Evaluation of brine discharge to rivers and streams: Methodology of rapid impact assessment     

Dirk Böhme 《Limnologica》2011,41(2):80-89

Induced by a brine discharge study for a submerse gas storage cavern project, a suitable methodology for rapid impact assessment had to be found. In this paper a simple stochastic, stationary model is described for assessment of intensity and temporal variability of chloride pollution at the regional scale of the rivershed. Chloride concentration is used as a proxy of salinity. It is assumed to be the result of deterministic process (flow-dependent) and stochastic variation (estimated for boundary conditions and tributaries by an additive error term based on PERT distribution). This approach is suited to conduct Monte Carlo simulations in order to calculate long-time means and percentiles of the prospective in-stream chloride concentration (exposure model). The biocoenoses exposed to this pollution has to be evaluated in terms of chloride tolerance. Herefore Maximum Field Distributions (MFD) of relevant species (aquatic macrophytes, macroinvertebrates, fish) were compiled and merged to Species Sensitivity Distributions (SSDs). Critical aspects of MFD data quality are discussed. Chloride model simulations representing different discharge scenarios provide exposure parameters (e.g. 90th percentile) that can be compared with SSD-derived protection levels (e.g. maximum loss of 10% of taxa) to quantify and evaluate possible adverse effects as well as potential recolonisation in case of load removal. Crosslinks to conservation issues are relevant in the selection and position of rare or protected species in the SSD. As an analysis of the German legal framework and technical guidelines revealed lack of guidance and best practices for such assessment and impact evaluation, recent experience highlights serious needs in applied research.  相似文献   

光照和盐度对海水介质中磷化氢转化的影响     

秦媛媛  宋秀贤  曹西华  袁涌铨  俞志明 《海洋与湖沼》2011,42(4):482-487

通过室内模拟实验,研究了光照和盐度对海水介质中磷化氢转化的影响。结果表明,不同光照条件下磷化氢转化率有明显差异,按对磷化氢转化促进作用由大到小排列依次为：UVC〉UVB〉日光〉UVA〉避光条件,单位辐照强度的UVC比UVB更能促进磷化氢的转化。在实验体系中加入臭氧、过碳酸钠的实验进一步验证自由基反应对磷化氢转化有促进作...  相似文献   

Assessment of salinity status in intensively cultivated soils under semiarid climate, Murcia, SE Spain   总被引：1，自引：0，他引：1  

J.A. Acosta  A. FazB. Jansen  K. KalbitzS. Martínez-Martínez 《Journal of Arid Environments》2011,75(11):1056-1066

This research presents the results from the assessment of the salinity status of a highly productive agricultural area, under a semiarid climate. The objectives were to: identify the origin of salts, assess seasonal changes of salt contents, and examine spatio-temporal and vertical variability of the presence and composition of salts. Soil samples from the surface horizon, and topsoil samples, soil profiles, water samples and salt precipitates on aggregates were collected in January and July 2009. High electrical conductivity was mainly the result of the poor low quality irrigation water. However, ions responsible for salinity were chlorides, sulfates, calcium, magnesium and sodium, while phosphates, ammonium, nitrates, and potassium were associated with fertilizers. SEM-EDX (scanning electron microscope-energy dispersive X-ray) analyses suggested that calcium sulfate came from both irrigation water and from a pedogenic source, as indicated by differences in crystal morphology and seasonal occurrence, which indicates that primary salinization is also a contributor to soil salinity in the area studied. Significant differences were reported between seasons. The electrical conductivity and concentrations of chloride, sulfates, calcium, magnesium, sodium, potassium, and nitrite are significantly higher in July. The observed differences were caused by the effect of soluble salt movement through evaporation and capillary rise, resulting in precipitation of salts on the surface. Multivariable, GIS and advanced laboratory analysis have confirmed to be useful techniques to identify the salts sources, spatial distribution of anions, and identification of vulnerable areas.  相似文献   

Variability and Climate Effect of the Salinity in the Pacific Warm Pool-cold Tongue Confluence Region     

Fan Wang  Chuanyu Liu  Shijian Hu  Shan Gao  Fan Jia  Linlin Zhang  Jianing Wang  Junqiao Feng 《地球科学进展》2018,33(8):775-782

This study focused on the warm pool-cold tongue confluence region (WCCR) in the central tropical Pacific Ocean where the warm and fresh water from the warm pool encounters with cold and saline water from the cold tongue. The WCCR is characterized by strong surface salinity front, shallow mixed layer and thick barrier layer. The WCCR is the key area for the development of different types of El Ni?o, and also the area with significant systematic bias in climate models. In order to reveal what role the structure and variability of salinity will play in the ocean dynamic and thermal conditions, and the cycle of the ENSO, a key project was approved by the National Natural Science Foundation of China (NSFC) in July, 2017. The key scientific issues that will be addressed in the project are as follows: ①to depict the three-dimensional structure and variability of salinity in the WCCR; ②to reveal the mechanism for the variability of salinity front and barrier layer; and ③to illustrate the main processes that control the impact of salinity on the upper-ocean variation in the tropical Pacific and the cycle of the ENSO. The present study will improve our understanding of the tropical ocean dynamics and ENSO dynamics, and will enhance the prediction skill of the ENSO.  相似文献   

Oxygen isotope-salinity relation in an Arctic fjord (Kongsfjorden): Implications to hydrographic variability     

《地学前缘(英文版)》2018,9(6):1937-1943

The global warming leads to a large freshwater influx into the Arctic Ocean, which has adverse implications to the sea-ice dynamics, ocean circulation, and acidification. The relationship between oxygen isotope ratio (δ¹⁸O) and salinity (S) is helpful in exploring various hydrographic processes related to the freshwater influx and is also required to accurately determine past salinity variability using oxygen isotope ratio of the carbonates. In view of this, systematic measurements of δ¹⁸O and salinity of water from an Arctic fjord (Kongsfjorden) were carried out during the summer season of 2013. Until now, the relationships between δ¹⁸O and salinity from such fjords were based on a limited number of samples collected during a very short span of time and thus may not accurately represent the long-term conditions prevailing in the fjord. The present study determines a more representative δ¹⁸O–salinity relationship as water samples from different depths and location over a long period were systematically collected. The water samples were collected from four different locations at different depths along the axis of the fjord representing the inner and outer fjords. The inner stations (I-8 and I-6) exhibit lower δ¹⁸O values than the outer stations (I-1 and I-3), which indicate the higher influence of freshwater from glacial melting in the inner stations. The δ¹⁸O–salinity relationship from the inner and outer fjords yield a slope of 0.54 (r² = 0.67, n = 56) and 0.39 (r² = 0.66, n = 68), respectively. The δ¹⁸O of freshwater influx in the fjord is estimated at –18.4‰, which is close to the widely accepted freshwater-δ¹⁸O value of the Arctic basin. The δ¹⁸O of glacial discharge, which is the largest source of freshwater influx to the fjord, is estimated at ca. –21.0‰, which will be useful for future freshwater budget calculations.  相似文献   

王集-新庄地区包裹体特征及油气成藏期次     

蒲洪果  ;崔秀青  ;朱伟鸿  ;刘臣  ;李丽娟 《四川地质学报》2014,(4):517-519

通过采集泌阳凹陷王集-新庄地区岩心样品,对其中包裹体进行盐度特征分析、镜下观察及均一温度测定;结果表明王集-新庄地区包裹体分为两期,与盆地埋藏史和热史研究划分的早、晚两个成藏期相对应。结合生排烃史综合分析,该区油气分两期成藏,早期油气成藏期主要发生在核一段末期~廖庄组沉积期,为小规模油气成藏,该期主要生成低熟油;晚期油气成藏期主要发生在廖庄末抬升期,为大规模油气成藏,是形成现今油田的主要成藏期。利用油气包裹体进行油气成藏研究,必须和宿主矿物的矿物岩石学分析及其他成藏期次分析方法结合使用,才能使分析结果更加客观可信。  相似文献   

On the determination of the absolute velocity of steady flows of a baroclinic fluid with applications to ocean currents     

《Dynamics of Atmospheres and Oceans》2021

The problem of determining the absolute velocity of marine currents, including its barotropic component, is revisited. A generalization of the classical Needler’s formula is discussed for a Boussinesq fluid and it is shown that the steady flow solution can be deduced from a variational principle that uses the constants of motion existing in the problem. A simple model of a steady flow is considered when the Bernoulli function consists of two terms. The first term is proportional to the square of Ertel’s potential vorticity and the second term is a quadratic function of the fluid buoyancy. This model is applied to mimic the circulation in the western Mediterranean Sea near the African coast. Alternatively, “potential temperature – salinity” coordinates are applied to construct the stream-tubes and infer the steady flow velocity in the simplest case of the Bernoulli function being proportional to the product of the above two variables.  相似文献   

20万年来南海古海洋研究的主要进展     

李琪  李前裕  王汝建 《地球科学进展》2012,27(2):224-239

南海第四纪古海洋学的研究,从ODP184航次以来获得了快速的发展,已经成为国内外古海洋研究的重点地区之一。试图对国内外文献作一综述,介绍近20万年以来高分辨率的南海古海洋研究进展。综述主要涉及温度、盐度、生产力和上层水体的变化,重点介绍南海季风的研究成果。南海浮游有孔虫氧同位素曲线具有MIS3.3和MIS6.5期偏轻,MIS5.5和MIS7.3期偏重的特征,已被称为"季风型氧同位素曲线"。不同于代表全球冰量变化的底栖有孔虫氧同位素曲线(即SPEC-MAP曲线),"季风型氧同位素曲线"具明显的2万年岁差周期,代表了季风降水的影响。快速气候变化事件也有较为完整的记录,揭示了热带地区在快速气候变化中也发挥着重要的作用。  相似文献   

Deciphering climatic history from lake sediments     

Sherilyn C. Fritz 《Journal of Paleolimnology》2008,39(1):5-16

Reconstructing climate from lake sediments can be challenging, because the response of lakes and various components of lake systems are mediated by non-climatic factors, such as geomorphic and hydrologic stetting. As a result, the magnitude of lake response to climatic forcing may be non-linear. In addition, changes in the lake system associated with the aging process or non-climatic influences may alter the response to a given climate perturbation. These non-linear and non-stationary characteristics can produce spatial heterogeneity in the pattern and timing of inferred change. One approach for generating regionally robust climatic interpretations from lakes is to increase coordinated efforts to generate and synthesize large data sets, so that localized influences can be more clearly distinguished from broad-scale regional patterns. This approach will be most successful for evaluating climate variation at multi-decadal or longer temporal scales; the climatic interpretation of higher frequency limnological variation can be more complicated, because of dating uncertainties and differential response times of individual proxies and systems. This paper is based on a plenary talk at the 10th International Paleolimnology Conference in Duluth, Minnesota in July 2006.  相似文献   

The influence of cadmium contamination and salinity on the survival,growth and phytoremediation capacity of the saltmarsh plant Salicornia ramosissima     

《Marine environmental research》2013

The major aim of this study was to evaluate the capacity of Salicornia ramosissima on Cadmium phytoremediation under distinct salinities and, consequently, the toxic effects on the plant's development. A greenhouse experiment was performed, using two Cd concentrations (50 and 100 μg l⁻¹) in different salinities (0, 5 and 10). Mortality and weight variation, observed at the end of the experiment, showed significant differences between some treatments, meaning that these variables were affected by the salinity and Cd concentrations. The highest Cd accumulation was detected in the roots, and decreased with the increase of salinity and Cd concentration. S. ramosissima is a potential candidate for Cd phytoremediation at salinities close to 0 and its capabilities in Cd phytoaccumulation and phytoestabilization proved to be quite interesting. The optimization of phytoremediation processes by S. ramosissima could turn possible the use of this plant in the recovery of contaminated ecosystems.  相似文献