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Результаты 1161-1170 из 3,208
Temporal pattern in biometrics and nutrient stoichiometry of the intertidal seagrass Zostera japonica and its adaptation to air exposure in a temperate marine lagoon (China): Implications for restoration and management Полный текст
2015
Zhang, Xiaomei | Zhou, Yi | Liu, Peng | Wang, Feng | Liu, Bingjian | Liu, Xujia | Yang, Hongsheng
In coastal areas of China, the seagrass Zostera japonica has drastically decreased in the past decades. Swan Lake is an exception, where we found extensive areas of Z. japonica beds. The growth of Z. japonica in the lagoon exhibited strong seasonal variation. The maximum shoot density of 9880±2786shootsm−2 occurred in August. The maximum specific growth rate (SGR) of 4.99±1.99%⋅d−1 was recorded in June 2012. SGR might be a good parameter for assessing the growth status of Z. japonica population. N and P contents in the rhizome were significantly lower than those in the leaf and leaf sheath. Lower C/P ratios suggested P enrichment of the seagrass. The occurrence of Z. japonica in Swan Lake was featured by adapting to the intertidal harsh environments. The transplantation method using sectioned rhizomes would be a potential way for restoration of degraded Z. japonica beds. The establishment of the Rongcheng Swan National Nature Reserve in China has contributed to the survival and expansion of Z. japonica in Swan Lake.
Показать больше [+] Меньше [-]Sewage contamination in a tropical coastal area (São Sebastião Channel, SP, Brazil) Полный текст
2015
Muniz, P. | da Silva, D.A.M. | Bícego, M.C. | Bromberg, S. | Pires-Vanin, A.M.S.
Urban effluent discharges in Brazilian coastal areas are a chronic problem and often lead to changes in the quality of the marine environment. São-Sebastião-Channel (SSC) is an important aquatic ecosystem to be monitored for urban sewage contamination due to the intense urban activities in that region, as well as the relative high biodiversity of marine organisms. In the area are present three submarine sewage outfalls, a commercial harbour and also the biggest oil terminal in Brazil. Total organic carbon (TOC), total nitrogen (TN), total sulphur (TS), steroids and linear alkylbenzenes (LABs) were measured in sediment samples collected in three strategic locations of the SSC in order to monitor urban sewage contamination. Total LAB and total sterols levels ranged from below DL–51.3ngg−1 and below DL–10.40μgg−1, respectively. Samples collected near sewage outfall in the central part of the SSC had higher concentrations of urban sewage-associated contaminants.
Показать больше [+] Меньше [-]The performance of biomass-based AMBI in lagoonal ecosystems Полный текст
2015
Mistri, Michele | Munari, Cristina
We studied the performance of the AZTI Marine Biotic Index AMBI manipulating input data collected from lagoonal ecosystems. Our data set consisted of macrofaunal abundance and biomass counts gathered at a variety of sites at which the disturbance status was known. Input data were also manipulated using a set of transformations of increasing severity. Biotic indices were calculated using raw and transformed abundance, biomass and production. Among the three categories of AMBI-based indices, medium transformation of data gave the highest correlation with pressures. However, increasing the severity of transformation generally resulted in a decrease of the correlation with environmental factors. The relative importance of ecological groups changed when using abundance or biomass, sometimes leading to an improved ecological status classification. Being biomass and production more ecologically relevant than abundance, using them to derive AMBI-based new indices seems intriguing, at least in lagoonal waters, where the community is naturally disturbed and dominated by opportunists.
Показать больше [+] Меньше [-]Occurrence of microplastics in the coastal marine environment: First observation on sediment of China Полный текст
2015
Qiu, Qiongxuan | Peng, Jinping | Yu, Xubiao | Chen, Fangchaizi | Wang, Jundong | Dong, Fenqiang
Microplastics in sediments from the Beibu Gulf and the coastline of China Sea were investigated to evaluate the occurrence and abundance of microplastics in China for the first time. Microplastics (<5mm) were taken from sediments by a flotation method. The number of microplastics was counted by a fluorescence microscope, an instrument that is rarely used in the detection of microplastics in sediments. This instrument led to results that were satisfactory. Compared with other sampled areas, microplastics were found in massive concentrations in China. Four types of microplastics, HDPE, PET, PE and PS, were identified. The results will provide useful background information for further investigations.
Показать больше [+] Меньше [-]Metal concentrations in demersal fish species from Santa Maria Bay, Baja California Sur, Mexico (Pacific coast) Полный текст
2015
Jonathan, M.P. | Aurioles-Gamboa, David | Villegas, Lorena Elizabeth Campos | Bohórquez-Herrera, Jimena | Hernández-Camacho, Claudia J. | Sujitha, S.B.
Concentrations of 11 trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, As, Hg) in 40 fish species from Santa Maria Bay, Baja California Sur, Mexico, the strategically important area for marine mammals and organisms were analyzed. Based on their concentrations the ranking of metals Fe>Zn>Ni>Cr>Mn>Pb>Cu>Co>As>Cd>Hg suggests that organism size, metabolism and feeding habits are correlated with metal concentrations. Local geological formations affect the concentrations of different metals in the aquatic environment and are subsequently transferred to fishes. The correlation analysis suggests that metabolism and nurturing habits impact the concentration of metals. Concentrations of Fe and Mn appear to be influenced by scavenging and absorption processes, which vary by species. The considerable variability in the metal concentrations obtained in different species underscores the importance of regular monitoring.
Показать больше [+] Меньше [-]Parametric study to determine the effect of temperature on oil solidifier performance and the development of a new empirical correlation for predicting effectiveness Полный текст
2015
Sundaravadivelu, Devi | Suidan, Makram T. | Venosa, Albert D.
Temperature can play a significant role in the efficacy of solidifiers in removing oil slicks on water. We studied and quantified the effect of temperature on the performance of several solidifiers using 5 different types of oils under a newly developed testing protocol by conducting experiments in constant temperature rooms set at 22°C and 5°C. The results indicated that solidifier efficiency decreased substantially at the lower temperature, especially at lower application rates. The removal efficiency of the solidifier was in general directly proportional to temperature, except for the heavier oils, where removal by attachment was observed. Solidifier products with lower powder bulk density exhibited the best removal effectiveness. Analysis of experimental data yielded empirical correlations involving certain operational variables such as application rate, temperature, solidifier property (bulk density), and oil property (viscosity). Regression analysis was used to fit a mathematical model to the experimental solidifier effectiveness data.
Показать больше [+] Меньше [-]Polluter identification with spaceborne radar imagery, AIS and forward drift modeling Полный текст
2015
Longépé, N. | Mouche, A.A. | Goacolou, M. | Granier, N. | Carrère, L. | Lebras, J.Y. | Lozach, P. | Besnard, S.
This study defines and assesses a new operational concept to identify the origin of pollution at sea, based on Synthetic Aperture Radar, Automatic Identification System, and a forward drift model. As opposed to traditional methodologies where the SAR detected pollution is backtracked in the past, our approach assumes that all the vessels pollute all along their way. Based on all the AIS data flows, the forward-tracked simulated pollutions are then compared to the detected pollution, and the potential polluter can be finally identified. Case studies are presented to showcase its usefulness in a variety of maritime situations with a focus on orphan pollutions in a dense traffic area. Out of the identification of the suspected polluters, the age and eventually the type of the pollution can be retrieved.
Показать больше [+] Меньше [-]Modelling the transport and accumulation of floating marine debris in the Mediterranean basin Полный текст
2015
Mansui, J. | Molcard, A. | Ourmières, Y.
In the era of plastic and global environmental issues, when large garbage patches have been observed in the main oceanic basins, this work is the first attempt to explore the possibility that similar permanent accumulation structures may exist in the Mediterranean Sea. The questions addressed in this work are: can the general circulation, with its sub-basins scale gyres and mesoscale instabilities, foster the concentration of floating items in some regions? Where are the more likely coastal zones impacted from open ocean sources?Multi-annual simulations of advected surface passive debris depict the Tyrrhenian Sea, the north-western Mediterranean sub-basin and the Gulf of Sirte as possible retention areas. The western Mediterranean coasts present very low coastal impact, while the coastal strip from Tunisia to Syria appears as the favourite destination. No permanent structure able to retain floating items in the long-term were found, as the basin circulation variability brings sufficient anomalies.
Показать больше [+] Меньше [-]Plastic in surface waters of the Inside Passage and beaches of the Salish Sea in Washington State Полный текст
2015
Davis, Wallace | Murphy, Anne G.
We summarize results of two independent studies on plastic pollution in the marine environment that overlap in time and space. One study evaluated the abundance of anthropogenic debris on 37 sandy beaches bordering the Salish Sea in Washington State while the other characterized plastic debris in surface waters of the Salish Sea and the Inside Passage to Skagway, Alaska. Both studies concluded that foam, primarily expanded polystyrene was the dominant pollutant. Plastic was found in surface waters the full length of the Inside Passage but was concentrated near harbors. At the wrack line, an average square meter of Washington’s 1180km of sandy beaches in the Salish Sea had 61 pieces of anthropogenic debris weighing approximately 5g. The total loading for the entire 1m wide band is estimated to be 72,000,000 pieces and 5.8metric tons. Most anthropogenic debris on beaches is generated within the region.
Показать больше [+] Меньше [-]Satellite-based observations of unexpected coastal changes due to the Saemangeum Dyke construction, Korea Полный текст
2015
Lee, Yoon-Kyung | Ryu, Joo-Hyung | Choi, Jong-Kuk | Lee, Seok | Woo, Han-Jun
Spatial and temporal changes around an area of conventional coastal engineering can be easily observed from field surveys because of the clear cause-and-effect observable in the before and after stages of the project. However, it is more difficult to determine environmental changes in the vicinity of tidal flats and coastal areas that are a considerable distance from the project. To identify any unexpected environmental impacts of the construction of Saemangeum Dyke in the area, we examined morphological changes identified by satellite-based observations through a field survey on Gomso Bay tidal flats (15km from Saemangeum Dyke), and changes in the suspended sediment distribution identified by satellite-based observations through a hydrodynamic analysis in the Saemangeum and Gomso coastal area. We argue that hydrodynamic changes due to conventional coastal engineering can affect the sedimentation pattern in the vicinity of tidal flats. We suggest that the environmental impact assessment conducted before a conventional coastal engineering project should include a larger area than is currently considered.
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