Within the framework of the international research project MELMARINA, seasonal dynamics of plankt... more Within the framework of the international research project MELMARINA, seasonal dynamics of plankton communities in three North African coastal lagoons (Merja Zerga, Ghar El Melh, and Lake Manzala) were investigated. The sampling period extended from July 2003 to September 2004 with the aim of evaluating hydrological and other influences on the structure, composition and space-time development of these communities in each lagoon. Phytoplankton in Merja Zerga showed a quasi-permanent predominance of marine diatoms in the open sea station and in the marine inlet channel. Dinoflagellates were abundant in summer and early autumn in the marine inlet and extended into the central lagoon station. In Ghar El Melh, marine species (especially diatoms and dinoflagellates) dominated despite occasional winter inflows of freshwater. In Lake Manzala, freshwater species generally predominated and the planktonic communities were comparatively very diverse. Chlorophyceae contributed 39% of the total species recorded and diatoms and cyanophyceans were also common; the Dinophyceae, Euglenophyceae, Chrysophyceae and Cryptophyceae less so. Zooplankton communities in both Ghar El Melh and Merja Zerga were dominated by marine copepods. Rotifera, Copepoda, Ostracoda, and Cladocera were recorded in both lagoons as were meroplanktonic larvae of Polychaeta, Cirripedia, Mysidacea and Gastropoda and free living nematodes. Ghar El Melh was the more productive of these two lagoons with spring and early
Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropog... more Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropogenic nutrient loading to lagoon food webs are often more pronounced than in other coastal ecosystems. For these reasons, many lagoons also provide an excellent environment for the deposition and accumulation of organic matter (OM). Sediment cores were retrieved from three North African lagoons to provide records of recent environmental changes. We measured percentage nitrogen (%N), nitrogen stable isotope values (d 15 N), and percentage organic matter (%OM), and we used radiometric dating techniques (210 Pb, 137 Cs) to examine the evidence for the intensification of upstream agricultural practices in sediment cores from Lake Manzala (Egypt), Ghar El Melh Lagoon (Tunisia), and Lagune de Nador (Morocco). With the exception of one core collected near a sewage outfall, sediments from Lake Manzala clearly reflected the impact of agricultural intensification following completion of the Aswan High Dam and delta barrages in the mid-1960s to early 1970s. Both %N and %OM more than doubled in three Manzala sediment cores, and d 15 N values declined from 5% to ,1%. These changes reflect the increasing use of synthetic fertilizers (d 15 N ' 0%) from the 1960s to the present. Sediments from Ghar El Melh show a similar trend, with %N more than tripling, %OM increasing by ;50%, and d 15 N declining from 6% to 2% since 1965. These changes are consistent with the increasing use of water from a nearby river for crop irrigation and agricultural fertilizer use. Lagune de Nador receives relatively little agricultural drainage water, and core data did not show the same trends as Manzala and Ghar El Melh. Overall, the sediment core data from these systems reflect environmental shifts in the quantity, quality, and isotope signature of the deposited organic matter and confirm the concerns of local scientists and environmental managers that eutrophication has had dramatic impacts on the coastal ecosystems, particularly at the Egyptian and Tunisian sites.
... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; ... more ... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; Karray, 1977; Bourgou, 1993, 1994; Oueslati, 1992, 1993 ... This landscape is found north of the sebkha facing the well populated settlements of Saida, Mellasine and Sidi Hsine, as well ...
This article describes the use of satellite imagery for identifying key environmental characteris... more This article describes the use of satellite imagery for identifying key environmental characteristics within three North African coastal lagoons (Merja Zerga, Morocco; Ghar El Melh, Tunisia and Lake Manzala, Egypt) and for detecting the major environmental changes within these environments. A combination of Landsat MSS, Landsat TM, Landsat ETM? and ASTER imagery was acquired for the three sites for a period covering the last three decades
Three North African coastal lagoons were selected as primary sites for integrated ecological and ... more Three North African coastal lagoons were selected as primary sites for integrated ecological and hydrological monitoring and modelling as part of the MELMARINA Project (see Flower & Thompson, 2009). The three sites, Merja Zerga (13.2 km 2 , Morocco), Ghar El Melh (35.6 km 2 , Tunisia) and Lake Manzala (c. 700 km 2 , Egypt), are permanent water bodies with at least one well-defined connection with the sea. This article provides an account of each lagoon's physical characteristics and recent development including the impacts of human activities. The two sites on the Mediterranean (Ghar El Melh and Lake Manzala) are characterised by small tidally driven variations in water level whilst Merga Zerga, on the Atlantic coast, experiences large tidally induced water level variations and so contains large inter-tidal environments. All the three lagoons receive freshwater inflows from their landward margins, varying in magnitude, seasonality and ecological significance. Freshwater inflows from drains strongly influence ecological conditions within Lake Manzala. All the three lagoons have significant biodiversity interest, especially for resident and migratory birds as well as fish, and support local human populations. Each lagoon experienced significant changes during the twentieth century possibly affecting declines in biodiversity value. These largely resulted from agricultural expansion and intensification and include reclamation and hydrological modifications which have both decreased freshwater inflows due to upstream diversions (Merja Zerga and Ghar El Melh) and increased the influx of freshwater through the return of irrigation drainage (Merja Zerga and Lake Manzala). All three sites experienced nutrient enrichment due to agricultural runoff and discharge of domestic wastewater. Industrial waste discharge is a particular, but not exclusive, problem for Lake Manzala. Problems of water quantity and quality will increase through the twenty-first century with increasing demands for water while effects of climate change will enhance freshwater scarcity. Conflicts between human and environmental uses of water will increase and unless improvements in water use efficiency and wastewater treatment can be brought about wetlands including coastal lagoons are likely to suffer further loss and degradation. These problems will be compounded by sea level rise.
This paper presents a new three-dimensional CMOS-SOI technology anddiscusses design issues for it... more This paper presents a new three-dimensional CMOS-SOI technology anddiscusses design issues for it. In this technology the P-channel devices arestacked over the N-channel ones. All gates are 0.1|ìm length. New designconstraints are introduced. Consequently, new design methodologies haveto be developed in order to fully take advantage of the outstanding featuresof D integration like for example the reduced length of interconnections.INTRODUCTION
Three North African coastal lagoons were selected as primary sites for integrated ecological and ... more Three North African coastal lagoons were selected as primary sites for integrated ecological and hydrological monitoring and modelling as part of the MELMARINA Project (see . The three sites, Merja Zerga (13.2 km 2 , Morocco), Ghar El Melh (35.6 km 2 , Tunisia) and Lake Manzala (c. 700 km 2 , Egypt), are permanent water bodies with at least one well-defined connection with the sea. This article provides an account of each lagoon's physical characteristics and recent development including the impacts of human activities. The two sites on the Mediterranean (Ghar El Melh and Lake Manzala) are characterised by small tidally driven variations in water level whilst Merga Zerga, on the Atlantic coast, experiences large tidally induced water level variations and so contains large inter-tidal environments. All the three lagoons
Hydrological and hydrodynamic characteristics are important controls in all wetlands including co... more Hydrological and hydrodynamic characteristics are important controls in all wetlands including coastal lagoons. Enhanced understanding of lagoon functioning can be obtained through the acquisition and interpretation of hydrological, meteorological and related data. The MELMARINA persist due to longer residence times of water within the lagoon. Freshwater inflows are central to the functioning of Lake Manzala. Large discharges of relatively freshwater are provided by major drains which cross the Nile Delta. These influence lake water levels and are responsible for the freshwater conditions within large parts of the lake. The small tidal range of the eastern Mediterranean, coupled with constricted connections with the sea, reduces the influence of lake-sea exchanges and tidally induced water level oscillations within Lake Manzala.
Ghar El Melh (Northern Tunisia) is a shallow eutrophicated lagoon (total surface area 35.6 km 2 )... more Ghar El Melh (Northern Tunisia) is a shallow eutrophicated lagoon (total surface area 35.6 km 2 ) which was one of the primary sites within the MELMARINA project. It is connected to the Mediterranean through a dredged opening and receives untreated sewage from two towns and a catchment of 131 km 2 . During the past decade the lagoon's water quality has deteriorated and vegetation has changed. Ruppia sp. has diminished and green macroalgae (mainly Cladophora sp.) has increased. Frequent resuspension of fine alluvial sediment has reduced both water transparency and angiosperm (Ruppia sp.) vegetation cover. Flash floods during winter deliver most of the load of sediment and nutrients from the catchment to the lagoon. Options for restoring the angiosperm cover in the lagoon have been analysed using a model system developed for the main part of the lagoon consisting of a 2-D hydrodynamic model coupled to an ecological model. The ecological model includes a combined description of eutrophication and sediment transport with rooted vegetation (Ruppia sp.), benthic macroalgae, benthic microalgae, phytoplankton and suspended matter and nutrients. A separate sediment module includes pools of nutrients, organic carbon and fine sediment. Deposition and resuspension of the sediment pools are dependent on current and wind-generated shear stress. The load of nutrients and fine sediment was estimated through calibrating the model against measured water quality data and sediment deposition rates. The anthropogenic load from July 2003 to July 2004 was 33,000 tonnes fine sediment, 182 tonnes total N and 26 tonnes total P. A net import of sediment and nutrients from the sea was simulated, driven by the relatively high concentrations of suspended matter and particulate-bound N and P measured in coastal Mediterranean water outside the lagoon. Scenario simulations indicate that the lagoon acts as a deposition area for sediment N and P for boundary concentrations down to 50% of the measured concentrations at the coast outside the lagoon. A range of simulations with decreasing load of sediment and nutrients indicate that angiosperm vegetation will slowly recover with loads of 25% of current loads, combined with increased filtration by bivalves which would decrease suspended matter concentrations and increase transparency. Elevated concentrations of suspended matter and nutrients in the sea outside the lagoon are discussed in relation to a 30-year flash flood of the Mejerda River in February 2003. Coastal erosion as well as nutrients and sediment delivered by this river probably account for a general elevation of these concentrations close to the coast.
... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; ... more ... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; Karray, 1977; Bourgou, 1993, 1994; Oueslati, 1992, 1993 ... This landscape is found north of the sebkha facing the well populated settlements of Saida, Mellasine and Sidi Hsine, as well ...
Within the framework of the international research project MELMARINA, seasonal dynamics of plankt... more Within the framework of the international research project MELMARINA, seasonal dynamics of plankton communities in three North African coastal lagoons (Merja Zerga, Ghar El Melh, and Lake Manzala) were investigated. The sampling period extended from July 2003 to September 2004 with the aim of evaluating hydrological and other influences on the structure, composition and space-time development of these communities in each lagoon. Phytoplankton in Merja Zerga showed a quasi-permanent predominance of marine diatoms in the open sea station and in the marine inlet channel. Dinoflagellates were abundant in summer and early autumn in the marine inlet and extended into the central lagoon station. In Ghar El Melh, marine species (especially diatoms and dinoflagellates) dominated despite occasional winter inflows of freshwater. In Lake Manzala, freshwater species generally predominated and the planktonic communities were comparatively very diverse. Chlorophyceae contributed 39% of the total species recorded and diatoms and cyanophyceans were also common; the Dinophyceae, Euglenophyceae, Chrysophyceae and Cryptophyceae less so. Zooplankton communities in both Ghar El Melh and Merja Zerga were dominated by marine copepods. Rotifera, Copepoda, Ostracoda, and Cladocera were recorded in both lagoons as were meroplanktonic larvae of Polychaeta, Cirripedia, Mysidacea and Gastropoda and free living nematodes. Ghar El Melh was the more productive of these two lagoons with spring and early
Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropog... more Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropogenic nutrient loading to lagoon food webs are often more pronounced than in other coastal ecosystems. For these reasons, many lagoons also provide an excellent environment for the deposition and accumulation of organic matter (OM). Sediment cores were retrieved from three North African lagoons to provide records of recent environmental changes. We measured percentage nitrogen (%N), nitrogen stable isotope values (d 15 N), and percentage organic matter (%OM), and we used radiometric dating techniques (210 Pb, 137 Cs) to examine the evidence for the intensification of upstream agricultural practices in sediment cores from Lake Manzala (Egypt), Ghar El Melh Lagoon (Tunisia), and Lagune de Nador (Morocco). With the exception of one core collected near a sewage outfall, sediments from Lake Manzala clearly reflected the impact of agricultural intensification following completion of the Aswan High Dam and delta barrages in the mid-1960s to early 1970s. Both %N and %OM more than doubled in three Manzala sediment cores, and d 15 N values declined from 5% to ,1%. These changes reflect the increasing use of synthetic fertilizers (d 15 N ' 0%) from the 1960s to the present. Sediments from Ghar El Melh show a similar trend, with %N more than tripling, %OM increasing by ;50%, and d 15 N declining from 6% to 2% since 1965. These changes are consistent with the increasing use of water from a nearby river for crop irrigation and agricultural fertilizer use. Lagune de Nador receives relatively little agricultural drainage water, and core data did not show the same trends as Manzala and Ghar El Melh. Overall, the sediment core data from these systems reflect environmental shifts in the quantity, quality, and isotope signature of the deposited organic matter and confirm the concerns of local scientists and environmental managers that eutrophication has had dramatic impacts on the coastal ecosystems, particularly at the Egyptian and Tunisian sites.
... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; ... more ... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; Karray, 1977; Bourgou, 1993, 1994; Oueslati, 1992, 1993 ... This landscape is found north of the sebkha facing the well populated settlements of Saida, Mellasine and Sidi Hsine, as well ...
This article describes the use of satellite imagery for identifying key environmental characteris... more This article describes the use of satellite imagery for identifying key environmental characteristics within three North African coastal lagoons (Merja Zerga, Morocco; Ghar El Melh, Tunisia and Lake Manzala, Egypt) and for detecting the major environmental changes within these environments. A combination of Landsat MSS, Landsat TM, Landsat ETM? and ASTER imagery was acquired for the three sites for a period covering the last three decades
Three North African coastal lagoons were selected as primary sites for integrated ecological and ... more Three North African coastal lagoons were selected as primary sites for integrated ecological and hydrological monitoring and modelling as part of the MELMARINA Project (see Flower & Thompson, 2009). The three sites, Merja Zerga (13.2 km 2 , Morocco), Ghar El Melh (35.6 km 2 , Tunisia) and Lake Manzala (c. 700 km 2 , Egypt), are permanent water bodies with at least one well-defined connection with the sea. This article provides an account of each lagoon's physical characteristics and recent development including the impacts of human activities. The two sites on the Mediterranean (Ghar El Melh and Lake Manzala) are characterised by small tidally driven variations in water level whilst Merga Zerga, on the Atlantic coast, experiences large tidally induced water level variations and so contains large inter-tidal environments. All the three lagoons receive freshwater inflows from their landward margins, varying in magnitude, seasonality and ecological significance. Freshwater inflows from drains strongly influence ecological conditions within Lake Manzala. All the three lagoons have significant biodiversity interest, especially for resident and migratory birds as well as fish, and support local human populations. Each lagoon experienced significant changes during the twentieth century possibly affecting declines in biodiversity value. These largely resulted from agricultural expansion and intensification and include reclamation and hydrological modifications which have both decreased freshwater inflows due to upstream diversions (Merja Zerga and Ghar El Melh) and increased the influx of freshwater through the return of irrigation drainage (Merja Zerga and Lake Manzala). All three sites experienced nutrient enrichment due to agricultural runoff and discharge of domestic wastewater. Industrial waste discharge is a particular, but not exclusive, problem for Lake Manzala. Problems of water quantity and quality will increase through the twenty-first century with increasing demands for water while effects of climate change will enhance freshwater scarcity. Conflicts between human and environmental uses of water will increase and unless improvements in water use efficiency and wastewater treatment can be brought about wetlands including coastal lagoons are likely to suffer further loss and degradation. These problems will be compounded by sea level rise.
This paper presents a new three-dimensional CMOS-SOI technology anddiscusses design issues for it... more This paper presents a new three-dimensional CMOS-SOI technology anddiscusses design issues for it. In this technology the P-channel devices arestacked over the N-channel ones. All gates are 0.1|ìm length. New designconstraints are introduced. Consequently, new design methodologies haveto be developed in order to fully take advantage of the outstanding featuresof D integration like for example the reduced length of interconnections.INTRODUCTION
Three North African coastal lagoons were selected as primary sites for integrated ecological and ... more Three North African coastal lagoons were selected as primary sites for integrated ecological and hydrological monitoring and modelling as part of the MELMARINA Project (see . The three sites, Merja Zerga (13.2 km 2 , Morocco), Ghar El Melh (35.6 km 2 , Tunisia) and Lake Manzala (c. 700 km 2 , Egypt), are permanent water bodies with at least one well-defined connection with the sea. This article provides an account of each lagoon's physical characteristics and recent development including the impacts of human activities. The two sites on the Mediterranean (Ghar El Melh and Lake Manzala) are characterised by small tidally driven variations in water level whilst Merga Zerga, on the Atlantic coast, experiences large tidally induced water level variations and so contains large inter-tidal environments. All the three lagoons
Hydrological and hydrodynamic characteristics are important controls in all wetlands including co... more Hydrological and hydrodynamic characteristics are important controls in all wetlands including coastal lagoons. Enhanced understanding of lagoon functioning can be obtained through the acquisition and interpretation of hydrological, meteorological and related data. The MELMARINA persist due to longer residence times of water within the lagoon. Freshwater inflows are central to the functioning of Lake Manzala. Large discharges of relatively freshwater are provided by major drains which cross the Nile Delta. These influence lake water levels and are responsible for the freshwater conditions within large parts of the lake. The small tidal range of the eastern Mediterranean, coupled with constricted connections with the sea, reduces the influence of lake-sea exchanges and tidally induced water level oscillations within Lake Manzala.
Ghar El Melh (Northern Tunisia) is a shallow eutrophicated lagoon (total surface area 35.6 km 2 )... more Ghar El Melh (Northern Tunisia) is a shallow eutrophicated lagoon (total surface area 35.6 km 2 ) which was one of the primary sites within the MELMARINA project. It is connected to the Mediterranean through a dredged opening and receives untreated sewage from two towns and a catchment of 131 km 2 . During the past decade the lagoon's water quality has deteriorated and vegetation has changed. Ruppia sp. has diminished and green macroalgae (mainly Cladophora sp.) has increased. Frequent resuspension of fine alluvial sediment has reduced both water transparency and angiosperm (Ruppia sp.) vegetation cover. Flash floods during winter deliver most of the load of sediment and nutrients from the catchment to the lagoon. Options for restoring the angiosperm cover in the lagoon have been analysed using a model system developed for the main part of the lagoon consisting of a 2-D hydrodynamic model coupled to an ecological model. The ecological model includes a combined description of eutrophication and sediment transport with rooted vegetation (Ruppia sp.), benthic macroalgae, benthic microalgae, phytoplankton and suspended matter and nutrients. A separate sediment module includes pools of nutrients, organic carbon and fine sediment. Deposition and resuspension of the sediment pools are dependent on current and wind-generated shear stress. The load of nutrients and fine sediment was estimated through calibrating the model against measured water quality data and sediment deposition rates. The anthropogenic load from July 2003 to July 2004 was 33,000 tonnes fine sediment, 182 tonnes total N and 26 tonnes total P. A net import of sediment and nutrients from the sea was simulated, driven by the relatively high concentrations of suspended matter and particulate-bound N and P measured in coastal Mediterranean water outside the lagoon. Scenario simulations indicate that the lagoon acts as a deposition area for sediment N and P for boundary concentrations down to 50% of the measured concentrations at the coast outside the lagoon. A range of simulations with decreasing load of sediment and nutrients indicate that angiosperm vegetation will slowly recover with loads of 25% of current loads, combined with increased filtration by bivalves which would decrease suspended matter concentrations and increase transparency. Elevated concentrations of suspended matter and nutrients in the sea outside the lagoon are discussed in relation to a 30-year flash flood of the Mejerda River in February 2003. Coastal erosion as well as nutrients and sediment delivered by this river probably account for a general elevation of these concentrations close to the coast.
... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; ... more ... its alluvial environment and wind accumulations on its shores (Pimenta, 1949; Jauzein, 1967; Karray, 1977; Bourgou, 1993, 1994; Oueslati, 1992, 1993 ... This landscape is found north of the sebkha facing the well populated settlements of Saida, Mellasine and Sidi Hsine, as well ...
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