Diversity and functional groups of copepods as a tool for interpreting trophic relationships and ecosystem functioning in estuaries.

We examined trophic relationships in estuarine planktonic food webs by focusing on the assemblages and functional groups of copepods and their effects on prey and predator. We also studied the relationship between biodiversity and ecosystem functioning in estuaries using different taxonomic and functional diversity indices of copepod assemblages and copepod biomass as a proxy of ecosystem functioning. We collected samples every 2 months over a 2-year period in four Brazilian estuaries. Taxonomic diversity indices showed a positive and negative relationship with chaetognath densities and ecosystem functioning, respectively. The functional indices were negatively related to the effect of predator diversity on prey. Different functional groups of copepods were positively correlated with chaetognath density, consistent with their generalist feeding habits. Thus, multifaceted approaches that use different indices and functional groups are recommended to provide a more realistic view of the trophic relationships and ecosystem functioning in estuaries.

Distribution, diversity, and habitat partitioning of Scolecitrichidae species (Copepoda: Calanoida) down to 1,200 m in the Southwestern Atlantic Ocean.

In this study, we analyzed the main distributional features of Scolecitrichidae species in the Southwestern Atlantic Ocean (northern region of Rio de Janeiro State) and determined and described their habitat partitioning, based on a night series of stratified samplings down to a depth of 1,200 m. A total of 18 species from seven genera were identified and grouped according to their depth distribution. Distinct vertical patterns of total density, richness, diversity, and evenness were observed, with a decrease in density and an increase in diversity and richness with increasing depth. The total scolecitrichid abundance was dominated by a few epipelagic migrant species (Scolecithrix danae, Scolecithricella minor, Amallothrix tenuiserrata, and Lophothrix frontalis). The nondominant species were distributed in different habitats in the mesopelagic layer (upper-mesopelagic, mesopelagic, and lower-mesopelagic species) according to their vertical patterns of abundance and occurrence in the two sampling periods (rainy and dry season). The total density of scolecitrichid copepods was positively related to temperature and nitrate, and negatively related to silicate at 1 m depth. The abundance of scolecitrichids copepods in the upper layer with warm and oligotrophic waters supports the hypothesis of the influence of different water masses on the scolecitrichid assemblage. High abundance of appendicularians (Oikopleura longicauda) at 1 m depth in the region implies a high production rate of discarded "houses", an important dietary component for Scolecitrichidae copepods. The observed patterns of seasonal cycles and vertical distribution suggest that the diverse scolecitrichid assemblage in the region may be structured mainly according to the partitioning of vertical habitats and food resources.

Differences in the structure of copepod assemblages in four tropical estuaries: Importance of pollution and the estuary hydrodynamics.

We examined the relationship between pollution and structure of copepod assemblages in estuaries, using sampling standardization of salinity range to reduce the effects of "Estuarine Quality Paradox". Copepod assemblages were analyzed in four Southeast Brazilian estuaries with different water quality levels and different hydrodynamic characteristics. The pollution negatively impacted the descriptors of the assemblage structure. The distribution of structure of copepod assemblages also showed a main separation trend between the most polluted estuaries and those less polluted. Temperature was the main factor affecting the assemblage structuring in the four estuaries. This factor acted in synergism with the effects of pollution impact and physical characteristics of the estuaries on the structure of copepod assemblages, supporting the potential vulnerability of coastal environments due to nutrient enrichment associated with climate change. Our study demonstrated the importance of sampling standardization of the salinity range in estuaries for reliable analysis of pollution effects on biota.

Variação da composição e abundância das espécies da Classe Appendicularia e seu uso como potenciais bioindicadoras de regiões e massas de água superficiais na área da Bacia de Campos, Rio de Janeiro, Brasil / Variation of species abundance of Class Appendicularia and their use as potential bioindicators of the regions and surface water mass in the area of the Campos Basin, Rio de Janeiro, Brazil

Studies about the relationship of the species of appendicularians with spatial gradients and water masses are rare, especially in the South Atlantic. The present study aims to fill the knowledge gap about the abundance of the community of appendicularians and on their bioindicator function in different regions (continental shelf and slope), with influence of different water masses in the South Atlantic. Sampling was conducted in the rainy season (February-April 2009) and the dry season (August-September 2009) in the subsurface layer. The water masses found on the continental shelf of the study area were the Tropical Water (AT), which was prevalent during the rainy season, and the Coastal Water (AC), which was prevalent in the dry season. In both sampling periods has not registered the presence of SACW on the surface over continental shelf. The appendicularians were more abundant in the region of the continental shelf influenced by the CW. A total of 18 species of appendicularian was registered. Oikopleura longicauda Vogt, 1854 and O. fusiformis Fol, 1872 were the most abundant appendicularian. Oikopleura dioica Fol, 1872 was found exclusively in the continental shelf on the CW. In despite of the SACW water had not registered on the surface, the presence of, high values of density of appendicularians in front of Cabo Frio region suggest the influence of an upwelling event in a anterior period in the region. In relation to the appendicularians abundance, high values were also observed in front of the Paraíba do Sul river with the CW influence. This fact suggests a high nutritional contribution of this river in the coastal marine area adjacent. The spatial variation and different water masses influenced the abundance and the composition of appendicularians. Among the species identified, only O. longicauda was considered as a bioindicator of the CW.

Estudos sobre a variação espacial das espécies de apendiculárias e sua relação com as massas de água são raros, principalmente no Atlântico Sul. O atual estudo pretende preencher a lacuna de conhecimento sobre a abundância, composição específica e a função de bioindicadora das apendiculárias, em diferentes regiões (plataforma continental e talude) e massas de água, no Atlântico Sul Ocidental. As coletas foram realizadas no período chuvoso (de fevereiro a abril de 2009) e no período seco (de agosto a setembro de 2009) na camada subsuperficial. As massas de água encontradas na superfície na plataforma continental da área de estudo foram a Água Tropical (AT), que predominou no período chuvoso, e a Água Costeira (AC), que predominou no período seco. Em ambos os períodos de coleta não foram registradas a presença da Água Central do Atlântico Sul (ACAS) na superfície na plataforma continental. As apendiculárias foram mais abundantes na região de plataforma continental influenciada pela AC. Foi identificado um total de 12 espécies da Classe Appendicularia. Oikopleura longicauda Vogt, 1854 e O. fusiformis Fol, 1872 foram as espécies mais abundantes. Oikopleura dioica Fol, 1872 foi encontrada exclusivamente na plataforma continental na AC. Apesar não ser observado a presença de ACAS na superfície, altos valores da densidade de apendiculária em frente a Cabo Frio sugerem a influência de uma pós-ressurgência no local. Também foram observados valores elevados na abundância das apendiculárias em frente ao rio Paraíba do Sul, com influência da AC. Este fato sugere a alta capacidade de incremento de nutrientes desse aporte fluvial. A variação espacial e as diferentes massas de água influenciaram a abundância e a composição das apendiculárias. Dentre as espécies identificadas, somente O. longicauda foi considerada como bioindicadora da AC.

Variação da composição e abundância das espécies da Classe Appendicularia e seu uso como potenciais bioindicadoras de regiões e massas de água superficiais na área da Bacia de Campos, Rio de Janeiro, Brasil

ABSTRACT Studies about the relationship of the species of appendicularians with spatial gradients and water masses are rare, especially in the South Atlantic. The present study aims to fill the knowledge gap about the abundance of the community of appendicularians and on their bioindicator function in different regions (continental shelf and slope), with influence of different water masses in the South Atlantic. Sampling was conducted in the rainy season (February-April 2009) and the dry season (August-September 2009) in the subsurface layer. The water masses found on the continental shelf of the study area were the Tropical Water (AT), which was prevalent during the rainy season, and the Coastal Water (AC), which was prevalent in the dry season. In both sampling periods has not registered the presence of SACW on the surface over continental shelf. The appendicularians were more abundant in the region of the continental shelf influenced by the CW. A total of 18 species of appendicularian was registered. Oikopleura longicauda Vogt, 1854 and O. fusiformis Fol, 1872 were the most abundant appendicularian. Oikopleura dioica Fol, 1872 was found exclusively in the continental shelf on the CW. In despite of the SACW water had not registered on the surface, the presence of, high values of density of appendicularians in front of Cabo Frio region suggest the influence of an upwelling event in a anterior period in the region. In relation to the appendicularians abundance, high values were also observed in front of the Paraíba do Sul river with the CW influence. This fact suggests a high nutritional contribution of this river in the coastal marine area adjacent. The spatial variation and different water masses influenced the abundance and the composition of appendicularians. Among the species identified, only O. longicauda was considered as a bioindicator of the CW.

RESUMO Estudos sobre a variação espacial das espécies de apendiculárias e sua relação com as massas de água são raros, principalmente no Atlântico Sul. O atual estudo pretende preencher a lacuna de conhecimento sobre a abundância, composição específica e a função de bioindicadora das apendiculárias, em diferentes regiões (plataforma continental e talude) e massas de água, no Atlântico Sul Ocidental. As coletas foram realizadas no período chuvoso (de fevereiro a abril de 2009) e no período seco (de agosto a setembro de 2009) na camada subsuperficial. As massas de água encontradas na superfície na plataforma continental da área de estudo foram a Água Tropical (AT), que predominou no período chuvoso, e a Água Costeira (AC), que predominou no período seco. Em ambos os períodos de coleta não foram registradas a presença da Água Central do Atlântico Sul (ACAS) na superfície na plataforma continental. As apendiculárias foram mais abundantes na região de plataforma continental influenciada pela AC. Foi identificado um total de 12 espécies da Classe Appendicularia. Oikopleura longicauda Vogt, 1854 e O. fusiformis Fol, 1872 foram as espécies mais abundantes. Oikopleura dioica Fol, 1872 foi encontrada exclusivamente na plataforma continental na AC. Apesar não ser observado a presença de ACAS na superfície, altos valores da densidade de apendiculária em frente a Cabo Frio sugerem a influência de uma pós-ressurgência no local. Também foram observados valores elevados na abundância das apendiculárias em frente ao rio Paraíba do Sul, com influência da AC. Este fato sugere a alta capacidade de incremento de nutrientes desse aporte fluvial. A variação espacial e as diferentes massas de água influenciaram a abundância e a composição das apendiculárias. Dentre as espécies identificadas, somente O. longicauda foi considerada como bioindicadora da AC.

Variação da composição e abundância das espécies da Classe Appendicularia e seu uso como potenciais bioindicadoras de regiões e massas de água superficiais na área da Bacia de Campos, Rio de Janeiro, Brasil / Variation of species abundance of Class Appendicularia and their use as potential bioindicators of the regions and surface water mass in the area of the Campos Basin, Rio de Janeiro, Brazil

Studies about the relationship of the species of appendicularians with spatial gradients and water masses are rare, especially in the South Atlantic. The present study aims to fill the knowledge gap about the abundance of the community of appendicularians and on their bioindicator function in different regions (continental shelf and slope), with influence of different water masses in the South Atlantic. Sampling was conducted in the rainy season (February-April 2009) and the dry season (August-September 2009) in the subsurface layer. The water masses found on the continental shelf of the study area were the Tropical Water (AT), which was prevalent during the rainy season, and the Coastal Water (AC), which was prevalent in the dry season. In both sampling periods has not registered the presence of SACW on the surface over continental shelf. The appendicularians were more abundant in the region of the continental shelf influenced by the CW. A total of 18 species of appendicularian was registered. Oikopleura longicauda Vogt, 1854 and O. fusiformis Fol, 1872 were the most abundant appendicularian. Oikopleura dioica Fol, 1872 was found exclusively in the continental shelf on the CW. In despite of the SACW water had not registered on the surface, the presence of, high values of density of appendicularians in front of Cabo Frio region suggest the influence of an upwelling event in a anterior period in the region. In relation to the appendicularians abundance, high values were also observed in front of the Paraíba do Sul river with the CW influence. This fact suggests a high nutritional contribution of this river in the coastal marine area adjacent. The spatial variation and different water masses influenced the abundance and the composition of appendicularians. Among the species identified, only O. longicauda was considered as a bioindicator of the CW.(AU)

Estudos sobre a variação espacial das espécies de apendiculárias e sua relação com as massas de água são raros, principalmente no Atlântico Sul. O atual estudo pretende preencher a lacuna de conhecimento sobre a abundância, composição específica e a função de bioindicadora das apendiculárias, em diferentes regiões (plataforma continental e talude) e massas de água, no Atlântico Sul Ocidental. As coletas foram realizadas no período chuvoso (de fevereiro a abril de 2009) e no período seco (de agosto a setembro de 2009) na camada subsuperficial. As massas de água encontradas na superfície na plataforma continental da área de estudo foram a Água Tropical (AT), que predominou no período chuvoso, e a Água Costeira (AC), que predominou no período seco. Em ambos os períodos de coleta não foram registradas a presença da Água Central do Atlântico Sul (ACAS) na superfície na plataforma continental. As apendiculárias foram mais abundantes na região de plataforma continental influenciada pela AC. Foi identificado um total de 12 espécies da Classe Appendicularia. Oikopleura longicauda Vogt, 1854 e O. fusiformis Fol, 1872 foram as espécies mais abundantes. Oikopleura dioica Fol, 1872 foi encontrada exclusivamente na plataforma continental na AC. Apesar não ser observado a presença de ACAS na superfície, altos valores da densidade de apendiculária em frente a Cabo Frio sugerem a influência de uma pós-ressurgência no local. Também foram observados valores elevados na abundância das apendiculárias em frente ao rio Paraíba do Sul, com influência da AC. Este fato sugere a alta capacidade de incremento de nutrientes desse aporte fluvial. A variação espacial e as diferentes massas de água influenciaram a abundância e a composição das apendiculárias. Dentre as espécies identificadas, somente O. longicauda foi considerada como bioindicadora da AC.(AU)

Horizontal and vertical distribution of mesozooplankton species richness and composition down to 2, 300 m in the southwest Atlantic Ocean

We describe the species richness, distribution and composition of mesozooplankton over the continental shelf and slope, and in the water masses in the Campos Basin, southwest Atlantic Ocean. We analyzed the mesozooplankton from two oceanographic cruises (rainy and dry seasons, 2009) with samples taken in five different water masses from the surface to 2,300 m depth. In the Subsurface Water (SS), in both sampling periods, more species were recorded over the slope (rainy: 100; dry: 128) than the continental shelf (rainy: 97; dry: 104). Over the slope, species richness decreased with increasing depth: the highest values were observed in the South Atlantic Central Water (SACW), and the lowest values in the North Atlantic Deep Water (NADW), in both sampling periods. We recorded 262 species in 10 groups (Hydrozoa, Siphonophora, Ctenophora, Branchiopoda, Copepoda, Euphausiacea, Decapoda, Chaetognatha, Appendicularia e Thaliacea), with 13 new occurrences for the southwest Atlantic. Copepoda was the group with the highest species richness, containing 138 species. In both periods, the samples from SS, SACW and Antarctic Intermediate Water (AAIW)/Upper Circumpolar Deep Water (UCDW) were clustered in different faunistic zones, based on species composition. This study confirmed that zooplankton richness in the southwest Atlantic Ocean is underestimated, and suggests that additional efforts must be directed toward a better understanding of this fairly unknown region.

Horizontal and vertical distribution of mesozooplankton species richness and composition down to 2, 300 m in the southwest Atlantic Ocean

We describe the species richness, distribution and composition of mesozooplankton over the continental shelf and slope, and in the water masses in the Campos Basin, southwest Atlantic Ocean. We analyzed the mesozooplankton from two oceanographic cruises (rainy and dry seasons, 2009) with samples taken in five different water masses from the surface to 2,300 m depth. In the Subsurface Water (SS), in both sampling periods, more species were recorded over the slope (rainy: 100; dry: 128) than the continental shelf (rainy: 97; dry: 104). Over the slope, species richness decreased with increasing depth: the highest values were observed in the South Atlantic Central Water (SACW), and the lowest values in the North Atlantic Deep Water (NADW), in both sampling periods. We recorded 262 species in 10 groups (Hydrozoa, Siphonophora, Ctenophora, Branchiopoda, Copepoda, Euphausiacea, Decapoda, Chaetognatha, Appendicularia e Thaliacea), with 13 new occurrences for the southwest Atlantic. Copepoda was the group with the highest species richness, containing 138 species. In both periods, the samples from SS, SACW and Antarctic Intermediate Water (AAIW)/Upper Circumpolar Deep Water (UCDW) were clustered in different faunistic zones, based on species composition. This study confirmed that zooplankton richness in the southwest Atlantic Ocean is underestimated, and suggests that additional efforts must be directed toward a better understanding of this fairly unknown region.(AU)