Editorial : Biodiversity in a changing world: How do species traits reflect anthropogenic changes in aquatic ecosystems?

Peer reviewe

CONDICIONANTES DE SAÚDE NOS LIVROS DIDÁTICOS DA 1ª SÉRIE DO ENSINO MÉDIO

O livro didático apresenta-se como ferramenta de grande importância no contexto escolar e na sociedade. No Brasil esse instrumento de trabalho tem sido o principal suporte do professor em sala. Nosso objetivo principal foi verificar como estes livros, especificamente, abordam o tema saúde dentro do conteúdo mencionado. A partir da averiguação dos três livros foi possível encontrar algumas das condicionantes de saúde que englobam aspectos socioeconômicos, culturais e biológicos. A partir da análise, verifica-se que o uso das condicionantes nos livros didáticos são de extrema importância, uma vez que as mesmas dispõem de ferramentas para promoção e proteção da saúde, possibilitando aos alunos uma maior concepção a respeito do tema

Ciliate Communities Respond via Their Traits to a Wastewater Treatment Plant With a Combined UASB-Activated Sludge System

Assessing functional diversity of communities is an efficient method to link community composition to ecosystem quality. Still, studies using functional traits of microeukaryote ciliate communities in biological wastewater treatment plants are lacking. The present work explores the functional diversity of the ciliate protist community in a wastewater treatment plant (WWTP) operating with a combined UASB-activated sludge system, and specifically to: 1) investigate the taxonomic and functional composition of the ciliate communities over time; 2) compare taxonomic and functional diversity indices with regard to its applicability in WWPS; 3) assess the relationship between the ciliate community's functional composition and the WWTPs temporal conditions; and 4) investigate the potential use of functional diversity as an indicator of WWTP efficiency. Totally, we recorded 21 ciliate species throughout 37 samplings. The number of species was low compared to other plants. Bacterivorous and flake-forming species were the main functional strategies found in the samples. The correlation between taxonomic and functional richness was significant, indicating a functionally redundant community. There was a correlation between the Simpson and Rao's quadratic entropy indexes suggesting that loss of taxonomic diversity leads to a loss of functional diversity. The homogeneity of the measured physical and chemical data led to functional homogenization and redundancy (homogenous CWM) of the ciliate community. The functional diversity is positively correlated with parameters of removal efficiency, indicating a promising application in WWTPs. Future studies will broaden knowledge on functional diversity in biological wastewater treatment systems, this being a first step with the unprecedented application of this methodology in artificial ecosystems.Peer reviewe

Influência da morfometria de lagos na diversidade fitoplanctônica

Morphometry is the measurement of various elements of form, and it includes methods to measure since the physical dimensions of an individual to the dimensions of a system. Morphological evaluations are good study mechanisms in many areas of science and work as fundamental tools from a microscopic scale to the dimensions of an ecosystem. In lakes, the understanding of the factors involving morphometric variables is of great importance. These factors can contribute with a lot of information about the structures and functions, on the dynamics of food chains, and on regulating the flow of substances such systems. The morphology of lakes is also an important factor in the species distribution at different levels of observation, whether local, regional or global. Results supporting this applicability were found in this study, which used the phytoplankton community as a model. It was performed surveys on morphometric features and phytoplankton richness in 26 Amazonian clear water lakes and on 40 different natural and artificial lakes, 20 lakes in Brazil and 20 lakes in different regions of the world. Through linear regression, we found significant positive relationships (p<0.005) between phytoplankton richness and morphometric parameters such as area, perimeter, volume, shoreline development and volume development. Although, the shoreline development was the one that best correlated to the phytoplankton diversity, featuring such an edge effect in lakes.A morfometria trata da quantificação e medida dos diversos elementos da forma, englobando, portanto, o conjunto de métodos para medir as dimensões físicas de um indivíduo ou sistema. As avaliações morfológicas têm sido um mecanismo de estudo de muitas áreas dentro da ciência e funcionam como ferramentas fundamentais tanto em escala microscópica, quanto em dimensões ecossistêmicas. Em sistemas lacustres, a compreensão dos fatores que envolvem variáveis morfométricas é de grande importância; pois, esses fatores, podem contribuir com muitas informações a respeito de suas estruturas e funções, sobre a dinâmica de cadeias tróficas, e a regulação do fluxo de substâncias desses ambientes. A morfologia dos sistemas lacustres é um fator importante também na distribuição de espécies em diferentes níveis de observação, sejam eles, locais, regionais ou globais. Resultados que suportam esta aplicabilidade foram encontrados neste estudo, que utilizou a comunidade fitoplanctônica como modelo de estudo. Foram realizados levantamentos morfométricos e de riqueza fitoplanctônica em 26 lagos amazônicos de águas claras e em 40 diferentes lagos naturais e artificiais, sendo 20 lagos brasileiros e 20 lagos de diferentes regiões do mundo. Através de regressões lineares simples, foram encontradas relações positivas significativas (p<0,005) entre a riqueza de espécies fitoplanctônicas e parâmetros morfométricos como área, perímetro, volume, índice de desenvolvimento de margem e índice de desenvolvimento de volume. No entanto, o índice de desenvolvimento de margem, foi o que me melhor representou a relação entre complexidade do sistema e a riqueza de espécies do fitoplâncton, caracterizando um efeito de borda em lagos

Spatial variation of sediment mineralization supports differential CO2 emissions from a tropical hydroelectric reservoir

Substantial amounts of organic matter (OM) from terrestrial ecosystems are buried as sediments in inland waters. It is still unclear to what extent this OM constitutes a sink of carbon, and how much of it is returned to the atmosphere upon mineralization to carbon dioxide (CO2). The construction of reservoirs affects the carbon cycle by increasing OM sedimentation at the regional scale. In this study we determine the OM mineralization in the sediment of three zones (river, transition and dam) of a tropical hydroelectric reservoir in Brazil as well as identify the composition of the carbon pool available for mineralization. We measured sediment OC mineralization rates and related them to the composition of the OM, bacterial abundance and pCO2 of the surface water of the reservoir. Terrestrial OM was an important substrate for the mineralization. In the river and transition zones most of the OM was allochthonous (56 % and 48 %, respectively) while the dam zone had the lowest allochthonous contribution (7 %). The highest mineralization rates were found in the transition zone (154.80 &#177; 33.50 mg C m-2 d-1) and the lowest in the dam (51.60 &#177; 26.80 mg C m-2 d-1). Moreover, mineralization rates were significantly related to bacterial abundance (r2 = 0.50, p &lt; 0.001) and pCO2 in the surface water of the reservoir (r2 = 0.73, p &lt; 0.001). The results indicate that allochthonous OM has different contributions to sediment mineralization in the three zones of the reservoir. Further, the sediment mineralization, mediated by heterotrophic bacteria metabolism, significantly contributes to CO2 supersaturation in the water column, resulting in higher pCO2 in the river and transition zones in comparison with the dam zone, affecting greenhouse gas emission estimations from hydroelectric reservoirs

Viruses and bacteria in floodplain lakes along a major Amazon tributary respond to distance to the Amazon River

Because of the massive water volume of the Amazon River, the Amazon tributaries have their water backed up by hundreds of kilometers upstream their mouth. This backwater effect is part of the complex hydrodynamics of Amazonian surface waters, which in turn drives the variation in concentrations of organic matter and nutrients, and also regulates planktonic communities such as viruses and bacteria. Viruses and bacteria are commonly tightly coupled, and their ecological role in aquatic food webs has been increasingly recognized. Here, we surveyed viral and bacterial abundances in 26 floodplain lakes along the Trombetas River, the largest clear-water tributary of the Amazon River’s north margin. We correlated viral and bacterial abundances with temperature, pH, dissolved inorganic carbon, dissolved organic carbon (DOC), phosphorus, nitrogen, turbidity, water transparency, partial pressure of carbon dioxide (pCO2), phytoplankton abundance and distance from the lake mouth until the confluence of the Trombetas with the Amazon River. We hypothesized that both bacterial and viral abundances would change along a latitudinal gradient, as the backwater effect becomes more intense with increased proximity to the Amazon River; different flood duration and intensity among lakes and waters with contrasting sources would cause spatial variation. Our measurements were performed during the low water period, when floodplain lakes are in their most lake-like conditions. Viral and bacterial abundances, DOC, pCO2 and water transparency increased as distance to the Amazon River increased. Most viruses were bacteriophages, as viruses were strongly linked to bacteria, but not to phytoplankton. We suggest that bacterial abundances increase in response to DOC quantity and possibly quality, consequently leading to increased viral abundances. Our results highlight that hydrodynamics plays a key role in the regulation of planktonic viral and bacterial communities in Amazonian floodplain lakes

Organic carbon burial efficiency in a large tropical hydroelectric reservoir

Hydroelectric reservoirs bury significant amounts of organic carbon (OC) in their sediments. Many reservoirs are characterized by high sedimentation rates, low oxygen concentrations in bottom water and a high share of terrestrially derived OC, and all of these factors have been linked to a high efficiency of OC burial. However, investigations of OC burial efficiency (OCBE, i.e., the ratio between buried and deposited OC) in reservoirs are limited to a few studies, none of which include spatially resolved analyses. In this study we determined the spatial variation in OCBE in a large subtropical reservoir and related it to sediment characteristics. Our results show that the sediment accumulation rate explains up to 92 % of the spatial variability in OCBE, outweighing the effect of other variables, such as OC source and oxygen exposure time. OCBE at the pelagic sites varied from 48 to 86 % (mean 67 %) and decreased towards the dam. At the margins, OCBE was lower (9–17 %) due to the low sediment accumulation in shallow areas. Our data show that the variability in OCBE both along the rivers–dam and the margin–pelagic axes must be considered in whole-reservoir assessments. Combining these results with a spatially resolved assessment of sediment accumulation and OC burial in the studied reservoir, we estimated a spatially resolved mean OC burial efficiency of 57 %. Being the first assessment of OCBE with such a high spatial resolution in a reservoir, these results suggest that reservoirs may bury OC more efficiently than natural lakes

Sediment drying-rewetting cycles enhance greenhouse gas emissions, nutrient and trace element release, and promote water cytogenotoxicity

Contains fulltext : 220262.pdf (publisher's version ) (Open Access

Avaliação temporal da quantidade e da qualidade físico-química e biológica das águas do ribeirão Espírito Santo

O objetivo do trabalho é realizar uma análise da quantidade e da qualidade físico-química e biológica das águas de um trecho doribeirão Espírito Santo, bem como avaliar a densidade e a riqueza das espécies fitoplanctônicas nas águas e quais nutrientes são determinantes na sua limitação. Foram realizadas 10 coletas ao longo de 5 anos em 3 pontosao longo da baciahidrográfica do ribeirão Espírito Santo.O ponto 1 se encontra em ambiente rural. O ponto 2 está situado após a captação de água da Estação de Tratamento de Água. O ponto 3 transpassa o Distrito Industrial de Juiz de Fora. O ponto 1 apresentou maior influência nos parâmetros físicos e químicos com o aumento da vazão do que os pontos 2 e 3. Fato esse que pode ser explicado pela contribuição do carreamento de compostos pelas chuvas. Algumas vazões medidas apresentaramvalores menores do que a Q7,10, revelando a importância da continuidade do monitoramento.O ponto 2 e 3 são influenciados pelos despejos de efluentes. Isso faz com que suas águas sejam nutricionalmente mais ricas do que o ponto 1, formando um ambiente favorável para adominância fitoplantônica. Ainda assim, o ponto 3 é o mais degradado, possuindo mais parâmetros em desconformidade com as normas