The Fundão dam failure: Iron ore tailing impact on marine benthic macrofauna.

The Fundão dam failure, the worst environmental disaster in Brazilian history, launched 50 million m3 of iron ore tailings mud through the Doce River, reaching the Atlantic Ocean. Generally, mine tailings increase the sediment inflow, leading to mud burial of epibenthic macrofauna, and the raise of metal(oid)s concentration causing macrofauna long-term changes. After almost four years, tailings mud was still spreading on the Doce River Shelf, while impacts on marine macrofauna were still unknown. Herein, the IMS index (a tracer of Fundão dam tailings mud), sediment variables, organic pollutants, and metal(oid)s were integrated to uncover the drives of macrofauna structure from Costas da Algas to Abrolhos bank MPAs. Tailings mud was present only in Doce River Mouth and Degredo, organic pollutants and metal(oid)s above safety levels were concentrated in those same areas. Tailings mud (IMS index) drastically reduced species richness and diversity, favoring the abundance of opportunistic species. Mud, IMS index and Al, Ba, and V, metal(oid)s linked to dam failure, structured macrofauna composition in this impacted area, dominated by resistant groups as Nuculidae, Spionidae, and Magelonidae. Conversely, an opposite pattern was found for further and deeper sites with high CaCO3 content and total nitrogen that also showed large grain size, in areas known to harbour biogenic structures, sustaining a macrofauna composition distinct from the impacted areas, dominated by Syllidae and Crassatellidae, sensitives to impacts. Macrofauna composition was most structured by sediment variables, followed by the intersection between metal(oid)s-IMS and Mud, both gradients acting almost entirely on a broad spatial scale. Benthic macrofauna at the Doce River Shelf is still impacted by Fundão dam tailings mud, even after almost four years of the disaster, and may continue to, since the influx of tailings does not stop, and sediment resuspension is a recurrent source for those impacts.

Correction: A synopsis of Salvatoria McIntosh, 1885 (Annelida: Syllidae: Exogoninae) from Brazilian coastal and oceanic waters.

[This corrects the article DOI: 10.1371/journal.pone.0250472.].

A synopsis of Salvatoria McIntosh, 1885 (Annelida: Syllidae: Exogoninae) from Brazilian coastal and oceanic waters.

We compiled the records for the genus Salvatoria from Brazilian coastal and oceanic habitats, collected by several projects along the years. Here we present 12 species, eight of which already reported-S. breviarticulata comb. nov., S. clavata, S. euritmica, S. heterocirra, S. limbata, S. longiarticulata comb. nov., S. neapolitana and S. cf. nitidula-with comments regarding the confidence of some of these records. We also describe three new species, S. marielleae n. sp. and Salvatoria nitiduloides n. sp., based on material from Fernando de Noronha and Trindade islands, off the Northeastern Brazilian coast, and S. ypsiloides n. sp., from Fernando de Noronha and also, Campos Basin, off Southeastern Brazilian coast, in depths down to 970 m. Finally, we report a probably undescribed species, Salvatoria sp., represented by only one specimen lacking median antenna, preventing us to proceed with further identification properly. A dichotomous identification key and a comparative table with morphological data of specimens belonging to these species are also provided.

Two new sponge-associated Branchiosyllis (Annelida: Syllidae: Syllinae) from Northeastern Brazil.

Here we describe two new species in the genus Branchiosyllis Ehlers, 1887 associated with sponges. Branchiosyllis belchiori sp. nov. was found in Todos os Santos Bay, state of Bahia, and in the Fernando de Noronha Island (Northeastern Brazil), and Branchiosyllis gonzaguinhai sp. nov. was found in the Fernando de Noronha Island and Rocas Atoll. We compare the species herein described with their morphologically most similar congeners and provide a synoptic table of the morphological variation among the type-series of the two new species. An identification key for the species of Branchiosyllis recorded in Brazil is also provided.

Avaliação do impacto de um cultivo de ostras sobre o ambiente bentônico / Impact assessment related to an oyster farming on the benthic environment

The Oyster farming has attracted attention in the Northeastern region of Brazil. This activity is considered to cause less damages to the environment compared to other cultures, once oysters are filter feeders, however there is a lack of knowledge related to its environmental impacts. It is important to investigate such impacts in order to permit the maintenance of the activity with low environmental risk and high sustainability. The present study was carried out in an estuarine region of the São Francisco river where two transects were delimited: 10 meters far from de farm (CONTROL) and just below farming structures (CULTIVE). In each transect three points with three sediment replicates each were sampled to the analysis of nematodes. Abiotic factors were also measured (Temperature, salinity, pH, dissolved oxygen and organic matter and granulometry of the sediments). Multivariate and univariate statistical analyses were applied such as: indices of diversity and eveness, T tests, ordination (MDS) and analysis of similarity. There were no significant differences among all of the environmental parameters measured.It was observed that the oyster farm structures changes sediment characteristics and hence meiofauna and nematofauna community structure, mainly regarded to density and diversity values, which were always higherin CONTROL than the CULTIVE (from 2,086 to 776 ind 10 cm-2 and from 0.8 to 0.7 for density and diversity, respecivelly). It seems that the farm has no effects on nematode trophic guilds. The impact was considered moderate.(AU)

A ostreicultura tem se destacado nos estuários do nordeste do Brasil e é considerada menos prejudicial ao ambiente que outros cultivos, devido ao hábito alimentar filtrador das ostras, porém há uma lacuna no conhecimento a respeito dos seus impactos. Para que esta atividade continue ocorrendo de forma sustentável, deve-se utilizar parâmetros que detectem e quantifiquem os impactos ambientais, minimizando riscos e/ou danos causados aos ecossistemas costeiros. O presente trabalho teve como objetivo avaliar alterações ambientais associadas à presença de uma ostreicultura no estuário do Rio São Francisco, através da observação de mudanças na estrutura da comunidade de Nematoda. Foram delimitados dois transectos: um abaixo do cultivo (CULTIVO) e outro a 10 m de distância do cultivo (CONTROLE). Nos transectos, foram coletadas amostras em três pontos, cada uma com três réplicas, para o estudo da nematofauna, e mensurados os parâmetros: temperatura, salinidade, pH e oxigênio dissolvido na água, e granulometria, teor de matéria orgânica e concentração de pigmentos nos sedimentos. Foram aplicadas análises estatísticas uni e multivariadas, tais como índices de diversidade e equitatividade, teste T, ordenação (MDS) e testes de similaridade. Não foram encontradas diferenças significativas entre os valores dos parâmetros ambientais medidos nos dois transectos. Quanto à densidade ediversidade da nematofauna, seus valores a 10 m de distância do cultivo (CONTROLE), respectivamente 2.086 ind 10 cm-2 e 0,8, foram significativamente superiores aos registrados abaixo do cultivo (CULTIVO): 776 ind 10 cm-2 e 0,7, respectivamente, não sendo afetada a estrutura trófica do ambiente. O impacto da ostreicultura foi considerado moderado.(AU)

Avaliação do impacto de um cultivo de ostras sobre o ambiente bentônico / Impact assessment related to an oyster farming on the benthic environment

The Oyster farming has attracted attention in the Northeastern region of Brazil. This activity is considered to cause less damages to the environment compared to other cultures, once oysters are filter feeders, however there is a lack of knowledge related to its environmental impacts. It is important to investigate such impacts in order to permit the maintenance of the activity with low environmental risk and high sustainability. The present study was carried out in an estuarine region of the São Francisco river where two transects were delimited: 10 meters far from de farm (CONTROL) and just below farming structures (CULTIVE). In each transect three points with three sediment replicates each were sampled to the analysis of nematodes. Abiotic factors were also measured (Temperature, salinity, pH, dissolved oxygen and organic matter and granulometry of the sediments). Multivariate and univariate statistical analyses were applied such as: indices of diversity and eveness, T tests, ordination (MDS) and analysis of similarity. There were no significant differences among all of the environmental parameters measured.It was observed that the oyster farm structures changes sediment characteristics and hence meiofauna and nematofauna community structure, mainly regarded to density and diversity values, which were always higherin CONTROL than the CULTIVE (from 2,086 to 776 ind 10 cm-2 and from 0.8 to 0.7 for density and diversity, respecivelly). It seems that the farm has no effects on nematode trophic guilds. The impact was considered moderate.

A ostreicultura tem se destacado nos estuários do nordeste do Brasil e é considerada menos prejudicial ao ambiente que outros cultivos, devido ao hábito alimentar filtrador das ostras, porém há uma lacuna no conhecimento a respeito dos seus impactos. Para que esta atividade continue ocorrendo de forma sustentável, deve-se utilizar parâmetros que detectem e quantifiquem os impactos ambientais, minimizando riscos e/ou danos causados aos ecossistemas costeiros. O presente trabalho teve como objetivo avaliar alterações ambientais associadas à presença de uma ostreicultura no estuário do Rio São Francisco, através da observação de mudanças na estrutura da comunidade de Nematoda. Foram delimitados dois transectos: um abaixo do cultivo (CULTIVO) e outro a 10 m de distância do cultivo (CONTROLE). Nos transectos, foram coletadas amostras em três pontos, cada uma com três réplicas, para o estudo da nematofauna, e mensurados os parâmetros: temperatura, salinidade, pH e oxigênio dissolvido na água, e granulometria, teor de matéria orgânica e concentração de pigmentos nos sedimentos. Foram aplicadas análises estatísticas uni e multivariadas, tais como índices de diversidade e equitatividade, teste T, ordenação (MDS) e testes de similaridade. Não foram encontradas diferenças significativas entre os valores dos parâmetros ambientais medidos nos dois transectos. Quanto à densidade ediversidade da nematofauna, seus valores a 10 m de distância do cultivo (CONTROLE), respectivamente 2.086 ind 10 cm-2 e 0,8, foram significativamente superiores aos registrados abaixo do cultivo (CULTIVO): 776 ind 10 cm-2 e 0,7, respectivamente, não sendo afetada a estrutura trófica do ambiente. O impacto da ostreicultura foi considerado moderado.