scholarly journals Main Threats in Mediterranean Coastal Wetlands. The Ebro Delta Case

2021 ◽  
Vol 9 (11) ◽  
pp. 1190
Author(s):  
Inmaculada Rodríguez-Santalla ◽  
Nuria Navarro

Coastal wetlands are dynamic ecosystems that exist at the interface between land and sea. They represent environments with a great diversity of habitats and communities, high carbon sequestration capacity and a wide range of ecosystem services. In the Mediterranean, the largest coastal wetlands are found in deltaic areas like that of the Ebro River (Spain), which has a coastline length of approximately 50 km, occupying a total area of 325 km2. The Ebro Delta is included in different national and international frameworks for environmental conservation, despite which there are several risks that threaten it. The lack of sedimentary contributions due to the regulation of the Ebro riverbed (irrigation, reservoirs, and hydroelectric power generation) has caused erosion and the retreat of certain sections of its coastline. To this situation of sediment deficit must be added the threat posed by the effects of global change, such as the rise in sea level, the increase in temperature and in the frequency and intensity of storms. This study analyses the particularities of the coastal wetland of the Ebro Delta, identifying the main threats it faces, as well as possible adaptation and mitigation strategies to these changes.

Wetlands ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 775-785 ◽  
Author(s):  
Xavier Benito ◽  
Rosa Trobajo ◽  
Carles Ibáñez

2021 ◽  
Author(s):  
Thaisa Bergamo ◽  
Raymond Ward ◽  
Christopher Joyce ◽  
Kalev Sepp

<p>Coastal meadows supply a wide range of ecosystem services, including high carbon storage, high plant species richness and a wide variety of habitat types, which supports breeding and migratory bird populations. However, global change (climate change, pollution and environmental degradation) poses several threats to the stability and ecosystem services supplied by coastal meadows. Specifically within the Baltic Sea, recent estimates foresee various degrees of sea level rise along the Estonian coast and salinity is expected to decrease in the eastern Baltic and increase in the west. In order to assess the effects of climate change in coastal wetlands, an investigation of the influence of changes in water level and salinity on coastal wetland plant communities was undertaken. Future scenarios of Estonian coastal wetlands were evaluated using a three-year mesocosm experiment simulating altered environmental conditions. The response of three plant communities (Open Pioneer, Lower Shore and Upper Shore) were assessed in terms of changes in species composition through time. The experiment included 45 mesocosms, 15 per community with 5 treatments (3 replicates per treatment) with control, altered water level and salinity. Exploratory analysis, ANOVA and NMDS, were used to assess changes in the plant communities throughout the duration of the project. Preliminary results show that Open Pioneer is more sensitive to decreased salinity. A decrease in percentage cover of species adapted to high salinity concentration (e.g. <em>Spergularia marina</em>) was observed. On the other hand, Lower Shore didn’t show any clear changes with the treatments. In order to obtain deeper insights, further analysis are needed to reveal complex community shifts under altered physical conditions.</p>


2021 ◽  
Vol 13 (8) ◽  
pp. 1450
Author(s):  
Alejandro Navarro ◽  
Mary Young ◽  
Peter I. Macreadie ◽  
Emily Nicholson ◽  
Daniel Ierodiaconou

Coastal wetland ecosystems, such as saltmarsh and mangroves, provide a wide range of important ecological and socio-economic services. A good understanding of the spatial and temporal distribution of these ecosystems is critical to maximising the benefits from restoration and conservation projects. We mapped mangrove and saltmarsh ecosystem transitions from 1991 to 2015 in south-eastern Australia, using remotely sensed Landsat data and a Random Forest classification. Our classification results were improved by the addition of two physical variables (Shuttle Radar Topographic Mission (SRTM), and Distance to Water). We also provide evidence that the addition of post-classification, spatial and temporal, filters improve overall accuracy of coastal wetlands detection by up to 16%. Mangrove and saltmarsh maps produced in this study had an overall User Accuracy of 0.82–0.95 and 0.81–0.87 and an overall Producer Accuracy of 0.71–0.88 and 0.24–0.87 for mangrove and saltmarsh, respectively. We found that mangrove ecosystems in south-eastern Australia have lost an area of 1148 ha (7.6%), whilst saltmarsh experienced an overall increase in coverage of 4157 ha (20.3%) over this 24-year period. The maps developed in this study allow local managers to quantify persistence, gains, and losses of coastal wetlands in south-eastern Australia.


Author(s):  
F. A. Khalid ◽  
D. V. Edmonds

The austenite/pearlite growth interface in a model alloy steel (Fe-1lMn-0.8C-0.5V nominal wt%) is being studied in an attempt to characterise the morphology and mechanism of VC precipitation at the growth interface. In this alloy pearlite nodules can be grown isothermally in austenite that remains stable at room temperature thus facilitating examination of the transformation interfaces. This study presents preliminary results of thin foil TEM of the precipitation of VC at the austenite/ferrite interface, which reaction, termed interphase precipitation, occurs in a number of low- carbon HSLA and microalloyed medium- and high- carbon steels. Some observations of interphase precipitation in microalloyed low- and medium- carbon commercial steels are also reported for comparison as this reaction can be responsible for a significant increase in strength in a wide range of commercial steels.The experimental alloy was made as 50 g argon arc melts using high purity materials and homogenised. Samples were solution treated at 1300 °C for 1 hr and WQ. Specimens were then solutionised at 1300 °C for 15 min. and isothermally transformed at 620 °C for 10-18hrs. and WQ. Specimens of microalloyed commercial steels were studied in either as-rolled or as- forged conditions. Detailed procedures of thin foil preparation for TEM are given elsewhere.


Alloy Digest ◽  
1984 ◽  
Vol 33 (2) ◽  

Abstract AISI 1566 is a high-carbon (nominally 0.66% carbon) steel containing 0.85-0.15% manganese. Its hardenability is low and on austenitizing and liquid quenching it develops a hard (martensitic) surface with a soft, ductile core. It can be used in the hot-rolled, annealed, normalized, cold-worked or liquid-quenched-and-tempered condition for a wide range of applications. It has good machinability and good workability. Its many uses include springs, shafts, hand tools, railway parts and agricultural machinery. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-100. Producer or source: Carbon steel mills.


Author(s):  
Sergei Soldatenko ◽  
Sergei Soldatenko ◽  
Genrikh Alekseev ◽  
Genrikh Alekseev ◽  
Alexander Danilov ◽  
...  

Every aspect of human operations faces a wide range of risks, some of which can cause serious consequences. By the start of 21st century, mankind has recognized a new class of risks posed by climate change. It is obvious, that the global climate is changing, and will continue to change, in ways that affect the planning and day to day operations of businesses, government agencies and other organizations and institutions. The manifestations of climate change include but not limited to rising sea levels, increasing temperature, flooding, melting polar sea ice, adverse weather events (e.g. heatwaves, drought, and storms) and a rise in related problems (e.g. health and environmental). Assessing and managing climate risks represent one of the most challenging issues of today and for the future. The purpose of the risk modeling system discussed in this paper is to provide a framework and methodology to quantify risks caused by climate change, to facilitate estimates of the impact of climate change on various spheres of human activities and to compare eventual adaptation and risk mitigation strategies. The system integrates both physical climate system and economic models together with knowledge-based subsystem, which can help support proactive risk management. System structure and its main components are considered. Special attention is paid to climate risk assessment, management and hedging in the Arctic coastal areas.


2018 ◽  
Vol 245 ◽  
pp. 15002 ◽  
Author(s):  
Roman Davydov ◽  
Valery Antonov ◽  
Dmitry Molodtsov ◽  
Alexey Cheremisin ◽  
Vadim Korablev

The rapid spread of storm floods over large areas requires flood management throughout the river basin by the creation an innovative system of flood control facilities of various functional purposes distributed in the area. The central part of the system is the hydro system with hydro power plant. In addition, the flood control facilities on the side tributaries with self-regulating reservoir are included in the system. To assess the effect of controlling extreme water discharges by flood control facilities, it is necessary to develop special mathematical models reflecting the specifics of their operation. Unified mathematical models of the operation modes of a hydro complex with hydroelectric power station and flood control facility are created. They are implemented in a computer program that provides the ability to determine the main parameters and operating characteristics of hydro systems when performing multivariate calculations in a wide range of initial data. This makes possible specifying the parameters and operation modes of each hydro system with the current economic and environmental requirements, to assess the energy-economic and environmental consequences in the operation of the system of flood control facilities distributed in the area. The article analyses the results of the extreme water discharge’s regulation by the hydro system on the main river and flood control facilities on the side tributaries, considering environmental requirements.


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