Freshwater-saltwater interface and estuarine sediment in situ assays based on post-exposure feeding of chironomids and polychaetes     

Sara Soares  Susana Moreira  Sofia Andrade  Lúcia Guilhermino  Rui Ribeiro 《Estuaries and Coasts》2005,28(2):314-319

An integrated approach for ecological and ecotoxicological sediment assessments along the freshwater saltwater interface (FSI) and estuarine areas in general was developed, through the adaptation of recently proposed methods for the midge larvaChironomus riparius (an in situ assay based on post-exposure feeding for sediment toxicity assessments in freshwater systems) and the development of new techniques for the polychaeteHediste (Nereis) diversicolor (an in situ post-exposure feeding assay). Based on the previously proposed methods, improvements were made to the feeding quantification ofC. riparius fourth instar larvae. A method to quantify the post-exposure feeding ofH. diversicolor was developed and optimized under laboratory conditions using newly hatchedArtemia franciscana nauplii as a food source. Assay chambers and procedures fromC. riparius assays were easily adapted forH. diversicolor in situ exposures. Sediment assays using this integrated approach were successfully performed at an uncontaminated river-estuarine system. They consisted of a 48-h exposure followed by a 1-h post-exposure feeding for chironomids and a 2-h post-exposure feeding for polychaetes. Good recovery rates were obtained after the 48-h field exposure. Fluctuations in various physicochemical variables at the FSI, due to the tidal regime, did not significantly influenceC. riparius larval post-exposure feeding rates, suggesting that uncontaminated freshwater sites located upstream of FSI areas can be used as reference sites forC. riparius in situ evaluations in estuaries. Adapted assay chambers and procedures were suitable forH. diversicolor in situ exposures.  相似文献   

Factors influencing human beach choice on three South African beaches: A multivariate analysis   总被引：1，自引：0，他引：1  

A. M. C. De Ruyck  A. G. Soares  A. McLachlan 《GeoJournal》1995,36(4):345-352

Knowledge of recreational use patterns, preferences and opinions of beach users can be useful in developing beaches in such a way as to ensure quality recreational experiences. This paper investigated, by means of questionnaire survey, a) the factors influencing human beach choice on three beaches with different levels of development and b) whether respondents on the different beaches considered different characteristics important on an ideal beach. By means of multiple discriminant analysis, visitors could be classified according to the beaches they were interviewed on, based solely on the different reasons given for visiting the beach as well as on the characteristics they considered important on a beach.Although factors relating to level of beach development were the most important in influencing beach choice on highly developed King's Beach and undeveloped Sardinia Bay, traditional/historical, socio-economic factors and accessibility (all unrelated to beach development) were more important on semi-developed Joorst Park, visited by people of a lower-socio-economic level. These people considered Joorst Park underdeveloped but were prevented by socio-economic restraints from visiting a beach of their choice, eg King's Beach. The highly and semi-developed beaches were visited for their facilities, social activities and accessibility. The undeveloped beach was visited for experiencing nature, peace and quiet, its few people and because dogs were allowed there. In addition, respondents' opinions were obtained on litter, additional facilities, preferred distances between groups on the beach and in the surf and whether dogs and off-road vehicles should be allowed on beaches. More basic facilities (toilets and refuse bins) were considered necessary on all beaches, especially on the semi-developed beach. Beyond a minimal level of amenities, additional comforts were undesired by users on the undeveloped beach and limited funds should rather be used to upgrade and improve beaches such as Joorst Park, that are already developed to attract people with greater demands for a wider range of facilities. However, beaches with different levels of development are necessary to cater for people who desire different recreational experiences. Limiting beach access beyond a certain number of visitors seems to be unpopular with the public.  相似文献   

Motional induction voltage measurements in estuarine environments: the Ria de Aveiro Lagoon (Portugal)     

Rita Nolasco  António Soares  João M. Dias  Fernando A. Monteiro Santos  N. A. Palshin  Patricia Represas  Nuno Vaz 《Geophysical Journal International》2006,166(1):126-134

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Valorization of coffee byproducts for bioethanol production using lignocellulosic yeast fermentation and pervaporation     

D. Dadi  A. Beyene  K. Simoens  J. Soares  M. M. Demeke  J. M. Thevelein  K. Bernaerts  P. Luis  B. Van der Bruggen 《International Journal of Environmental Science and Technology》2018,15(4):821-832

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Changes in physicochemical properties of biodiesel after degradation and remediation     

V. F. Mello  T. C. Soares  M. G. Fonseca  L. N. Batista 《International Journal of Environmental Science and Technology》2018,15(8):1713-1718

Biodiesel is the main substitute for petrodiesel being constituted by several alkyl esters including unsaturated compounds. It can undergo partial oxidation when stored for long periods and transported over long distances. The aims of this study were to analyze the impact of the oxidation process on the physicochemical properties of biodiesel and its remediation through distillation and esterification. Due to its high susceptibility to oxidation, sunflower biodiesel was used as a model. Specific mass, cloud point, cold filter plugging point, oxidation stability and iodine value were the properties analyzed. The results revealed that the treatments affected each sample differently, and in some cases the product after remediation had properties close to or even better than the initial biodiesel. The results reported here indicate that although biodiesel undergoes degradation during storage and transport, this does not mean the affected fuel cannot be marketed. Some important properties can be recovered with simple treatment.  相似文献   

Optimized History Matching with Direct Sequential Image Transforming for Non-Stationary Reservoirs     

M. Helena Caeiro  Vasily Demyanov  Amilcar Soares 《Mathematical Geosciences》2015,47(8):975-994

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Hydrogeochemical and Geophysical Evaluation of the Recharge Zone of Guarani Aquifer in Municipally of Candelária,Rio Grande do Sul,Brazil     

Moreno  Wilmer Emilio García  Soares  Gabriela Borges  Pires  Júlio César Gall  Sotelo  Daniela Govoni  Moura  Cássio Stein 《Geotechnical and Geological Engineering》2021,39(6):4593-4613

Geotechnical and Geological Engineering - A large part of the Guarani Aquifer is located in the state of Rio Grande do Sul (Brazil) and additionally possesses a recharge area located in its central...  相似文献   

Offshore structure modelling : By S. K. Chakrabarti. World Scientific Publishing Co. 1994. ISBN 981-02-1513-4     

C. Guedes Soares 《Applied Ocean Research》1995,17(6):391-392

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Assessment of the uncertainty in visual observations of wave height     

C. Guedes Soares   《Ocean Engineering》1986,13(1)

Visual observations of wave height are still the main source of statistical information available for the prediction of extreme wave conditions to be used in the design of ship structures. However, the observations need to be calibrated with measurements. This work examines previous calibration studies and after joining the old with more recent data sets a reanalysis of the complete data sets is performed leading to updated regression equations.  相似文献   

Characteristics of abnormal waves in North Sea storm sea states   总被引：1，自引：0，他引：1  

C. Guedes Soares  Z. Cherneva  E. M. Anto 《Applied Ocean Research》2003,25(6):658-344

A data set of storm wave records from the North Sea is analysed. Using current definitions of abnormal waves, eight of the largest wind waves are defined as abnormal waves. Twenty-four of the largest waves in time series, with a height larger than 10 m and with big vertical asymmetry are chosen for further analysis. Their individual characteristics are investigated and related to the global sea state characteristics. A comparison between measured data, second-order theory predictions and offshore basin data is made. The results for the chosen waves do not coincide with predictions of second-order theory. Considering that wind wave is second- and third-order non-linear, a new relationship between skewness and kurtosis is proposed for the sea states in which extremely asymmetric large waves have occurred. Another relationship between kurtosis and abnormality index of maximum waves is proposed too.  相似文献