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1.
Trace metals are known to stimulate the activity of anaerobic methanogenic bacteria involved in the degradation of organic matter. The objective of this research was to investigate the effect of three trace metals, iron, nickel and cobalt on the activity of halophilic methanogens, digester sludge and a mixed culture of halophilic bacteria and digester sludge, at various salt concentrations. Iron slightly stimulated both initial and maximum specific methanogenic activity (SMA) of halophilic methanogens at all salt concentrations. Iron addition was also able to increase both initial and maximum SMA of the mixed culture. Iron could not stimulate either initial or maximum SMA of digester sludge at salt concentrations of more than 10 g/L. Adding cobalt showed no benefit on the initial and maximum SMA of halophilic methanogens. A slight increase in the initial SMA was observed in mixed culture when cobalt was injected to the system containing sodium concentrations of 10–30 g/L. At salt concentrations above 40 g/L, cobalt could stimulate the maximum SMA of mixed culture. No benefits were found when cobalt was added to the digester sludge at sodium concentrations higher than 20 g/L. Nickel was observed to increase the initial SMA of digester sludge at all salt concentrations, and the maximum SMA of mixed culture at salt concentrations of 30–50 g/L.  相似文献   
2.
Geochemical stream sediment survey in Winder Valley, Balochistan, Pakistan   总被引:1,自引:0,他引:1  
A pilot scale geochemical survey of sediments from the Winder Stream (SW Pakistan) and its tributaries was carried out. The Winder Stream mainly receives sediment from the southern extensions of the Mor and Pab Ranges in the District of Lasbela (Balochistan). In these two mountain ranges, rocks from Jurassic to Cretaceous age are exposed. Rocks of the Ferozabad Group comprise of carbonates and siliciclastics of Lower–Middle Jurassic age and occupy the dominant part of the Mor Range. These strata host syngenetic and epigenetic Zn–Pb–Ba mineralizations of Stratiform Sediment-Hosted (SSH) and Mississippi Valley Type (MVT) deposits.Quantitative estimates of mobile and immobile elements were made from active stream sediments of the Winder stream and its tributaries. The samples were analyzed for Ag, Zn, Pb, Cu, Ni, Co, V, Mn, Fe and Ba using atomic absorption spectroscopy. The abundance of these elements is discussed in relation to local geological conditions such as bedrock, climate, weathering, mobility and pH of the dispersing waters. A number of Zn anomalies have been distinguished in the study area. Kharrari (Zn, 360 ppm), Sand (Zn, 340 ppm) and Draber (Zn, 210 ppm) are demarcated as new areas for Zn mineralization. The present study also indicates prospects of Ag, Cu and V in the rocks of the Mor Range.Relationships between various elements have been identified from scattergrams and reflect genetic associations. Whereby the positive correlation between Cu–Zn (0.55, n=18) and Cu–Pb (0.63) is related to possible sulphide mineralization.  相似文献   
3.
Heavy metal concentrations were investigated in overbank sediments of the Mala Panew River, southern Poland. Samples were collected from seven vertical profiles located within channel infills of a 20th century floodplain at three sites, each up to 50 m wide. In each profile, 15–24 samples were collected and analysed for Ba, Cd, Cu, Pb, and Zn. Sequential extraction of these elements was carried out in the 0.063-mm fraction of selected samples. Additionally, the age of the oldest trees growing close to the profiles has been used to estimate the initiation of sediment accumulation there. Ba, Cu, and Pb, which occur mostly in less mobile, moderately reducible, and residual fractions, were used for sediment dating. Zn and Cd, which in 50–75% occur in the mobile exchangeable fraction, were not suitable for dating. Correlation of Ba, Cu, and Pb concentrations in vertical profiles with changes in the load of effluents discharged to the river showed abrupt changes in the thickness of the strongly polluted sediments across the floodplains. A comparison of the relative changes between heavy metal peaks in sediments of similar age in the different profiles suggests a variable rate of downward metal migration. In general, none of the heavy metals investigated seems to have been mobilised within the stratigraphic layers above the water table. In layers located at stratigraphically lower levels, the Zn and Cd peaks seem to migrate several centimetres to several decimetres down in the profile. In profiles inundated for several weeks every year, Zn and Cd, as well as the relatively less mobile Ba, Cu, and Pb, have migrated downward by several decimetres. The investigation shows that frequent fluctuations of the water table have blurred the original depositional metal patterns of metal concentrations within a period of less than 40 years.  相似文献   
4.
Nannorrhops ritchiana ( Mazari Palm) is a distinctive flora growing in the Saharo-Sindian region. It is well distributed on the ultramafic soil, derived from the Bela Ophiolite in the Khuzdar District, Balochistan, Pakistan. Quantitative estimation of Ca, Mg, Fe and Ni in soil and plant ash has been carried out. The constituents of plant ash have been discussed in relation to soil chemistry, pH, climate, mobility, average abundance in plant ash and exclusion mechanism of the flora. Relationship among Ca, Mg, Fe and Ni has been established using scattergrams to evaluate the biogeochemistry of the plant. High contents of Mg and high coefficient of biological absorption allow it to be classed as Mg-flora. Both Ca and Fe appeared to be antagonistic to Mg. The metal assemblage of N. ritchiana nicely reflected the nature of the bed rock as being serpentinized ultramafic, and its corresponding soils. Good exclusion mechanism of N. ritchiana did not allow it to absorb high Ni from the soil. Relatively high concentrations of Ni in N. ritchiana from the Baran Lak area can be used to localize Ni-mineralization in the study area. Statistical analyses, such as minimum, maximum, mean, mode, median, standard deviations, and coefficient of correlation, were also made to improve raw geochemical data and interpretations.  相似文献   
5.
INTRODUCTION Theinteractionofcomplextectonicphasesinthe IndusbasinduringtheCretaceoushasimpartedascal lopedoutlineinthesedimentarysequences.Thedevel opmentofdiversifiedsedimentaryformationsduringthe Cretaceousensuresexcellentsources(SembarandGoru formations)andreservoirs(MoghalKotandPabfor mations)forhydrocarbons.Numerousplaysandpros pectsofhydrocarbonareassociatedwiththeCretaceous system,consequentlytheIndusbasinisattractiveto petroleumexplorationcompaniesinPakistan(Sheikh andNa…  相似文献   
6.
Nannorrhops ritchiana (Mazari Palm) is a distinctive flora growing in the Saharo-Sindian region. It is well distributed on the ultramafic soil, derived from the Bela Ophiolite in the Khuzdar District, Balochistan, Pakistan. Quantitative estimation of Ca, Mg, Fe and Ni in soil and plant ash has been carried out. The constituents of plant ash have been discussed in relation to soil chemistry, pH, climate, mobility, average abundance in plant ash and exclusion mechanism of the flora. Relationship among Ca, Mg, Fe and Ni has been established using scattergrams to evaluate the biogeochemistry of the plant. High contents of Mg and high coefficient of biological absorption allow it to be classed as Mg-flora. Both Ca and Fe appeared to be antagonistic to Mg. The metal assemblage ofN. ritchiana nicely reflected the nature of the bed rock as being serpentinized ultramafic, and its corresponding soils. Good exclusion mechanism ofN. ritchiana did not allow it to absorb high Ni from the soil. Relatively high concentrations of Ni inN. ritchiana from the Baran Lak area can be used to localize Ni-mineralization in the study area. Statistical analyses, such as minimum, maximum, mean, mode, median, standard deviations, and coefficient of correlation, were also made to improve raw geochemical data and interpretations.  相似文献   
7.
Remotely sensed thermal infrared (TIR) data have been widely used to retrieve land surface temperature (LST). LST is an important parameter in the studies of urban thermal environment and dynamics. In the study, an attempt has been made using LANDSAT 8 thermal imagery to compute LST and the associated land cover parameters viz; land surface emissivity (LSE), normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI) and normalized difference water index (NDWI). Landsat 8 TIRS band 10 & 11 (thermal bands) during 21 Oct. 2016, 22 Nov.2016, 24 Dec. 2016 and 09 Jan. 2017 were processed for LST analysis. However, band 5 & band 4 of the imagery was processed for NDVI, band 6 & band 5 for NDBI and band 2 & band 5 for NDWI analysis. LST has been derived from both the bands 10 &11 and validated by in-situ observations on the date and time of satellite overpass from the study area. Band 10 derived LST have shown much temperature difference while comparing with the in-situ observations. However, LST derived from band 11 found similar & close to the in-situ measurements. Relationship between band 11 results and in-situ observed measurements were developed, which has showing a strong correlation with (r2 = 0.991). Land surface emissivity were also evaluated which shows variation in different land cover surfaces like vegetation, settlement, forest cover and water body. The study has proven that land surface temperature derived from satellite band 11 is the actual surface temperature of the study area.  相似文献   
8.
Malik  Anurag  Kumar  Anil  Kisi  Ozgur  Khan  Najeebullah  Salih  Sinan Q.  Yaseen  Zaher Mundher 《Natural Hazards》2021,105(2):1643-1662
Natural Hazards - Drought is a complex natural disaster that adversely affects human life and the ecosystem. A variety of drought indexes are available for monitoring meteorological drought events....  相似文献   
9.
With the ability of multibeam echo sounders (MBES) to measure backscatter strength (BS) as a function of true angle of insonification across the seafloor, came a new recognition of the potential of backscatter measurements to remotely characterize the properties of the seafloor. Advances in transducer design, digital electronics, signal processing capabilities, navigation, and graphic display devices, have improved the resolution and particularly the dynamic range available to sonar and processing software manufacturers. Alongside these improvements the expectations of what the data can deliver has also grown. In this paper, we identify these user-expectations and explore how MBES backscatter is utilized by different communities involved in marine seabed research at present, and the aspirations that these communities have for the data in the future. The results presented here are based on a user survey conducted by the GeoHab (Marine Geological and Biological Habitat Mapping) association. This paper summarises the different processing procedures employed to extract useful information from MBES backscatter data and the various intentions for which the user community collect the data. We show how a range of backscatter output products are generated from the different processing procedures, and how these results are taken up by different scientific disciplines, and also identify common constraints in handling MBES BS data. Finally, we outline our expectations for the future of this unique and important data source for seafloor mapping and characterisation.  相似文献   
10.
The site characteristics of Gulmarg, Kashmir at an altitude of about 2743.2 m above sea level is based on analysis of meteorological conditions, cloud cover, temperature, wind speed, wind direction, relative humidity and atmospheric pressure, etc. Analysis and characterization of meteorological conditions suggest that Gulmarg, Kashmir is a potential site for carrying out photometric as well as spectroscopic observations of celestial objects.  相似文献   
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