Abstract The degradation of tropical coastal lagoon systems in urban areas of the least developed countries has been associated with an increase in impermeable areas and poor domestic sewage treatment, increasing land-based runoff of nutrients and suspended solids from catchments. This study aimed to assess the biogeochemical changes caused by human interventions through the analysis of the spatial distribution of sedimentary phosphorus (P) and its mass balance in the Itaipu lagoon, located on the east coast of the state of Rio de Janeiro. Human intervention in the Itaipu lagoon system has caused severe imbalances in biogeochemical cycles over the past decades. Watercourses have been channeled to normalize the hydrological regime and increase hydraulic energy, improving sediment transport capacity. In this context, the increase in runoff from the coastal urban basin into the Itaipu lagoon has buried an increasing amount of phosphorus in the sediment. Recently, a regional increase in storm events caused a series of landslides and floods, which have been reported as possible consequences of global climate change. In recent decades, the synergy between landslides and river channeling has increased TP loads, accelerating phosphorus settling and changing P spatial distribution in surface sediments. This has accelerated siltation of the lagoon with an accumulation of nutrients and organic matter, leading in some cases to sediment anoxia. The lagoon has undergone strong eutrophication, changing its trophic state from meso- to hypertrophic in less than 30 years, even though P loads are not as high as in other coastal lagoons. Our findings confirm that human intervention impacts nutrient loads, which in turn disrupt the balance of biogeochemical cycles, compromising coastal water resources. This leads to the collapse of ecosystem services, another step towards degrading planetary boundaries.

Abstract The atmospheric dispersion atmospheric plume of the metropolitan region and neighborhoods of the city of Rio de Janeiro was investigated through elemental analyzes (Na, K, Al, Mn, Pb, Ni, Cr) and stable lead isotopes in two epiphytes; the lichen Parmotrema crinitum (Ach.) and the bromeliad Tillandsia usneoides (L.). All the elements had lower concentrations in epiphytes than in rocks of the local geological basement, with the exception of K, which was similar to rocks. This behavior was attributed to the nutritional essentiality and abundance of this element in the environment. The concentrations of Na, Pb and the 206Pb/207Pb and 208Pb/206Pb ratios indicated the presence of spatial gradients in the path (a) sea shore → continent, and (b) urban center → farmlands. These patterns were associated with the mesoscale atmospheric circulation regime, in which, during the arrival of cold fronts, air masses from the metropolitan region of Rio de Janeiro are transported towards the mountainous region of Teresópolis, which acts as a barrier to the dispersion of pollutants. The bromeliad Tillandsia usneoides and the lichen Parmotrema crinitum were linked to Na and Pb atmospheric levels, respectively.

No sul do Brasil a circulação de dois subtipos de HIV-1 com características diferentes representa importante cenário para o estudo do impacto da diversidade do HIV-1 na evolução da epidemia e na AIDS. O HIV-1 B, variante predominante nos países industrializados e o HIV-1 C, o subtipo mais prevalente em áreas com maiores taxas de crescimento da epidemia, estão implicados na maioria das infecções. Avaliamos amostras de sangue de 128 pacientes sem exposição a antirretrovirais, recrutados ao ingressarem no maior serviço ambulatorial de HIV/AIDS de Porto Alegre. Com base no sequenciamento parcial da região pol, o HIV-1 C foi observado em 29%, HIV-1 B em 22,6% e uma forma recombinante recentemente descrita, CRF31_BC, foi observada em 23,4% entre 128 voluntários. Outras variantes encontradas foram HIV-1 F em 10% e outros mosaicos em 5,5%. Para avaliar associações entre características sócio-comportamentais e subtipos do HIV-1 foram realizadas entrevistas e exames laboratoriais na entrada do estudo. Nossos dados sugerem uma epidemia estabelecida dessas três variantes principais, sem evidência de compartilhamento em nenhum subgrupo analisado. Entretanto, prática sexual anal se mostrou associada à transmissão de subtipo B, o que pode indicar maior transmissibilidade das variantes não-B por intercurso vaginal. Este estudo permite delinear uma linha de base para o monitoramento epidemiológico das mudanças nas características moleculares da epidemia do HIV-1 nesta região.

In South Brazil the circulation of two HIV-1 subtypes with different characteristics represents an important scenario for the study of the impact of HIV-1 diversity on the evolution of the HIV-1 epidemic and AIDS disease. HIV-1 B, the predominant variant in industrialized countries and HIV-1 C, the most prevalent subtype in areas with rapid epidemic growth, are implicated in most infections. We evaluated blood samples from 128 antiretroviral (ARV) naïve patients recruited at entry to the largest HIV outpatient service in Porto Alegre. Based on partial pol region sequencing, HIV-1 C was observed in 29%, HIV-1 B in 22.6% and, the recently identified CRF31_BC, in 23.4% of 128 volunteers. Other variants were HIV-1 F in 10% and other mosaics in 5.5%. In order to evaluate the association of socio-behavioral characteristics and HIV-1 subtypes, interviews and laboratory evaluation were performed at entry. Our data suggest an established epidemic of the three major variants, without any evidence of partitioning in either of the subgroups analyzed. However, anal sex practices were associated with subtype B, which could indicate a greater transmissibility of non-B variants by vaginal intercourse. This study provides baseline information for epidemiologic surveillance of the changes of the molecular characteristics of HIV-1 epidemics in this region.