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Decrease in osmotically driven water flux and transport through mangrove roots after oil spills in the presence and absence of dispersants Full text
2015
Tansel, Berrin | Arreaza, Ariadna | Tansel, Derya Z. | Lee, Mengshan
The objective of this study was to evaluate the effect of crude oil on water transport through mangroves roots in the presence and absence of dispersants. Water transport through the roots were evaluated experimentally using red mangrove root segments exposed to salt water contaminated with Louisiana crude oil for seven days in the presence and absence of Corexit 9500A (dispersant). Experimental observations were interpreted in view of the structural integrity and fouling phenomena observed on the epidermis and endodermis layers of the roots. The effects of oil on the radial water flux through the epidermis and endodermis were analyzed using a dual layer filtration model. Progression of fouling due to accumulation and penetration of the contaminants through the root layers were interpreted in relation to observed mangrove health (long and short term effects) reported in the literature.
Show more [+] Less [-]Changes to the biomass and species composition of Ulva sp. on Porphyra aquaculture rafts, along the coastal radial sandbank of the Southern Yellow Sea Full text
2015
Huo, Yuanzi | Han, Hongbin | Shi, Honghua | Wu, Hailong | Zhang, Jianheng | Yu, Kefeng | Xu, Ren | Liu, Caicai | Zhang, Zhenglong | Liu, Kefu | He, Peimin | Ding, Dewen
Compositions, changes and biomass of attached Ulva species on Porphyra rafts along the radial sandbank in the Yellow Sea were investigated, and potential contributions to green tides was analyzed. Ulva prolifera, Ulva flexuosa and Ulva linza were all appeared throughout the investigated period. U. prolifera and U. flexuosa dominated attached Ulva population on Porphyra rafts. Attached Ulva species biomass showed obviously spatial and temporal variations. Temperature, Ulva microscopic propagules and human activities were main factors to influence attached Ulva species biomass. The total attached Ulva species biomass was more than 20,000 fresh weight tons in April, and the green tide causative species U. prolifera accounted 51.03% in April 2013 before green tides occurred. The high biomass of attached Ulva species would contribute most to green tides in the Yellow Sea. But how attached Ulva species on Porphyra rafts contributing to green tides in the Yellow Sea should be further studied.
Show more [+] Less [-]Persistent organic pollutants and polycyclic aromatic hydrocarbons in mosses after fire at the Brazilian Antarctic Station Full text
2015
Colabuono, Fernanda Imperatrice | Taniguchi, Satie | Cipro, Caio Vinícius Zecchin | da Silva, Josilene | Bícego, Márcia Caruso | Montone, Rosalinda Carmela
A fire at the Brazilian Antarctic Station on February 25th, 2012 led to the burning of material that produced organic pollutants. To evaluate the impact in the surrounding area, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs) were analyzed in moss samples collected in the vicinities of the station before and after the incident and compared to findings from previous studies in the same region. PCBs were on the same magnitude as that reported in previous studies, which could be associated to the global dispersion of these compounds and may not be related to the local fire. In contrast, concentrations of HCB and PAHs were higher than those reported in previous studies. No PBDEs were found above the method detection limit. Organic contaminant concentrations in mosses decreased a few months after the fire, which is an important characteristic when considering the use of mosses for monitoring recent exposure.
Show more [+] Less [-]Hypoxia in a transient estuary caused by summer lake-water discharge from artificial dykes into Chunsu Bay, Korea Full text
2015
Jung, Kwang Young | Ro, Young Jae | Choi, Yang Ho | Kim, Baek Jin
We investigated bottom-water hypoxia induced by freshwater discharge from two artificial dykes into Chunsu Bay (CSB), Korea, during the summer of 2010. Field observations and model results of the dynamic and water-quality parameters indicated that the triggering mechanism of the hypoxia was strong stratification formed by the freshwater discharge from both dykes, which limited the dissolved oxygen (DO) supply in bottom water. Beneath the pycnocline, DO was consumed by sediment oxygen demand (SOD) during the summer. To investigate these processes, model experiments were conducted using a simplified DO budget model coupled with a 3D hydrodynamic model. The DO concentration in the northern part of CSB reached hypoxic conditions very quickly after 3.4days of discharge and lasted 18days until normal conditions resumed. In sum, in the CSB, marked stratification and its maintenance played a critical role in hypoxia in bottom water.
Show more [+] Less [-]The use of diagnostic ratios, biomarkers and 3-way Kohonen neural networks to monitor the temporal evolution of oil spills Full text
2015
Fernández-Varela, R. | Gómez-Carracedo, M.P. | Ballabio, D. | Andrade, J.M.
Oil spill identification relies usually on a wealth of chromatographic data which requires advanced data treatment (chemometrics). A simple approach based on Kohonen neural networks to handle three-dimensional arrays is presented. A suite of 28 diagnostic ratios was considered to monitor six oils along four months. It was found that some traditional diagnostic ratios were not stable enough. In particular, alkylated PAHs (e.g. 1-methyldibenzothiophene, 4-methylpyrene, 27bbSTER and the TA21 and TA26 triaromatic steroids) seemed less resistant to medium-weathering than biomarkers. One (or two) ratios were found to differentiate each product: 30O, 28ab (and 25nor30ab), C3-dbt/C3-phe, 27Ts, TA26 and 29Ts characterized Ashtart, Brent, Maya, Sahara, IFO and Prestige oils, respectively.
Show more [+] Less [-]Biomass burning emissions contaminate winter snowfalls in urban Beijing: A case study in 2012 Full text
2015
You, Chao | Gao, Shaopeng | Xu, Chao
Three monosaccharide anhydrides levoglucosan, mannosan and galactosan were detected in winter snowfall samples of 2012 in urban Beijing. Concentrations of three isomers vary from 0.15 to 54.43ngmL−1, with an average value of 10.49ngmL−1. Levoglucosan is the most abundant component. Winter snowfalls are contaminated by biomass burning emissions seriously in urban Beijing. The main sources are softwood and crop residue burnings around Beijing from late autumn to early winter, while long-range transport of biomass burning emissions contribute more during the late winter. Concentrations of monosaccharide anhydrides in snowfall samples may be affected by both topography and the meteorological conditions around urban Beijing.
Show more [+] Less [-]Micronucleus test in fishes as indicators of environmental quality in subestuaries of the Río de la Plata (Uruguay) Full text
2015
Gutiérrez, Juan Manuel | Villar, Silvia | Acuña Plavan, Alicia
Genotoxic agents may exert damage that may be active through following generations. Micronuclei are cytoplasmic chromatin masses outside the main cell nucleus, indicators of chromosomal damage. This study applied micronuclei test to evaluate genetic damage of fish in three breeding and nursery areas of commercially important fishes exposed to differing degrees of anthropogenic impact: Pando, Solís Chico and Solís Grande sub-estuaries. The micronuclei test revealed differences in the presence and concentrations of genotoxic components in these sub-estuaries. Fish in the urban and industrialized Pando sub-estuary presented the highest percentages of micronuclei. The absence of seasonal changes in micronuclei in Pando fish could be explained by physical characteristics of the sub-estuary and by regional weather conditions. Odontesthes argentinensis (Valenciennes, 1835) was the species most susceptible to genotoxic components. It is recommended the use of a battery of biomarkers to better explain the health of organisms in that important nursery area.
Show more [+] Less [-]Comparative analysis of modeled nitrogen removal by shellfish farms Full text
2015
Rose, Julie M. | Bricker, Suzanne B. | Ferreira, Joao G.
The use of shellfish aquaculture for nutrient removal and reduction of coastal eutrophication has been proposed. Published literature has indicated that nitrogen contained in harvested shellfish can be accurately estimated from shell length:nitrogen content ratios. The range of nitrogen that could be removed by a typical farm in a specific estuarine or coastal setting is also of interest to regulators and planners. Farm Aquaculture Resource Management (FARM) model outputs of nitrogen removal at the shellfish farm scale have been summarized here, from 14 locations in 9 countries across 4 continents. Modeled nitrogen removal ranged from 105lbsacre−1year−1 (12gm−2year−1) to 1356lbsacre−1year−1 (152gm−2year−1). Mean nitrogen removal was 520lbsacre−1year−1 (58gm−2year−1). These model results are site-specific in nature, but compare favorably to reported nitrogen removal effectiveness of agricultural best management practices and stormwater control measures.
Show more [+] Less [-]The English Channel: Contamination status of its transitional and coastal waters Full text
2015
Tappin, A.D. | Millward, G.E.
The chemical contamination (organic compounds, metals, radionuclides, microplastics, nutrients) of English Channel waters has been reviewed, focussing on the sources, concentrations and impacts. River loads were only reliable for Pb, whereas atmospheric loads appeared robust for Cd, Pb, Hg, PCB-153 and γ-HCH. Temporal trends in atmospheric inputs were decreasing. Contaminant concentrations in biota were relatively constant or decreasing, but not for Cd, Hg and HBCDD, and deleterious impacts on fish and copepods were reported. However, data on ecotoxicological effects were generally sparse for legacy and emerging contaminants. Intercomparison of activity concentrations of artificial radionuclides in sediments and biota on both Channel coasts was hindered by differences in methodological approaches. Riverine phosphate loads decreased with time, while nitrate loads remained uniform. Increased biomass of algae, attributable to terrestrial inputs of nutrients, has affected benthic production and shellfisheries. A strategic approach to the identification of contaminant impacts on marine biota is recommended.
Show more [+] Less [-]Diving behaviour of wildlife impacted by an oil spill: A clean-up and rehabilitation success? Full text
2015
Chilvers, B.L. | Morgan, K.M. | Finlayson, G. | Sievwright, K.A.
The value of rehabilitating oiled wildlife is an on-going global debate. On October 5, 2011, the cargo vessel C/V Rena grounded on Astrolabe Reef, New Zealand (NZ), spilling over 300 tonnes of heavy fuel oil. As part of the Rena oil spill response, 383 little blue penguins (LBP, Eudyptula minor) were captured, cleaned, rehabilitated and released back into a cleaned environment. This research investigates foraging behaviour changes due either to the oil spill or by the rehabilitation process by comparing the diving behaviour of rehabilitated (n=8) and non-rehabilitated (n=6) LBPs and with LBP populations throughout NZ. Stabile isotope analysis of feathers was also used to investigate diet. There were no foraging behaviour differences between rehabilitated and non-rehabilitated LBPs and the overall diving behaviour of these LBPs have similar, if not less energetic, foraging behaviour than other LBPs in NZ. This suggests the rehabilitation process and clean-up undertaken after the Rena appears effective and helps justify the rehabilitation of oiled wildlife across the world.
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