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Research on microplastics in Latin America is limited compared to a global perspective. Brazil plays a significant role in this context, as it possesses 12% of the world's freshwater reserves, constituting 53% of South America's water resources. There has been growing concern regarding the plastic pollution of the country's freshwater systems in recent years. Therefore, this study investigated the impact of plastic pollution on the Guaíba River, a significant watercourse in the southern region of Brazil that is subjected to high anthropogenic pressure. Additionally, we examined correlations between the presence of microplastics and key factors influencing their distribution in the river. Thus, freshwater was collected in seven sampling campaigns from 2019 to 2020, totaling 66 samples. The microplastics were quantified and characterized according to their color, shape, and polymeric composition. The concentration of microplastics varied between 2.9 and 53.8 items m−3, and the distribution and transport were positively influenced by the population density, precipitations, and depth of each sampling point. White-transparent color category (51%) and fragment shape (89%) were predominant among the found particles. Polyethylene (PE) and polypropylene (PP) represented 37% and 57% of the analyzed particles. The non-metric multidimensional scaling (nMDS) analysis indicated that similar contamination sources, such as domestic sewage, could influence three out of ten sampled points. Several microplastics presented the formation of cracks, with sizes smaller than 10 μm on their surface, which might indicate an erosion process, resulting in the formation of nanoplastics. The color fading observed in microplastics suggests that the particles were subjected to environmental stressors, leading to the leaching or degradation of the dye on the plastic. The results confirmed the ubiquity of microplastics in Guaíba River, highlighting the importance of improving the regulations on plastic waste disposal in the country to prevent the contamination of freshwater bodies. [ABSTRACT FROM AUTHOR]

We have developed a new method for the interpretation of a magnetic anomaly profile by idealized-geometrical bodies using the variance analysis. This method is based on estimating the fourth horizontal derivative of the magnetic data profile. The advantage behind the use of the fourth horizontal derivative method is to reduce the regional background effect. The model parameters estimated are the depth and shape of the buried body using all available window lengths (s-value). Then, the variance value for the calculated depth at each shape value is estimated using all available s-values. The minimum variance is considered as the best criterion for determining the best-inverted parameters (depth and shape). The developed method has been verified on some noise free examples. Following that, the accuracy of the method was assessed by studying the impact of synthetic data with 5%, 10%, and 15% random noise, the effect of the regional background, the influence of interfering structures, and the selection for the wrong origin of the body. The presented method has been successfully applied to three real case studies from Brazil and India from mineral exploration. [ABSTRACT FROM AUTHOR]

Marine hardground bottom (subtidal) benthic (sessile) communities (HBBC) are subjected to various biotic, abiotic, and anthropogenic factors that can vary over space and time and interact with one another. To evaluate the main drivers of the structure of HBBC in a large tropical bay in the southwest Atlantic (Ilha Grande Bay, Brazil), a total of 98 HBBC were sampled using visually estimated quadrats. Ten variables (depth, grazing intensity, irradiance, temperature, salinity, dissolved oxygen, nutrients (nitrite, nitrate, and phosphate), and chlorophyll a concentrations) were also measured. A total of 74 main space‐occupying taxon/functional groups were recorded which fell into six major HBBC groups. These were organized by depth/irradiance and grazing intensities which explained part of the HBBC variation: (a) Communities dominated by zoantharians occurred in the shallow, highest irradiance sites; (b) foliose and erect algae were inversely related to depth and grazing intensity; (c) crustose coralline algae dominated at greater depths and/or under higher grazing intensity; (d) zooxanthellate corals were associated with shallower and heterotrophic invertebrates with deeper stations; (e) photosynthetically efficient algae were associated with deeper stations, with more encrusting forms under higher grazing intensities; and (f) multi‐species turf‐forming algae were ubiquitous (did not present association with any of the measured variables). As communities' components and main structuring factors were similar to those found in coral reefs, these communities represent compatible receptor habitats for poleward escape, migration, and range extension under the present global warming scenario. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga 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.)

Lithophaga aristata is a boring bivalve native to the Caribbean Sea, first recorded in 2005 as an introduced species on the Southeastern Brazilian coast. The geographic distribution and density of L. aristata and of its native congeneric L. bisulcata were assessed in four areas of Brazil (24 sites), additionally considering their relationship with types of substrate, depth and wave exposure. This study records the first occurrence of L. aristata in the Sepetiba Bay and also reports the species at five new localities in the Arraial do Cabo Bay. Lithophaga aristata is established in the four surveyed regions. At intertidal habitats, the exotic species only colonizes the infralittoral fringe but its density was not related to wave action. At subtidal habitats, the species colonizes natural and artificial substrates, from shallow (0.5m) to deep (5.0-7.0m) zones but no relationship between density and these evaluated factors was detected. Broad geographical and ecological distributions and higher densities of this introduced species in relation to its native congeneric are suggested as contrary to Darwin's naturalization hypothesis and instead indicate a high invasiveness potential. [ABSTRACT FROM AUTHOR]

Intense wind events at the southern Brazilian coast cause severe socio-economic losses. Generally, such events have been associated with extratropical cyclones over the Southwest Atlantic Ocean. The purpose of this study is to identify favoured locations and the processes through which the winds are associated with the extratropical cyclones. Using a statistical analysis, the wind speed observed at nine meteorological stations was compared with cyclone depth and offshore distance. Both cyclone depth and location were obtained through an objective procedure of identifying and tracking. Generally, the winds are well associated with the extratropical cyclones only south of 28°S. Altitude also plays an important role in this relationship. Furthermore, the cyclones influence the observed wind field up to 1200 km inland at higher latitude locations. For stations near 28°S, cyclones further from the coast have an influence, but with smaller statistical significance. Copyright © 2010 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Biociencias is the property of Revista Brasileira de Biociencias 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.)

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia 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.)

• This study evaluates the capability of IMERG in defining sub-daily rainfall events and their properties. • The MIT criterion was used to define the independent rainfall events determined by dry periods. • IMERG effectively captures the sub-daily rainfall depth for all MIT considered in this study. • Considerable errors of IMERG are evidenced for rainfall duration and intensity. Sub-daily rainfall information is essential for many hydrological applications, but ground-based data availability is still an issue in poorly gauged regions worldwide. Satellite remote sensing missions, such as the Global Precipitation Measurement (GPM) mission, have been playing a key role in estimating sub-daily rainfall data globally. However, the quality of such information needs to be carefully evaluated. Previous studies evaluating sub-daily data from the Integrated multi-satellitE Retrievals for GPM (IMERG) product considered only the rainfall depth over pre-defined periods (e.g., hourly or half-hourly), with no analysis of the ability and quality of the product in defining the actual rainfall events and the associated properties. Thus, the objective of this study is to evaluate the performance of the IMERG Final Run Version 06B (V06B) product in capturing sub-daily rainfall events and their properties (depth, duration and intensity) over Brazil. The analysis consisted of comparing the satellite estimates against the ground-based data from 1757 sub-daily rainfall gauges for a period of three years (2015–2017). This study used the minimum inter-event time (MIT) criterion to define independent rainfall events determined by dry periods: 1, 6 and 24 h. Results show that IMERG can properly estimate the sub-daily rainfall depth for the three MITs considered, with the best results found in the southern part of the country. This means that the IMERG product represents a good source of sub-daily rainfall depth data for hydrological and hydroclimatic applications in Brazil. On the other hand, the evaluation shows large overestimations and underestimations of the IMERG product for rainfall duration and intensity properties, respectively. The results obtained from this study provide a reference for IMERG users who require sub-daily rainfall data based on events and further knowledge about its properties. [ABSTRACT FROM AUTHOR]

The Borborema Province is characterized by a succession of tectonic events, including compressive periods associated with amalgamation of lithospheric blocks during the Brasiliano orogeny in the Neoproterozoic, superimposed by extension events related to the breaking of the continents and the South Atlantic formation in the Cretaceous. Ten seismographic broadband stations belonging to the Geoterm Network were installed in the Transversal Zone and South Domains to collect the data used in this work in the southern Borborema Province, northeastern Brazil. Thus, this study aims to determine the thickness of the Moho and Mid-Crustal ("Conrad") discontinuities and estimate the Vp/Vs ratios to define rock composition using the receiver function over a time window, using the HK-stacking method. The station in the Alto Moxotó Terrain determined a crustal thickness of 35.4 km. The two stations in the Pernambuco-Alagoas Terrain estimated thickness of approximately 37 km and no thinning trend in the geotectonic context. The four stations in the Sergipano Folding Belt indicated thickness ranging between 34.6 and 37.2 km, and a South-North crustal thickening. Mid-crustal discontinuity depth estimates ranged between 10 and 19 km, indicating a WNW-ESE thinning of the upper crust in the middle of the area. The P and S wave velocity ratios appeared to have no geological or tectonic correlation and ranged between 1.68 and 1.77, indicating that the crustal composition is predominantly felsic. [ABSTRACT FROM AUTHOR]