Spatio-temporal sublittoral macrobenthic distribution and dominant species in Guanabara Bay, Rio de Janeiro, Brazil / Distribuição espaço-temporal do macrobentos de infralitoral e espécies dominantes na Baía de Guanabara, Rio de Janeiro, Brasil

Abstract Soft-bottom macrobenthic invertebrates are sensitive to natural or anthropogenic changes in aquatic ecosystems. The distribution patterns of sublittoral macrobenthic species in Guanabara Bay were studied from 2005 to 2007. Samples were collected at ten stations during six surveys throughout the rainfall regime (dry, early and late rainy). Ten replicates were collected at each station by Gravity corer or skin diving. Van Dorn bottles (bottom water) and by Ekman sediment sampler (granulometry) provided material for abiotic data. Stations were grouped into sectors (Entrance, Intermediary and Inner) based on abiotic data and location. The Redundancy Analysis (RDA) and Parsimonious RDA for all years and each annual cycle showed indicator taxa with high dominance in each sector. PERMANOVA indicated a regular seasonality between the surveys for the first annual cycle (p <0.05), and an atypical pattern for the second (p> 0.05), possibly due the low rainfall observed during this period. The mosaic of soft-bottom substrates infers structural variables, and patterns of temporal distribution were basically influenced by parameters those indicating pollution and the SACW (South Atlantic Central Water) intrusion, as well as ecological attributes among species, such as: predation, competition. The Ervilia concentrica and Cypridinidae could be used as indicators for anthropic and natural impacts in the Guanabara Bay for the Entrance sector, while Cyprideis salebrosa and Cyprideis sp. for the Intermediary sector and Heleobia australis for the Inner sector.

Resumo Os invertebrados macrobentônicos são sensíveis as alterações naturais e antrópicas nos ecossistemas aquáticos. O padrão de distribuição das espécies macrobentônicas do infralitoral da Baía de Guanabara foram estudados de 2005 até 2007. Amostras foram coletadas em dez estações durante seis campanhas em todo o regime pluviométrico (seco, pré e pós chuvoso). Dez réplicas foram coletadas em cada estação por meio do amostrador Gravity corer ou por mergulho livre. Os dados abióticos foram coletados por meio de garrafa oceanográfica do tipo van Dorn (água de fundo) e por busca fundo do tipo Ekman (granulometria). As estações foram agrupadas em setores (Entrada, Intermediária e Interna) baseada nos dados abióticos e localização. A Análise de Redundância (RDA) e RDA Parcimoniosa para todos os anos e em cada ano evidenciou taxa indicadores como elevada dominância em cada setor. A PERMANOVA indicou sazonalidade regular entre as campanhas para o primeiro ciclo anual (p<0.05), padrão atípico para o segundo ano (p> 0.05), possivelmente por causa da baixa pluviosidade observada durante esse período. O mosaico do substrato não consolidado infere que as variáveis estruturais, e os padrões de distribuição temporal foram basicamente influenciadas por parâmetros que indicam poluição e intrusão de ACAS (Água Central do Atlântico Sul), bem como atributos ecológicos entre espécies, tais como: predação, competição, entre outros. Ervilia concentrica e Cypridinidae podem ser utilizados como indicadores de alterações naturais e antrópicos no setor da Entrada da Baía de Guanabara, enquanto Cyprideis salebrosa e Cyprideis sp. para o setor Intermediário e Heleobia australis para o setor Interno.

Diving into the unknown: identification of antimicrobial resistance hotspots in a tropical urban estuary.

Antimicrobial resistance is widely studied and well-characterized from a clinical perspective. However, considerably less information is available regarding resistance in environmental settings, especially in aquatic habitats. This study presents data regarding the occurrence, distribution and the antimicrobial susceptibility profile of bacteria isolated from Guanabara Bay (GB), a heavily polluted tropical urban estuary and an important tourist attraction in Rio de Janeiro, Brazil. Water samples from sites characterized by growing degrees of pollution were analysed by culture-dependent methods, revealing the presence of multidrug-resistant bacteria and clinically relevant indicators of antimicrobial resistance, such as extended-spectrum beta-lactamases. Isolates were identified by mass spectrometry, which indicated the presence of potential human pathogens such as Aeromonas spp. and Vibrio spp. Bacteria harbouring beta-lactam resistance genes were also detected. Although GB is widely used as a recreational and fishing area, there is a substantial knowledge gap regarding the monitoring of antimicrobial resistance and the risk that exposure to these waters poses to public health. Thus, this study reveals new information that calls for better comprehension of antimicrobial resistance in aquatic environments, especially those used for recreational purposes.

Spatio-temporal sublittoral macrobenthic distribution and dominant species in Guanabara Bay, Rio de Janeiro, Brazil.

Soft-bottom macrobenthic invertebrates are sensitive to natural or anthropogenic changes in aquatic ecosystems. The distribution patterns of sublittoral macrobenthic species in Guanabara Bay were studied from 2005 to 2007. Samples were collected at ten stations during six surveys throughout the rainfall regime (dry, early and late rainy). Ten replicates were collected at each station by Gravity corer or skin diving. Van Dorn bottles (bottom water) and by Ekman sediment sampler (granulometry) provided material for abiotic data. Stations were grouped into sectors (Entrance, Intermediary and Inner) based on abiotic data and location. The Redundancy Analysis (RDA) and Parsimonious RDA for all years and each annual cycle showed indicator taxa with high dominance in each sector. PERMANOVA indicated a regular seasonality between the surveys for the first annual cycle (p <0.05), and an atypical pattern for the second (p> 0.05), possibly due the low rainfall observed during this period. The mosaic of soft-bottom substrates infers structural variables, and patterns of temporal distribution were basically influenced by parameters those indicating pollution and the SACW (South Atlantic Central Water) intrusion, as well as ecological attributes among species, such as: predation, competition. The Ervilia concentrica and Cypridinidae could be used as indicators for anthropic and natural impacts in the Guanabara Bay for the Entrance sector, while Cyprideis salebrosa and Cyprideis sp. for the Intermediary sector and Heleobia australis for the Inner sector.

Ecogenomics and metabolic potential of the South Atlantic Ocean microbiome.

The unique combination of depth, salinity, and water masses make the South Atlantic Ocean an ecosystem of special relevance within the global ocean. Yet, the microbiome of this ecosystem has received less attention than other regions of the global Ocean. This has hampered our understanding of the diversity and metabolic potential of the microorganisms that dwell in this habitat. To fill this knowledge gap, we analyzed a collection of 31 metagenomes from the Atlantic Ocean that spanned the epipelagic, mesopelagic and bathypelagic zones (surface to 4000 m). Read-centric and gene-centric analysis revealed the unique taxonomic and functional composition of metagenomes from each depth zone, which was driven by differences in physical and chemical parameters. In parallel, a total of 40 metagenome-assembled genomes were obtained, which recovered one third of the total community. Phylogenomic reconstruction revealed that many of these genomes are derived from poorly characterized taxa of Bacteria and Archaea. Genomes derived from heterotrophic bacteria of the aphotic zone displayed a large apparatus of genes suited for the utilization of recalcitrant organic compounds such as cellulose, chitin and alkanes. In addition, we found genomic evidence suggesting that mixotrophic bacteria from the bathypelagic zone could perform carbon fixation through the Calvin-Benson-Bassham cycle, fueled by sulfur oxidation. Finally, we found that the viral communities shifted throughout the water column regarding their targeted hosts and virus-to-microbe ratio, in response to shifts in the composition and functioning their microbial counterparts. Our findings shed light on the microbial and viral drivers of important biogeochemical processes that take place in the South Atlantic Ocean.

Intra-annual variation in rainfall and its influence of the adults Cyprideis spp (Ostracoda, Crustacea) on a eutrophic estuary (Guanabara Bay, Rio de Janeiro, Brazil) / Variação intra-annual na chuva e a sua influência nos adultos de Cyprideis spp (Ostracoda, Crustacea) em um estuário eutrofizado (Guanabara Bay, Rio de Janeiro, Brasil)

Abstract Spatial and temporal distribution of two species of adult´s ostracods (Cyprideis sp. and Cyprideis salebrosa) were studied as a function of the rainfall patterns in the Guanabara Bay, Rio de Janeiro, Brazil. Samples were taken in ten stations, along six surveys representing three periods (Dry, Early and Late Rainy) for two years. Stations were nested in four areas (Outer, Central, EPA Guapimirim and Impacted). The bottom water (temperature, salinity, dissolved oxygen and oxygen saturation) were measured in each area to characterize the influence of seasonal variations by rainfall. Cyprideis sp. and Cyprideis salebrosa showed patterns distribution to seasonality/surveys (p = 0,002 and p <0,001, respectly). The spatial distribution of Cyprideis sp was significantly different areas studied (p <0.001) indicated well defined areas and distribution in along of the surveys. However, C. salebrosa showed homogeneous distribution in along of the areas within of each survey (p <0.001). Redundancy Analysis (RDA) for the two years evidenced environment preference of the Cyprideis sp. for areas with marine conditions (high influence for channel central) and C. salebrosa for brackish water (high influence of the rivers). This observation reinforces of the existence of areas created by the seasonality of pluviometric regime, a possible dispersion of the adult's ostracods and possibility the use with bioindicators.

Resumo A distribuição espacial e temporal de duas espécies de ostracodes adultos (Cyprideis sp. e Cyprideis salebrosa) foi estudada em função do padrão pluviométrico na Baía de Guanabara, Rio de Janeiro, Brasil. As amostras foram coletadas em dez estações ao longo de seis campanhas, representando três períodos (Seco, Pré e Pós Chuvoso) por dois anos. As estações foram agrupadas em quatro áreas (Externo, Central, EPA Guapimirim e Impactado). A água do fundo (temperatura, salinidade, oxigênio dissolvido e saturação de oxigênio) foi medida em cada área para caracterizar a influência das variações sazonais pela chuva. Cyprideis sp. e Cyprideis salebrosa mostrou distribuição de padrões para sazonalidade/campanhas (p = 0,002 e p <0,001, respctivamente). A distribuição espacial de Cyprideis sp. foi significativamente diferente das áreas estudadas (p <0,001) indicou áreas bem definidas e distribuição ao longo das campanhas. No entanto, C. salebrosa mostrou distribuição homogênea ao longo das áreas dentro de cada campanha (p <0,001). A Análise de Redundância (RDA) para os dois anos evidenciou a preferência ambiental dos Cyprideis sp. para áreas com condições marinhas (alta influência para o canal central) e C. salebrosa para águas salobras (alta influência dos rios). Essa observação reforça a existência de áreas criadas pela sazonalidade do regime pluviométrico, uma possível dispersão dos adultos de ostracodes e a possibilidade do uso como bioindicadores.

Intra-annual variation in rainfall and it's influence of the adult's Cyprideis spp (Ostracoda, Crustacea) on a eutrophic estuary (Guanabara Bay, Rio de Janeiro, Brazil).

Spatial and temporal distribution of two species of adult´s ostracods (Cyprideis sp. and Cyprideis salebrosa) were studied as a function of the rainfall patterns in the Guanabara Bay, Rio de Janeiro, Brazil. Samples were taken in ten stations, along six surveys representing three periods (Dry, Early and Late Rainy) for two years. Stations were nested in four areas (Outer, Central, EPA Guapimirim and Impacted). The bottom water (temperature, salinity, dissolved oxygen and oxygen saturation) were measured in each area to characterize the influence of seasonal variations by rainfall. Cyprideis sp. and Cyprideis salebrosa showed patterns distribution to seasonality/surveys (p = 0,002 and p <0,001, respectly). The spatial distribution of Cyprideis sp was significantly different areas studied (p <0.001) indicated well defined areas and distribution in along of the surveys. However, C. salebrosa showed homogeneous distribution in along of the areas within of each survey (p <0.001). Redundancy Analysis (RDA) for the two years evidenced environment preference of the Cyprideis sp. for areas with marine conditions (high influence for channel central) and C. salebrosa for brackish water (high influence of the rivers). This observation reinforces of the existence of areas created by the seasonality of pluviometric regime, a possible dispersion of the adult's ostracods and possibility the use with bioindicators.

Modelling the influence of environmental parameters over marine planktonic microbial communities using artificial neural networks.

Guanabara Bay is a tropical estuarine ecosystem that receives massive anthropogenic impacts from the metropolitan region of Rio de Janeiro. This ecosystem suffers from an ongoing eutrophication process that has been shown to promote the emergence of potentially pathogenic bacteria, giving rise to public health concerns. Although previous studies have investigated how environmental parameters influence the microbial community of Guanabara Bay, they often have been limited to small spatial and temporal gradients and have not been integrated into predictive mathematical models. Our objective was to fill this knowledge gap by building models that could predict how temperature, salinity, phosphorus, nitrogen and transparency work together to regulate the abundance of bacteria, chlorophyll and Vibrio (a potential human pathogen) in Guanabara Bay. To that end, we built artificial neural networks to model the associations between these variables. These networks were carefully validated to ensure that they could provide accurate predictions without biases or overfitting. The estimated models displayed high predictive capacity (Pearson correlation coefficients ≥0.67 and root mean square error ≤ 0.55). Our findings showed that temperature and salinity were often the most important factors regulating the abundance of bacteria, chlorophyll and Vibrio (absolute importance ≥5) and that each of these has a unique level of dependence on nitrogen and phosphorus for their growth. These models allowed us to estimate the Guanabara Bay microbiome's response to changes in environmental conditions, which allowed us to propose strategies for the management and remediation of Guanabara Bay.

Intra-annual variation in rainfall and its influence of the adults Cyprideis spp (Ostracoda, Crustacea) on a eutrophic estuary (Guanabara Bay, Rio de Janeiro, Brazil)

Abstract Spatial and temporal distribution of two species of adult´s ostracods (Cyprideis sp. and Cyprideis salebrosa) were studied as a function of the rainfall patterns in the Guanabara Bay, Rio de Janeiro, Brazil. Samples were taken in ten stations, along six surveys representing three periods (Dry, Early and Late Rainy) for two years. Stations were nested in four areas (Outer, Central, EPA Guapimirim and Impacted). The bottom water (temperature, salinity, dissolved oxygen and oxygen saturation) were measured in each area to characterize the influence of seasonal variations by rainfall. Cyprideis sp. and Cyprideis salebrosa showed patterns distribution to seasonality/surveys (p = 0,002 and p 0,001, respectly). The spatial distribution of Cyprideis sp was significantly different areas studied (p 0.001) indicated well defined areas and distribution in along of the surveys. However, C. salebrosa showed homogeneous distribution in along of the areas within of each survey (p 0.001). Redundancy Analysis (RDA) for the two years evidenced environment preference of the Cyprideis sp. for areas with marine conditions (high influence for channel central) and C. salebrosa for brackish water (high influence of the rivers). This observation reinforces of the existence of areas created by the seasonality of pluviometric regime, a possible dispersion of the adults ostracods and possibility the use with bioindicators.

Resumo A distribuição espacial e temporal de duas espécies de ostracodes adultos (Cyprideis sp. e Cyprideis salebrosa) foi estudada em função do padrão pluviométrico na Baía de Guanabara, Rio de Janeiro, Brasil. As amostras foram coletadas em dez estações ao longo de seis campanhas, representando três períodos (Seco, Pré e Pós Chuvoso) por dois anos. As estações foram agrupadas em quatro áreas (Externo, Central, EPA Guapimirim e Impactado). A água do fundo (temperatura, salinidade, oxigênio dissolvido e saturação de oxigênio) foi medida em cada área para caracterizar a influência das variações sazonais pela chuva. Cyprideis sp. e Cyprideis salebrosa mostrou distribuição de padrões para sazonalidade/campanhas (p = 0,002 e p 0,001, respctivamente). A distribuição espacial de Cyprideis sp. foi significativamente diferente das áreas estudadas (p 0,001) indicou áreas bem definidas e distribuição ao longo das campanhas. No entanto, C. salebrosa mostrou distribuição homogênea ao longo das áreas dentro de cada campanha (p 0,001). A Análise de Redundância (RDA) para os dois anos evidenciou a preferência ambiental dos Cyprideis sp. para áreas com condições marinhas (alta influência para o canal central) e C. salebrosa para águas salobras (alta influência dos rios). Essa observação reforça a existência de áreas criadas pela sazonalidade do regime pluviométrico, uma possível dispersão dos adultos de ostracodes e a possibilidade do uso como bioindicadores.

Spatio-temporal sublittoral macrobenthic distribution and dominant species in Guanabara Bay, Rio de Janeiro, Brazil

Abstract Soft-bottom macrobenthic invertebrates are sensitive to natural or anthropogenic changes in aquatic ecosystems. The distribution patterns of sublittoral macrobenthic species in Guanabara Bay were studied from 2005 to 2007. Samples were collected at ten stations during six surveys throughout the rainfall regime (dry, early and late rainy). Ten replicates were collected at each station by Gravity corer or skin diving. Van Dorn bottles (bottom water) and by Ekman sediment sampler (granulometry) provided material for abiotic data. Stations were grouped into sectors (Entrance, Intermediary and Inner) based on abiotic data and location. The Redundancy Analysis (RDA) and Parsimonious RDA for all years and each annual cycle showed indicator taxa with high dominance in each sector. PERMANOVA indicated a regular seasonality between the surveys for the first annual cycle (p 0.05), and an atypical pattern for the second (p> 0.05), possibly due the low rainfall observed during this period. The mosaic of soft-bottom substrates infers structural variables, and patterns of temporal distribution were basically influenced by parameters those indicating pollution and the SACW (South Atlantic Central Water) intrusion, as well as ecological attributes among species, such as: predation, competition. The Ervilia concentrica and Cypridinidae could be used as indicators for anthropic and natural impacts in the Guanabara Bay for the Entrance sector, while Cyprideis salebrosa and Cyprideis sp. for the Intermediary sector and Heleobia australis for the Inner sector.

Resumo Os invertebrados macrobentônicos são sensíveis as alterações naturais e antrópicas nos ecossistemas aquáticos. O padrão de distribuição das espécies macrobentônicas do infralitoral da Baía de Guanabara foram estudados de 2005 até 2007. Amostras foram coletadas em dez estações durante seis campanhas em todo o regime pluviométrico (seco, pré e pós chuvoso). Dez réplicas foram coletadas em cada estação por meio do amostrador Gravity corer ou por mergulho livre. Os dados abióticos foram coletados por meio de garrafa oceanográfica do tipo van Dorn (água de fundo) e por busca fundo do tipo Ekman (granulometria). As estações foram agrupadas em setores (Entrada, Intermediária e Interna) baseada nos dados abióticos e localização. A Análise de Redundância (RDA) e RDA Parcimoniosa para todos os anos e em cada ano evidenciou taxa indicadores como elevada dominância em cada setor. A PERMANOVA indicou sazonalidade regular entre as campanhas para o primeiro ciclo anual (p 0.05), padrão atípico para o segundo ano (p> 0.05), possivelmente por causa da baixa pluviosidade observada durante esse período. O mosaico do substrato não consolidado infere que as variáveis estruturais, e os padrões de distribuição temporal foram basicamente influenciadas por parâmetros que indicam poluição e intrusão de ACAS (Água Central do Atlântico Sul), bem como atributos ecológicos entre espécies, tais como: predação, competição, entre outros. Ervilia concentrica e Cypridinidae podem ser utilizados como indicadores de alterações naturais e antrópicos no setor da Entrada da Baía de Guanabara, enquanto Cyprideis salebrosa e Cyprideis sp. para o setor Intermediário e Heleobia australis para o setor Interno.

Spatial patterns of distribution and the influence of seasonal and abiotic factors on demersal ichthyofauna in an estuarine tropical bay.

This study focused on the influence of local-scale environmental factors on key metrics of fish community structure and function at Guanabara Bay, an estuarine system that differs from all other south-western Atlantic estuaries due to the influence of an annual low-intensity upwelling event during late spring and summer, between November and March, when a warm rainy climate prevails. The spatial patterns of the bottom temperature and salinity were more heterogeneous during the rainy season than the dry season, being linked to total precipitation and seasonal oceanographic events. The study identified 130 species and 45 families, placing Guanabara Bay as one of the most species-rich tropical estuarine ecosystems, far exceeding 22 other Brazilian estuaries. These results, in addition to characteristics such as a relatively well-preserved mangrove forest, high productivity and favourable conditions for the growth and reproduction of estuarine species, indicate that Guanabara Bay plays a central role in supporting large populations of fishes, including commercially important species.

Spatial distribution of intertidal sandy beach polychaeta along an estuarine and morphodynamic gradient in an eutrophic tropical bay.

The spatial distribution of polychaeta along pollution gradients often reflects different degrees of disturbance. In order to evaluate polychaeta fauna of an organically polluted tropical bay, 20 sandy beaches distributed in five areas were sampled. The relationship between community structure, slope, beach index, exposure, sediment and water quality parameters were analysed. Multivariate analysis of variance (PERMANOVA) showed differences among areas and beaches. Scolelepis chilensis dominated at mouth of bay beaches whereas Streblospio gynobranchiata and Capitella capitata complex, at inner beaches. Highest polychaete density was recorded at areas 3 and 5 with the dominance of Saccocirrus sp. and the organic indicator species C. capitata complex and Polydora sp. The most important factors obtained from canonical analysis were sorting, slope, mud and organic matter percentage. Marine biotic index (AMBI) showed that areas 3 and 5 were highly affected by anthropogenic factors, given that a poor polychaeta fauna, dominated by opportunistic species, were found. Polychaete assemblages were affected by eutrophication along an estuarine gradient as well as by morphodynamic condition of the beaches.

Prokaryotic diversity in one of the largest hypersaline coastal lagoons in the world.

Araruama Lagoon is an environment characterized by high salt concentrations. The low raining and high evaporation rates in this region favored the development of many salty ponds around the lagoon. In order to reveal the microbial composition of this system, we performed a 16S rRNA gene survey. Among archaea, most clones were related to uncultured environmental Euryarchaeota. In lagoon water, we found some clones related to Methanomicrobia and Methanothermococcus groups, while in the saline pond water members related to the genus Haloarcula were detected. Bacterial community was dominated by clones related to Gamma-proteobacteria, Actinobacteria, and Synechococcus in lagoon water, while Salinibacter ruber relatives dominated in saline pond. We also detected the presence of Alpha-proteobacteria, Pseudomonas-like bacteria and Verrucomicrobia. Only representatives of the genus Ralstonia were cosmopolitan, being observed in both systems. The detection of a substantial number of clones related to uncultured archaea and bacteria suggest that the hypersaline waters of Araruama harbor a pool of novel prokaryotic phylotypes, distinct from those observed in other similar systems. We also observed clones related to halophilic genera of cyanobacteria that are specific for each habitat studied. Additionally, two bacterioplankton molecular markers with ecological relevance were analyzed, one is linked to nitrogen fixation (nifH) and the other is linked to carbon fixation by bacterial photosynthesis, the protochlorophyllide genes, revealing a specific genetic distribution in this ecosystem. This is the first study of the biogeography and community structure of microbial assemblages in Brazilian tropical hypersaline environments. This work is directed towards a better understanding of the free-living prokaryotic diversity adapted to life in hypersaline waters.

Flow cytometry assessment of bacterioplankton in tropical marine environments.

Flow cytometry was used to characterize bacterioplankton from two tropical environments in Brazil: the eutrophic Guanabara Bay and the oligotrophic southwest Atlantic Ocean. Bacterial abundance was evaluated by flow cytometry, and cells were stained with SYTO 13, allowing demonstration of differences in nucleic acid content. Bacterial production was also evaluated by means of 3H-leucine incorporation. Bacterial numbers were different for both sites. In Atlantic Ocean samples, we found a maximum of 5.50 x 10(5) cells ml(-1), and low nucleic acid content organisms predominated. In Guanabara Bay, bacterial numbers were one order of magnitude higher than in the ocean, and they varied from outer bay (1.01 x 10(6) cells ml(-1)) to inner bay (6.90 x 10(6) cells ml(-1)). Bacterial activity in ocean samples varied from 4.6 to 126 ng C l(-1) h(-1), while in the bay, mean values ranged from 1.95 microg C l(-1) h(-1) (outer bay) to 7.35 microg C l(-1) h(-1) (inner bay). Values found for both parameters are characteristic of different trophic situations. These results illustrate the utility of cytometric analyses of bacterioplankton populations in characterizing their large spatial and temporal scales of distribution in aquatic ecosystems.