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Resultados 1711-1720 de 5,098
Distribution correlations of cadmium to calcium, phosphorus, sodium and chloridion in mangrove Aegiceras corniculatum root tissues
2018
Li, Jian | Yu, Junyi | Yan, Chongling | Du, Daolin | Liu, Jingchun | Lu, Haoliang
Nutriment distributions might influence Cd distribution and Cd tolerance in mangrove plant roots. To demonstrate this, Aegiceras corniculatum was stressed by Cd, and the distributions of Cd, Ca, P, Na and Cl in plant roots were detected with the aid of SEM-EDX. It was found that endodermis, pith and xylem were the predominant tissues for retardation and regional enrichment of Cd. Na and Cl distributions suggest a critical role of salt resistance tissues on Cd tolerance in roots. P participated in Cd retardation and regional enrichment of endodermis and xylem. P, Na, Cl and Ca distribution had a high correlation to that of Cd in roots. The synergetic accumulation between Ca and Cd could be a crucial mechanism for Cd tolerance in A. corniculatum roots. In conclusion, the research of Cd and nutriment distributions in A. corniculatum roots deepens the understanding on Cd tolerance in mangrove plants.
Mostrar más [+] Menos [-]Low prevalence of microplastic contamination in planktivorous fish species from the southeast Pacific Ocean
2018
Ory, Nicolas | Chagnon, Catherine | Felix, Fernando | Fernandez, Cesar | Ferreira, Joana Lia | Gallardo, Camila | Garcés Ordóñez, Ostin | Henostroza, Aida | Laaz, Enrique | Mizraji, Ricardo | Mojica, Hermes | Murillo Haro, Vladimir | Ossa Medina, Luis | Preciado, Mercy | Sobral, Paula | Urbina, Mauricio A. | Thiel, Martin
The gut contents of 292 planktivorous fish, from four families (Atherinopsidae, Clupeidae, Engraulidae and Scombridae) and seven species, captured along the coast of the southeast Pacific, were examined for microplastic contamination. Only a small fraction of all studied fish (2.1%; 6 individuals) contained microplastic particles in their digestive tract. Microplastics found were degraded hard fragments and threads, ranging from 1.1 to 4.9 (3.8±SD 2.4) mm in length, and of various colours, which suggests that the planktivorous fish species examined herein did not capture microplastics on the basis of their colour. The low prevalence of microplastic contamination in planktivorous fishes found in this study suggests that the risk of accidental ingestion by these species might be limited in the coastal upwelled waters of the southeast Pacific, perhaps due to small human population and highly dynamic oceanographic processes.
Mostrar más [+] Menos [-]Biodegradation of dispersed oil in seawater is not inhibited by a commercial oil spill dispersant
2018
Brakstad, Odd G. | Ribicic, Deni | Winkler, Anika | Netzer, Roman
Chemical dispersants are well-established as oil spill response tools. Several studies have emphasized their positive effects on oil biodegradation, but recent studies have claimed that dispersants may actually inhibit the oil biodegradation process. In this study, biodegradation of oil dispersions in natural seawater at low temperature (5°C) was compared, using oil without dispersant, and oil premixed with different concentrations of Slickgone NS, a widely used oil spill dispersant in Europe. Saturates (nC10-nC36 alkanes), naphthalenes and 2- to 5-ring polycyclic aromatic hydrocarbons (PAH) were biotransformed at comparable rates in all dispersions, both with and without dispersant. Microbial communities differed primarily between samples with or without oil, and they were not significantly affected by increasing dispersant concentrations. Our data therefore showed that a common oil spill dispersant did not inhibit biodegradation of oil at dispersant concentrations relevant for response operations.
Mostrar más [+] Menos [-]Use of unmanned aerial vehicles for efficient beach litter monitoring
2018
Martin, Cecilia | Parkes, Stephen | Zhang, Qiannan | Zhang, Xiangliang | McCabe, Matthew F. | Duarte, Carlos M.
A global beach litter assessment is challenged by use of low-efficiency methodologies and incomparable protocols that impede data integration and acquisition at a national scale. The implementation of an objective, reproducible and efficient approach is therefore required. Here we show the application of a remote sensing based methodology using a test beach located on the Saudi Arabian Red Sea coastline. Litter was recorded via image acquisition from an Unmanned Aerial Vehicle, while an automatic processing of the high volume of imagery was developed through machine learning, employed for debris detection and classification in three categories. Application of the method resulted in an almost 40 times faster beach coverage when compared to a standard visual-census approach. While the machine learning tool faced some challenges in correctly detecting objects of interest, first classification results are promising and motivate efforts to further develop the technique and implement it at much larger scales.
Mostrar más [+] Menos [-]Microplastics in the intestinal tracts of East Asian finless porpoises (Neophocaena asiaeorientalis sunameri) from Yellow Sea and Bohai Sea of China
2018
Xiong, Xiong | Chen, Xianchuan | Zhang, Kai | Mei, Zhigang | Hao, Yujiang | Zheng, Jinsong | Wu, Chenxi | Wang, Kexiong | Ruan, Yuefei | Lam, Paul K.S. | Wang, Ding
The direct evidences for the ingestion of microplastics by cetaceans, especially the cetaceans in Asian marine areas are limited. In this study, residue of microplastics in the intestinal tracts of East Asian finless porpoises (Neophocaena asiaeorientalis sunameri) was investigated. Microplastics were detected in all specimens, with mean abundance of 19.1 ± 7.2 items/individual. With respect to microplastics properties, fibers, blue items, and polypropylene were predominant in shapes, colors, and plastic materials, respectively. Trophic transfer and unintentional ingestion might be the potential pathways for microplastics ingested by finless porpoise. The specific intestinal structure might account for the predominance of fibers and the accumulation of microplastics at the beginning portion of intestines. This study indicates that cetaceans in Chinese marine areas also suffer from microplastics pollution. Further studies on the fate and ecological effects of microplastics should be conducted to reveal their potential risks to cetaceans.
Mostrar más [+] Menos [-]Sponge-microbe partnerships are stable under eutrophication pressure from mariculture
2018
Baquiran, Jake Ivan P. | Conaco, Cecilia
Sponges harbor a great diversity of symbiotic microorganisms. However, environmental stresses can affect this partnership and influence the health and abundance of the host sponges. In Bolinao, Pangasinan, Philippines, chronic input of organic materials from mariculture activities contributes to a eutrophic coastal environment. To understand how these conditions might affect sponge-microbial partnerships, transplantation experiments were conducted with the marine sponge Gelliodes obtusa. High-throughput sequencing of 16S rRNA revealed that the associated microbial community of the sponges did not exhibit significant shifts after six weeks of transplantation at a eutrophic fish farm site compared to sponges grown at a coral reef or a seagrass area. However, sponges at the fish farm revealed higher abundance of the amoA gene, suggesting that microbiome members are responsive to increased ammonium levels at the site. The stable association between G. obtusa and its microbiome indicates that the sponge holobiont can withstand eutrophication pressure from mariculture.
Mostrar más [+] Menos [-]Exploration of microplastics from personal care and cosmetic products and its estimated emissions to marine environment: An evidence from Malaysia
2018
Praveena, Sarva Mangala | Shaifuddin, Siti Norashikin Mohamad | Akizuki, Shinichi
This study aims understand microplastics from personal care and cosmetic products in Malaysia via quantification and characterization of microplastics together with emission estimation to marine environment. A total of 214 respondents from all over Malaysia were surveyed with identification of top ten personal care and cosmetic products usage. Particles found in facial cleaner/scrub and toothpaste were colored and colorless with majority of granular shapes. Particles in toothpaste were found between 3 and 145 μm while particles in facial cleaner/scrub were found to be between 10 and 178 μm, stipulating the presence of microplastics. Plastic polymers (LDPE and polypropylene) were found in all facial cleaner/scrub samples while only plastic polymers (LDPE) were present in toothpaste sample G. A total of 0.199 trillion microplastics are expected to be released annually to marine environment in Malaysia. Personal care and cosmetic products are seen as one of the microplastics sources for Malaysia and worldwide.
Mostrar más [+] Menos [-]Are semi-terrestrial crabs threatened by human noise? Assessment of behavioural and biochemical responses of Neohelice granulata (Brachyura, Varunidae) in tank
2018
Filiciotto, Francesco | Sal Moyano, María Paz | de Vincenzi, Giovanni | Hidalgo, Fernando | Sciacca, Virginia | Bazterrica, Maria Cielo | Corrias, Valentina | Lorusso, Martìn | Mazzola, Salvatore | Buscaino, Giuseppa | Gavio, María Andrea
This study examined the effects of human lab-generated noise (sweep tone) on the behaviour and biochemistry of a semi-terrestrial crab (Neohelice granulata). The experiment was carried out in tanks equipped with video- and audio-recording systems on a total of seventy-eight specimens. In total, 42 experimental trials with sweep-tone exposure and control conditions were performed using crabs in single and group layouts. After a habituation period of 30 min, the locomotor and acoustic (sound signals emitted by the crabs) behaviours were monitored for 30 min. During this time, the animals in sweep-tone conditions were exposed to ascending sweeps in a bandwidth range of 2.5–25 kHz. Exposure to sweep-tone noise produced significant changes in the number of signals emitted, locomotor behaviours and plasma parameters, such as haemolymph total haemocyte count and glucose, lactate and total protein concentrations, revealing that human noise could represent a disturbance for this crustacean species.
Mostrar más [+] Menos [-]Spatial distribution and ecological risk assessment of the coastal surface sediments from the Red Sea, northwest Saudi Arabia
2018
Kahal, Ali Y. | El-Sorogy, Abdelbaset S. | Alfaifi, Hussain J. | Almadani, Sattam | Ghrefat, Habes A.
To assess the spatial distribution and ecological risk assessment along the Red Sea coast, Saudi Arabia, 30 samples were collected for aluminum, chromium, copper, zinc, cadmium, lead, mercury, iron, cobalt, nickel and organic matter analysis. The descending order of metal concentrations was Al > Fe > Cr > Cu > Zn > Ni > Co > Pb > Hg > Cd. Average values of enrichment factor of Hg, Cd, Cu, Co, Cr, Ni, Pb and Zn were higher than 2 (209.50, 25.52, 20.36, 9.62, 7.28, 6.52, 6.21 and 6.07 respectively), which means anthropogenic sources of these metals. The average levels most of the studied metals were lower than those of the background shale and the earth crust and those recorded along most worldwide coasts, while the average values of zinc, copper, cobalt and nickel were higher than the values recorded from the Red Sea coast, the Gulf of Aqaba and some Caspian Sea coasts. The Duba bulk plant-Saudi Aramco, Duba refinery station and the tourist resort were the possible anthropogenic sources of pollutants in the southern part of the study area; and the landfilling, cement factory and Duba port and shipment operations in the central part, while the landfilling resulting from construction of the green Duba power plant and crowded fish boats were the possible sources in the northern part.
Mostrar más [+] Menos [-]Modeling for the allocation of oil spill recovery capacity considering environmental and economic factors
2018
Ha, Min-Jae
This study presents a regional oil spill risk assessment and capacities for marine oil spill response in Korea. The risk assessment of oil spill is carried out using both causal factors and environmental/economic factors. The weight of each parameter is calculated using the Analytic Hierarchy Process (AHP). Final regional risk degrees of oil spill are estimated by combining the degree and weight of each existing parameter. From these estimated risk levels, oil recovery capacities were determined with reference to the recovery target of 7500kl specified in existing standards. The estimates were deemed feasible, and provided a more balanced distribution of resources than existing capacities set according to current standards.
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