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981.
Tanya M. Silveira Catarina Frazão Santos Francisco Andrade 《Journal of Coastal Conservation》2013,17(4):825-832
In the winter of 2006/2007 approximately 200,000 m3 of high quality sand from the dredging of the local marina were placed at the ocean-side beaches in the vicinity of a tourism development in Tróia, Portugal. The beach-quality sediment provided a source of “sand of opportunity” which was used to increase the dry-beach width of the highly used coastal stretch. The sediment was placed along approximately 600 m of shoreline and a monitoring program has since being carried out twice a year. High-resolution topographic surveys and sediment analysis are being conducted to evaluate the performance and response of the fill to the local forcing factors and ultimately to evaluate the effectiveness of the fill project. Two years after the nourishment, the sediment has been distributed both cross-shore and alongshore. The pre-nourishment beach slope was attained and the new shoreline has acquired a natural shape. Berm width increased by a maximum of 100 m, and a set of new dune ridges has developed, due to sand accumulation promoted by the settlement of vegetation. In conclusion, 2 years after its completion, the beach nourishment in Tróia can be viewed as a successful project in which the beneficial use of dredged material resulted in: 1) area for increased dune field growth and development, 2) enhancement of potential shorebird nesting areas and habitat, and 3) increased area for recreation purposes. 相似文献
982.
P. C. Roebeling L. Costa L. Magalhães-Filho V. Tekken 《Journal of Coastal Conservation》2013,17(3):389-395
Coastal zones experience increased rates of coastal erosion, due to rising sea levels, increased storm surge frequencies, reduced sediment delivery and anthropogenic transformations. Yet, coastal zones host ecosystems that provide associated services which, therefore, may be lost due to coastal erosion. In this paper we assess to what extent past and future coastal erosion patterns lead to losses in land cover types and associated ecosystem service values. Hence, historical (based on CORINE land cover information) and projected (based on Dynamic and Interactive Vulnerability Assessment - DIVA - simulations) coastal erosion patterns are used in combination with a benefits transfer approach. DIVA projections are based on regionalized IPCC scenarios. Relative to the period 1975–2050, a case study is provided for selected European coastal country member states. For historical (1975–2006) coastal erosion trends, we observe territory losses in coastal agricultural, water body and forest & semi-natural areas – total coastal erosion equaling over 4,500 km2. Corresponding coastal ecosystem service values decrease from about €22.3 billion per year in 1975 to about €21.6 billion per year in 2006. For future (2006–2050) coastal erosion projections, total territory losses equal between ~3,700 km2 and ~5,800 km2 – coastal wetland areas being affected most severely. Corresponding coastal ecosystem service values decrease to between €20.1 and €19.4 billion per year by 2050. Hence, we argue that the response strategy of EU member states to deal with coastal erosion and climate change impacts should be based on the economic as well as the ecological importance of their coastal zones. 相似文献
983.
Araceli Loredo-Treviño Gerardo Gutiérrez-Sánchez Raúl Rodríguez-Herrera Cristóbal N. Aguilar 《Journal of Polymers and the Environment》2012,20(1):258-265
Plastics are present in a lot of aspects of everyday life. They are very versatile and resistant to microbial attack. Polyurethanes
are used in several industries and are divided in polyester and polyether polyurethanes and there are different types among
them. Despite their microbial resistance, they are susceptible to the attack of fungi and bacteria but the mechanism to elucidate
its biodegradation are unknown. There are reports from bacteria and fungi that are capable of degrading polyurethane but the
studies about the enzymes that attack the plastic are focused on bacterial enzymes only. The enzymes reported are of type
esterase and protease mainly since these enzymes are very unspecific and can recognize some regions in the polyurethane molecule
and hydrolyze it. Fungal enzymes have been studied prior the 1990s decade but recently, some authors report the use of filamentous
fungi to degrade polyurethane and also report some characteristics of the enzymes involved in it. This review approaches polyurethane
biodegradation by focusing on the enzymes reported to date. 相似文献
984.
Nini Johanna Cadena Camilo Rey Marcela Hernández-Hoyos J. Darío Sánchez Stanislas Teillaud Nestor Ardila Juan A. Sánchez 《Marine Biology》2010,157(5):1003-1010
Branching growth is present both in plants and animals, either marine or terrestrial. Although cellular and other modular
levels of organization in plants and animals have evolved through different molecular and physiological mechanisms, several
aspects of their branching modular system and morphology are similar. We studied vessel organization and colony integration,
in order to comprehend underlying relationships between different structural components in a gorgonian coral network. The
theoretical formalism was validated in the gorgonian coral Eunicea mammosa (Plexauridae, Octocorallia) in Belize. As in vascular plants, these colonial animals create a complex network of connections
among modular branches integrated in stem canals downstream toward the base. A new formalism is proposed for describing gorgonian
branching. A global property of a colony is for instance the size of its base or its weight whereas a local property is the
size of branch in a particular place of the colony. However, a global property is not the simple addition of local modular
properties, as the case of stem canals in the colony base. Theoretically, the process of branching is tightly intertwined
with the internal network organization. The colony network centralization is driven by a linear relationship between the total
number of branches and the stem canals at the base of the colony. If stem canals play important roles in the transport of
nutrients throughout the colony and the biomechanical support from the base up to the tips, we can assume that there is an
underlying association between the number of stem canals at the base and the number of for example, terminal branches. These
associations may provide new findings that extend our understanding of the functional organization of tree-like networks in
octocorals and their vascular systems. The idea that the external components of a tree-like plant network are directly correlated
and connected down to the main trunk seems to be analogous in an animal system. 相似文献
985.
Sofia Gamito Paula Chainho João Paulo Medeiros João Carlos Marques 《Ecological modelling》2010,221(3):459-466
The brackish water amphipod Corophium orientale is the dominant macroinvertebrate species in the upper Mira estuary, a small mesotidal system located in the southwest coast of Portugal. As climate changes will increase the frequency and intensity of extreme events such as floods and droughts, these will have a negative effect on benthic estuarine invertebrates, namely C. orientale. In order to understand the effects of these events on C. orientale, a dynamic model, based on published information and calibrated with field data, was developed and different scenarios were tested.For model construction, the annual development of three cohorts of C. orientale, their growth rates, and the establishment of the timing of each cohort rise and extinction are introduced. This structure can be repeated indefinitely, for years, and few parameters are required. The model simulations highlight the need for refuge areas that enable a fast recovery of the amphipod population after an extreme event and the recolozination of the affected areas. 相似文献
986.
Velasco H Carreño E Rodríguez M Belle M Sansone U 《Journal of environmental radioactivity》2004,73(2):223-230
RSP (Radioecological Software Package) is an interactive support system that simulates the behaviour of radionuclides in semi-natural environments and the consequences on the population in terms of the external exposure. RSP consists of three modules: the first one, soil mobility, simulates the vertical transport of radionuclide in soil using the mathematical model RABES. The second module, soil -to-plant transfer, simulates the radionuclide soil-to-plant transfer factor reported in the literature. Soil properties, vegetation types and environmental conditions are taken into consideration in the simulation process. In the third module, dose assessment, the dose-rate factor in air at a height of 1 m above ground can be calculated for sources distributed in a slab of finite thickness dn sources which are exponentially distributed with depth. The calculations are performed using DAGES Model, a Monte Carlo algorithm developed to simulated the photon transport for the soil/air configuration. A free copy of RSP can be downloaded from the website: http://imasl-apat.unsl.edu.ar. 相似文献
987.
Mechanical Property and Biodegradability of Cast Films Prepared from Blends of Oppositely Charged Biopolymers 总被引:1,自引:0,他引:1
M.?O.?Rutiaga L.?J.?Galan L.?H.?Morales S.?H.?Gordon S.?H.?ImamEmail author W.?J.?Orts G.?M.?Glenn K.?A.?Ni?o 《Journal of Polymers and the Environment》2005,13(2):185-191
Biodegradable cast films of about 50 m thickness were fabricated by blending oppositely charged biopolymers such as anionic starch–chitosan, and cationic starch–pectin. The tensile strength and elongation at break (%) of films were evaluated as well as their capacity to degrade in compost. Films recovered from soil every 48 h showed consistent degradation (weight loss), diminution of the polymers characteristic peak absorbance in the carbohydrate fingerprint region of the FTIR, and changes in the surface morphology via scanning electron microscopy (SEM). Anionic starch–chitosan films had much superior tensile strength and elongation compared to cationic starch–pectin, suggesting that the ionic bonds formed between anionic-starch and positively charged groups in chitosan polymer were much more stable and stronger. Initially, both films lost about 36% weight within 96 h, which also correlated well with the loss in the characteristic absorption peaks in the region of the infrared spectrum typical of biopolymers. The total mineralization of films by microorganisms in compost soil was also measured using respirometric techniques. Though the rate of mineralization differed for two formulations, total mineralization (extent) for both films were achieved within 45 days. 相似文献
988.
Mussel transplantation and biomarkers as useful tools for assessing water quality in the NW Mediterranean 总被引:12,自引:0,他引:12
Roméo M Hoarau P Garello G Gnassia-Barelli M Girard JP 《Environmental pollution (Barking, Essex : 1987)》2003,122(3):369-378
Mussels, coming from an aquaculture farm located in a clean open bay, were transplanted to several stations of the bays of Nice and Cannes (NW Mediterranean) including a reference site for one month at three periods. Several biomarkers: activities of glutathione S-transferase (GST; exposure to organics), of catalase (exposure to oxidative stress) and of acetylcholinesterase (inhibited by some pesticides) and the lipid peroxidation (thiobarbituric acid reactive substances: TBARS) were measured in transplanted mussels. Cd, Cu and Zn concentrations were also measured as well as their condition index. The results demonstrated some seasonal variations in GST and catalase activities with higher levels in June compared to October. The condition index was also higher in June than in October. Principal component analyses performed with the whole set of data allowed to separate stations or groups of stations according to their responses. The mussels from the harbour of Nice were characterized by high TBARS levels and catalase activity in October 1999 whereas in the harbour of Cannes, animals presented very high copper concentrations and GST activities in June 2000. At the reference site, mussels generally presented low enzymatic activities (except AChE activity) and peroxidation levels and low heavy metal concentrations. 相似文献
989.
Jorge E. Moreira Cedeño 《Disasters》1986,10(2):107-111
Inasmuch as health is at cross purposes with illness, suffering, disability and death, it is clear that all measures that are adopted with foresight to reduce the repercussions of natural disasters have consequences for health 相似文献
990.
Hugo A. Loaiciga Miguel A. Mario 《Journal of the American Water Resources Association》1987,23(4):541-554
ABSTRACT: This paper presents criteria for establishing the identification status of the inverse problem for confined aquifer flow. Three linear estimation methods (ordinary least squares, two-stage least squares, and three-stage least squares) and one nonlinear method (maximum likelihood) are used to estimate the matrices of parameters embedded in the partial differential equation characterizing confined flow. Computational experience indicates several advantages of maximum likelihood over the linear methods. 相似文献