (OP, r>0.8) and with total phosphorus (TP, r>0.7), but only moderate correlations were found with organic carbon (OC, r>0.5). No correlations were found between MBP concentrations and the age of the sediments. It was confirmed that high MBP concentrations are indicative of a phosphorus rich environment. The results tend to support the premise that MBP is generated by microbial attack on OP under anaerobic conditions.
Afficher plus [+] Moins [-]Antifouling strategies: History and regulation, ecological impacts and mitigation Texte intégral
2011
Dafforn, Katherine A. | Lewis, John A. | Johnston, Emma L.
Biofouling increases drag on marine vessels resulting in higher fuel consumption and can also facilitate the transport of harmful non-indigenous species (NIS). Antifouling technologies incorporating biocides (e.g., copper and tributyltin) have been developed to prevent settlement of organisms on vessels, but their widespread use has introduced high levels of contamination into the environment and raised concerns about their toxic effects on marine communities. The recent global ban on tributyltin (1 January 2008) and increasing regulation of copper have prompted research and development of non-toxic paints. This review synthesises existing information regarding the ecological impact of biocides in a wide range of organisms and highlights directions for the management of antifouling paints. We focus particularly on representatives of the recent past (copper and tributyltin) and present (copper and ‘booster’) biocides. We identify knowledge gaps in antifouling research and provide recommendations relating to the regulation and phasing-out of copper.
Afficher plus [+] Moins [-]Occurrence of Pyrodinium bahamense var. compressum along the southern coast of the Baja California Peninsula Texte intégral
2011
Gárate Lizárraga, Ismael | González-Armas, Rogelio
As part of a continuing toxic microalgae monitoring program, 22 phytoplankton samples were collected from July to November 2010 at several sampling stations along the southern coast of the Baja California Peninsula. For the first time, the toxic dinoflagellate Pyrodinium bahamense var. compressum was found along the southeastern and southwestsern coasts of the peninsula. P. bahamense var. bahamense was first observed off San José del Cabo, which is an extension of the range of this variety. Both varieties occur as solitary cells. P. bahamense var. compressum occurred at temperatures ranging between 24.5°C and 31°C, whereas var. P.bahamense occurred at 28.5°C to 29°C, indicating its tropical and subtropical nature. Occurrence of P. bahamense var. compressum along this coastline may be related to El Niño 2009–2010.
Afficher plus [+] Moins [-]Assessment of Hurricane Ivan impact on chlorophyll-a in Pensacola Bay by MODIS 250m remote sensing Texte intégral
2011
Huang, Wenrui | Mukherjee, Debraj | Chen, Shuisen
The impact of Hurricane Ivan on water quality in Pensacola Bay was investigated by MODIS 250m remote sensing of chlorophyll-a concentrations at different time slots before and after the hurricane event. Before the hurricane, the mean chlorophyll-a in the Bay was 5.3μg/L. Heavy rainfall occurred during the hurricane landfall. The 48h rainfall reached 40cm and the peak storm surge reached 3m on 9/16. After the rainstorm and during the storm surge on 9/17/2004, the mean chlorophyll-a concentration substantially increased to 14.7μg/L. 26.3% water area was in the poor-water-quality condition (chl-a>20μg/L). This indicates that heavy nutrient loads from urban stormwater runoff and storm-surge inundation simulated chlorophyll bloom. After the end of the storm surge on 9/18/2004, the mean chlorophyll dropped to 2.0μg/L, suggesting the effective flushing of polluted water from the bay to the Gulf of Mexico by the storm-surge. The good water quality condition lasted for almost several weeks after the storm surge. The peak river flow, arriving on the 4th day after the peak storm surge, did not alter the good water quality situation in the bay. This indicates that urban stormwater runoff rather than the river inflow is the major pollutant source for water quality in Pensacola Bay during the hurricane.
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