Long-term monitoring projects of Brazilian marine and coastal ecosystems.

Biodiversity assessment is a mandatory task for sustainable and adaptive management for the next decade, and long-term ecological monitoring programs are a cornerstone for understanding changes in ecosystems. The Brazilian Long-Term Ecological Research Program (PELD) is an integrated effort model supported by public funds that finance ecological studies at 34 locations. By interviewing and compiling data from project coordinators, we assessed monitoring efforts, targeting biological groups and scientific production from nine PELD projects encompassing coastal lagoons to mesophotic reefs and oceanic islands. Reef environments and fish groups were the most often studied within the long-term projects. PELD projects covered priority areas for conservation but missed sensitive areas close to large cities, as well as underrepresenting ecosystems on the North and Northeast Brazilian coast. Long-term monitoring projects in marine and coastal environments in Brazil are recent (<5 years), not yet integrated as a network, but scientifically productive with considerable relevance for academic and human resources training. Scientific production increased exponentially with project age, despite interruption and shortage of funding during their history. From our diagnosis, we recommend some actions to fill in observed gaps, such as: enhancing projects' collaboration and integration; focusing on priority regions for new projects; broadening the scope of monitored variables; and, maintenance of funding for existing projects.

Unravelling the foraging behavior of the southern stingray, Hypanus americanus (Myliobatiformes: Dasyatidae) in a Southwestern Atlantic MPA

Previous study suggested that the southern stingray (Hypanus americanus) displays a marked ontogenetic shift in its habitat use in the Fernando de Noronha Archipelago (FNA), an attractive touristic spot in Brazil, that could be associated with changes in its feeding habits and foraging strategies. Here, we conducted underwater visual surveys (~100 h a 3 years' study) at this site to describe the foraging behavior of the same species in details and to assess diel patterns in activity. We observed that H. americanus is capable of several complex and highly plastic behaviors (we described more than 21 of them) while foraging. The foraging events' timing appears to be related to the size (as well as sex) of the stingrays, environment and depth. In addition, our results support a segregation of habitat mediated by the size and sex of the stingrays, but it is able to modulate its foraging repertoire based mainly on environmental stimulus. Finally, we found that H. americanus forage intermittently throughout the day and tidal cycle, yet are less active during non-crepuscular periods and at flood and ebb tides. These results, coupled with the fact that the species uses both reef and beach environments, should be considered by decision makers in management plans.(AU)

Um estudo anterior sugeriu que a raia-prego (Hypanus americanus) apresenta uma marcante mudança ontogenética no seu uso de hábitat no Arquipélago de Fernando de Noronha (FNA), local turístico atraente no Brasil, que pode ser associado a mudanças em seus hábitos alimentares e estratégias de forrageamento. Aqui, nós conduzimos amostragens visuais subaquáticas (~100 h em 3 anos de estudo) nesse local para descrever o comportamento de forrageamento dessa mesma espécie em detalhes e acessar seu padrão de atividade diário. Nós observamos que H. americanus tem capacidade para comportamentos complexos e altamente plásticos (nós descrevemos mais de 21 deles) enquanto forrageia. O tempo dos eventos de forrageamento parece estar relacionado com o tamanho (e também sexo) das raias, ambiente e profundidade. Além disso, nossos resultados apoiam a ideia de uma segregação de hábitat mediada pelo tamanho e sexo das arraias, mas que ela é capaz de modular seu repertório de forrageio baseado principalmente em estímulos ambientais. Finalmente, nós descobrimos que H. americanus forrageia de forma intermitente ao longo do dia e ciclos de marés, mas é menos ativa durante os períodos não-crepusculares e nas enchentes e vazantes das marés. Esses resultados, somado ao fato que a espécie utiliza tanto ambientes recifais quanto praianos, devem ser considerados pelos tomadores de decisão em planos de manejo.(AU)

Investigating heavy metal bioaccumulation by macrofauna species from different feeding guilds from sandy beaches in Rio de Janeiro, Brazil.

The relationship between metal accumulation and feeding behavior of macrofauna species is a key concept to understand the bioavailability of different metals in the marine environment. We examined and compared the concentrations of eight heavy metals (Cr, Zn, Pb, Ni, Cu, Cd, Co and V) in different feeding guilds of macrofauna species, from a data set including 68 sandy beaches along the Rio de Janeiro coast. For this purpose, macrofauna species were classified in five feeding guild categories: carnivorous, herbivorous, detritivorous, suspensivorous and filter feeders. The coast of Rio de Janeiro was divided into seven regions according to environmental characteristics and historical human activities. For each region, generalized linear models were adjusted to test for differences between feeding guild abundances. Redundancy Analysis was performed to explore the relationship among the feeding guilds composition and the environmental variables. We found high variability in abundance and composition among feeding guilds, linked with environmental heterogeneity. In general, carnivorous species showed a higher heavy metal concentrations compared to other trophic guilds evaluated. However, bioaccumulation across the feeding guild was not the rule and patterns varied across regions. Our hypothesis is that variations are probably related to the different magnitudes of metal contamination along the coast as also in to the trophic structure found in each beach. This data highlighted the crucial role of the relationship between variability of environmental drivers and bioaccumulation in macrofauna species in sandy beaches ecosystem.

Heavy metal contamination in sandy beach macrofauna communities from the Rio de Janeiro coast, Southeastern Brazil.

We evaluated concentrations of eight heavy metals Cr, Zn, Pb, Ni, Cu, Cd, Co and V, in tissues of representative macrofauna species from 68 sandy beaches from the coast of Rio de Janeiro state. The links between contamination levels and community descriptors such as diversity, evenness, density and biomass, were also investigated. Metal concentrations from macrofaunal tissues were compared to maximum permissible limits for human ingestion stipulated by the Brazilian regulatory agency (ANVISA). Generalized linear models (GLM's) were used to investigate the variability in macrofauna density, richness, eveness and biomass in the seven different regions. A non-metric multidimensional scaling analysis (n-MDS) was used to investigate the spatial pattern of heavy metal concentrations along the seven regions of Rio de Janeiro coast. Variation partitioning was applied to evaluate the variance in the community assemblage explained by the environmental variables and the heavy metal concentrations. Our data suggested high spatial variation in the concentration of heavy metals in macrofauna species from the beaches of Rio de Janeiro. This result highlighted a diffuse source of contamination along the coast. Most of the metals concentrations were under the limits established by ANVISA. The variability in community descriptors was related to morphodynamic variables, but not with metal contamination values, indicating the lack of direct relationships at the community level. Concentration levels of eight heavy metals in macrofauna species from 68 sandy beaches on Rio de Janeiro coast (Brazil) were spatially correlated with anthropogenic activities such as industrialization and urbanization.

Feeding ecology of elasmobranch species in southeastern Brazil

The feeding ecology of five elasmobranch species was studied on the southern coast of Rio de Janeiro, southwestern Atlantic Ocean. The specimens were caught with a trawl or bottom longline between January 2006 and August 2007. The diets of Psammobatis rutrum and Psammobatis extenta appeared to be basically carcino-benthophagous, with a very small niche width. Rioraja agassizii was basically carcino/ichthyo-benthophagous, also with a narrow niche, including teleost fish and shrimp, but in different proportions according to age and sex. Rhizoprionodon lalandii was ichthyophagous, not influenced by age or sex. The analyses of these species and Atlantoraja cyclophora indicated two trophic groups: one composed of the smaller rays, P. extenta and P. rutrum, which basically fed on small crustaceans, polychaetes and nematodes; and the other of R. lalandii and the larger rays R. agassizii and A. cyclophora, which preyed on teleost fish and brachyurans.(AU)

Devido à lacuna de conhecimento sobre os elasmobrânquios estudamos a ecologia alimentar de cinco espécies desse grupo, no litoral sul do Rio de Janeiro. Os exemplares foram capturados por rede de arrasto e espinhel de fundo, entre janeiro de 2006 e agosto de 2007. As dietas de Psammobatis rutrum e Psammobatis extenta se mostraram basicamente carcino-bentofagas, com uma largura de nicho estreito. Rioraja agassizii foi considerada carcino/ictio-bentófaga, também com uma largura de nicho estreita. A espécie se alimenta com peixe e camarão, mas em proporções diferentes de acordo com a idade e sexo. A dieta de Rhizoprionodon lalandii foi considerada ictiófaga e não é influenciada pela idade ou sexo. As análises destas espécies e Atlantoraja cyclophora indicaram a formação de dois grupos tróficos: um composto pelas raias menores, P. extenta e P. rutrum, que basicamente se alimentam de pequenos crustáceos, poliquetos e nematodas; e o outro de R. lalandii e as raias maiores R. agassizii e A. cyclophora, que predam peixes teleósteos e brachyuras.(AU)

Evaluation of the complexity and performance of marine planktonic trophic models.

Planktonic models represent a powerful tool for creating hypotheses and making predictions about the functioning of marine ecosystems. Their complexity varies according to the number of state variables and the choice of functional forms. We evaluated plankton models during the last 15 years (n =145) with the aims of understanding why they differ in complexity, evaluating model robustness, and describing studies of plankton modelling around the globe. We classified models into four groups: Nutrient-Phytoplankton-Zooplankton (NPZ), Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD), Size-Structured (SS) and Plankton-Functional-Type (PFT). Our results revealed that the number of state variables varied according to the question being addressed: NPZ models were more frequently applied in physical-biological studies, while PFT models were more applied for investigating biogeochemical cycles. Most models were based on simple functional forms which neglect important feedback related to control of plankton dynamics. Modelling studies sometimes failed to describe sensitivity analysis, calibration and validation. The importance of testing different functional forms was commonly overlooked, and the lack of empirical data affected the verification of model robustness. Lastly, we highlight the need to develop modelling studies in the Southern Hemisphere, including Brazil, in order to provide predictions that assist the management of marine ecosystems.

A survey on cultivable heterotrophic bacteria inhabiting a thermally unstratified water column in an Atlantic Rainforest lake.

Due to the importance of heterotrophic bacteria in biogeochemical cycles and their influence on water quality, many studies have assessed the composition of the bacterial community. Most of these were made in temperate freshwaters. Eighteen heterotrophic bacteria communities distributed over time and space in the water column of Carioca Lake, not exposed to anthropogenic activities, were analyzed to characterize their composition. A polyphasic approach was used, including 16S rDNA restriction analysis, 16S rRNA gene sequence analysis, BIOLOG Ecoplates and statistical methods. The physiological profiles among the 18 microbial communities were diverse. Clustering analysis and the metabolic fingerprint of the Biolog Ecoplate(TM) system data separated the communities based on temporal scale. A set of 673 isolates were recovered on high nutrient medium. The 673 isolates obtained yielded 360 Amplified Ribosomal DNA Restriction Analysis (ARDRA) Operational Taxonomic Units (OTUs). Most (313) of the ARDRA patterns, OTUs, were from isolates obtained in a single sampling point, in temporal and spatial scales, indicating changes in the bacterial community. A subset of representative isolates for each ARDRA OTU was identified by 16S rRNA gene fragment sequencing and categorized into five phyla, Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Deinococcus-Thermus, represented by 38 genera. The results of this work contribute to a better understanding about the phylogeny of tropical freshwater heterotrophic bacteria.

Do the changes in temperature and light affect the functional response of the benthic mud snail Heleobia australis (Mollusca: Gastropoda)?

The aim of this study was to determine the influence of temperature increase combined to conditions of light incidence on functional response of Heleobia australis. Experiments were conducted using nine to ten food concentrations for each treatment: 20°C without light; 30°C without light and, 30°C under low light intensity. For each experiment, the functional response type III (sigmoidal) was fitted and equation parameters were determined. Results suggest that, if the sediment temperature increases, H. australis will not have its ingestion rates affected negatively, whilst its feeding behavior seems to be negatively affected by light. Ingestion rates estimated for organic content in the Guanabara Bay were: 0.34 µgC ind-1h-1 at 20°C without light, 1.44 µgC ind-1h-1 at 30°C without light and 0.64 µgC ind-1h-1 at 30°C under light incidence. Higher ingestion rates were estimated at the high temperature, even under light incidence, and temperature seems to have outweighed the light effect. In contrast, if higher carbon content is considered, despite high temperature, the experiment conducted with light incidence showed lower ingestion rates than those from the experiment at 20°C without light. This study provides the first quantification of H. australis ingestion rates and the effects that changes in temperature and light have on its feeding behavior.

Reproduction and structure of the population of the Chaetognath Parasagitta friderici in Guanabara Bay (Brazil) based on short term sampling.

The aim of this study was to describe the total density, densities of developmental stages and the reproduction period of Parasagitta friderici. Weekly samples were collected at one station in the channel of Guanabara Bay, Rio de Janeiro, during one year. Three vertical hauls were made for each sample, and P. friderici was separated, the developmental stages were identified, and body length (BL), ovary length (OL) and seminal vesicle width (SVW) were measured. Throughout the year P. friderici was the most abundant chaetognath species occurring in all four developmental stages, the densities of which varied from week to week. Higher densities of adults occurred in the spring, followed by peaks of juveniles in the summer. Although P. friderici seems to reproduce continuously in Guanabara Bay, a reproductive peak was apparent during the spring. The intensification of reproduction during the spring, with juveniles occurring in the summer, seems to be related to the period of higher food supply during the rainy season and intrusions of the South Atlantic Central Water.

Structuring of bacterioplankton diversity in a large tropical bay.

Structuring of bacterioplanktonic populations and factors that determine the structuring of specific niche partitions have been demonstrated only for a limited number of colder water environments. In order to better understand the physical chemical and biological parameters that may influence bacterioplankton diversity and abundance, we examined their productivity, abundance and diversity in the second largest Brazilian tropical bay (Guanabara Bay, GB), as well as seawater physical chemical and biological parameters of GB. The inner bay location with higher nutrient input favored higher microbial (including vibrio) growth. Metagenomic analysis revealed a predominance of Gammaproteobacteria in this location, while GB locations with lower nutrient concentration favored Alphaproteobacteria and Flavobacteria. According to the subsystems (SEED) functional analysis, GB has a distinctive metabolic signature, comprising a higher number of sequences in the metabolism of phosphorus and aromatic compounds and a lower number of sequences in the photosynthesis subsystem. The apparent phosphorus limitation appears to influence the GB metagenomic signature of the three locations. Phosphorus is also one of the main factors determining changes in the abundance of planktonic vibrios, suggesting that nutrient limitation can be observed at community (metagenomic) and population levels (total prokaryote and vibrio counts).

Seasonal variation in fish larvae at the entrance of Guanabara Bay, Brazil

Devido a crescente ação antrópica a qual está sujeita e sua importância sócio-econômica, a baía de Guanabara vem despertando grande interesse na comunidade científica. O presente trabalho objetivou analisar a variação quali-quantitativa temporal das larvas de peixes, relacionar a densidade das larvas com o ciclo nictemeral e verificar a influência dos ciclos de maré. Foram realizadas coletas, em um ponto localizado na entrada da baía, em setembro de 1995 e março de 1996. As coletas ocorreram nas marés de enchente e vazante ao longo de três dias. Os arrastos foram oblíquos, utilizando uma rede do tipo bongô com malhas de 500 µm. Foi coletado um total de 42 táxons. As famílias Engraulidae (Cetengraulis edentulus e Anchoa lyolepis) e Clupeidae (Harengula jaguana) ocorreram em grandes densidades e dominaram nas duas campanhas. As maiores densidades de larvas de peixes ocorreram durante a campanha de março, que apresentou altas temperaturas e baixas salinidades. Observou-se um padrão nictemeral em relação a abundância de larvas, com altas densidades durante a noite e baixas durante o dia. Os altos índices de diversidade encontrados ressaltam a importância desse ecossistema para várias espécies de peixes.