50 research outputs found

    Sediment fluxes of the Sebou river (Morocco)

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    Annual pre-dam and post-dam data for one of Morocco’s largest rivers, the Sebou,were analysed using there water discharge and suspended sediment loads. Results from theses analyses indicated significant reduction of water discharge and sediment fluxes by 70 and 95% respectively. Otherwise, the Sebou reservoirs,suffered from siltation due to the high rate of natural and accelerated erosion. In fact, the trap efficiency calculated for the Sebou dams ranges from 85-99%, and their life-span from 42-910 years. For instance, Al Wahda, the second largest dam of Africa, with a capacity of 3.8 103 Km3, takes 374 years to be filled with sediments. This huge siltation has a serious environmental and socio-economical impact, since it reduces the reservoirs capacity, and could affect the morphological equilibrium of the coastline. In semiarid region, environmental impacts of dams are particularly emphasised because of the irregular nature of climate and the intensity of erosive forces

    DYNAMICS OF ABSORPTION OF SOME BIOGENIC SALTS IN MODIFIED SALINE MEDIUM

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    The measuring of Ca2+, Mg2+, K+ has been carried out. This quantity determination had two purposes. It allows us, on the one hand, to show that the assimilation rate of the studied mineral elements and the synthesis of the dry matter are in relation with the composition of the plant organs. On the other hand, to analyse the Na+/ NH4 + antagonism in constantly keeping the concentration of each anion and cation. Within the adjusted saline water T1C, T2C, T3C changing the proportion of NH4 + from 15% to 25% in the total mineral nitrogen of the modified saline solution T1 mod, T2mod, T3, mod. At the level of the two studied species, tomato and bean, the K+ is very abundant with regard to the cations Ca2+, Mg2+, and Na+ probably due to the weak capacity of the cationic root exchange of these plants. The roots of the tomato plants are less loaded with Na+ than the aerial parts. However, the bean stores much more Na+ at the level of the roots, which migrate with difficulty to the aerial parts [2]

    DYNAMICS OF ABSORPTION OF SOME BIOGENIC SALTS IN MODIFIED SALINE MEDIUM

    Get PDF
    The measuring of Ca2+, Mg2+, K+ has been carried out. This quantity determination had two purposes. It allows us, on the one hand, to show that the assimilation rate of the studied mineral elements and the synthesis of the dry matter are in relation with the composition of the plant organs. On the other hand, to analyse the Na+/ NH4 + antagonism in constantly keeping the concentration of each anion and cation. Within the adjusted saline water T1C, T2C, T3C changing the proportion of NH4 + from 15% to 25% in the total mineral nitrogen of the modified saline solution T1 mod, T2mod, T3, mod. At the level of the two studied species, tomato and bean, the K+ is very abundant with regard to the cations Ca2+, Mg2+, and Na+ probably due to the weak capacity of the cationic root exchange of these plants. The roots of the tomato plants are less loaded with Na+ than the aerial parts. However, the bean stores much more Na+ at the level of the roots, which migrate with difficulty to the aerial parts [2]

    DYNAMICS OF ABSORPTION OF SOME BIOGENIC SALTS IN MODIFIED SALINE MEDIUM

    Get PDF
    The measuring of Ca2+, Mg2+, K+ has been carried out. This quantity determination had two purposes. It allows us, on the one hand, to show that the assimilation rate of the studied mineral elements and the synthesis of the dry matter are in relation with the composition of the plant organs. On the other hand, to analyse the Na+/ NH4 + antagonism in constantly keeping the concentration of each anion and cation. Within the adjusted saline water T1C, T2C, T3C changing the proportion of NH4 + from 15% to 25% in the total mineral nitrogen of the modified saline solution T1 mod, T2mod, T3, mod. At the level of the two studied species, tomato and bean, the K+ is very abundant with regard to the cations Ca2+, Mg2+, and Na+ probably due to the weak capacity of the cationic root exchange of these plants. The roots of the tomato plants are less loaded with Na+ than the aerial parts. However, the bean stores much more Na+ at the level of the roots, which migrate with difficulty to the aerial parts [2]

    DYNAMICS OF ABSORPTION OF SOME BIOGENICS SALTS AT TOMATO AND BEAN PLANT CULTIVATED IN SALINE MEDIUM

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    The study carried out on the mineral assimilation in saline environment by tomato and bean cultures allowed us to distinguish through the various studied stages, a specifi c assimilation of the mineral element Ca, Mg, K, Na. This study aimed at looking at how assimilation rate of the studied mineral element. The dry matter is in relation with the mineral composition of the plant organs

    Social-environmental analysis for the management of coastal lagoons in North Africa

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    This study provides an overview of 11 lagoons in North Africa, from the Atlantic to the Eastern Mediterranean. Lagoons are complex, transitional, coastal zones providing valuable ecosystem services that contribute to the welfare of the human population. The main economic sectors in the lagoons included fishing, shellfish harvesting, and salt and sand extraction, as well as maritime transport. Economic sectors in the areas around the lagoons and in the watershed included agriculture, tourism, recreation, industrial, and urban development. Changes were also identified in land use from reclamation, changes in hydrology, changes in sedimentology from damming, inlet modifications, and coastal engineering. The human activities in and around the lagoons exert multiple pressures on these ecosystems and result in changes in the environment, affecting salinity, dissolved oxygen, and erosion; changes in the ecology, such as loss of biodiversity; and changes in the delivery of valuable ecosystem services. Loss of ecosystem services such as coastal protection and seafood affect human populations that live around the lagoons and depend on them for their livelihood. Adaptive management frameworks for social–ecological systems provide options that support decision makers with sciencebased knowledge to deliver sustainable development for ecosystems. The framework used to support the decision makers for environmental management of these 11 lagoons is Drivers–Activities–Pressures–State Change–Impact (on Welfare)–Responses (as Measures).info:eu-repo/semantics/publishedVersio

    Contribution of remote sensing technologies to a holistic coastal and marine environmental management framework: a review

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    Coastal and marine management require the evaluation of multiple environmental threats and issues. However, there are gaps in the necessary data and poor access or dissemination of existing data in many countries around the world. This research identifies how remote sensing can contribute to filling these gaps so that environmental agencies, such as the United Nations Environmental Programme, European Environmental Agency, and International Union for Conservation of Nature, can better implement environmental directives in a cost-e ective manner. Remote sensing (RS) techniques generally allow for uniform data collection, with common acquisition and reporting methods, across large areas. Furthermore, these datasets are sometimes open-source, mainly when governments finance satellite missions. Some of these data can be used in holistic, coastal and marine environmental management frameworks, such as the DAPSI(W)R(M) framework (Drivers–Activities–Pressures–State changes–Impacts (on Welfare)–Responses (as Measures), an updated version of Drivers–Pressures–State–Impact–Responses. The framework is a useful and holistic problem-structuring framework that can be used to assess the causes, consequences, and responses to change in the marine environment. Six broad classifications of remote data collection technologies are reviewed for their potential contribution to integrated marine management, including Satellite-based Remote Sensing, Aerial Remote Sensing, Unmanned Aerial Vehicles, Unmanned Surface Vehicles, Unmanned Underwater Vehicles, and Static Sensors. A significant outcome of this study is practical inputs into each component of the DAPSI(W)R(M) framework. The RS applications are not expected to be all-inclusive; rather, they provide insight into the current use of the framework as a foundation for developing further holistic resource technologies for management strategies in the future. A significant outcome of this research will deliver practical insights for integrated coastal and marine management and demonstrate the usefulness of RS to support the implementation of environmental goals, descriptors, targets, and policies, such as theWater Framework Directive, Marine Strategy Framework Directive, Ocean Health Index, and United Nations Sustainable Development Goals. Additionally, the opportunities and challenges of these technologies are discussed.Murray Foundation: 25.26022020info:eu-repo/semantics/publishedVersio

    DYNAMICS OF ABSORPTION OF SOME BIOGENICS SALTS AT TOMATO AND BEAN PLANT CULTIVATED IN SALINE MEDIUM

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    The study carried out on the mineral assimilation in saline environment by tomato and bean cultures allowed us to distinguish through the various studied stages, a specifi c assimilation of the mineral element Ca, Mg, K, Na. This study aimed at looking at how assimilation rate of the studied mineral element. The dry matter is in relation with the mineral composition of the plant organs

    DYNAMICS OF ABSORPTION OF SOME BIOGENICS SALTS AT TOMATO AND BEAN PLANT CULTIVATED IN SALINE MEDIUM

    Get PDF
    The study carried out on the mineral assimilation in saline environment by tomato and bean cultures allowed us to distinguish through the various studied stages, a specifi c assimilation of the mineral element Ca, Mg, K, Na. This study aimed at looking at how assimilation rate of the studied mineral element. The dry matter is in relation with the mineral composition of the plant organs
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