Biological effects of anthropogenic salt-load on the aquatic Fauna: A synthesis of 17 years of biological survey on the rivers Werra and Weser

The reduction and the smoothened amplitudes of the chloride concentrations since 2000 have resulted in a gradual positive development of the aquatic fauna in the River Werra. In the salinized section of the river increasing species numbers have been determined along the salinity gradient, which shows maximum chloride concentrations of about 2500 mg/l, maximum potash concentrations at approximately 200 mg/l, and magnesia concentrations peaked at 320 mg/l. As an immediate consequence of the reduction in salt concentration the immigration of various caddis fly species into the lower River Werra was observed. The Number of taxa per sample rose from 5 to more than 30 in the lower Werra region. Changes in species-richness could be seen more frequently in river sections where chloride concentrations fluctuated around 1500 mg/l.     

硫酸铁钾转化法制取硫酸钾

以钛白副产绿矾和氯化钾为原料 ,采取硫酸铁钾转化法制备硫酸钾。该工艺既具有反应时间短、操作控制方便、产品质量符合国标要求等优点 ,又治理了钛白粉厂环境污染 ;既具有一定的经济效益 ,又有一定的社会效益。     

Chloride in precipitation and streamwater for the upland catchment of river severn,mid-wales; some consequences for hydrochemical models

Variations in the concentration of Cl in rainfall and stream runoff are presented for two catchments in the Hafren forest of mid-Wales, Great Britain. Despite the large fluctuations in rainfall concentrations, Cl in the streamwater remains relatively constant. Using the two-reservoir Birkenes model, an attempt was made to simulate observed Cl in streamwater. The original model was unable to reproduce the observations and several modifications are suggested to provide better simulations. The resulting model is not the only one capable of reproducing the observations; other hydrochemical models will most probably also achieve this although emphasis will in each case be placed on different aspects. In this paper, it is suggested that the stochastic properties of water movement and chemical processes can account for the streamwater chemistry responses observed. On the catchment scale these processes will lead to an apparently deterministic behaviour that may well be described by simple relationships.     

The mass-balance characteristics and sensitivities to climate variables of Laohugou Glacier No. 12, western Qilian Mountains, China

Due to global warming, glaciers on the Tibetan Plateau(TP) are experiencing widespread shrinkage; however, the mechanisms controlling glacier variations across the TP are still rather unclear, especially on the northeastern TP. In this study, a physically based, distributed surface-energy and mass-balance model was used to simulate glacier mass balance forced by meteorological data. The model was applied to Laohugou No. 12 Glacier, western Qilian Mountains, China, during2010~2012. The simulated albedo and mass balance were validated and calibrated by in situ measurements. The simulated annual glacier-wide mass balances were-385 mm water equivalent(w.e.) in 2010/2011 and-232 mm w.e. in 2011/2012,respectively. The mean equilibrium-line altitude(ELA) was 5,015 m a.s.l., during 2010~2012, which ascended by 215 m compared to that in the 1970 s. The mean accumulation area ratio(AAR) was 39% during the two years. Climatic-sensitivity experiments indicated that the change of glacier mass balance resulting from a 1.5 °C increase in air temperature could be offset by a 30% increase in annual precipitation. The glacier mass balance varied linearly with precipitation, at a rate of130 mm w.e. per 10% change in total precipitation.     

Study of evaporation and recharge in desert soil using environmental tracers, New Mexico, USA

 The purpose of this study is to investigate the rates and mechanisms of recharge and evaporation in soils of a desert environment using two environmental tracers (chloride and oxygen-18). The profiles of chloride concentration and oxygen-18 enrichment in soil-water, together with the depth distribution of water content in soil, reveal information about long-term recharge and instantaneous evaporation processes without needing to know the physical properties of the soil. Three holes were hand-augured, in different desert settings in southeastern New Mexico. The chloride concentration profiles were used, with the chloride mass balance method, to estimate long-term recharge rates in these three holes as 0.5, 0.8, and 2.4 mm yr^–1. Analysis using a bimodal flow and transport model shows that possibly 85% of the recharge occurs via movement of water through preferred pathways in the root zone. Preferential flow was evident in all three sampling sites. Clay layers have a noticeable effect on the development of water content distribution and thus on oxygen-18 enrichment and chloride concentration profiles. The spatial variation in clay layering partly explains the variation in recharge rate estimates. Received: 13 October 1995 · Accepted: 15 November 1995     

Changes in the northern Gulf of St. Lawrence ecosystem estimated by inverse modelling: Evidence of a fishery-induced regime shift?

Mass-balance models have been constructed using inverse methodology for the northern Gulf of St. Lawrence for the mid-1980s, the mid-1990s, and the early 2000s to describe ecosystem structure, trophic group interactions, and the effects of fishing and predation on the ecosystem for each time period. Our analyses indicate that the ecosystem structure shifted dramatically from one previously dominated by demersal (cod, redfish) and small-bodied forage (e.g., capelin, mackerel, herring, shrimp) species to one now dominated by small-bodied forage species. Overfishing removed a functional group in the late 1980s, large piscivorous fish (primarily cod and redfish), which has not recovered 14 years after the cessation of heavy fishing. This has left only marine mammals as top predators during the mid-1990s, and marine mammals and small Greenland halibut during the early 2000s. Predation by marine mammals on fish increased from the mid-1980s to the early 2000s while predation by large fish on fish decreased. Capelin and shrimp, the main prey in each period, showed an increase in biomass over the three periods. A switch in the main predators of capelin from cod to marine mammals occurred, while Greenland halibut progressively replaced cod as shrimp predators. Overfishing influenced community structure directly through preferential removal of larger-bodied fishes and indirectly through predation release because larger-bodied fishes exerted top-down control upon other community species or competed with other species for the same prey. Our modelling estimates showed that a change in predation structure or flows at the top of the trophic system led to changes in predation at all lower trophic levels in the northern Gulf of St. Lawrence. These changes represent a case of fishery-induced regime shift.     

Isotopic and hydrochemical studies of groundwater flow and salinity in the Southern Upper Rhine Graben

In order to determine the origin and the propagation mechanisms of highly concentrated chloride brines within the Quaternary aquifer system in the southern part of the Upper Rhine Graben, a combined isotope (H, O, C) and hydrochemical analysis was carried out. Groundwater recharge in this area is a complex system, consisting of local precipitation, river bank filtration, lateral flow from the Graben borders and, to a minor extent, an old Pleistocene component. In some areas, groundwater consists of up to 90% of recent bank filtrate, reaching depths down to at least 100 m. The isotopic and hydrochemical results show, that the elevated chloride concentrations in the Quaternary aquifer mainly result from leaky settling basins charged by the French potash mines until the mid 1970s. Input of natural brines coming from tertiary salt diapirs is of only minor importance. While infiltrating, the anthropogenic brines were strongly diluted by local river bank filtrate of the Rhine. Nevertheless, maximum chloride concentrations nowadays still reach some 10,000 mg/l at the base of the aquifer at a depth of more than 100 m below surface. The main volume of the brines is stored in the less permeable lower part of the quaternary sediments (Breisgau-Formation) whereas only a minor part is transported northwards with the rapid convective groundwater flow. Brines undergoing only dilution preserve their hydrochemical characteristics (NaCl-type). In contrast, brines recirculated from the Breisgau-Formation show a northwards increasing alteration through ion exchange processes. Potassium and sodium may be fixed in the fine grained aquifer material while calcium is set free into the groundwater. After a flow distance of about 12 km, complex hydraulic interactions between groundwater and surface waters lead to the rise of strongly diluted and hydrochemically altered brines with chloride contents up to maximum 700 mg/l. The presented case study is an example for a detailed analysis of a multi-component groundwater mixing system using combined isotope and hydrochemical methods. Furthermore, cation exchange is shown as a major process affecting the hydrochemical evolution of the young groundwater in the southern Upper Rhine Graben which is locally strongly polluted by chloride as a consequence of former potash mining.     

Hydrogeochemical Anomalies in the Springs of the Chiayi Area in West-central Taiwan as Possible Precursors to Earthquakes

Water samples from both hot and artesian springs in Kuantzeling in west-central Taiwan have been collected on a regular basis from July 15, 1999 to the end of August 2001 to measure cation and anion concentrations as a tool to detect major earthquake precursors. The data identify chloride and sulfate ion anomalies few days prior to major quakes and lasting a few days afterward. These anomalies are characterized by increases in Cl^- concentrations from 34.9% to 41.2% and 71.5% to 138.1% as well as increases in SO₄^2- concentrations from 232.7% to 276.8% and 100.0% to 155.1% above the means in both hot and artesian springs. The occurrence of these anomalies is probably explained first as stress/strain-induced pressure changes in the subsurface water systems which then generate precursory limited geochemical discharges at the levels of subsurface reservoirs. Therefore, finally leading to the mixing of previously separated subsurface water bodies occurs. This suggests that the hot and artesian springs in the Kuantzeling area are possible ideal sites for recording strain changes serving well as earthquake precursors.     

N—P—K复肥四元体系KCl—KH_2PO_4—CO（NH_2）_2—H_2O在

基于Ｎ—Ｐ—Ｋ三元复肥的物理化学基础．首次测定了四元体系ＫＣｌ—ＫＨ２ＰＯ４—ＣＯ（ＮＨ２）２在２９８．２Ｋ时的溶度及饱和溶液的折光率，绘制了体系的溶度图和折光率──组成图。该体系的溶度图属低共饱型，平衡固相为组份化合物，低共饱点组成为：１００ｇ饱和溶液中．ＫＣｌ１３．３１ｇ，ＫＨ２ＰＯ４３．３３ｇ，ＣＯ（ＮＨ２）２４７．２６ｇ，Ｈ２Ｏ３６．１０／１０ｇ。     

Statistical models for the estimation of net phosphorus sedimentation in lakes

The empirical adequacy of four phosphorus mass-balance models is evaluated with respect to how the prediction error variance of the corresponding net sedimentation parameters is propagated in the steadystate equations. Using the criterion of minimum propagation error variance (PEV), different groups of lakes can be distinguished for which different empirical equations are used to predict net phosphorus sedimentation. The classification reduced prediction error significantly and also reflected different patterns of sedimentation. Application of this criterion to time-series of individual lakes shows that it is possible to determine a priori whether net annual sedimentation will be better correlated to the annual loading or to the lake content. The correlations depended also on the load/lake content ratio, suggesting that net sedimentation is best viewed as the sum of the partial sedimentation of the load and of the partial sedimentation of the lake content. On average, 25% of the load and 18% of the lake content are sedimented annually. Viewing net phosphorus sedimentation as a function of both the load and the lake content can also explain and predict the well-known cross-sectional correlation between phosphorus retention and water residence time.