Navegando por Assunto "phytoplankton"

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    A dinâmica do fitoplâncton em uma várzea Amazônica variações sazonal e nictimeral (Várzea do Lago Grande de Curuai Pará, Brasil)
    (Universidade Federal de Goiás, 2011-03-28) ALVES, Carla Patrícia Pereira; NOGUEIRA, Ina de Souza; http://lattes.cnpq.br/3877834258990173
    The river-floodplain systems are environments submitted a lateral overflow of river channel due the rains and/or underground waters. They are controlled by the type of climate, morphology and local effects. The lowland lakes are also highly productive because of the rich sources of primary carbon. The sediments transport and suspended and dissolved matter are done by the rivers between the land and aquatic phases. These phases strongly influence nutrient cycling, primary and secondary production and decomposition. The phytoplankton dynamics in tropical floodplain lakes is as variable as the seasonal and isolation patterns of flooding. For this reason, the aims of this work were i) to assess the rotation influence of potamophase and limnophase upon the phytoplankton of the Curuai Lake (PA, Brazil) and about the connectivity between other lakes, and ii) to evaluate the phytoplankton dynamics in a nictemeral cycling related to changes in CO2 in water, and what phytoplankton groups which were most important in this process. The phytoplankton community and environmental variables of the floodplain lakes of the Curuai Lake were sampled in the potamophase and limnophase (2009) and in a nictemeral cycling (2010). The informations summarized were obtained through the principal component analysis (PCA), canonical correspondence analysis (CCA), redundancy analysis (RDA) and nonmetric multidimensional scaling (MDS). The community structure was different among the periods with greater richness, density and phytoplanktonic biovolume in limnophase. There was predominance of Cryptophyceae (mainly Cryptomonas brasiliensis Castro, Bicudo & Bicudo) in potamophase and Cyanophyceae [Dolichospermum circinalis (formerly Anabaena circinalis) (Rabenh. ex Bornet et Flah.) Wacklin et al.] in limnophase, both influenced by environmental variables. In addition, the high phytoplanktonic biomass was favored by the highs temperatures and also responsible by the CO2 depletion in water caused by photosynthesis, which is reflected for the high carbon content in phytoplankton organisms. Despite the entry of water in the floodplain that connects the lakes, these environmental were distinct in relation a phytoplankton composition and a limnological variables. The phytoplanktonic community in Curuai Lake showed daily variation of biovolume because of high temperature and light availability. The development of persistent cyanobacteria bloom, with species predominance of Dolichospermum genius [functional group H1, D. spiroides (formerly A. spiroides) (Klebahn) Wacklin et al.] and Microcystis protocystis Crow (functional group M) caused the CO2 depletion in lake surface layer during the period of increased photosynthesis. The cyanobacteria bloom occurred mainly due to the attributes of group, which became it expressive competitors in relation another microalgae ones.
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    Comunidade fitoplanctônica e parâmetros físico-químicos em lagoa de estabilização (Trindade,Go)
    (Universidade Federal de Goiás, 2012-07-12) D\'ALESSANDRO, Emmanuel Bezerra; AGUILA, Nora Katia Saavedra Del; http://lattes.cnpq.br/1447294667795452
    The Wastewater Treatment Plant (WWTP) of Trindade (16 ° 39'09'' S and 49 ° 31'50'' W), also known as Barro Preto WWTP, consists of preliminary treatment followed initially by three modules in parallel (A, B and C), each containing one anaerobic pond, one facultative pond and one maturation pond in series (Australian system), being the effluent released in the stream Barro Preto. The WWTP began operating in 1997 and had the final plan in 2011. This study aimed to evaluate treatment efficiency and the module based on algal community structure and physico-chemical variables during a period of six months (September, October, November, December 2010 and April and May 2011), which contains the dry and rainy periods. Were analyzed in reference to the structure and dynamics of algae: biomass, density, richness, diversity, equality, abundance and dominance; for physic-chemical analysis were: flow rate, wastewater temperature, depth, euphotic zone, HDT, pH, DO, CND, TP, PO4 -3, NH4 +, NO3, DOB5 20°C, COD, TSS, FSS, VSS and also climatic variables. The algae were collected through non-selective process (Van Dorn bottle). The samples abiotic, chlorophyll a and pheophytin were processed according to APHA, and the density algal by the Utermöhl method. Principal Component Analysis (PCA) were performed to characterize the physic-chemical processes and the spatial and temporal differentiation. It was also made a Canonical Correspondence Analysis (CCA). The facultative and maturation ponds shown to be influenced by the seasonality of the region, and presented variance in depth. In average, the module A showed an efficiency of COD removal of 45%, and optimal efficiency in removing DBO5 20°C (84%). The facultative pond showed the highest mean of PO4 -3 efficiency removal (48%), NH4 + (36%) NO3 - (44%), BOD5 20°C (74%). OD profile of type clinograde and thermal stratification was recorded in three months of collection. The maturation pond showed higher mean removal efficiency of PT (27%) and COD (19%). In just two months was recorded thermal stratification, and found clinograde profile throughout the study. The ponds presented one of the largest ever recorded phytoplankton densities in stabilization ponds and 170 taxa recorded throughout the study, being 40% of cyanobacteria are potentially toxic. The most abundant species in both ponds and throughout the study were Chlorella vulgaris, Chlorella minutissima, Closteriopsis acicularis, Merismopedia tenuissima, Synechococcus sp and Synechocysitis sp (dominant). The ponds presented according to the indices, low species diversity and low beta diversity. The beta diversity showed that the maturation pond has more flexibility in the rainy season and optional in the dry season. The canonical correspondence analysis (CCA) showed the most abundant species when best developed in seasonality. C. acicularis in the rainy season, C. minutissima in the end of the rainy season and the beginning of the dry season, M. tenuissima in late dry season, C. vulgaris and Synechococcus sp in late dry season and beginning of precipitation. This analysis showed which environmental variables can also influence the in distribution of species.