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Macrobenthos habitat potential mapping using GIS-based artificial neural network models
2013
Lee, Saro | Park, Inhye | Koo, Bon Joo | Ryu, Joo-Hyung | Choi, Jong-Kuk | Woo, Han Jun
This paper proposes and tests a method of producing macrobenthos habitat potential maps in Hwangdo tidal flat, Korea based on an artificial neural network. Samples of macrobenthos were collected during field work, and eight control factors were compiled as a spatial database from remotely sensed data and GIS analysis. The macrobenthos habitat potential maps were produced using an artificial neural network model. Macrobenthos habitat potential maps were made for Macrophthalmus dilatatus, Cerithideopsilla cingulata, and Armandia lanceolata. The maps were validated by compared with the surveyed habitat locations. A strong correlation between the potential maps and species locations was revealed. The validation result showed average accuracies of 74.9%, 78.32%, and 73.27% for M. dilatatus, C. cingulata, and A. lanceolata, respectively. A GIS-based artificial neural network model combined with remote sensing techniques is an effective tool for mapping the areas of macrobenthos habitat potential in tidal flats.
显示更多 [+] 显示较少 [-]Tracing organic matter removal in polluted coastal waters via floating bed phytoremediation
2013
Huang, Lingfeng | Zhuo, Jianfu | Guo, Weidong | Spencer, Robert G.M. | Zhang, Zhiying | Xu, Jing
Organic matter removal by cultured Sesuvium portulacastrum in constructed floating beds was studied during a 20day greenhouse experiment and an 8month field campaign in the polluted Yundang Lagoon (southeastern China). Experiments were traced via dissolved organic carbon (DOC) concentration, fluorescence excitation–emission matrix and absorption spectroscopy. Two ‘terrestrial’ humic-like, one ‘marine’ humic-like and one protein-like components were identified by parallel factor analysis. The ‘terrestrial’ humic-like and protein-like components, DOC and absorption coefficient (a280) decreased during the greenhouse experiment. The intensities of four fluorescence components were all reduced during the field experiment. These results demonstrate the clear potential of floating bed phytoremediation techniques for reducing organic pollution degree in brackish environments. The rhizosphere may play an important role during phytoremediation. Our results show that spectrophotometric measurements such as fluorescence provide a useful tool for examining the removal of different organic moieties during various bioremediation processes.
显示更多 [+] 显示较少 [-]Dispersion model evaluation of PM2.5, NOx and SO2 from point and major line sources in Nova Scotia, Canada using AERMOD Gaussian plume air dispersion model
2013
Gibson, Mark D. | Kundu, Soumita | Satish, Mysore
AERMOD was used to model the air dispersion of point and major line emissions of PM2.5 in Halifax and Pictou, NOX in Halifax and SO2 in Halifax, Sydney and Port Hawkesbury, Nova Scotia, Canada. Emission inventory data for 2004 were used in simulations within four, 50 km x 50 km, domains over annual, monthly and 1–hour averaging periods. Annual averaged surface concentration maps are reported. Modeled versus observed comparisons were made within each domain at the Government, National Air Pollution Surveillance (NAPS) monitoring sites (discrete receptors). Evaluation of the model was conducted on the annual, monthly and hourly results using a number of statistical methods that included R2, fractional bias, normalized mean square error and the fraction of predictions within a factor of two of the observations. The AERMOD model evaluation showed that there was good agreement between the modeled and observed SO2 concentration for the annual and monthly comparison but less skill at estimating the hourly comparisons for SO2 in Halifax and Sydney. AERMOD showed poor model skill at predicting SO2 in Port Hawkesbury over the same averaging periods. The model evaluation for PM2.5 in Halifax, PM2.5 in Pictou and NOX in Halifax showed poor agreements and model skill. The surface concentrations from the point and major lines sources in all domains from all metrics were found to be well below the National Air Quality Standards. AERMOD has shown its utility as a suitable model for conducting dispersion modeling from point and line sources in Nova Scotia with good model skill for estimating annual and monthly SO2 concentrations in Halifax and Sydney. The study highlights the validity of using emission inventory data to estimate the surface impact of major point and line sources within domains containing complex terrain, differing land use types and with large variability within the annual meteorology.
显示更多 [+] 显示较少 [-]Towards quantitative ecological risk assessment of elevated carbon dioxide levels in the marine environment
2013
de Vries, Pepijn | Tamis, Jacqueline E. | Foekema, Edwin M. | Klok, Chris | Murk, Albertinka J.
The environmental impact of elevated carbon dioxide (CO2) levels has become of more interest in recent years. This, in relation to globally rising CO2 levels and related considerations of geological CO2 storage as a mitigating measure. In the present study effect data from literature were collected in order to conduct a marine ecological risk assessment of elevated CO2 levels, using a Species Sensitivity Distribution (SSD). It became evident that information currently available from the literature is mostly insufficient for such a quantitative approach. Most studies focus on effects of expected future CO2 levels, testing only one or two elevated concentrations. A full dose-response relationship, a uniform measure of exposure, and standardized test protocols are essential for conducting a proper quantitative risk assessment of elevated CO2 levels. Improvements are proposed to make future tests more valuable and usable for quantitative risk assessment.
显示更多 [+] 显示较少 [-]Polybrominated diphenyl ethers in fat samples from White-chinned Petrels (Procellaria aequinoctialis) and Spectacled Petrels (P. conspicillata) off southern Brazil
2013
Cipro, Caio V.Z. | Colabuono, Fernanda I. | Taniguchi, Satie | Montone, Rosalinda C.
Polybrominated diphenyl ethers (PBDEs) have been gaining much visibility in environmental chemical studies due to their similarity to PCBs and growing reports of harmful effects. The fact that these contaminants have not yet undergone bans or restrictions on the global level underscores the need for data on their occurrence. In the present study, fat samples from 26 White-chinned Petrels (Procellaria aequinoctialis) and 3 Spectacled Petrels (P. conspicillata) collected dead ashore or as bycatch of longline fisheries in southern Brazil were analyzed to determine concentrations of seven congeners (IUPAC #28, 47, 99, 100, 153, 154 and 183). Concentrations of ΣPBDEs ranged from not detectable to 72.70ngg−1 (wet weight), comparatively lower than concentrations reported for seabird samples in northern hemisphere. The most detected congeners were 153, 154 and 183. This pattern is close to that previously reported for birds of the same group, but not those from the same region.
显示更多 [+] 显示较少 [-]Abundance of class 1–3 integrons in South Carolina estuarine ecosystems under high and low levels of anthropogenic influence
2013
Uyaguari, Miguel I. | Scott, Geoffrey I. | Norman, R Sean
The impact of human activity on the spread of antibiotic resistant bacteria throughout coastal estuarine ecosystems is not well characterized. It has been suggested that laterally transferred genetic agents, such as integrons, play a role in the spread of resistant bacteria throughout ecosystems. This study compares the distribution of three integron classes throughout a coastal estuarine ecosystem. To determine integron distribution patterns, DNA was extracted from sediment and water collected at seven sites throughout two estuaries with different levels of anthropogenic input and integrons analyzed using quantitative PCR. The data show that while all three integron classes are present, the relative abundance is different, with class 2 integrons significantly elevated in areas of high anthropogenic input and class 1 integrons elevated in areas of low input. Our results provide a foundation for using integron gene distribution as a biomarker of urban impact on antibiotic resistance gene flow and ecosystem health.
显示更多 [+] 显示较少 [-]Sedimentary PBDEs in urban areas of tropical Asian countries
2013
Kwan, Charita S. | Takada, Hideshige | Mizukawa, Kaoruko | Saha, Mahua | Rinawati, | Santiago, Evangeline C.
Polybrominated diphenyl ethers (PBDEs) were measured in surface sediment samples collected from urban canals or rivers in Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, Malaysia and Japan. The total PBDE concentrations in the sediments ranged from 0.83 to 3140ng/g dry wt. BDE-209 was predominant, ranging from 43% to 97% of total PBDEs, followed by nona-BDEs and some detectable concentrations of BDEs 47, 49, 99, 100, 153, 154 and 183. Sedimentary PBDE levels in Malaysia, Cambodia, the Philippines and Thailand were generally higher than those reported for highly industrialized countries. Spatial distribution of PBDEs indicated that inland sources may impact coastal areas. The presence of BDE congeners which are not contained in technical mixtures and the higher proportions of nona-BDEs relative to BDE-209 in the sediments were identified as indicators of debromination. BDE-209 was possibly debrominated under anaerobic conditions in some of the sediment samples.
显示更多 [+] 显示较少 [-]Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico
2013
Pettit, L.R. | Hart, M.B. | Medina-Sánchez, A.N. | Smart, C.W. | Rodolfo-Metalpa, R. | Hall-Spencer, J.M. | Prol-Ledesma, R.M.
Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74–207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution.
显示更多 [+] 显示较少 [-]Biodegradation of phenanthrene in bioaugmented microcosm by consortium ASP developed from coastal sediment of Alang-Sosiya ship breaking yard
2013
Patel, Vilas | Patel, Janki | Madamwar, Datta
A phenanthrene-degrading bacterial consortium (ASP) was developed using sediment from the Alang–Sosiya shipbreaking yard at Gujarat, India. 16S rRNA gene-based molecular analyses revealed that the bacterial consortium consisted of six bacterial strains: Bacillus sp. ASP1, Pseudomonas sp. ASP2, Stenotrophomonas maltophilia strain ASP3, Staphylococcus sp. ASP4, Geobacillus sp. ASP5 and Alcaligenes sp. ASP6. The consortium was able to degrade 300ppm of phenanthrene and 1000ppm of naphthalene within 120h and 48h, respectively. Tween 80 showed a positive effect on phenanthrene degradation. The consortium was able to consume maximum phenanthrene at the rate of 46mg/h/l and degrade phenanthrene in the presence of other petroleum hydrocarbons. A microcosm study was conducted to test the consortium’s bioremediation potential. Phenanthrene degradation increased from 61% to 94% in sediment bioaugmented with the consortium. Simultaneously, bacterial counts and dehydrogenase activities also increased in the bioaugmented sediment. These results suggest that microbial consortium bioaugmentation may be a promising technology for bioremediation.
显示更多 [+] 显示较少 [-]Assessing the damage caused by Deepwater Horizon: Not just another Exxon Valdez
2013
Perrons, Robert K.
In light of the high stakes of the Deepwater Horizon civil trial and the important precedent-setting role that the case will have on the assessment of future marine disasters, the methodologies underpinning the calculations of damage on both sides will be subjected to considerable scrutiny. Despite the importance of the case, however, there seems to be a pronounced lack of convergence about it in the academic literature. Contributions from scientific journals frequently make comparisons to the Ixtoc I oil spill off the coast of Mexico in 1979; the legal literature, by stark contrast, seems to be much more focused on the Exxon Valdez spill that occurred off the shores of Alaska in 1989. This paper accordingly calls for a more thorough consideration of other analogs beyond the Exxon Valdez spill—most notably, the Ixtoc I incident—in arriving at an assessment of the damage caused by the Deepwater Horizon disaster.
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