Wastewater effluents from irrigation and the domestic and industrial sectors have serious impacts in deteriorating water quality in many rivers, particularly in areas under tidal influence. There is a need to develop an approach that considers the impact of human and natural causes of salinization. This study uses a multi-objective optimization–simulation model to investigate and describe the interactions of such impacts in the Shatt al-Arab River, Iraq. The developed model is able to reproduce the salinity distribution in the river given varying conditions. The salinity regime in the river varies according to different hydrological conditions and anthropogenic activities. Due to tidal effects, salinity caused by drainage water is seen to intrude further upstream into the river. The applied approach provides a way to obtain optimal solutions where both river salinity and deficit in water supply can be minimized. The approach is used for exploring the trade-off between these two objectives. 相似文献
Stochastic Environmental Research and Risk Assessment - While Stochastic Weather Generators (SWGs) are used intensively in climate and hydrological applications to simulate hydroclimatic time... 相似文献
The extension and structure of functional traits variation in response to different soil factors between invasive and native plants are poorly understood. Functional traits and soil factors of the invasive plant Amaranthus palmeri and its coexisting plant Polygonum orientale are investigated under three heterogeneous habitats: roadside (rs), wasteland (wl), and riverbank (rb) in Tianjin, China. The shoot dry weight (SDW) and leaf nitrogen (LN) of A. palmeri are significantly higher compared with P. orientale, while A. palmeri has significantly lower leaf dry weight (LDW), leaf area (LA), leaf carbon (LC), and leaf C/N ratio under different habitats. The larger phenotypic plasticity of A. palmeri is one of the important reasons for their successful invasion to heterogeneous habitats. Similarly, the soil water content (SWC) of both species shows a significant difference (p < 0.05) with maximum in riverbank habitat to lowest in roadside habitat. Soil N/P ratio, C/N ratio, and C/P ratio of rb habitats are significantly lower compared to wl and rs habitats (p < 0.05). A redundancy analysis indicates that SWC is the dominant soil factor affecting the functional traits of A. palmeri and P. orientale. However, A. palmeri forms an environmental adaptation strategy by changing traits of SDW, LN, and leaf C/N ratio, which is different from P. orientale by changing traits of LA and LDW. 相似文献
Oil from the Oligocene oil sands of the Lower Ganchaigou Formation in the Northern Qaidam Basin and the related asphaltenes was analyzed using bulk and organic geochemical methods to assess the organic matter source input, thermal maturity, paleo-environmental conditions, kerogen type, hydrocarbon quality, and the correlation between this oil and its potential source rock in the basin. The extracted oil samples are characterized by very high contents of saturated hydrocarbons (average 62.76%), low contents of aromatic hydrocarbons (average 16.11%), and moderate amounts of nitrogen–sulfur–oxygen or resin compounds (average 21.57%), suggesting that the fluid petroleum extracted from the Oligocene oil sands is of high quality. However, a variety of biomarker parameters obtained from the hydrocarbon fractions (saturated and aromatic) indicate that the extracted oil was generated from source rocks with a wide range of thermal maturity conditions, ranging from the early to peak oil window stages, which are generally consistent with the biomarker maturity parameters, vitrinite reflectance (approximately 0.6%), and Tmax values of the Middle Jurassic carbonaceous mudstones and organic-rich mudstone source rocks of the Dameigou Formation, as reported in the literature. These findings suggest that the studied oil is derived from Dameigou Formation source rocks. Furthermore, the source- and environment-related biomarker parameters of the studied oil are characterized by relatively high pristane/phytane ratios, the presence of tricyclic terpanes, low abundances of C27 regular steranes, low C27/C29 regular sterane ratios, and very low sterane/hopane ratios. These data suggest that the oil was generated from source rocks containing plankton/land plant matter that was mainly deposited in a lacustrine environment and preserved under sub-oxic to oxic conditions, and the data also indicate a potential relationship between the studied oil and the associated potential source rocks. The distribution of pristane, phytane, tricyclic terpanes, regular steranes and hopane shows an affinity with the studied Oligocene Lower Ganchaigou Formation oil to previously published Dameigou Formation source rocks. In support of this finding, the pyrolysis–gas chromatography results of the analyzed oil asphaltene indicate that the oil was primarily derived from type II organic matter, which is also consistent with the organic matter of the Middle Jurassic source rocks. Thus, the Middle Jurassic carbonaceous mudstones and organic rock mudstones of the Dameigou Formation could be significantly contributing source rocks to the Oligocene Lower Ganchaigou Formation oil sand and other oil reservoirs in the Northern Qaidam Basin.
In order to characterize the seasonal, bathymetric, and spatial distribution of the species, Palaemon adspersus, Palaemon elegans, and Crangon crangon, shrimps were sampled with a beam trawl in four stations at depths between 1 and 30 m from February 2002 to January 2004 on the Sinop Peninsula coasts of the southern Black Sea. One-way analysis of similarity (ANOSIM) results demonstrated that the caridean composition was significantly different (p < 0.001) between seasons and between sampling areas. No significant relationship of the caridean composition was evident between depth zones ranging from 1 to 30 m. These three carideans occurred together in 28.5% of the sampling occasions. Different seasonal migration pattern was evident for all the three species. Palaemon adspersus migrated inshore during relatively higher water temperatures, whereas C. crangon density decreased in the shallow waters during the same period, and P. elegans population was mostly observed at depth zones of 5–10 m and was only observed in the 30 m depth zone in winter. The abiotic factors that characterize the coexistence of these three carideans were primarily determined by the habitat types and bottom structures. 相似文献
On the western and southern margins of the sickle shaped Vindhyan basin of north Indian shield, there are basal Vindhyan mafic volcanic rocks referred to as Khairmalia volcanics and Jungel volcanics respectively. These volcanics vary in composition from low-Ti tholeiite to high-Ti alkali basalt showing close affinity with continental flood basalts (CFB) and ocean island basalts (OIB) respectively. The parental magmas of Khairmalia and Jungel alkali basalts were formed by different degrees of partial melting of a garnet lherzolite. The magma of Khairmalia tholeiites was generated by a relatively higher degrees of partial melting of a garnet + spinel lherzolite. The geochemical data coupled with available geological and geophysical data favour a rift type origin of this basin which evolved as a peripheral basin showing many similarities with Paleogene Himalayan foreland basin. The existing radiometric age data suggest that the origin of Vindhyan basin is linked with Aravalli–Satpura orogeny. At about 1800–1600 Ma collision occurred along the Aravalli-Delhi fold belt (ADFB) and Central Indian Tectonic Zone (CITZ) with west and south subduction respectively. During this process the subducting lithosphere suffered extensional deformation on its convex side and some pre-existing large faults in the already thin leading edge of subducted plate also reactivated and tapped magma generated by decompressional melting of the subcontinental mantle. The simultaneous processes such as flexural subsidence, reactivation of pre-existing faults, heating, thermal cooling and contraction during volcanism, resulted in the formation of curvilinear warp parallel to the emerging mountain front. The Lower Vindhyan volcano–sedimentary succession was deformed and exposed to erosion before the deposition of Upper Vindhyan rocks. The orogenic forces were active intermittently throughout the Vindhyan sedimentation. 相似文献
The objective of this research was to investigate the morphology, genesis and classification of organic soils formed on depression
and flat land around Lake Yenicaga, west-central Turkey. Formation of the area has been influenced by tectonic and karst
processes. This peatland is important in this area due to its extensive use as a horticultural plant growth medium resulting
from positive physical and chemical properties. Organic soils in the study area were formed in nutrient-rich conditions and
it is classified as typical basin peat. Four representative pedons were excavated in the study area based on extensive observations
performed with random grid method using an auger. Samples were taken from horizons in each profile for laboratory analyses.
Organic matter contents ranged from 12.5 to 91.5% across all four pedons. Fiber contents were between 4.3 and 91.5%, and N ranged from 0.56 to 2.19%. Cation exchange capacity ranged from 37 to 222 cmol kg−1, bulk density from 0.09 to 0.78 g cm−3, lime from 0.15 to 2.62%. The pH and ECe values ranged from 5.38 to 7.92 and 0.50 to 3.80 dS m−1, respectively. Sand, silt and clay contents of the organic soils ranged between 0.75–3.92, 40.70–74.77 and 24.15–57.30%,
respectively. Differences in organic soils were found to depend on the environment, botanical origins, decomposition degrees,
and groundwater composition. The organic soils of the research area were classified in the typic, hemic and hydric subgroups
of Medifibrists (Soil Taxonomy 1999). 相似文献
The coal quality is an important aspect of coal mine planning. This paper presents a case study in which an underground coal mine is faced with severe penalty cost because it does not consider in situ coal quality control at all. To help short term planning of the coal production the mean calorific values of the blocks inside the production panels are estimated by kriging. The estimated calorific values are compared with those obtained from actual production. The ratio of the calorific values of actual production to estimated values is found to be 0.73 in average due to adverse effect of dilution on the quality of run-of-mine coal. This study reveals the importance of geostatistical block modelling in short term mine planning. 相似文献
Groundwater is a crucial resource on the Manukan Island as it is the only source of freshwater available on the island. The aquifer has deteriorated to a high degree, during the last decade. Nine domestic wells were sam-pled from March 2006 to January 2007 to probe the hydrochemical components that influence the water quality. Geochemical data on dissolved major constituents in groundwater samples from the Manukan Island revealed the main processes responsible for their geochemical evolution. The results using statistical analyses, graphical method and numerical model output (PHREEQC) showed that the groundwater was chemically highly enriched in Na and Cl, indicative of seawater intrusion into the aquifer as also supported from the Na-Cl signature on the Piper diagram. From the PHREEQC simulation model, calcite, dolomite and aragonite solubility showed positive values of the saturation indices (SI), indicating supersaturation which led to mineral precipitation condition of water by these min-erals. 相似文献
