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941.
Lowe et al. (Estuaries and Coasts, 34:630–639, 2011) hypothesized that juvenile southern flounder Paralichthys lethostigma
(Jordan and Gilbert 1884) would migrate from the Gulf of Mexico into the Mobile-Tensaw River Delta (AL, USA) and use low-salinity
(oligohaline/freshwater) habitats during, at least, a portion of their first year of life. Thus, they analyzed the Sr/Ca ratio
profiles along the sagittal otoliths of southern flounder collected in the Mobile-Tensaw River Delta and observed that one
third of the flounders had low Sr/Ca levels in the otoliths’ core and throughout the otolith, suggesting that these fishes
hatched in freshwater or low-salinity habitats where they spend the majority of their life. The other two thirds of southern
flounder showed high levels of Sr/Ca ratio in the otoliths’ core following a marked decline of Sr/Ca ratio, which then maintained
along the remainder of the otolith. This pattern was interpreted as larvae hatched in higher salinity waters before entering
the Mobile-Tensaw River Delta; however, in this paper, I list several arguments to support an alternative interpretation for
this pattern. I suggest that the high levels of Sr/Ca ratios in the otoliths’ core of southern flounder does not reflect the
saline conditions where larvae hatched, instead it reflects the location where the female progenitor hydrated the eggs. Thus,
adding my interpretation on the data of Lowe et al. (Estuaries and Coasts, 34:630–639, 2011), it seems that southern flounder
might hatch in or near freshwater habitats and the migration of southern flounder into an estuarine ecosystem to spawn might
exist. 相似文献
942.
Y. Pousada-Ferradás S. Seoane-Labandeira A. Mora-Gutierrez A. Nú?ez-Delgado 《International Journal of Environmental Science and Technology》2012,9(1):21-29
The purpose of this work was to study the risks of water pollution due to the use of mixtures containing wood ash and sewage sludge. Mixtures including sludge and ash may be recycled as fertilizers, and they are economical as they do not integrate commercial limes, but Escherichia coli counts may keep significantly high in such mixtures, because their pH is not alkaline enough. In view of that, it seems interesting to study the E. coli survival in lixiviate from ash?Csludge mixtures including limes rather than from ash?Csludge mixtures alone. Two kinds of experiments were performed using laboratory column trials under saturated flow conditions. The first experiment investigated the chemical leaching behaviour of a mixture of 70% timber-industry wood ashes and 30% urban sewage sludge (% dry weight) at doses equivalent to 10 and 30?Mg/ha. The second experiment studied the survival of E. coli in lixiviates generated from 30?Mg/ha of a mixture consisting in 75% wood ash, 20% sewage sludge and 5% quicklime (% dry weight). In the first experiment, admixture of the ash and sludge achieved a stabilization of elements such as aluminium, iron, magnesium, nickle, carbon monoxide, cadmium, chromium and molybdenum that reduced their solubility compared with that in the ash or sludge alone. Significant solubilisation of heavy metals was not observed, with overall minor risk of chemical water pollution. In the second experiment, although including quicklime E. coli counts were still detected in the lixiviate, indicating risk of water contamination. 相似文献
943.
Jens-Olaf?DelfsEmail author Frank?Blumensaat Wenqing?Wang Peter?Krebs Olaf?Kolditz 《Environmental Earth Sciences》2012,65(5):1439-1457
This paper presents the hydrological coupling of the software framework OpenGeoSys (OGS) with the EPA Storm Water Management
Model (SWMM). Conceptual models include the Saint Venant equation for river flow, the 2D Darcy equations for confined and
unconfined groundwater flow, a two-way hydrological coupling flux in a compartment coupling approach (conductance concept),
and Lagrangian particles for solute transport in the river course. A SWMM river–OGS aquifer inter-compartment coupling flux
is examined for discharging groundwater in a systematic parameter sensitivity analysis. The parameter study involves a small
perturbation (first-order) sensitivity analysis and is performed for a synthetic test example base-by-base through a comprehensive
range of aquifer parametrizations. Through parametrization, the test cases enables to determine the leakance parameter for
simulating streambed clogging and non-ocillatory river-aquifer water exchange rates with the sequential (partitioned) coupling
scheme. The implementation is further tested with a hypothetical but realistic 1D river–2D aquifer model of the Poltva catchment,
where discharging groundwater in the upland area affects the river–aquifer coupling fluxes downstream in the river course
(propagating feedbacks). Groundwater contribution in the moving river water is numerically determined with Lagrangian particles.
A numerical experiment demonstrates that the integrated river–aquifer model is a serviceable and realistic constituent in
a complete compartment model of the Poltva catchment. 相似文献
944.
Frank?DethlefsenEmail author Christoph?Haase Markus?Ebert Andreas?Dahmke 《Environmental Earth Sciences》2012,65(4):1105-1117
One of the uncertainties in the field of carbon dioxide capture and storage (CCS) is caused by the parameterization of geochemical
models. The application of geochemical models contributes significantly to calculate the fate of the CO2 after its injection. The choice of the thermodynamic database used, the selection of the secondary mineral assemblage as
well as the option to calculate pressure dependent equilibrium constants influence the CO2 trapping potential and trapping mechanism. Scenario analyses were conducted applying a geochemical batch equilibrium model
for a virtual CO2 injection into a saline Keuper aquifer. The amount of CO2 which could be trapped in the formation water and in the form of carbonates was calculated using the model code PHREEQC.
Thereby, four thermodynamic datasets were used to calculate the thermodynamic equilibria. Furthermore, the equilibrium constants
were re-calculated with the code SUPCRT92, which also applied a pressure correction to the equilibrium constants. Varying
the thermodynamic database caused a range of 61% in the amount of trapped CO2 calculated. Simultaneously, the assemblage of secondary minerals was varied, and the potential secondary minerals dawsonite
and K-mica were included in several scenarios. The selection of the secondary mineral assemblage caused a range of 74% in
the calculated amount of trapped CO2. Correcting the equilibrium constants with respect to a pressure of 125 bars had an influence of 11% on the amount of trapped
CO2. This illustrates the need for incorporating sensitivity analyses into reaction pathway modeling. 相似文献
945.
946.
Evaluation of the water resource reproducible ability on Tarim River Basin in south of Xinjiang,northwest China 总被引:1,自引:1,他引:0
With the over-exploitation of water resources, water pollution and poor management of water infrastructures are exacerbated.
Ecosystem degradation is apparent at the basin level. The Tarim River Basin in northwest China has seen intensive confrontation
between environmental protection and economic development over the past five decades. Ambitious agricultural development and
land reclamation projects implemented by the Chinese government in the early 1960s led to several influences. For example,
the construction of dams like the Daxihaizi Reservoir disrupted the stream-flow to the lower reaches. Water resource reproducible
ability (WRRA) refers to the ability of water resources to be continually added by the natural water cycle. It includes the
supplementation of water quantity and the self-purification of water quality in the natural cycle of water resources. This
study discusses the WRRA index and introduces the computational method for calculating the WRRA index for the Tarim River
Basin. The following conclusions are observed: (1) from 1956 to 2005, the indices of WRRA in the Hotan River Basin, Yarkand
and Aksu River Basin are 0.26, 0.55, 0.58, respectively, which are between 0 and 1. The results indicate that the hydrological
cycle in these three sub-basins is in a reproducible state. (2) The WRRA index in the Kaidu-Kong River Basin is 1.23 > 1,
which indicates that floods may occur in the Kaidu-Kong River Basin. (3) The index of WRRA in the main stream is 0, which
indicates that the WRRA is very weak at this location, and zero-flow may occur. Calculating the WRRA of a basin can provide
a basis for corresponding basin water resources management. 相似文献
947.
C. Lorz G. Abbt-Braun F. Bakker P. Borges H. B?rnick L. Fortes F. H. Frimmel A. Gaffron N. Hebben R. H?fer F. Makeschin K. Neder L. H. Roig B. Steiniger M. Strauch D. Walde H. Wei? E. Worch J. Wummel 《Environmental Earth Sciences》2012,65(5):1575-1586
Land-use/cover change (LUCC) and climate change are major controlling factors for water resources in the Distrito Federal in Western Central Brazil. Dynamic LUCC in the region has severe impacts on water resources, while climate changes during the last three decades is thought to have only moderate effects. LUCC affects water quantity mostly during base flow conditions. River basins with substantial expansion of agriculture since the end 1970s show a dramatic decrease of base flow discharge by 40?C70%, presumably due to irrigation. In contrast, the effects of urbanization on runoff are less distinct, since factors controlling runoff generation might be more variable. For water quality, we found urban areas to have a strong influence on the parameters CSB, NH4 +, and suspended solids. In addition, we assume emerging pollutants, e.g. organic (micro)pollutants, might play a major role in the future. The project IWAS-áGUA DF focuses on creating the scientific base to face these problems in frame of an IWRM concept for the region. Results of our study will be a contribution to an IRWM concept for the Distrito Federal and will help to maintain high standards in water supply for the region. 相似文献
948.
Electrical resistivity response due to variation in embankment shape and reservoir levels 总被引:1,自引:1,他引:0
The safety of the center-core type of fill dam structure was assessed by examining the effects of the distortion of electrical
response verified in terms of two-dimensional (2D) apparent resistivity and its inverted sections from three-dimensional (3D)
modeling for the embankment. The distortion effect is due to 2D interpretation of the 3D structure of the embankment. From
the analysis, it was found that water level was correctly described by the resistivity section around the middle part rather
than each side at the end of the embankment. This is due to the 3D terrain effect when the material of the embankment is assumed
to be horizontally uniform. In addition, when the slope of the outer rock-fill section is set as uniform, the resistivity
section is more similar for sharper center-core slopes. On the other hand, when the rock-fill slope is steep, the resistivity
section shows the water level at a lower position than the real one, and the 3D distortion effect at the end of the embankment
is enhanced. 相似文献
949.
Heavy metal pollution in the surrounding ore deposits and mining activity: a case study from Koyulhisar (Sivas-Turkey) 总被引:1,自引:1,他引:0
The oxidation of sulfide minerals generates acidic waters containing high levels of SO4 and Fe. The study area has active Pb?CZn?CCu mining. It is thought that the surface/subsurface/underground sulfide minerals in the region generally contribute to the acidification of groundwater. Low pH values are also responsible for dissolved metals (Al, Fe, Mn, SO4, Pb, Zn) in the groundwater and river. Furthermore, current mining wastes have affected concentrations of trace elements in the water. High Fe and Mn concentrations are generally found in the spring which has acidic and low Eh values, while Al, Fe and Mn concentrations in the acidic waters show notable increases with the maximum values reaching 8,829, 19,084 and 1,708?ppb, respectively. These values exceed the Turkish drinking water standard of 200, 200 and 50?ppb, respectively. 相似文献
950.
Ryoko Fujiyoshi Hikaru Amano Yousuke Sakuta Kazumasa Okamoto Takashi Sumiyoshi Ivan Kobal Janja Vaupoti? 《Environmental Earth Sciences》2012,67(1):133-140
Carbon sources were estimated by measuring carbon isotope ratios (??13C and ??14C) with accelerator mass spectrometry (AMS) in forest soils of different lithology. Six locations were selected in temperate deciduous and coniferous stands in Slovenia (?irovski vrh, Idrija, Ko?evski Rog, Pohorje, Gori?nica, and Rakitna), where carbonate rocks consisting of limestone and dolomite are abundant as underlying bedrock. Carbon isotope fractionation would not have occurred in two carbonaceous soils, since the values of both ??13C and ??14C changed consistently in these soils after thermal (550°C, 2?h) or chemical (1?M HCl, 24?h) treatments. Organic components were found to be predominant carbon sources (70?C100%) in the uppermost portions (0?C2?cm in depth). In deeper portions at a depth of about 30?C35?cm, soil carbon may be derived completely from underlying carbonate minerals in Idria, western part of Slovenia. The Combination of heat and chemical treatments with AMS provides practical information on soil carbon sources in carbonaceous soils. 相似文献