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Effect of different enrichment strategies on microbial community structure in petroleum-contaminated marine sediment in Dalian, China Texte intégral
2017
Chen, Chao | Liu, Qiu | Liu, Changjian | Yu, Jicheng
An oil spill occurred at Xingang Port, Dalian, China in 2010. Four years after this spill, oil contamination was still detected in samples collected nearby. In this study, the strains that evolved in the sediment were screened by high-throughput sequencing technology. Most of these strains were genera reported to have functions associated with crude oil biodegradation. The diversities and numbers of microbes were monitored through enrichment culturing; the dominant strains propagated at first, but the enrichment could not be continued, which indicated that the prolonged culture was not effective in the enrichment of the micro-consortium. Oxygen was also observed to affect the propagation of the dominant microbes. The results showed the role of culture strategies and oxygen in the enrichment of the petroleum-degrading microbes. Therefore, dominant strains could be screened by optimizing both the enrichment time and oxygen concentration used for culturing to facilitate oil biodegradation in the marine ecosystem.
Afficher plus [+] Moins [-]Intertidal pool fish Girella laevifrons (Kyphosidae) shown strong physiological homeostasis but shy personality: The cost of living in hypercapnic habitats Texte intégral
2017
Benítez, S. | Duarte, C. | Opitz, T. | Lagos, N.A. | Pulgar, J.M. | Vargas, C.A. | Lardies, M.A.
Tide pools habitats are naturally exposed to a high degree of environmental variability. The consequences of living in these extreme habitats are not well established. In particular, little it is known about of the effects of hypercanic seawater (i.e. high pCO2 levels) on marine vertebrates such as intertidal pool fish. The aim of this study was to evaluate the effects of increased pCO2 on the physiology and behavior in juveniles of the intertidal pool fish Girella laevifrons. Two nominal pCO2 concentrations (400 and 1600μatm) were used. We found that exposure to hypercapnic conditions did not affect oxygen consumption and absorption efficiency. However, the lateralization and boldness behavior was significantly disrupted in high pCO2 conditions. In general, a predator-risk cost of boldness is assumed, thus the increased occurrence of shy personality in juvenile fishes may result in a change in the balance of this biological interaction, with significant ecological consequences.
Afficher plus [+] Moins [-]Assessment of human-induced change and biological risk posed by contaminants in estuarine/harbour sediments: Sydney Harbour/estuary (Australia) Texte intégral
2017
Birch, G.F.
A rapid, simple yet scientifically sound scheme providing two important types of information used in assessment of estuarine sediments is presented. The mean enrichment quotient (MEQ) (fine contemporary sediment metal concentration/fine fraction background metal concentration) for Cu, Pb and Zn provides the magnitude of human-induced change, (deviation from the pristine condition), while sediment quality guidelines (SQGs) assess the risk posed by sedimentary contaminants to the benthic community.Maximum metal enrichment for sediment in Sydney estuary (Australia) is >100 times for Cu, Pb and Zn and the MEQ is >10 times for most of the estuary. Adverse effect on benthic populations due to Cu, Pb and Zn are expected in 2%, 50% and 36% of the waterway, respectively. SQGs for contaminant mixtures predict ~2% of the estuary has the highest risk of adverse effects, while 25% has intermediate risk. The scheme is well suited to initial assessments of estuarine sediments worldwide.
Afficher plus [+] Moins [-]Real-time eutrophication status evaluation of coastal waters using support vector machine with grid search algorithm Texte intégral
2017
Kong, Xianyu | Sun, Yuyan | Su, Rongguo | Shi, Xiaoyong
The development of techniques for real-time monitoring of the eutrophication status of coastal waters is of great importance for realizing potential cost savings in coastal monitoring programs and providing timely advice for marine health management. In this study, a GS optimized SVM was proposed to model relationships between 6 easily measured parameters (DO, Chl-a, C1, C2, C3 and C4) and the TRIX index for rapidly assessing marine eutrophication states of coastal waters. The good predictive performance of the developed method was indicated by the R2 between the measured and predicted values (0.92 for the training dataset and 0.91 for the validation dataset) at a 95% confidence level. The classification accuracy of the eutrophication status was 86.5% for the training dataset and 85.6% for the validation dataset. The results indicated that it is feasible to develop an SVM technique for timely evaluation of the eutrophication status by easily measured parameters.
Afficher plus [+] Moins [-]Reduction of CO2 emissions with automatic mooring systems. The case of the port of Santander Texte intégral
2017
Ortega Piris, Andrés | Díaz-Ruiz-Navamuel, Emma | Pérez-Labajos, Carlos A. | Oria Chaveli, Jesús
The revolutions in the maritime industry resulting from the implementation of integrated transport systems (bulk) and containerization (regular lines) at first had little effect on traditional mooring systems for ships in port. However, the research into innovation in automated mooring systems with increasingly advanced technologies carried on regardless.The so-called “Automatic Mooring Systems” (AMS), automatic systems that allow vessels to be moored without ropes, are being increasingly implemented in numerous ports in many different countries in the world, particularly in those whose traffic volumes have allowed the threshold of profitability of these infrastructures to be reached. But besides the financial benefits, the implantation of the AMS is having positive effects on the environment by reducing CO2 emissions in many commercial ports.The present work aims to measure for the first time the reduction in the CO2 emissions of merchant vessels as a consequence of the substitution of traditional mooring systems with the new automatic systems, continuing along the lines of previous works in the field of the reduction in CO2 emissions in ports.The estimation is made by applying the EPA and ENTEC “bottom-up” methodologies to the traffic in the port of Santander (Spain) in the year 2014.The implementation of the AMS, when compared to the traditional mooring systems, leads to a reduction in CO2 emissions of 76.78% calculated using the EPA method and 76.63% using the ENTEC method. Hence, the Port Authorities in their long-term planning decisions should promote the introduction of automatic mooring systems wherever the profitability thresholds of traffic allow it, as this will lead to significant environmental benefits by substantially reducing CO2 emissions during the maneuvers of merchant ships in maritime commercial ports.
Afficher plus [+] Moins [-]Assessing the toxicity of triphenyltin to different life stages of the marine medaka Oryzias melastigma through a series of life-cycle based experiments Texte intégral
2017
Yi, Xianliang | Leung, Kenneth M.Y.
Toxic effects of triphenyltin (TPT) to different life stages of the marine medaka Oryzias melastigma were investigated through a series of life-cycle based exposure experiments. In embryo stage, TPT exposure could elevate the heartbeat rate at Day 6–8 post-fertilization and increase the expression levels of five heart development related genes (i.e., ATPase, COX2, BMP4, GATA4 and NKX2.5). In larval stage, TPT shortened the body length at ≥10μg/L and suppressed the swimming activity of the fish larvae at Day 1 post-hatching at 50μg/L. In reproductive stage, TPT exposure resulted in a male-biased sex ratio (2μg/L) and reduced the gonadosomatic index (GSI) in females (≥ 0.1μg/L), which might in turn lead to a decline in their population fitness. The reproductive stage of O. melastigma was more sensitive to TPT than other stages, while the GSI of female medaka was the most sensitive endpoint.
Afficher plus [+] Moins [-]Hypoxia off the Changjiang (Yangtze River) estuary and in the adjacent East China Sea: Quantitative approaches to estimating the tidal impact and nutrient regeneration Texte intégral
2017
Zhu, Zhuo-Yi | Wu, Hui | Liu, Su-Mei | Wu, Ying | Huang, Da-Ji | Zhang, Jing | Zhang, Guo-Sen
Large areas of hypoxia have been reported off The Changjiang Estuary and in the East China Sea. Five cruises, covering winter, spring, and summer, were carried out from 2007 to 2013 in this region, and in August 2013 (summer), an extensive hypoxic event (11,150km2) was observed, which was characterized by an estimated bulk oxygen depletion of 5.1 million tons. A strong tidal impact was observed associated with the bottom oxygen depletion, with the periodicity of diel variations in dissolved oxygen being 12h (i.e., similar to the tidal cycle). A conservative estimate of nutrient regeneration suggested that during the hypoxic event of August 2013, the amount of regenerated nitrogen (as nitrate) and phosphorus (as dissolved inorganic phosphorus) was 27,000–30,000 tons and 1300–41,000tons, respectively. Estimates of the absolute (bulk) regenerated nutrient fluxes were much greater than the conservative estimates.
Afficher plus [+] Moins [-]Post-breeding dispersal of frigatebirds increases their exposure to mercury Texte intégral
2017
Mott, Rowan | Herrod, Ashley | Clarke, Rohan H.
Migration and dispersal can expose wildlife to threats in different parts of their range, particularly for localized anthropogenic threats. Wildlife exposure to metal contaminants may correlate with local anthropogenic emissions. Feather mercury concentrations of adult and juvenile Lesser Frigatebirds (Fregata ariel) and Great Frigatebirds (F. minor) were determined for individuals breeding in the eastern Indian Ocean. Low mercury concentration in juveniles relative to adults, higher mercury concentration in adult females than adult males, and a trend for Lesser Frigatebirds to have higher mercury concentration than Great Frigatebirds implicate non-breeding ground exposure as the major influence on mercury burden. Aspects of foraging ecology are congruent with high exposure occurring in inshore waters of the non-breeding range, particularly in the South China Sea. These findings highlight the need for tighter mercury emission regulations in southeast Asia to minimise the potential threat to frigatebirds and other species dependent on marine resources including humans.
Afficher plus [+] Moins [-]Sedimentary heavy metal(loid) contamination in the Veracruz shelf, Gulf of Mexico: A baseline survey from a rapidly developing tropical coast Texte intégral
2017
Celis-Hernandez, Omar | Rosales Hoz, Leticia | Cundy, Andrew B. | Carranza-Edwards, Arturo
This study examines sediment texture, geochemistry and sediment accumulation in cores from four sites in the Veracruz shelf area of the Gulf of Mexico, to assess the inputs of heavy metal(loid)s (and their potential biological impacts) in this carbonate-dominated shelf system, and to examine the rate of sedimentation near to the mouths of the La Antigua and Jamapa Rivers. The use of different pollution indices showed enrichment with Pb in all cores studied, although based on sediment quality guidelines As was the only element that has potential to occasionally cause damage to the benthic organisms present in the area. Heavy metal(loid) and sediment input from terrestrial and coastal sources is limited compared to more proximal, near-shore areas. The sediment core data presented however give a baseline dataset for heavy metal(loid) concentrations in the Veracruz shelf, against which future anthropogenic inputs can be assessed.
Afficher plus [+] Moins [-]Evaluation of metal contamination in the Mand River delta, Persian Gulf Texte intégral
2017
Pourkerman, Majid | Amjadi, Sedigheh | Beni, Abdolmajid Naderi | Lahijani, Hamid | Mehdinia, Ali
Mand River is one of four permanent rivers flowing into the Persian Gulf. Intense industrial activities have significantly impacted its watershed and estuary. In order to evaluate metal contamination and their provenance nine sediment samples were taken from the Mand Delta. Enrichment factors were employed to detect anthropogenic contributions to levels of metal pollution. We also calculated weathering indices in order to identify the source of the metals, related to geological units. Pollution levels were assessed using the modified degree of contamination. Geological units, oil combustion, aerosols and industrial activities are the main factors controlling the abundance of Cr, As, Ni and Pb. Wave action, coastal currents, grain-size parameters, mineralogy, bio-accommodation and organic matter are the factors affecting the distribution and concentration of metals in the study area. More studies are needed to evaluate the impact of metal pollution on the fisheries industry and public health.
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