Seasonal Monitoring of Hydrocarbon Degraders in Alabama Marine Ecosystems Following the Deepwater Horizon Oil Spill   总被引：1，自引：0，他引：1  

Agota Horel  Behzad Mortazavi  Patricia A. Sobecky 《Water, air, and soil pollution》2012,223(6):3145-3154

Following the Deepwater Horizon explosion and crude oil contamination of a marsh ecosystem in AL in June 2010, hydrocarbon-degrader microbial abundances of aerobic alkane, total hydrocarbon, and polycyclic aromatic hydrocarbon (PAH) degraders were enumerated seasonally. Surface sediment samples were collected in October and December of 2010 and in April and July of 2011 along 40?C70-m transects from the high tide to the intertidal zone including Spartina alterniflora-vegetated marsh, seagrass (Ruppia maritima)-dominated sediments, and nonvegetated sediments. Alkane and total hydrocarbon degraders in the sediment were detected, while PAH degraders were below detection limit at all locations examined during the sampling periods. The highest counts for microbial alkane degraders were observed at the high tide line in April and averaged to 8.65?×?10⁵ of cells/g dry weight (dw) sediment. The abundance of alkane degraders during other months ranged from 9.49?×?10³ to 3.87?×?10⁴, while for total hydrocarbon degraders, it ranged between 5.62?×?10³ and 1.14?×?10⁵ of cells/g dw sediment. Pore water nutrient concentrations (NH ₄ ⁺ , NO ₃ ^? , NO ₂ ^? , and PO ₄ ^3? ) showed seasonal changes with minimum values observed in December and April and maximum values in October and July. Concentrations of total petroleum hydrocarbons in sediments averaged 100.4?±?52.4 and 141.9?±?57.5?mg/kg in January and July, 2011, respectively. The presence of aerobic microbial communities during all seasons in these nearshore ecosystems suggests that an active and resident microbial community is capable of mineralizing a fraction of petroleum hydrocarbons.  相似文献   

Effect of large dietary doses of beta-carotene on plasma retinoid and beta-carotene levels and on progesterone production in the granulosa cells of Japanese quail     

Pusztai A  Agota G  Bárdos L 《Acta veterinaria Hungarica》2000,48(1):81-87

An experiment was conducted to study the effect of large-dose beta-carotene supplementation on blood retinoid and beta-carotene levels as well as on the progesterone secretion of the granulosa cells in Japanese quail. Laying quails were assigned to three dietary groups. The control group (Group C) received the basal diet (laying feed containing 9000 IU vitamin A/kg). In the treated groups (Groups BC1 and BC2) the basal diet was supplemented with 10(2) and 10(3) mg/kg beta-carotene (BC), respectively. At the end of the two-week feeding period, 10 birds from each group were euthanised. Blood samples were analysed for retinol, retinyl palmitate and beta-carotene concentrations. Granulosa cells were isolated from ovarian follicles (F1 and F2), and PMSG-induced in vitro progesterone (P4) secretion was measured. Similar retinol concentrations were found in both beta-carotene supplemented groups, indicating saturation of the retinol-transporting system. beta-carotene supplementation was accompanied by hypercarotenaemia, but did not increase the retinyl palmitate levels in the blood. PMSG-induced P4 production of the granulosa cells decreased significantly in Groups BC1 and BC2 in a dose-dependent manner.  相似文献   

Modelling the impact of climate change on sediment yield in a highly erodible Mediterranean catchment   总被引：2，自引：0，他引：2  

Gianbattista Bussi  Félix Francés  Enguerrand Horel  José Andrés López-Tarazón  Ramón J. Batalla 《Journal of Soils and Sediments》2014,14(12):1921-1937

Purpose

The assessment of climate change impacts on the sediment cycle is currently a primary concern for environmental policy analysts in Mediterranean areas. Nevertheless, quantitative assessment of climate change impacts is still a complex task. The aim of this study was to implement a sediment model by taking advantage of sediment proxy information provided by reservoir bottom deposits and to use it for climate change assessment in a Mediterranean catchment.

Materials and methods

The sediment model was utilised in a catchment that drains into a large reservoir. The depositional history of the reservoir was reconstructed and used for sediment sub-model implementation. The model results were compared with gauged suspended sediment data in order to verify model robustness. Then, the model was coupled with future precipitation and temperature scenarios obtained from climate models. Climatological model outputs for two emission scenarios (A2 and B2) were simulated and the results compared with a reference scenario.

Results and discussion

Model results showed a general decrease in soil moisture and water discharge. Large floods, which are responsible for the majority of sediment mobilisation, also showed a general decrease. Sediment yield showed a clear reduction under the A2 scenario but increased under the B2 scenario. The computed specific sediment yield for the control period was 6.33 Mg ha^?1 year^?1, while for the A2 and B2 scenarios, it was 3.62 and 7.04 Mg ha^?1 year^?1, respectively. Furthermore, sediment transport showed an increase in its time compression, i.e. a stronger dependence of total sediment yield from the largest event contributions.

Conclusions

This study shows a methodology for implementing a distributed sediment model by exploiting reservoir sedimentation volumes. This methodology can be applied to a wide range of catchments, given the high availability of reservoir sedimentation data. Moreover, this study showed how such a model can be used in the framework of a climate change study, providing a measure of the impact of climate change on soil erosion and sediment yields.  相似文献   

Relationships between force-feeding and some physiological parameters in geese bred for fatty liver   总被引：2，自引：0，他引：2  

Janan J  Bódi L  Agota G  Bárdos L  Rudas P  Kozák J  Karsai M 《Acta veterinaria Hungarica》2000,48(1):89-97

The susceptibility of geese of different genotypes and sexes to force-feeding, some plasma biochemical parameters (thyroid hormones, cholesterol, retinoids, total protein and albumin) of force-fed geese, and the relationship between force-feeding, fat storage and the above-mentioned parameters were studied. Sixty (30 male and 30 female) geese of three genotypes (Hungarian, Landes and their crossbred called Babat Hybrid) were divided in two groups at 12 weeks of age. Geese in one group (5 males and 5 females from each genotype) received mixed feeding ad libitum. Birds in the other group were force-fed with maize. After 3 weeks all birds were bled, blood samples were taken, and the above-mentioned plasma parameters were determined. Thyroxine (T4) levels were significantly lower in force-fed (11.6 +/- 3.5 ng/ml) than in control geese (22.7 +/- 4.09 ng/ml). Plasma triiodothyronine (T3) level was also lower in the force-fed than in the control group, but the difference was not significant (1.87 +/- 0.23 ng/ml and 2.11 +/- 0.28 ng/ml, respectively). Plasma total protein (TP, 45.2 +/- 4.5 g/l), albumin (ALB, 16.51 +/- 2.8 g/l), beta-carotene (BC, 3504 +/- 3107 micrograms/l), retinol (ROL, 1160 +/- 505 micrograms/l), retinyl palmitate (RP, 1745 +/- 405 micrograms/l) and total cholesterol (TCh, 4.32 +/- 0.55 mmol/l) levels were elevated in the force-fed group as compared to the control (TP = 36.4 +/- 5.1 g/l, ALB = 15.6 +/- 0.9 g/l, BC = 1657 +/- 1681 micrograms/l, ROL = 687 +/- 375 micrograms/l, RP = 1398 +/- 607 micrograms/l, and TCh = 2.83 +/- 1.98 mmol/l). All differences were significant except those found for albumin and beta-carotene. No significant sex- or genotype-related effects were observed for these parameters.  相似文献   

Average evoked responses and learning     

J A Horel  C J Vierck  K H Pribram  D N Spinelli  E R John  D S Ruchkin 《Science (New York, N.Y.)》1967,158(799):394-395

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