A novel Amazonian reef biome was discovered, encompassing large rhodolith and sponge beds under low light, low oxygen, and high POC.

No abstract

The impacts of the SAMARCO iron tailing spill along more than 650 km, between the dam and the plume of the Doce River in the Atlantic, were assessed by the determination of toxic metals. The tailing spill caused a substantial increase in suspended sediment loads (up to 33,000 mg L−1), in addition to large depositions of waste along the Doce basin. The highest estimated transport of dissolved metals was observed for Fe (58.8 μg s−1), Ba (37.9 μg s−1) and Al (25.0 μg s−1). Sediments reached the highest enrichment factors (EFs) for Hg (4,234), Co (133), Fe (43), and Ni (16), whereas As (55), Ba (64), Cr (16), Cu (17), Mn (41), Pb (38) and Zn (82) highest EFs were observed for suspended particulate matter (SPM). Iron, As, Hg, Mn exceeded sediment quality guidelines. Therefore, the risk of occurrence of adverse effects is highly possible, not only due to the dam failure, but also due to the Fe mining and the artisan Au mining. Heavy rain episodes will likely cause enhanced erosion, remobilization, and transport of contaminated particles, sustaining high inputs of SPM and metals for the years to come and threatening the ecosystem services.

The health of the coral reefs of the Abrolhos Bank (southwestern Atlantic) was characterized with a holistic approach using measurements of four ecosystem components: (i) inorganic and organic nutrient concentrations, [1] fish biomass, [1] macroalgal and coral cover and (iv) microbial community composition and abundance. The possible benefits of protection from fishing were particularly evaluated by comparing sites with varying levels of protection. Two reefs within the well-enforced no-take area of the National Marine Park of Abrolhos (Parcel dos Abrolhos and California) were compared with two unprotected coastal reefs (Sebastião Gomes and Pedra de Leste) and one legally protected but poorly enforced coastal reef (the “paper park” of Timbebas Reef). The fish biomass was lower and the fleshy macroalgal cover was higher in the unprotected reefs compared with the protected areas. The unprotected and protected reefs had similar seawater chemistry. Lower vibrio CFU counts were observed in the fully protected area of California Reef. Metagenome analysis showed that the unprotected reefs had a higher abundance of archaeal and viral sequences and more bacterial pathogens, while the protected reefs had a higher abundance of genes related to photosynthesis. Similar to other reef systems in the world, there was evidence that reductions in the biomass of herbivorous fishes and the consequent increase in macroalgal cover in the Abrolhos Bank may be affecting microbial diversity and abundance. Through the integration of different types of ecological data, the present study showed that protection from fishing may lead to greater reef health. The data presented herein suggest that protected coral reefs have higher microbial diversity, with the most degraded reef (Sebastião Gomes) showing a marked reduction in microbial species richness. It is concluded that ecological conditions in unprotected reefs may promote the growth and rapid evolution of opportunistic microbial pathogens.

RESUMOO presente estudo foi realizado a partir de amostras de um Cambissolo Háplico Ta Eutrófico vértico, localizado em Campos dos Goytacazes, norte do estado do Rio de Janeiro, e submetido ao cultivo por longo tempo com cana-deaçúcar. Em uma das áreas de coleta, a cana foi cultivada, por 55 anos, sem a queima por ocasião da colheita. Na outra, por 35 anos, houve a adição anual de cerca de 120 m 3 ha -1 de vinhaça, por meio de irrigação por aspersão e colheita com a cana queimada. Outras duas áreas, respectivamente adjacentes a essas, onde se realizou a queima por ocasião da colheita durante 55 anos e não se procedeu à adição de vinhaça por 35 anos e colhida com queima do canavial, foram utilizadas para coleta

Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km2. In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g., virus, KPC-producing bacteria, and fecal coliforms), or that proliferate in such conditions (e.g., vibrios). Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift toward flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay’s degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series of plans to restore the bay’s water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro.

Soils and porewater of the rhizosphere of mangrove trees, Rhizophora mangle L. and Avicennia schaueria Leech., of the salt marsh grass Spartina alterniflora Loisel, and of unvegetated mud flats, were analyzed salinity, platinum electrode redox potential, organic matter content, sulfide concentrations, and the total changeable concentrations of trace metals (Fe, Zn, Cu, Pb and Cd). The study was conducted in a fringe m forest in Sepetiba Bay, Rio de Janeiro, Brazil. The rhizospheres differed in their biogeochemistry. Mud f Rhizophora soils were very reducing, with highest concentrations of sulfide. Avicennia soils showed t variability of the variables measured, with the rhizosphere changing from oxic to anoxic conditions. Spa on the other hand, were generally oxic, with very low sulfide concentration.The distribution of trace metals in these soils varied with the major physical and chemical characteris flat soils presented the highest total trace metal concentrations followed by mangrove soils and Spartina soils. exchangeable trace metals were similar among the different soils with the exception of Avicennia soils, wh their characteristic instability of redox conditions, presented much higher exchangeable trace metals conc RESUMO Solos e aguas intersticiais sob a influencia da rizosfera de arvores de mangue (Rhizophora mangle L. e Avicennia schaueriana Stapf & Leech.), de graminea de marisma Spartina alterniflora Loisel, e de areas sem vegetacao em planicies de lama, foram analizados em relacao ao pH, potencial redox, salinidade, teor de materia organica e concentraSao de sulfetos, e das concentraoces totais e trocaveis de metais traco (Fe, Zn, Cu, Pb e Cd), em uma floresta de mangue de franja na Baia de Sepetiba, Rio de Janeiro. Os resultados mostraram que a rizosfera das diferentes plantas mostraram diferenSas significativas em sua biogeoquimica. Os solos de planicie de mare e sob Rhizophora apresentaram-se mais redutores e com altas concentrac6es de sulfetos. Os solos sob Avicennia mostraram as maiores variaSoes dos parametros medidos, alternado condioces 6xicas e an6xicas. Por outro lado, os solos sob Spartina apresentaram-se geralmente 6xicos, com baixas concentra,ces de sulfetos.As concentraoces de metais traco tambem foram diferentes entre os diferentes solos, variando de acordo com as principais caracteristicas fisico-quimicas. Os solos de planicie de mare apresentaram as maiores concentraoces de metais totais, seguindo-se os solos de mangue e por ultimo os solos sob Spartina. Entretanto, as concentraoces trocaveis de metais traSo foram semelhantes para todos os solos, menos aqueles sob Avicennia, que devido a sua tipica instabilidade de potencial redox, apresentou a maiores concentrazces de metais trocaveis.

Holocene stromatolites characterized by unusually positive inorganic δ(13) CPDB values (i.e. up to +16‰) are present in Lagoa Salgada, a seasonally brackish to hypersaline lagoon near Rio de Janeiro (Brazil). Such positive values cannot be explained by phototrophic fixation of CO2 alone, and they suggest that methanogenesis was a dominating process during the growth of the stromatolites. Indeed, up to 5 mm methane was measured in the porewater. The archaeal membrane lipid archaeol showing δ(13) C values between -15 and 0‰ suggests that archaea are present and producing methane in the modern lagoon sediment. Moreover, (13) C-depleted hopanoids diplopterol and 3β-methylated C32 17β(H),21β(H)-hopanoic acid (both -40‰) are preserved in lagoon sediments and are most likely derived from aerobic methanotrophic bacteria thriving in the methane-enriched water column. Loss of isotopically light methane through the water column would explain the residual (13) C-enriched pool of dissolved inorganic carbon from where the carbonate constituting the stromatolites precipitated. The predominance of methanogenic archaea in the lagoon is most likely a result of sulphate limitation, suppressing the activity of sulphate-reducing bacteria under brackish conditions in a seasonally humid tropical environment. Indeed, sulphate-reduction activity is very low in the modern sediments. In absence of an efficient carbonate-inducing metabolic process, we propose that stromatolite formation in Lagoa Salgada was abiotically induced, while the (13) C-enriched organic and inorganic carbon pools are due to methanogenesis. Unusually, (13) C-enriched stromatolitic deposits also appear in the geological record of prolonged periods in the Palaeo- and Neoproterozoic. Lagoa Salgada represents a possible modern analogue to conditions that may have been widespread in the Proterozoic, at times when low sulphate concentrations in sea water allowed methanogens to prevail over sulphate-reducing bacteria.