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Resultados 1711-1720 de 5,149
Increased temperature but not pCO2 levels affect early developmental and reproductive traits of the economically important habitat-forming kelp Lessonia trabeculata Texto completo
2018
González, Claudio P. | Edding, Mario | Torres, Rodrigo | Manríquez, Patricio H.
The effects of ocean warming and ocean acidification on developmental and reproductive traits of Lessonia trabeculata were evaluated. Meiospores were cultured for 35 days in an experimental mesocosm where temperature (~15 and 19 °C) and partial CO2 pressure (pCO2, ~400 and 1300 μatm) were controlled. The results indicate that germination was reduced at 19 °C, whereas the increase of pCO2 only had effects at 15 °C. Likewise, the increase in temperature significantly affected the vegetative growth of female gametophytes. Sex ratio was not affected significantly by any of the variables studied. Fertility and reproductive success decreased by about 50% at 19 °C. The pCO2 levels had no significant effects on most early developmental traits. The results suggest that ocean warming or periodic warming events (e.g. an El Niño event) might affect the recruiting capacity of this or other similar species by affecting their early developmental stages.
Mostrar más [+] Menos [-]Intertidal geothermal hot springs as a source of trace elements to the coastal zone: A case study from Bahía Concepción, Gulf of California Texto completo
2018
Leal-Acosta, María Luisa | Shumilin, Evgueni | Mirlean, Nicolai | Baturina, Elena Lounejeva | Sánchez-Rodríguez, Ignacio | Delgadillo-Hinojosa, Francisco | Borges-Souza, José
We investigated the influence of the intertidal geothermal hot spring (GHS) on the biogeochemistry of trace elements in Santispac Bight, Bahía Concepción (Gulf of California). The geothermal fluids were enriched in As and Hg mainly in ionic form. The suspended particulate matter of the GHS had elevated enrichment factor (EF) >1 of As, Bi, Cd, Co, Cu, Mn, Mo, Sb, Sn, Sr, Ti, U and Zn. The sediment core from GHS1 had high concentration of As, Hg, Corg, S, V, Mo, and U and the extremely high EF of these elements at 8cm of the core. The maximum bioaccumulation of As and Hg was in seaweeds Sargassum sinicola collected near the GHS2. The results confirm the input of trace elements to the coastal zone in Bahía Concepción from geothermal fluids and the evident modification of the chemical composition of the adjacent marine environment.
Mostrar más [+] Menos [-]Cost effective and practically viable oil spillage mitigation: Comprehensive study with biochar Texto completo
2018
Kandanelli, Ramesh | Meesala, Lavanya | Kumar, Jatin | Raju, Chinthalapati Siva Kesava | Peddy, V.C Rao | Gandham, Sriganesh | Kumar, Pramod
Biochar is carbonaceous mass that is produced from pyrolysis or gasification of biomass. It is so far majorly explored for soil remediation application, but recently it has attracted a lot of interest because of its unexplored applications in the area of adsorption. In this work, detailed study on biochars produced from two different feeds (rice husk and saw dust), at two different temperatures (450 and 550°C) and two different rates (fast and slow) of pyrolysis are discussed for oil spill mitigation. Biochar is characterized in detail by various techniques such as FTIR, 13C CPMAS, FESEM, RAMAN, TGA to determine the structural composition and observe the extent of pyrolysis. Tests to assess the performance of produced biochars as sorbents for oil spill mitigation have been demonstrated. The as produced biochars selectively absorbed crude oil from oil/water biphasic mixtures in various capacities.
Mostrar más [+] Menos [-]PAHs contamination in edible gastropods from north Patagonian harbor areas Texto completo
2018
Primost, M.A. | Commendatore, M. | Torres, P.J. | Bigatti, G.
PAHs contamination in edible gastropods from north Patagonian harbor areas Texto completo
2018
Primost, M.A. | Commendatore, M. | Torres, P.J. | Bigatti, G.
PAHs are persistent pollutants released into the environment by fossil fuels burning and leak during petroleum operations. Associated with suspended particles upon entering marine ecosystem are accumulated by benthic fauna. Human exposure occurs mainly from ingestion such as gastropods consumption. The objective was to determine PAHs in sediments and in the marine gastropod Buccinanops globulosus in sites with different maritime and urban influences. In sampling sites located 20 km from the harbor, PAHs were non-detected; while in harbor gastropods, the level of PAH4 was exceeded according to international normative. Level of dibenzo[a,h]anthracene in sediments was between the ISQG and PEL. Since these are the first results of PAHs in edible gastropods in South America, we concluded that PAHs can be dangerous for consumers according to ingestion frequency. Integrative studies are necessary to evaluate the interaction among pollutants in maritime areas and the incidence in human health due to shellfish consumption.
Mostrar más [+] Menos [-]PAHs contamination in edible gastropods from north Patagonian harbor areas Texto completo
2018
Primost, Monica Angelina | Commendatore, Marta Graciela | Torres, Pablo Javier | Bigatti, Gregorio
PAHs are persistent pollutants released into the environment by fossil fuels burning and leak during petroleum operations. Associated with suspended particles upon entering marine ecosystem are accumulated by benthic fauna. Human exposure occurs mainly from ingestion such as gastropods consumption. The objective was to determine PAHs in sediments and in the marine gastropod Buccinanops globulosus in sites with different maritime and urban influences. In sampling sites located 20 km from the harbor, PAHs were non-detected; while in harbor gastropods, the level of PAH4 was exceeded according to international normative. Level of dibenzo[a,h]anthracene in sediments was between the ISQG and PEL. Since these are the first results of PAHs in edible gastropods in South America, we concluded that PAHs can be dangerous for consumers according to ingestion frequency. Integrative studies are necessary to evaluate the interaction among pollutants in maritime areas and the incidence in human health due to shellfish consumption. | Fil: Primost, Monica Angelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Tecnológica Nacional; Argentina | Fil: Commendatore, Marta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina | Fil: Torres, Pablo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina | Fil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina
Mostrar más [+] Menos [-]Organochlorine pesticides and polychlorinated biphenyls in the Bering flounder (Hippoglossoides robustus) from the Sea of Okhotsk Texto completo
2018
Lukyanova, Olga N. | Tsygankov, Vasiliy Yu | Boyarova, Margarita D.
The purpose of this study is to establish the presence of POPs in the Bering flounder (Hippoglossoides robustus) from the Sea of Okhotsk (North-West Pacific). Concentration of OCPs (α-HCH, β-HCH, γ-HCH, o,p′-DDT, p,p′-DDT, o,p′-DDD, p,p′-DDD, o,p′-DDE and p,p′-DDE) and PCBs (28, 52, 155, 101, 118, 143, 153, 138, 180, 207) in samples were measured by GC–MS and GC–ECD. The mean OCP concentrations in flounder from East and South areas of the Sea of Okhotsk were 99.8 ± 125.4 and 53.6 ± 40.5 ng/g lipid, respectively; PCB congeners – 112 ± 94.2 and 88.8 ± 50.8 ng/g lipid, respectively. POPs in fish tissue decreased in the order: PCBs > HCHs > DDTs. Our results indicate that consumers will have no health risk due to fish consumption from Sea of Okhotsk. OCP and PCB levels in the Sea of Okhotsk may be considered as background level for the North Pacific.
Mostrar más [+] Menos [-]Comparative Risk Assessment of spill response options for a deepwater oil well blowout: Part 1. Oil spill modeling Texto completo
2018
French-McCay, Deborah | Crowley, Deborah | Rowe, Jill J. | Bock, Michael | Robinson, Hilary | Wenning, Richard | Walker, Ann Hayward | Joeckel, John | Nedwed, Tim J. | Parkerton, Thomas F.
Oil spill model simulations of a deepwater blowout in the Gulf of Mexico De Soto Canyon, assuming no intervention and various response options (i.e., subsea dispersant injection SSDI, in addition to mechanical recovery, in-situ burning, and surface dispersant application) were compared. Predicted oil fate, amount and area of surfaced oil, and exposure concentrations in the water column above potential effects thresholds were used as inputs to a Comparative Risk Assessment to identify response strategies that minimize long-term impacts. SSDI reduced human and wildlife exposure to volatile organic compounds; dispersed oil into a large water volume at depth; enhanced biodegradation; and reduced surface water, nearshore and shoreline exposure to floating oil and entrained/dissolved oil in the upper water column. Tradeoffs included increased oil exposures at depth. However, since organisms are less abundant below 200 m, results indicate that overall exposure of valued ecosystem components was minimized by use of SSDI.
Mostrar más [+] Menos [-]Elevated concentrations of naturally occurring radionuclides in heavy mineral-rich beach sands of Langkawi Island, Malaysia Texto completo
2018
Khandaker, Mayeen Uddin | Asaduzzaman, Khandoker | Sulaiman, Abdullah Fadil Bin | Bradley, D.A. | Isinkaye, Matthew Omoniyi
Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide ⁴⁰K and the natural-series indicator radionuclides ²²⁶Ra and ²³²Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of ²²⁶Ra, ²³²Th and ⁴⁰K from 451±9 to 2411±65Bqkg⁻¹ (mean of 1478Bqkg⁻¹); 232±4 to 1272±35Bqkg⁻¹ (mean of 718Bqkg⁻¹) and 61±6 to 136±7Bqkg⁻¹ (mean of 103Bqkg⁻¹) respectively. Conversely, in white sands the respective values for ²²⁶Ra and ²³²Th were appreciably lower, at 8.3±0.5 to 13.7±1.4Bqkg⁻¹ (mean of 9.8Bqkg⁻¹) and 4.5±0.7 to 9.4±1.0Bqkg⁻¹ (mean of 5.9Bqkg⁻¹); ⁴⁰K activities differed insubstantially from that in black sands, at 85±4 to 133±7Bqkg⁻¹ with a mean of 102Bqkg⁻¹. The mean activity concentrations of ²²⁶Ra and ²³²Th in black sands are comparable with that of high background areas elsewhere in the world. The heavy minerals content gives rise to elevated ²²⁶Ra and ²³²Th activity concentrations in all of black sand samples. Evaluation of the various radiological risk parameters points to values which in some cases could be in excess of recommendations providing for safe living and working. Statistical analysis examines correlations between the origins of the radionuclides, also identifying and classifying the radiological parameters. Present results may help to form an interest in rare-earth resources for the electronics industry, power generation and the viability of nuclear fuels cycle resources.
Mostrar más [+] Menos [-]Trapping of plastics in semi-enclosed seas: Insights from the Bohai Sea, China Texto completo
2018
Li, Yanfang | Wolanski, Eric | Dai, Zhenfei | Lambrechts, Jonathan | Tang, Cheng | Zhang, Hua
Microplastics are abundant in semi-enclosed seas, presumably because of local trapping. To investigate this trapping effect, we confronted the SLIM plastic oceanography model with field data of the distribution of microplastics in the Bohai Sea, China. Seven source locations were selected to reveal the fate of plastic debris from industrial and domestic usages. The model predictions compared well with the observed distribution of microplastics, highlighting that most plastics were trapped in the Bohai Sea. The model suggests that microplastics distribution within the Bohai Sea both in the water and on the bottom varies seasonally with wind and currents and depends on a complex interaction between source locations, prevailing hydrodynamic conditions, degradation, settling and resuspension rates. Further field studies are warranted to enable the models to better parameterize the fate of microplastics, and particularly the accumulation zones, in other poorly flushed semi-enclosed seas worldwide, where microplastics should be classified as a persistent pollutant.
Mostrar más [+] Menos [-]Ingestion of plastic by fish: A comparison of Thames Estuary and Firth of Clyde populations Texto completo
2018
McGoran, Alexandra R. | Cowie, Phillip R. | Clark, Paul F. | McEvoy, James P. | Morritt, David
This study compared plastic ingestion between pelagic and benthic fish populations from two UK watersheds: the Thames Estuary and the Firth of Clyde. The alimentary canals of 876 individuals were examined. Of twenty-one estuarine species investigated, fourteen ingested plastics, including predator (fish) and prey (shrimp) species. Overall, 32% of organisms ingested plastic, mostly fibres (88% of total plastics). More flatfish (38%) ingested plastics than other benthic species (17%). In the Thames, more plastic was ingested by pelagic species (average number of plastic pieces ingested: 3.2) and flatfish (average number of plastic pieces ingested: 2.9) than by shrimp (average number of plastic pieces ingested: 1). More fish from the Clyde ingested plastic than similar Thames species (39% compared to 28% respectively); however, the average amount of plastic ingested did not differ between the sites.
Mostrar más [+] Menos [-]Contamination level, chemical fraction and ecological risk of heavy metals in sediments from Daya Bay, South China Sea Texto completo
2018
Liu, Jin-Jun | Ni, Zhi-Xin | Diao, Zeng-Hui | Hu, Yong-Xia | Xu, Xiang-Rong
Contamination level, chemical fraction and ecological risk of heavy metals in sediments from Daya Bay (DYB) were conducted in this study. The results revealed that the concentration of Cr, Cu, Zn, As, Cd and Pb in sediments were in the range of 36.38–90.33, 9.54–61.32, 33.54–207.33, 7.80–18.43, 0.13–0.43 and 15.89–30.01 mg kg−1, respectively, with bioavailable fractions of 13.29, 54.16, 47.60, 32.74, 68.14, 26.59%, respectively. A modified potential ecological risk index (MRI) was used for the ecological risk assessment, with ecological risk contribution ratios of 75.73, 14.29, 5.47, 1.74, 1.57 and 1.21% for Cd, As, Cu, Cr, Pb and Zn, respectively. The main contaminants were Cd and As, with their ecological risks “High” and “Moderate” levels, and their enrichment degrees “Moderately Severe” and “Moderate”, respectively. The multivariate statistical analysis suggested that the various anthropogenic activities along the bay might contribute mainly to the heavy metals contamination in DYB.
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