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Resultados 1451-1460 de 4,042
Heavy metal accumulation in tissues of two sea cucumbers, Holothuria leucospilota and Holothuria scabra in the northern part of Qeshm Island, Persian Gulf Texto completo
2016
Mohammadizadeh, Maria | Bastami, Kazem Darvish | Ehsanpour, Maryam | Afkhami, Majid | Mohammadizadeh, Flora | Esmaeilzadeh, Marjan
The concentrations of some heavy metals (Cd, Cu, Zn andPb) were investigated in the sediments and the two species of sea cucumber (Holothuria leucospilota and Holothuria scabra) from northern part of Qeshm Island, Persian Gulf. The levels of Cu, Zn and Pb in sediment varied significantly among sampling sites (p<0.05). The highest levels of Zn and Pb in H. leucospilota were recorded in body wall whereas the highest contents of Zn and Pb in H. scabra were measured in respiratory tree organ, respectively. Cu and Cd were the most abundant elements in gonads of H. leucospilota while highest levels of Cd and Cu in H. scabra were measured in the gonad and derm, respectively. Cu and Zn concentrations were below permissible limits for human consumption while Cd and Pb were above permissible limits for human consumption.
Mostrar más [+] Menos [-]Reduced resilience of a globally distributed coccolithophore to ocean acidification: Confirmed up to 2000 generations Texto completo
2016
Jin, Peng | Gao, Kunshan
Reduced resilience of a globally distributed coccolithophore to ocean acidification: Confirmed up to 2000 generations Texto completo
2016
Jin, Peng | Gao, Kunshan
Ocean acidification (OA), induced by rapid anthropogenic CO2 rise and its dissolution in seawater, is known to have consequences for marine organisms. However, knowledge on the evolutionary responses of phytoplankton to OA has been poorly studied. Here we examined the coccolithophore Gephyrocapsa oceanica, while growing it for 2000 generations under ambient and elevated CO2 levels. While OA stimulated growth in the earlier selection period (from generations ~700 to ~1550), it reduced it in the later selection period up to 2000 generations. Similarly, stimulated production of particulate organic carbon and nitrogen reduced with increasing selection period and decreased under OA up to 2000 generations. The specific adaptation of growth to OA disappeared in generations 1700 to 2000 when compared with that at 1000 generations. Both phenotypic plasticity and fitness decreased within selection time, suggesting that the species' resilience to OA decreased after 2000 generations under high CO2 selection.
Mostrar más [+] Menos [-]Reduced resilience of a globally distributed coccolithophore to ocean acidification: Confirmed up to 2000 generations Texto completo
2016
Jin, Peng | Gao, Kunshan
Ocean acidification (OA), induced by rapid anthropogenic CO2 rise and its dissolution in seawater, is known to have consequences for marine organisms. However, knowledge on the evolutionary responses of phytoplankton to OA has been poorly studied. Here we examined the coccolithophore Gephyrocapsa oceanica, while growing it for 2000 generations under ambient and elevated CO2 levels. While OA stimulated growth in the earlier selection period (from generations 700 to 1550), it reduced it in the later selection period up to 2000 generations. Similarly, stimulated production of particulate organic carbon and nitrogen reduced with increasing selection period and decreased under OA up to 2000 generations. The specific adaptation of growth to OA disappeared in generations 1700 to 2000 when compared with that at 1000 generations. Both phenotypic plasticity and fitness decreased within selection time, suggesting that the species' resilience to OA decreased after 2000 generations under high CO2 selection.
Mostrar más [+] Menos [-]Potential effects of sediment contaminants on diatom assemblages in coastal lagoons of New Jersey and New York States Texto completo
2016
Potapova, Marina | Desianti, Nina | Enache, Mihaela
Sediment samples from the coastal lagoons and estuaries of New York and New Jersey were used to investigate the influence of contaminants on diatom assemblages. Multivariate analyses demonstrated correspondence between composition of diatom assemblages and concentrations of several metals and total PAH. The effects of the individual contaminants were difficult to disentangle because of the considerable correlations between their concentrations. The most conspicuous trend was the increase in the relative abundance of small centric planktonic diatoms in response to contamination and the corresponding decrease in the benthic flora. The high relative abundance of planktonic species on contaminated sediments apparently resulted not so much from their tolerance to pollution, but from the paucity of benthic species. A comparison of the assemblages on the surface and at the depth of approximately 8–10cm revealed a statistically significant temporal change in community composition towards planktonic diatoms.
Mostrar más [+] Menos [-]Spatial distribution of floating marine debris in offshore continental Portuguese waters Texto completo
2016
Sá, Sara | Bastos-Santos, Jorge | Araujo, Helder | Ferreira, Marisa | Duro, Virginia | Alves, Flávia | Panta-Ferreira, Bruno | Nicolau, Lídia | Eira, Catarina | Vingada, José
This study presents data on abundance and density of macro-floating marine debris (FMD), including their composition, spatial distribution and potential sources off continental Portugal. FMD were assessed by shipboard visual surveys covering ±252,833km2 until the 220nm limit. The FMD average density was 2.98items/km2 and abundance amounted to 752,740 items. Unidentified plastics constitute the major bulk of FMD (density=0.46items/km2; abundance=117,390 items), followed by styrofoam, derelict or lost materials from fisheries, paper/cardboard and wood material. The North sector of the area presents higher FMD diversity and abundances, probably as a result of the high number of navigation corridors and fisheries operating in that sector. Most FMD originate from local sources, namely discharges from vessels and derelict material from fisheries. Considering the identifiable items, cables and fishing lines were the only fishing related items among the top ten FMD items in Portuguese offshore waters.
Mostrar más [+] Menos [-]Occurrence and distribution of polycyclic aromatic hydrocarbons in mussels from the gulf of Naples, Tyrrhenian Sea, Italy Texto completo
2016
Mercogliano, Raffaelina | Santonicola, Serena | De Felice, Alessandra | Anastasio, Aniello | Murru, Nicoletta | Ferrante, Maria Carmela | Cortesi, Maria Luisa
To assess the potential impact of the industrial activity on food safety and risk for consumers, the aim of the study was to evaluate the levels of 14 polycyclic aromatic hydrocarbons (PAH) in 69 samples of wild and farm Mytilus galloprovincialis, collected in sites of coast of Gulf of Naples, Tyrrhenian Sea.All hydrocarbons were found in samples. Higher levels of pyrolytic PAHs were in wild than in farm mussels. Benzo(a)pyrene exceeded the Regulation (EC) n.835/11 levels of 1μg/kg in 15 samples (71.42%) of wild and 25 samples (65.79%) of farm mussels. System of sum of 4 hydrocarbons exceeded the law level in 15 samples (71.42%) of wild and 21 samples (55.26%) of farm mussels. Wild mussel levels showed a potential impact of pyrolytic sources of PAH on food safety. Occurrence of carcinogenic PAHs should be a cause for concern, in areas where the mussels are being farmed for human consumption.
Mostrar más [+] Menos [-]Preliminary assessment of post-Haiyan mangrove damage and short-term recovery in Eastern Samar, central Philippines Texto completo
2016
Primavera, J.H. | dela Cruz, M. | Montilijao, C. | Consunji, H. | dela Paz, M. | Rollon, R.N. | Maranan, K. | Samson, M.S. | Blanco, A.
Strong winds and storm surges from Typhoon Haiyan caused damage of US$12–15billion and >10,000 human casualties in central Philippines in November 2013. To validate a proposed government US$22million mangrove replanting program, mangrove damage and short-term recovery were surveyed in seven natural and planted mangrove sites in Eastern Samar province at 2.5month and 4.5month post-Haiyan. The preliminary assessment showed that natural mangroves (except for those directly hit by the storm) were recovering by means of tree sprouts and surviving seedlings and saplings compared to the devastated plantation. Likewise, tree mortality was higher in the plantation and natural forests hit by the storm surge, compared to more undamaged and partially damaged trees in natural mangroves. Hence the main recommendations to government are (1) to protect recovering mangroves by not releasing rehabilitation funds (that will inadvertently pay for clearing of live trees and for removal of seedlings), (2) to only plant in totally damaged sites (e.g., plantations), and (3) to only plant naturally dominant species, e.g., Sonneratia alba and Avicennia marina (instead of the popular Rhizophora apiculata, R. mucronata and R. stylosa).
Mostrar más [+] Menos [-]A combined input–output and sensitivity analysis of CO2 emissions in the high energy-consuming industries: A case study of China Texto completo
2016
Yuan, Rong | Zhao, Tao
This paper employed an input–output approach combined with a sensitivity analysis to explore the impact of technological changes on CO2 emissions in the high energy-consuming industries. In contrast to most papers in the literature, which focused on the changes between two input–output tables in two different periods, this study analyzed the sensitivity of variations in the quantity of emissions caused by small changes in technical coefficients. An indicator, namely TCE (technical coefficient elasticity), was established to identify the transactions between economic sectors which lead to a large impact on CO2 emissions in the high energy-consuming industries. Additionally, by analyzing factors affecting TCE, this paper divided TCE into structure-relevant TCE and technology-relevant TCE. Sectors have a higher structural TCE value because their products are much demanded by other sectors. Sectors have a higher technological TCE value because they have a large propensity to consume inputs which require many products of the high energy-consuming industries. Our results show that technical coefficients with a higher TCE value correspond to the direct requirements by the high energy-consuming industries themselves. However, the impacts of technological changes in the non-high energy-consuming industries on high energy-consuming industries cannot be overlooked, especially in Transportation industry, Construction industry and manufacturing industries. Several industries have a higher structural TCE value, thus, their influence on CO2 emissions in the high energy-consuming industries is related to a high level of demand of their respective products. However, several industries have a higher technological TCE value, thus, technology innovation will be more effective to decrease CO2 emissions. Therefore, different measures should be adopted for reducing CO2 emissions in the high energy-consuming industries according to different conditions.
Mostrar más [+] Menos [-]Diazo-coupling spectrophotometric determination of nitrogen oxides in the air Texto completo
2016
Huang, Yingying | Shi, Wenjian | Zhang, Caihong | Li, Liang | Wen, Haifeng
A new accurate, sensitive, rapid and convenient measurement for the determination of nitrogen oxides in the air was established. After being oxidized by chromium trioxide (CrO3), nitrogen oxides in the air existed in the form of NO2, then forming nitrite and nitrate after being absorbed by the alkaline aqueous solution. Under acidic condition, the diazo reaction is specific to the nitrite and primary aromatic amine. In this paper, the structure of diazo and coupling compounds were selected and tested through the experiments. The relationship between the azo compound's molecular structure and the sensitivity of the method as well as the electronic flow direction in the conjugated system of azo compounds were studied. A theory that conjugated system's electron cloud in azo compound's molecule flowed from coupling compounds to diazo compounds through nitrogen and nitrogen double bond was proposed. This theory had a guiding function for exploiting highly sensitive chromogenic agents. Furthermore, the conditions and methods of diazo reaction and coupling chromogenic reaction were investigated. A spectrophotometry that p-aminobenzenesulfonic acid as diazo compound and 2-amino-5-naphthol-7-sulfonic acid (J acid) as coupling compound for the determination of nitrogen oxides in the air was established. The maximum absorption wavelength of p-aminobenzenesulfonic acid-J acid azo compound was at 480 nm. And the molar absorptivity was 4.01 × 104 L mol−1 cm−1 with recovery of 98.5%–100.9% and R.S.D. of 1.82%. In addition, the determination limit of measurement was 0.017 mg m−3 nitrogen oxides and the determination range was 0.027–2.0 mg m−3 nitrogen oxides. This method can be easily applied to the determination of the nitrogen oxides in the air.
Mostrar más [+] Menos [-]Method and application of ocean environmental awareness measurement: Lessons learnt from university students of China Texto completo
2016
Umuhire, Marie Louise | Fang, Qinhua
Different studies have proved that enhancing public Ocean Environmental Awareness (OEA) will lead to increased public support for ocean environmental protection. Our study develops a questionnaire to investigate current levels of students’ OEA from three aspects including ocean environmental concerns, ocean environment knowledge and willingness to participate in ocean related activities. This questionnaire was applied to students from Xiamen University to understand the OEA of university students in China, of which there are few studies. Using data gathered from a random purposive sample, the OEA level of students in Xiamen University was investigated and then the influencing factors (education, geographical situation, age and gender etc.) were further analyzed. Findings suggest that most students are concerned about the ocean environment but their knowledge is not enough that makes the willingness to participate in ocean related actions limited as well. The results show there is an urgent need to improve students’ OEA.
Mostrar más [+] Menos [-]Circadian rhythm of a red-tide dinoflagellate Peridinium quadridentatum in the port of Veracruz, Gulf of Mexico, its thecal morphology, nomenclature and geographical distribution Texto completo
2016
Okolodkov, Yuri B. | Campos-Bautista, Guadalupe | Gárate Lizárraga, Ismael
A circadian rhythm of the dinoflagellate Peridinium quadridentatum was studied at a time-series station in the southwestern Gulf of Mexico, in May 2007. Different substrates (water column, the seagrass Thalassia testudinum, macroalgae, coral rubble and sandy sediment surface) were sampled at the site at 1.5–3.5m depth. In the samples of coral rubble, P. quadridentatum was scarce. In the water column, the species showed an abundance peak at 15:00. The cell abundance of P. quadridentatum in Thalassia samples increased from 15:00 until 18:00 (1.81×104cells/gsubstratewet weight), and then continuously decreased until 06:00. Changes in P. quadridentatum cell abundance on macroalgae followed the same trend as on Thalassia, with the maximal value at 18:00. The higher abundance of P. quadridentatum (up to 1.40×104cells/gSWW) in macroalgae samples showed the preference for seaweeds. P. quadridentatum has a neritic tropical–boreal distribution. A new combination is proposed: Peridinium quadridentatum var. trispiniferum.
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