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Determination of radioactivity levels and heavy metal concentrations in seawater, sediment and anchovy (Engraulis encrasicolus) from the Black Sea in Rize, Turkey Full text
2017
Baltas, Hasan | Kiris, Erkan | Sirin, Murat
Seawater, sediment and fish (anchovy) samples consumed in the Rize province of the Eastern Black Sea region of Turkey were collected from five different stations. The radioactivity levels (226Ra, 232Th, 40K and 137Cs) were determined in all the samples using a high-purity germanium detector. While 226Ra, 232Th and 40K radionuclides were detected in all samples, the radionuclide concentration of 137Cs, except for the sediment samples (mean activity is 9±1.4Bqkg−1), was not detected for the seawater and fish samples. The total annual effective dose rates from the ingestion of these radionuclides for fish were calculated using the measured activity concentrations in radionuclides and their ingested dose conversion factor. Also, the concentrations of some heavy metals in all the samples were determined. The activity and heavy metal concentration values that were determined for the seawater, sediment and fish samples were compared among the locations themselves and with literature values.
Show more [+] Less [-]A novel hybrid-Garch model based on Arima and SVM for PM2.5 concentrations forecasting Full text
2017
Wang, Ping | Zhang, Hong | Qin, Zuodong | Zhang, Guisheng
Air-quality forecasting is difficult because air quality time series are heterogeneous, consisting of one-dimension series data and multi-dimension panel data. Therefore, a hybrid forecasting model with both linear and nonlinear models may be appropriate to represent the complex behavior of a heterogeneous time series data set. In this paper, a new hybrid-Garch (Generalized Autoregressive Conditional Heteroskedasticity) methodology is proposed in order to integrate the individual forecasting models of the ARIMA (Autoregressive Integrated Moving Average) and SVM(Support Vector Machine). The hybrid-Garch approach for time series prediction is tested by 10-day hourly PM2.5 concentrations data including linear and non-linear, in Shenzhen, China. Empirical results from six station data sets indicate that: 1) the PM2.5 concentrations of Shenzhen experiences a regular fluctuation during the 24 h of the whole day with the peak value in working hours due to factory and vehicle emissions. 2) Spatial difference of PM2.5 concentrations is not noticeable because of the geographical and meteorological conditions. 3) The proposed hybrid model generates a more reliable and accurate forecast capability. 4) The proposed hybrid model analyses the time series data with possibly conditional heteroscedasticity characteristics and estimates the variance for the volatility of the PM2.5 concentrations.
Show more [+] Less [-]Seasonal variations and sources of sedimentary organic carbon in Tokyo Bay Full text
2017
Kubo, Atsushi | Kanda, Jota
Total organic carbon (TOC), total nitrogen (TN) contents, their stable C and N isotope ratio (δ13C and δ15N), and chlorophyll a ([Chl a]sed) of surface sediments were investigated monthly to identify the seasonal variations and sources of organic matter in Tokyo Bay. The sedimentary TOC (TOCsed) and TN (TNsed) contents, and the sedimentary δ13C and δ15N (δ13Csed and δ15Nsed) values were higher in summer than other seasons. The seasonal variations were controlled by high primary production in the water column and hypoxic water in the bottom water during summer. The fraction of terrestrial and marine derived organic matter was estimated by Bayesian mixing model using stable isotope data and TOC/TN ratio. Surface sediments in Tokyo Bay are dominated by marine derived organic matter, which accounts for about 69±5% of TOCsed.
Show more [+] Less [-]Fast assessment of bioaccessible metallic contamination in marine sediments Full text
2017
Terán-Baamonde, J. | Carlosena, A. | Soto-Ferreiro, R.M. | Andrade, J.M. | Prada, D.
A fast (16min) procedure to assess the bioaccessible metallic fraction of Cd, Cr, Cu, Ni, Pb and Zn simultaneously extracted (SEM) from marine sediments plus an indirect approach to determine acid volatile sulfides (AVS) are presented. For the extraction process magnetic agitation was compared with ultrasonic stirring (using a bath and a probe), and several stirring times were assayed. The proposed SEM procedure uses an ultrasonic probe and 1mL of HCl. It dramatically minimizes the turnaround time and the residues. AVS were evaluated as the difference between the amounts of sulphur in the solid residue after the extraction and total sulphur in the original sample. These procedures are fast, easy to implement and cost-effective to assess the potential risk posed by metals in marine sediments. They were tested using several CRMs and applied to sediments from two Galician Rias (NW Spain); their SEM-AVS differences indicated no biological risk.
Show more [+] Less [-]Microplastics in Baltic bottom sediments: Quantification procedures and first results Full text
2017
Zobkov, M | Esiukova, E
Microplastics in the marine environment are known as a global ecological problem but there are still no standardized analysis procedures for their quantification. The first breakthrough in this direction was the NOAA Laboratory Methods for quantifying synthetic particles in water and sediments, but fibers numbers have been found to be underestimated with this approach. We propose modifications for these methods that will allow us to analyze microplastics in bottom sediments, including small fibers. Addition of an internal standard to sediment samples and occasional empty runs are advised for analysis quality control. The microplastics extraction efficiency using the proposed modifications is 92±7%. Distribution of microplastics in bottom sediments of the Russian part of the Baltic Sea is presented. Microplastic particles were found in all of the samples with an average concentration of 34±10 items/kg DW and have the same order of magnitude as neighbor studies reported.
Show more [+] Less [-]Homing pigeons as a biomonitor for atmospheric PAHs and PCBs in Guangzhou, a megacity in South China Full text
2017
Pei, Yuanyuan | Halbrook, Richard S. | Li, Huizhen | Yau, Ching
The occurrence of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCBs) in urban atmosphere in Guangzhou, China were assessed using homing pigeons as a biomonitor. Contaminant concentrations in lung were significantly higher than those in liver and fat, indicating chemical uptake was mainly through respiratory route. Tricyclic PAHs and low chlorinated PCBs dominated composition of PAHs and PCBs in homing pigeons, similar as their composition in local atmosphere. Different age-dependent bioaccumulation patterns were noted for PAHs and PCBs. For 1-year old homing pigeons, higher levels of PAHs and PCBs in lung and liver tissues were probably ascribed to more intense flying than 5- and 10-year groups. Fat concentrations of PCBs were greater in aged pigeons than 1-year old pigeons, but PAH concentrations in fat slightly decreased in aged pigeons because of relatively fast biotransformation. Overall, homing pigeons could serve as a suitable biomonitor for urban atmospheric contaminants in coastal cities.Homing pigeons could serve as a good biomonitor for PAHs and PCBs in urban atmosphere, yet different biotransformation potential of the chemicals caused different bioaccumulation patterns in pigeon fat.
Show more [+] Less [-]The two facets of species sensitivity: Stress and disturbance on coralligenous assemblages in space and time Full text
2017
Montefalcone, Monica | Morri, Carla | Bianchi, Carlo Nike | Bavestrello, Giorgio | Piazzi, Luigi
Marine coastal ecosystems are affected by a vast array of human-induced disturbances and stresses, which are often capable of overwhelming the effects of natural changes. Despite the conceptual and practical difficulty in differentiating between disturbance and stress, which are often used interchangeably, the two terms bear different ecological meanings. Both are external agents, but the former causes mortality or physical damage (subtraction of biomass), whereas the latter causes physiological alteration (reduction in productivity). Sensitivity of marine organisms may thus have a dual connotation, being influenced in different ways by disturbance and by stress following major environmental change. Coralligenous assemblages, which shape unique biogenic formations in the Mediterranean Sea, are considered highly sensitive to change. In this paper, we propose a method to differentiate between disturbance and stress to assess the ecological status of the coralligenous assemblages. Disturbance sensitivity level (DSL) and stress sensitivity level (SSL) of the sessile organisms thriving in the coralligenous assemblages were combined into the integrated sensitivity level of coralligenous assemblages (ISLA) index. Changes in the coralligenous status were assessed in space, along a gradient of stress (human-induced pressures) at several sites of the western Mediterranean, and in time, from a long-term series (1961–2008) at Mesco Reef (Ligurian Sea) that encompasses a mass mortality event in the 1990s. The quality of the coralligenous assemblages was lower in highly urbanised sites than that in sites in both marine protected areas and areas with low levels of urbanisation; moreover, the quality of the assemblages at Mesco Reef decreased during the last 50years. Reduction in quality was mainly due to the increase in stress-tolerant and/or opportunist species (e.g. algal turfs, hydroids and encrusting sponges), the disappearance of the most sensitive macroalgae (e.g. Udoteaceae and erect Rhodophyta) and macro-invertebrates (e.g. Savalia savaglia, Alcyonium coralloides and Smittina cervicornis), and the appearance of invasive alien algal species. Although the specific indices of SSL or DSL well illustrated the changes in the spatial or temporal datasets, respectively, their integration in the ISLA index was more effective in measuring the change experienced by the coralligenous assemblages in both space and time.
Show more [+] Less [-]Restoring rocky intertidal communities: Lessons from a benthic macroalgal ecosystem engineer Full text
2017
Bellgrove, Alecia | McKenzie, Prudence F. | Cameron, Hayley | Pocklington, Jacqueline B.
As coastal population growth increases globally, effective waste management practices are required to protect biodiversity. Water authorities are under increasing pressure to reduce the impact of sewage effluent discharged into the coastal environment and restore disturbed ecosystems. We review the role of benthic macroalgae as ecosystem engineers and focus particularly on the temperate Australasian fucoid Hormosira banksii as a case study for rocky intertidal restoration efforts. Research focussing on the roles of ecosystem engineers is lagging behind restoration research of ecosystem engineers. As such, management decisions are being made without a sound understanding of the ecology of ecosystem engineers. For successful restoration of rocky intertidal shores it is important that we assess the thresholds of engineering traits (discussed herein) and the environmental conditions under which they are important.
Show more [+] Less [-]Organic matter in surface sediments from the Gulf of Mexico and South China Sea: Compositions, distributions and sources Full text
2017
Wang, Cuiping | Jia, Weili | Wang, Dong | Song, Zhiguang
Sediments from the Gulf of Mexico (GOM) and the South China Sea (SCS) were analyzed. The low δ13 C values of pentamethylicosane (PMIs) and fatty acids (−81.3 to −85.2‰) were found in only the S-1 sample collected from the GOM, indicating that methanogenic archaea associated with gas hydrate formation contributed to the sediment organic matter. Principle component analysis of fatty acids suggested that similar microbial biomass was found in the S-1, S-9, O-3 and O-5 samples. However, a comparison of the alkanes, fatty acids, and alcohols indicated that the percentage of n-alkan-2-ols in the S-1 sample from the GOM was the highest, while n-alkanes and n-fatty acids were the highest percentages in other samples from the GOM and SCS. This finding suggests that microbial species or the oxidation/reduction environment of the sample site of S-1 were different from those of the other samples. The present study provides a basis for detecting gas hydrate sites on the seafloor of the SCS.
Show more [+] Less [-]Seasonal changes in stress biomarkers of an exotic coastal species – Chaetopleura angulata (Polyplacophora) – Implications for biomonitoring Full text
2017
Madeira, Diana | Vinagre, Catarina | Mendonça, Vanessa | Diniz, Mário Sousa
Seasonal changes in stress biomarkers of an exotic coastal species – Chaetopleura angulata (Polyplacophora) – Implications for biomonitoring Full text
2017
Madeira, Diana | Vinagre, Catarina | Mendonça, Vanessa | Diniz, Mário Sousa
Knowledge on baseline values of stress biomarkers in natural conditions is urgent due to the need of reference values for monitoring purposes. Here we assessed the cellular stress response of the chiton Chaetopleura angulata in situ. Biomarkers commonly used in environmental monitoring (heat shock protein 70kDa, total ubiquitin, catalase, glutathione-S-transferase, superoxide-dismutase, lipid peroxidation) were analyzed in the digestive system, gills and muscle of C. angulata, under spring and summer conditions in order to assess seasonal tissue-specific responses. Season had an effect on all targeted organs, especially affecting the digestive system which displayed clear seasonal clusters. The respective Integrated Biomarker Response (IBR) showed a 7.2-fold seasonal difference. Muscle and gills showed similar IBRs between seasons making them appropriate organs to monitor chemical pollution as they were less responsive to seasonal variation. The most stable biomarkers in these organs were ubiquitin and superoxide-dismutase thus being reliable for monitoring purposes.
Show more [+] Less [-]Seasonal changes in stress biomarkers of an exotic coastal species – Chaetopleura angulata (Polyplacophora) – Implications for biomonitoring Full text
2017
Madeira, Diana | Vinagre, Catarina | Mendonça, Vanessa | Diniz, Mário S.
Knowledge on baseline values of stress biomarkers in natural conditions is urgent due to the need of reference values for monitoring purposes. Here we assessed the cellular stress response of the chiton Chaetopleura angulata in situ. Biomarkers commonly used in environmental monitoring (heat shock protein 70kDa, total ubiquitin, catalase, glutathione-S-transferase, superoxide-dismutase, lipid peroxidation) were analyzed in the digestive system, gills and muscle of C. angulata, under spring and summer conditions in order to assess seasonal tissue-specific responses. Season had an effect on all targeted organs, especially affecting the digestive system which displayed clear seasonal clusters. The respective Integrated Biomarker Response (IBR) showed a 7.2-fold seasonal difference. Muscle and gills showed similar IBRs between seasons making them appropriate organs to monitor chemical pollution as they were less responsive to seasonal variation. The most stable biomarkers in these organs were ubiquitin and superoxide-dismutase thus being reliable for monitoring purposes. | info:eu-repo/semantics/publishedVersion
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