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111.
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113.
Assessment of oxytetracycline and tetracycline antibiotics in manure samples in different cities of Khuzestan Province,Iran 总被引:2,自引:0,他引:2
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115.
This paper reports on the firstPhaeocystis sp. (hereafterPhaeocystis) bloom in the Arabian Gulf. Total lipids from threePhaeocystis colonies sampled in November 1987 and in March and May 1988, comprised ca 11.0% of the dry biomass. Triacylglycerols (TG) and/or free fatty acids (FA) predominated in the lipids of all three samples. Polar lipids consisted of mixtures of phospholipids and glycolipids. Diacylglycerotrimethylhomoserines (DGTH) were present in all extracts, whilst conventional phospholipids only occurred in low concentrations. The predominant glycolipids were monogalactosyldiacylglycerols (MGDG) digalactosyldiacylglycerols (DGDG), sulfoquinovosyldiacylglycerols (SQDG) and steryl glycosides (SG). The predominant fatty acids in the total lipids of all three samples were palmitic (16:0) and oleic (18:1) acids. Total lipids of the November sample contained the smallest proportion of palmitic and the largest of polyunsaturated fatty acids (PUFA) — especially C16. The proportion of PUFA was considerable in individual polar lipids. C16 PUFA were more common in individual polar lipid classes of the November and March samples than that of May. The concentration of constituent C18 PUFA was relatively low. PUFA with chains longer than 18 C atoms only occurred in very low concentrations, and were confined to certain polar and nonpolar lipid classes of the November sample only. 相似文献
116.
A Study of Plant Species Extinction in Singapore: Lessons for the Conservation of Tropical Biodiversity 总被引:5,自引:0,他引:5
I.M. Turner H.T.W. Tan Y.C. Wee Ali Bin Ibrahim P.T. Chew R.T. Corlett 《Conservation biology》1994,8(3):705-712
The native vascular plant flora of the Republic of Singapore has suffered the extinction of 594 out of a total 2277 species. These represent local, not global, species extinctions. Coastal habitats, including mangroves, have lost 39% of their species, while inland forests have last 29%. Epiphytic species (62% loss) appear particularly prone to extinction, which is reflected in a similar disposition exhibited by the Orchidaceae. Deforestation and disturbance have been the main cause of plant species extinction in Singapore. The rich mangrove epiphyte flora has been totally exterminated, and a number of tree species are reduced to populations of a few mature individuals. Many more species continue to survive than the species-area relationship would predict given the 99.8% loss of primary forest. This is interpreted as a result of the failure of equilibrium to be achieved yet in the remnant forest fragments, even after more than a century of isolation. Singapore's secondary forests appear to accrete plant diversity very slowly, even if contiguous with primary forest areas. We conclude that remnant fragments of primary tropical forest, even of very small size, can play a major role in the conservation of tropical biodiversity. The patterns of extinction observed in Singapore indicate that coastal and estuarine sites are in greatest demand for development and therefore must be given high priority for conservation despite their somewhat lower biodiversity. Epiphyte and orchid diversity appear to be very good indicators of the degree of disturbance suffered by a habitat in the humid tropics. 相似文献
117.
ABSTRACTThe present research aimed to determine the lowest levels of three heavy metals (Pb, Cd and Cu) to which the larvae of Southern House Mosquito, Culex quinquefasciatus are susceptible in water. The study also aimed to investigate the effects of these heavy metals on the development of Cx. quinquefasciatus at concentrations set by Pakistan Environmental Protection Agency (Pak-EPA) as permissible levels for liquid industrial effluents. The 2nd instar larvae of Cx. quinquefasciatus were exposed to different concentrations of Pb, Cd and Cu and their effects on oviposition preference, egg hatching rate and larval development were studied. The LC50 values of Pb, Cd and Cu were 12.6, 6.3 and 2.6?ppm, respectively. Gravid female mosquito adults deposited a significantly lower number of egg rafts in containers containing 0.50?ppm Pb or 1.0?ppm Cu in water. Each of the heavy metals in water resulted in significantly (p?<?0.05) lower egg hatching rate, prolonged time to pupation, lower pupation rate, prolonged time to adult emergence, lower adult emergence rate and higher female to male ratio. It is concluded that the 2nd instar larvae of Cx. quinquefasciatus are susceptible to Pak-EPA permissible levels of Pb, Cd and Cu in municipal and liquid industrial effluents. 相似文献
118.
Ali Mekki Fathi Aloui Sami Sayadi 《Journal of the Air & Waste Management Association (1995)》2019,69(7):867-877
Organic matter amendments have been proposed as a means to enhance soil carbon stocks on degraded soils, particularly under arid climate. Soil organic carbon (SOC) plays a critical role in terrestrial carbon cycling and is central to preserving soil quality. The effects of biowaste compost (BWC) on soil carbon storage were investigated. In addition, changes in soil organic matter (SOM) and even soil organic carbon (SOC) in BWC-amended soils following different applications were studied. The added BWC quantities were as followed: BWC/soil (weight/weight (w/w) respectively: 1/8, 1/4, and 1/2). The different BWC-amended soils were assessed during 180 days under arid ambient conditions and in comparison with control soil. Results showed a significant increase in SOM and SOC with relation to BWC quantities applied. This increase was relatively clear up to 120 days, after which decrease in SOM and SOC levels were observed. Furthermore, results showed improved microbiological activities of the amended soils in comparison with the control soil. This was reflected by the increase of the amended soils’ respirometric activities as cumulative carbon dioxide carbon (C-CO2) as function of incubation time and also in terms of specific respiration expressed as C-CO2/SOC ratios.
Implications: Mediterranean soils under arid climate such as Tunisian soils are poor in organic matter content. Biowastes are potential source for soil fertilization. Composting process is the best method for the stabilization of organic matter of diverse origins. The biowaste compost amendment improves the soil organic carbon storage and enhances the soil microbial activity. 相似文献
119.
Tripathi RD Vajpayee P Singh N Rai UN Kumar A Ali MB Kumar B Yunus M 《Chemosphere》2004,54(11):1581-1588
Plants of Cassia siamea Lamk were grown in garden soil (control), fly-ash (100%) and fly-ash amended by various ameliorants (cowdung manure, press-mud, garden soil; 1:1, w/w). The plants survived in fly-ash (100%) though their growth was less in comparison to the treatments. Fly-ash+press-mud (1:1, w/w) proved to be the best combination as growth (total biomass, leaf number, photosynthetic area, total chlorophyll and protein) was significantly high in this treatment followed by cowdung manure and garden soil. Leaves and roots accumulated significant amount of Cu, Zn, Ni and and Fe. However, the concentration of all the metals was more in roots than leaves except Ni. Although, fly-ash contains high amount of metals but the metal uptake was more in the plants grown in fly-ash+press-mud mixture. Inspite of high metal availability in fly-ash and press-mud mixture, plant growth was good. This might be attributed to the some metal detoxification mechanism active in this treatment. The present study concluded that C. siamea seems to be a suitable plant for developing a vegetation cover on fly-ash dumps. 相似文献
120.
Baseline study of methane emission from open digesting tanks of palm oil mill effluent treatment 总被引:1,自引:0,他引:1
Anthropogenic release of greenhouse gases, especially CO2 and CH4 has been recognized as one of the main causes of global warming. Several measures under the Kyoto Protocol 1997 have been drawn up to reduce the greenhouse gases emission. One of the measures is Clean Development Mechanisms (CDM) that was created to enable developed countries to cooperate with developing countries in emission reduction activities. In Malaysia, palm oil industry particularly from palm oil mill effluent (POME) anaerobic treatment has been identified as an important source of CH4. However, there is no study to quantify the actual CH4 emission from the commercial scale wastewater treatment facility. Hence, this paper shall address the CH4 emission from the open digesting tanks in Felda Serting Hilir Palm Oil Mill. CH4 emission pattern was recorded for 52 weeks from 3600 m3 open digesting tanks. The findings indicated that the CH4 content was between 13.5% and 49.0% which was lower than the value of 65% reported earlier. The biogas flow rate ranged between 0.8 l min−1 m−2 and 9.8 l min−1 m−2. Total CH4 emission per open digesting tank was 518.9 kg day−1. Relationships between CH4 emission and total carbon removal and POME discharged were also discussed. Fluctuation of biogas production was observed throughout the studies as a result of seasonal oil palm cropping, mill activities, variation of POME quality and quantity discharged from the mill. Thus only through long-term field measurement CH4 emission can be accurately estimated. 相似文献