Extracting sea level residual in tidally dominated estuarine environments

Sea level comprises a mean level, tidal elevation and a residual elevation. Knowledge of what causes maximum water levels is often key in coastal management. However, different methods to extract deviations in water level (residuals) from modelled and observed elevation can give different results. The Dee Estuary, northwest England is a macrotidal estuary that undergoes periodic stratification. It is used here to demonstrate methods to extract the residual water level in response to the following interactive processes: tidal, river-induced stratification and flow, meteorology and waves. Using modelling techniques, the interaction and contribution of different physical processes are investigated. Classical harmonic tidal analysis, model simulations and filtering techniques have been used to “de-tide” the total elevation for short-term (approximately month long) records. Each technique gives a different result highlighting the need to select the correct method for a required study. Analysis of the residual components demonstrates that all processes inducing residuals interact with the tide generating a semi-diurnal residual component. It is suggested that modelling methods enable the full effect of tidal interaction to remain in the residual, whilst harmonic tidal analysis (partly) modify and filtering methods (fully) remove this component of the residual. The analysis methods presented and their influences on the resultant residual are applicable to other study sites. However, when applied specifically to the mouth of the Dee Estuary, the external surge is found to be the main contributor to the total residual, whilst local wind and stratification effects are of secondary importance.     

Web-oriented GIS system for monitoring, conservation and law enforcement of the Brazilian Amazon

A web GIS (WGIS) system for the Brazilian Amazon, named ImazonGeo and based on open source and public domain data, is presented. ImazonGeo was built following three principles. First, the system is based on Spatial Data Infrastructure architecture and web interface built using free software and public domain data. Second, we went beyond visualization of maps and spatial queries by providing information obtained with spatial analysis models. To do that, we designed a database that stores the results of previously defined spatial analyses and developed customized reports and query tools to facilitate fast access of information by end-users. Finally, the system is application-oriented in the areas of forest monitoring, conservation and forest law enforcement, meaning that it aims to contribute to support the protection of Brazilian Amazon forests. We illustrate these principles by presenting ImazonGeo’s technology, architecture, content and tools. Moreover, we present two successful cases to demonstrate how the system is being used. We conclude the paper discussing the challenges and potential solutions to turning our WGIS-SDI system into an internet hub of geo-information about the Brazilian Amazon.     

An introspective glance into damage assessment: challenges and lessons learned from the Paso Robles (San Simeon) earthquake

This paper underscores the importance of damage assessment and recognizes the direct effect it has on post-disaster response and recovery operations. The paper first explores the literature on this subject, including the history, types, methods, and problems relating to damage assessment. After discussing the employed research methodology, the paper uses the Paso Robles (San Simeon, California) earthquake as a case study to illustrate the challenges and successes with regard to damage assessment. Logistics, politics, information management, coordination, preparedness, and other topics are discussed in this section. The paper concludes with lessons and opportunities for research and its application.     

A new U–Pb zircon age dating and palynological data from a Lower Permian section of the southernmost Paraná Basin,Brazil: Biochronostratigraphical and geochronological implications for Gondwanan correlations

Index species useful for correlations with the International Stratigraphical Column are rare or absent in the Pennsylvanian–Permian strata of the Paraná Basin in Brazil, preventing accuracy in geochronologic assignments. Besides, absolute datings are very scarce in comparison with other Gondwana basins. This paper presents palynological data from an outcrop on the surroundings of the Candiota coal mine, southmost Brazil, from several levels of the Rio Bonito and Palermo formations. The presence of certain index species of spore–pollen allowed the recognition of two Permian palynozones: the Vittatina costabilis and the Lueckisporites virkkiae zones. Furthermore, U–Pb in zircons from a volcaniclastic level interbedded in the coal strata of the former unit was analyzed through LA-MC-ICP-MS method, providing a new absolute age dating of 281.4 ± 3.4 Ma (Cisuralian, Early Permian). This dating is assumed as the oldest occurrence of the L. virkkiae Zone in Paraná Basin, which contains index species that are widespread in other Gondwana basins. A well distributed surface boundary occurs in this section also, allowing local and regional correlations. These new biostratigraphical and geochronological data are integrated, in order to offer a deep analysis on the stratigraphical significance for correlations across the Occidental Gondwana.     

Climatic consequences of gradual desertification in the semi-arid area of Northeast Brazil

The climatic impacts of gradual desertification in the semi-arid area of Northeast Brazil (SANEB) were evaluated using the MM5 regional model. Simulations for the rainy season of SANEB (March, April, and May) were performed. Desertification simulations were grouped into three numerical runs: total (all SANEB covered by desert), partial (desert areas placement based on future environmental degradation scenarios for SANEB), and random desertification (desert areas placed randomly within SANEB). Total desertification led to a pronounced and significant precipitation reduction in large parts of SANEB. Climatic impacts of partial desertification were guided by the southward expansion of desert areas. For intermediate desertification extensions, a dipole pattern with precipitation reduction (increase) in the northern (southern) areas of SANEB was found. Random desertification led to climatic impacts spread over the whole SANEB. In both partial and random desertification, a quasi-linear precipitation reduction was found as desertification extension increases.     

Cotton Fiber/ZrO2, A New Material for Adsorption of Cr(VI) Ions in Water

The natural cotton fiber was used to synthesize an anion exchange, containing ZrO₂ film on its surface, NCFZC (natural cotton fiber/ZrO₂ composite). This anion exchanger was produced by the reaction of the zirconium oxychloride and hydroxyl groups on surface of the natural cotton fiber. The material was used for Cr(VI) ions adsorption studies. Adsorption equilibrium time and optimum pH for Cr(VI) adsorption were found to be 6 h and 4.0, respectively. The Langmuir and Temkin isotherms were used to models adsorption equilibrium data. The adsorption capacity of NCFZC was found to be 1.33 mmol/g. Kinetic studies showed that the rate of adsorption of Cr(VI) on NCFZC obeyed a pseudo‐second‐order kinetic model.     

Sun–earth relationship inferred by tree growth rings in conifers from Severiano De Almeida,Southern Brazil

This study of Sun–Earth relationships is based on tree growth rings analysis of araucarias (Araucaria angustifolia) collected at Severiano de Almeida (RS) Brazil. A chronology of 359 years was obtained, and the classical method of spectral analysis by iterative regression and wavelet method was applied to find periodicities and trends contained in the tree growth. The analysis of the dendrochronological series indicates representative periods of solar activity of 11 (Schwabe cycle), 22 (Hale cycle), and 80 (Gleissberg cycle) years. The result shows the possible influence of the solar activity on tree growth in the last 350 years. Periods of 2–7 years were also found and could represent a response of the trees to local climatic conditions. Good agreement between the time series of tree growth rings and the 11 year solar cycle was found during the maximum solar activity periods.     

Differences in the neighborhood: Structural variations in the carapace of shore crabs Carcinus maenas (Decapoda: Portunidae)

The present study compared the carapace structure of Carcinus maenas in two nearby sites (2 km apart) within Minho estuary, submitted to different physicochemical and ecological conditions (water temperature, pH, crabs’ density and sex ratio). The carapace structure of the carapace and chelae of the crabs presented significant differences between sampling sites (t-test; p < 0.01). The SIMPER analysis revealed that the Weight/CW and Thickness/CW ratios explained all the dissimilarities found among sites. Overall, the male carapace was proportionally thicker at station 2 (t-test; p < 0.01), while the female carapace was proportionally thicker at station 1 (t-test; p < 0.001). A thicker carapace can be advantageous when competing for food or a sexual partner. We hypothetized that, since at station 2, the density of individuals was twice higher than at station 1, it is likely that agonistic encounters are more frequent, thus favouring a thicker carapace.     

Paleoecology and radiocarbon dating of the Pleistocene megafauna of the Brazilian Intertropical Region

During the Pleistocene a fauna composed of large (biomass > 44 kg) and giant mammals (biomass > 1000 kg) that are usually associated with open environments lived in the Brazilian Intertropical Region. We present here new information concerning the paleoecology and chronology of some species of this megafauna. Carbon isotope analyses were performed for a better understanding of the paleoecology of the species Eremotherium laurillardi (Lund, 1842), Notiomastodon platensis (Ameghino, 1888) and Toxodon platensis (Owen, 1849). The δ¹³C data allow attributing a generalist diet to these species, which varied according to the kind of habitat in which they lived. In more open habitats all species were grazers; in mixed habitats E. laurillardi and T. platensis were mixed feeders, and N. platensis was grazer; and in more closed habitats all species were mixed feeders.