Search

In this work, the potential of reagent generation assisted by ultrasonic irradiation was evaluated for Cr(III) oxidation and arsine formation. Free radical formation by sonolysis of aqueous solutions was evaluated. The sonication of an aqueous solution saturated with CCl4 leads to chlorine radical formation while the irradiation of water in the presence of metallic zinc leads to hydrogen production. The low relative standard deviations of the proposed procedures indicate that the method can be applied for analytical purposes.

Copyright of Austral Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Changes in vegetation cover due to increasing frequencies of extreme climate events and anthropogenic pressure are already underway; so, predicting the impacts of the near‐future climate will be essential for developing mitigation strategies. We modelled the responses of Brazilian biomes to a future scenario (2070) of steady increases in atmospheric CO2 levels, adding soil data to better represent the multidimensional space of the environmental suitability of each biome. We also assessed the effects of changes in environmental suitability on the Brazilian network of protected areas and projected those effects on 1 km resolution maps. The area predicted to be affected by future climate change in Brazil and the consequent loss of suitable habitat surface is 2.59 Mkm2 – larger than the combined areas of Central America and Mexico – leading the current vegetation to a progressive replacement. We project major changes in the vegetation of the Amazon basin, with the replacement of rainforest by dryer vegetation in the southern and eastern regions of that basin, and the opening of a dry corridor in Pará State. We also project an expansion of 41% of the current caatinga cover in the Brazilian semiarid region, with large losses of suitable habitat surface of the current deciduous forest. Approximately, 37% of the coverage of protected areas in Brazil will be affected – with greater damage to indigenous lands. The speed of current environmental change is now unprecedented for the post‐glacial era, and will almost certainly lead to increased rates of extinction and the collapse of transition ecosystems. We propose the urgent creation of protected areas in regions designed without significant impacts, but contiguous to those that will be more seriously affected by climate change. Those areas will act as refugia preserving biodiversity, ecosystem services, and the cultural heritages of traditional populations. [ABSTRACT FROM AUTHOR]

Topsoil transposition is an efficient technique for recovering mining-degraded areas. However, storage time may reduce its functionality. To evaluate the effect of storage and litter addition, physical (microstructure) and chemical (fertility) properties were assessed in stored (3-months) and non-stored topsoils. Twelve months after transposition, regardless of the storage time, soil fertility and microstructure were improved, due to the mechanical work of plant roots recruited from topsoil seed bank or rain, and decomposition of pre-existing plant fragments. Litter addition did not affect chemical attributes but influenced microstructure transformations. Paedogenetic evolution was clearly fed by revegetation establishing a sustainable feedback system. [ABSTRACT FROM AUTHOR]

The "Santana do Riacho" shelter is one of the oldest human occupation sites in Brazil. Dated to the Late Pleistocene, this shelter contains over 40 buried individuals. The shelter is located on the edge of the Espinhaço Range in Mesoproterozoic quartzites. This study aims to investigate the relationship between human activities and in situ soil formation. To this end, chemical, physical, X-ray fluorescence, X-ray diffraction using synchrotron light, micromorphology, and scanning electron microscope with energy-dispersive X-ray spectroscopy analyses were performed. In situ anthropogenic practices, such as fires and burials, have had the greatest influence on the geochemical parameters. Pedological processes were clearly detected, including (1) the formation of secondary carbonates; (2) the formation of secondary phosphates; (3) the formation of magnetic Fe nodules, and (4) degradation ofmagnetite into maghemite. Themobility of P, Ca, and C resulted in the enrichment of these elements in layers stratigraphically considered "sterile." The amounts of available P, K, Ca, total organic carbon, and the pH values can be considered indicators of human occupation. This study provides information on the pedological processes in rockshelters and represents one of the few pedological and geochemical studies on deposits in a tropical rockshelter in quartzite bedrock. [ABSTRACT FROM AUTHOR]

This research was conducted for the purpose to evaluate the contribution Giant petrels and Brown skuas nestings in the formation of ornithogenic soils by the phosphatization process in Harmony Point, Maritime Antarctic. Ten nests were selected to collect topsoil samples (0-20 cm), from 0 m up to 20 m away, with regular spacing of 2 m. The analysis of the samples included the physical, chemical, mineralogical and geochemical analyzes. Phosphate minerals were identified. The presence of high content of some trace elements, such as Zn, Cu and Sr is associated with the bird's excrements. Total-P and bioavailable-P recorded higher levels. This result demonstrates the importance of the time factor in the bird's nesting, as well as in the development of the soil in these soil-forming environment. Phosphatization in these areas is not restricted to the specific location of the nest, since high values of P have been identified at distances between 8 and 12 m, from de nest's top. This suggests the transport of P rich solutions and phosphatized material along fractures by the freeze-thaw cycles, contributing to increase the geographical expression of this phenomenon in this ice-free area, consequently the development of soils and the establishment of vegetation.

This article carried out the first scientometric and spatial analysis of Brazilian scientific production on Antarctic soils and permafrost, based on all publications available from the Scopus and Web of Science databases. Information on co-authorship, citation, research topics, and sampling sites was used to understand the social and theoretical structure as well as the spatial dynamics of this research field in Brazil over the last 25 years. We highlight that Brazil is presently, the main country to study the soils and permafrost of Maritime Antarctica, in addition to having an international robust and prolific production, with high impact on the literature, and widely distributed throughout the studied region. It was also possible to identify potential future international partners, new research locations and strategic research themes.