This research investigated the source and fate of different chemical species of N and P on a deep tropical urban reservoir, the artificial Lake Paranoá, located in the city of Brasilia (Brazil). To determine an N and P budget, nutrient input from the external load (four main tributaries and two wastewater treatment plants), internal load (from sediment) and nutrient output (from a downstream dam) were estimated empirically. Nutrient storage was evaluated in two compartments: water column and sediment. Nutrient input from the tributaries varied by season presenting higher loads in the wet season, especially N. Nutrient budgets in our study indicated that Lake Paranoá retained dissolved inorganic nitrogen (DIN), PO43−-P, total organic phosphorus (TOP) and exported total organic nitrogen (TON), both on a seasonal and annual scale. Surface sediment is the major storage compartment for both N and P. These results show the pressing need for action to reduce the P outcome charges, mainly, from the wastewater treatment plants. The data here presented contributes to the recognition of this situation and to a better comprehension of these nutrient dynamics, as well as an understanding of the behavior of tropical deep-water reservoirs. This can help to promote more effective management, providing a reference for other similar systems.
Nutrient enrichment and eutrophication are among the main problems that lead to the deterioration of water quality in lakes and reservoirs. In this study, spatial and temporal variations in the concentrations of organic and inorganic species of nitrogen and phosphorus in the water column of Lake Paranoá-DF (Brazil) were evaluated between 2016 and 2017. Seasonality was the main factor in the variations in concentrations of the investigated parameters. Additionally, we found differences in behavior for different nutrients and other variables that indicate different main sources of each nutrient as well as different biogeochemical processes predominating in each season. For example, the electrical conductivity (EC), dissolved silicon, PO43−, and NO3− showed mean concentrations significantly higher in the rainy season, indicating greater inputs in these periods (which is in part related to increasing soil leaching and runoff). Agricultural activities were the main source of NO3− and wastewater treatment plants (WWTP) proved to be the main source of nutrients, mainly NH4+ and all forms of phosphorus. These two allochthonous sources are also the determining factors of the trophic state and the degradation of the water quality of Lake Paranoá. The lake is in the transition process from a mesotrophic to a eutrophic condition.
RESUMO -A Spirulina é uma microalga rica em proteínas (45-60%), que também apresenta em sua composição vitaminas e nutrientes tais como carboidratos. A obtenção de biocompostos de interesse da biomassa microalgal pode ser influenciada por fatores do cultivo como aeração, temperatura, composição do meio e pH. Em vista do exposto, este trabalho teve por objetivo avaliar o teor de proteína da biomassa da microalga Spirulina sp. LEB 18 cultivada em meio Zarrouk e diferentes concentrações de resíduo cervejeiro e vazões de ar. Para isto utilizou-se planejamento experimental 2², com 3 repetições no ponto central, para avaliar o efeito da concentração de resíduo cervejeiro (Trub) e vazão de ar sobre o teor de proteínas da biomassa obtida. A biomassa apresentou elevado conteúdo proteico, entre 67,84 e 74,27 %. Resultados obtidos demonstraram que os fatores estudados não afetam significativamente a variável resposta. Através deste estudo, foi possível verificar o cultivo de microalgas com a utilização de resíduos para esta finalidade, visando produção de biocompostos de interesse e o reaproveitamento de resíduos.
Neste artigo é abordado o real significado da missão evangelizadora e como ela deve ser compreendida em termos conceituais, assim como aplicar a prática argumentativa na enunciação de sua mensagem de uma forma que ela traga a significação correta a partir da cosmovisão cristã bíblica. Compreendese que as principais características da argumentação, bem como da construção do discurso em que a mensagem do evangelho é apresentada, podem mudar e transformar o indivíduo, por isso resta, então, definir os padrões normativos que implicam no método evangelístico escolhido a ser desenvolvido no contexto da sociedade, utilizando a evangelização e o discipulado como principal fonte de comunicação do evangelho no contexto de igrejas evangélicas. Por fim, é observado, ainda, a partir da prática argumentativa, a maneira como ocorre a
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