The Brazilian coastal zone presents a large extension and a variety of environments. Nevertheless, little is known about biological diversity and ecosystem dynamics. Environmental changes always occur; however, it is important to distinguish natural from anthropic variability. Under these scenarios, the aim of this work is to present a Data Mining methodology able to access the quality and health levels of the environmental conditions through the biological integrity concept. A tenyear time series of physical, chemical and biological parameters from an influenced upwelling area of Arraial do Cabo-RJ were used to generate a classification model based on association rules. The model recognizes seven different classes of water based on biological diversity and a new trophic index (PLIX). Artificial neural networks were evolved and optimized by genetic algorithms to forecast these indices, enabling environmental diagnostic to be made taking into account control mechanisms of topology, stability and complex behavioral properties of food web.
RESUMOA zona costeira brasileira apresenta grande extensão e variedade de ambientes. Contudo, pouco se sabe sobre sua diversidade biológica e o funcionamento dos ecossistemas. Como mudanças ambientais são constantes, é muito importante distinguir entre variabilidade natural e antrópica. Nesse cenário, o objetivo deste trabalho é apresentar a metodologia para o desenvolvimento de um Sistema Inteligente de Gerenciamento Integrado do Ecossistema Costeiro (SIGIEC) capaz de acessar o nível de qualidade e saúde ambiental através do conceito de Integridade Biológica. Foram usadas séries temporais de dez anos de parâmetros físicos, químicos e biológicos para extrair conhecimento e gerar modelos de regras de associação para classificar sete diferentes tipos de condições ambientais, analisadas através da diversidade biológica e um novo índice trófico (PLIX). Redes neurais artificiais foram otimizadas por algoritmos genéticos para fazer predições desses índices e apresenta-se um diagnóstico ambiental baseado na análise dos mecanismos de controle da topologia, estabilidade e propriedades do comportamento complexo de redes alimentares .
This work correlates time series of biological and physical variables to the marine viruses across trophic gradients within Arraial do Cabo upwelling system, Southeast of Brazil. The objective is to investigate the major controlling factors of virioplankton dynamics among different water masses. It was used an in situ and ex situ flow cytometry for accessing the plankton community. Viruses were highly correlated to bacteria and phytoplankton, but although the lack of direct correlation with physicals, upwelling turned out to be the main contributing factor to the highest values of viral abundance and virus:bacterial ratio.Our data suggest that the lowest temperature of upwelled South Atlantic Central Waters would help to maintain a high viral abundance and higher temperatures of Coastal and Tropical Waters might be another ecological niche allowing the co-existence.
Investigations surrounding the variability of productivity in upwelling regions are necessary for a better understanding the physical-biological coupling in these regions by monitoring systems of environmental impacts according to the needs of the regional coastal management. Using a spatial and temporal database from National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric (NCAR) Research reanalysis, Quick Scatterometer vector wind, and surface stations from the Southeast coast of Brazil, we investigate the meteorological influences due to the large-scale systems in the variability of the nutrient and larvae concentration, and chlorophyll a, describing statistically relationships between them in upwelling regions. In addition, we used multivariate analysis, such as PCA and clustering to verify spatial and temporal variances and describe more clear the structure and composition of the ecosystem. Correlation matrix analyses were applied for different water masses present in the study area to identify the relations between physical and biogeochemical parameters in a region, where frequently upwelling occur. Statistical approaches and seasonal variability show that the period of November to March is more sensitive to nutrients (1.20 mg/m(3) for chlorophyll a, 2.20 μmol/l for total nitrogen and 5.5 ml/l for DO) and larvae concentrations (120 org/m(3) for most of the larvae, except for cirripedia that presented values around 370 org/m(3)) relating to the influence of large and mesoescale meteorological patterns. The spatial and temporal variables analyzed with multivariate approach show meaningful seasonality variance of the physical and biological samples, characterizing the principal components responsible for this variance in spring and summer (upwelling period), emphasizing the monitoring of species as crustaceans and mussels that are present in the local economy. Then, the spring and summer season are characterized by high productivity due to the occurrence of upwelling in this period.
This aim of this paper is to assess the use of the heterotrophic/autotrophic ratio as an early indicator of trophic status as a part of development of a real time monitoring program at Anjos Bay, Rio de Janeiro, Brazil. An in-situ flow cytometer was used to quantify the abundances of phytoplankton and cyanobacteria, which were identified by chlorophyll and phycoerythrin autofluorescence, respectively. Heterotrophic prokaryotes and viruses were quantified by DNA-binding fluorochromes; merozooplankton larvae were collected by plankton net and quantified by stereomicroscopy. The temporal and spatial distributions of these variables were evaluated on the basis of weekly observations from August 2006 to September 2007. The heterotrophic/autotrophic ratio and the viral abundance were correlated with upwelling events and assume an apparently seasonal pattern. A possible control mechanism and influential factors are discussed, and it is concluded that this ecosystem is bottom-up controlled under eutrophic conditions and top-down controlled under oligotrophic conditions
Arraial do Cabo is where upwelling occurs more intensively on the Brazilian coast. Although it is a protection area it suffers anthropogenic pressure such as harbor activities and sporadic sewage emissions. Short-time studies showed a high variability of bacterial production (BP) in this region but none of them evaluated BP during long periods in a large spatial scale including stations under different natural (upwelling and cold fronts) and anthropogenic pressures. During 2006, we sampled surface waters 10 times (5 in upwelling and 5 in subsidence periods) in 8 stations and we measured BP, temperature as well as the concentrations of inorganic nutrients, pigments and particulate organic matter (POM). BP was up to 400 times higher when sewage emissions were observed visually and it had a positive correlation with ammonia concentrations. Therefore, in 2007, we did two samples (each during upwelling and subsidence periods) during sewage emissions in five stations under different anthropogenic pressure and we also measured particles abundance by flow cytometry. The 12 samples in the most impacted area confirmed that BP was highest when ammonia was higher than 2 μM, also reporting the highest concentrations of chlorophyll a and suspended particles. However, considering all measured variables, upwelling was the main disturbing factor but the pressure of fronts should not be neglected since it had consequences in the auto-heterotrophic coupling, increasing the concentrations of non fluorescent particles and POM. Stations clustered in function of natural and anthropogenic pressures degrees and both determined the temporal-spatial variability.
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