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201.
本研究对发育于亚热带地区花岗岩和变质岩风化壳之上的两个红壤剖面进行了系统的环境磁学测量及色度分析,探讨在同一地区不同母质上发育的红壤磁性差异的原因及其环境意义.研究区的两个剖面分别位于福建省南平市高铁北站和纺织厂附近,相距约15 km,气候条件基本相同.研究结果表明:(1)较强磁性的花岗岩母质层上发育的南平北站红壤(NPN),在发育过程因母质层中多畴(MD)颗粒磁赤铁矿化的磁铁矿溶解,剖面上部的淋溶层和淀积层虽以较细的稳定单畴(SSD)颗粒和少量的假单畴(PSD)颗粒磁铁矿为主,但剖面磁性自下而上减弱.相较而言,南纺红壤(NF)剖面发育在磁性较弱的变质砂岩上,其过渡层和母质层以赤铁矿为主,因成壤过程中生成较细的超顺磁(SP)磁铁矿使得土壤淋溶层和淀积层磁性增强;说明母质不同是亚热带地区红壤磁性差异的主要原因.(2) NPN和NF两个剖面的气候条件基本相同,磁性差异比色度指标差异更为显著.亚热带地区因剖面受母质影响显著,整体磁性特征不能反映气候;黄度和红度的比值(b*/a*)远小于磁性的差异,说明针铁矿和赤铁矿的比值更能反映研究区的平均气候状况,即反映次生磁性矿物含量的参数为更适合的气候指标. 相似文献
202.
U. Irmer 《洁净——土壤、空气、水》2000,28(1):7-14
The New EC Framework Water Directive: Assessment of the Chemical and Ecological Status of Surface Waters The main objective of the draft EC Framework Water Directive is the good quality of all surface waters. The directive provides for an assessment of the chemical status of surface waters (EU‐wide valid environmental quality standards for approximately 30 priority substances) and a five‐stage ecological classification of waters, comprising the stages high, good, moderate, poor, and bad. The starting point for the assessment are the reference conditions, which are defined as corresponding to high water quality and characterising a water status with no significant anthropogenic impact. The reference sites in the various water body types are to be selected using hydromorphological and physico‐chemical parameters and subsequently characterised by means of biological parameters. For surface waters, three groups of characteristics are provided for, namely: 1. with priority the biology – in the case of surface waters – with the four elements phytoplankton, macrophytes/phytobenthos, benthic invertebrate fauna, and fish fauna; 2. supporting the hydromorphology, e.g. flowing waters with the three elements hydrological regime, river continuity, and morphological conditions and 3. supporting the physico‐chemical conditions with the three elements general conditions, specific synthetic pollutants, and specific non synthetic pollutants (other than the priority substances of the chemical status). 相似文献
203.
《China Geology》2020,3(3):462-472
The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain, the transition zone between the Dabie Mountain Area and Jianghan Plain. It’s a great field test site to study the material and energy exchange among rainfall, soil moisture, and groundwater of the Earth ’s critical zone in subtropical monsoon climate plain areas. This paper analyzed the connection between rainfall and volume water content (VWC) of soil at different depths of several soil profiles, and the dynamic feature of groundwater was discussed, which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata. The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge, while the lateral recharge is the main supplement source. There were 75 effective rainfall events among 120 rainfall events during the monitoring period, with an accumulated amount of 672.9 mm, and the percentages of effective rainfall amount and duration time were 62.50% and 91.56%, respectively. The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m. The soil profile was divided into four zones: (1) The sensitive zone of rainfall infiltration within 1.4 m, where the material and energy exchange frequently near the interface between atmosphere and soil; (2) the buffer zone of rainfall infiltration between 1.4 m and 3.5 m; (3) the migration zone of rainfall infiltration between 3.5 m and 5.0 m; and (4) the rainfall infiltration and groundwater level co-influenced zone below 5.0 m. The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth ’s critical zone, which is of great theoretical and practical significance for groundwater resources evaluation and development, groundwater environmental protection, ecological environmental improvement, drought disaster prevention, and flood disaster prevention in subtropical monsoon climate plain areas. 相似文献
204.
Effects of heavy metal pollution on farmland soils and crops: A case study of the Xiaoqinling Gold Belt,China 总被引:1,自引:0,他引:1
《China Geology》2020,3(3):402-410
This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt. According to the geochemical analysis results of the soils observed in the gold belt, the soils are most highly enriched in Pb, followed by Cr, Cu, and Zn. Furthermore, they are relatively poor in Hg, Cd, and As. It is also shown that the heavy metals in all kinds of soils have the same geochemical characteristics in the gold belt. As for the crops (such as corn and wheat) in the gold belt, Zn and Cu are the most abundant elements, followed by Pb and Cr. Meanwhile, Hg, Cd, and As were found to have relatively low concentrations in the crops. The heavy metals in wheat and corn have the same geochemical characteristics in the gold belt in general. Compared to the aeolian loess soils and the crops therein, heavy metals are more enriched in diluvial and alluvial soils and the crops therein. As shown by relevant studies, the Hg, Pb, Cd, Cu, and Zn pollution are mainly caused by mining activities. Corn and wheat in the gold belt have a high tendency of risk exposure to heavy metal pollution since they are mostly affected by mining activities and feature high background values of heavy metal concentrations. Furthermore, wheat is more liable to be enriched in heavy metals than corn is grown in all types of soils. The Hg pollution in soils leads to Hg accumulation, increasing the risk of Hg uptake in crops, and further affecting human health. This study will provide a scientific basis for the control and management of heavy metals in farmland soils of mining areas. 相似文献
205.
《Limnologica》2020
Temperature plays an essential role in the ecology and biology of aquatic ecosystems. The use of dams to store and subsequently re-regulate river flows can have a negative impact on the natural thermal regime of rivers, causing thermal pollution of downstream river ecosystems. Autonomous thermal loggers were used to measure temperature changes downstream of a large dam on the Macquarie River, in Australia’s Murray-Darling Basin to quantify the effect of release mechanisms and dam storage volume on the downstream thermal regime. The magnitude of thermal pollution in the downstream river was affected by different release mechanisms, including bottom-level outlet releases, a thermal curtain (which draws water from above the hypolimnion), and spill-way release. Dam storage volume was linked to the magnitude of thermal pollution downstream; high storage volumes were related to severe thermal suppressions, with an approximate 10 °C difference occurring when water originated from high and low storage volumes. Downstream temperatures were 8 ̶ 10 °C higher when surface releases were used via a thermal curtain and the spillway to mitigate cold water pollution that frequently occurs in the river. Demonstrating the effectiveness of engineering and operational strategies used to mitigate cold water pollution highlight their potential contribution to fish conservation, threatened species recovery and environmental remediation of aquatic ecosystems. 相似文献
206.
In this paper our previously developed advanced system identification technique [1] has been applied to extract the frequency dependent roll damping from a series of model tests run in irregular (random) waves. It is shown that this methodology accurately models the roll damping which can then be used to produce accurate predictions of the ships roll motion. These roll motion predictions are not only more accurate than the potential flow predictions but more accurate than potential flow models corrected using either empirical prediction methods [2] and even those corrected using roll damping obtained from free decay sallying experiments. This methodology has the potential to significantly improve roll motion prediction during full scale at sea trails of vessels in order to dramatically improve safety of critical operations such as helicopter landing or ship to ship cargo transfer. 相似文献
207.
《Marine Policy》2017
The EU enlargement brought the Baltic Sea into the sphere of EU environmental policymaking, making the sea, with the exception of Russia, an EU inland sea. Yet, the state of the Baltic Sea environment is deteriorating at an alarming pace. This paper describes the evolution of the EU governance of the Baltic Sea environment, focussing on governance barriers. The findings demonstrate how the choice of analytical lens influences the construction of governance barriers and the respective intervention strategies. Such understanding can help policy practitioners in their search for successful measures to improve the governance situation in the Baltic Sea region. 相似文献
208.
《Marine Policy》2017
Global coral reef related tourism is one of the most significant examples of nature-based tourism from a single ecosystem. Coral reefs attract foreign and domestic visitors and generate revenues, including foreign exchange earnings, in over 100 countries and territories. Understanding the full value of coral reefs to tourism, and the spatial distribution of these values, provides an important incentive for sustainable reef management. In the current work, global data from multiple sources, including social media and crowd-sourced datasets, were used to estimate and map two distinct components of reef value. The first component is local “reef-adjacent” value, an overarching term used to capture a range of indirect benefits from coral reefs, including provision of sandy beaches, sheltered water, food, and attractive views. The second component is “on-reef” value, directly associated with in-water activities such diving and snorkelling. Tourism values were estimated as a proportion of the total visits and spending by coastal tourists within 30 km of reefs (excluding urban areas). Reef-adjacent values were set as a fixed proportion of 10% of this expenditure. On-reef values were based on the relative abundance of dive-shops and underwater photos in different countries and territories. Maps of value assigned to specific coral reef locations show considerable spatial variability across distances of just a few kilometres. Some 30% of the world's reefs are of value in the tourism sector, with a total value estimated at nearly US$36 billion, or over 9% of all coastal tourism value in the world's coral reef countries. 相似文献
209.
《Marine Policy》2017
There has been global interest in the exploitation of rich hydrocarbon resources in the Arctic for decades. However, recent low oil prices, a low carbon economy climate agenda, and technical challenges of Arctic oil extraction have curbed interest in these Arctic resources. Despite a recent reluctance to explore and develop an offshore Arctic drilling industry, a resurgence in oil and gas prices could spark renewed interests that could pose unacceptable risks of pollution from oil spills. These risks are further compounded by complex governance and sovereignty issues between circumpolar nations. This paper (i) compares cycles of Arctic hydrocarbon exploration and exploitation activity with global energy prices; (ii) outlines current pollution abatement techniques under pan-Arctic national regulations to identify potential gaps; (iii) describes current international frameworks for Arctic governance to highlight how problems could arise if offshore oil drilling returns to the Arctic and associated spills migrate to international waters; and (iv) provides policy recommendations to aid both national and international policy-makers regarding pollution abatement methods for future Arctic drilling. 相似文献
210.
相比陆上油气开发工程和其他海洋工程而言,海洋油气开发工程有其自身的特点,海洋油气开发工程环境影响评价应关注的内容与其他工程有所不同。文章通过分析海洋油气开发工程的特点以及对环境影响的特点,提出海洋油气开发工程环境影响评价要点,即包括施工期悬浮泥沙及钻井液钻屑排放对海洋生态环境的影响、运营期含油生产水排放对海洋生态环境的影响、工程建设对海洋环境敏感目标的影响、溢油事故环境风险分析、污染防治及生态保护措施,并针对目前海洋油气开发工程环境影响评价存在的问题提出改进建议。 相似文献