332 resultados para Macroalgae
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Seasonal variation of abundance of Ecballocystis pulvinata Bohlin in a stream of central-southern region of Parana State. The temporal dynamics of E. pulvinata and its relation to abiotic variables were evaluated monthly during January to December 2007 in a stream located in the central-southern part of Parana State (25 degrees 11'16 '' S - 51 degrees 021'25 '' W). The abundance of the population in terms of percentage cover was obtained by means of the quadrat technique and the following stream water variables were measured: current velocity, irradiance, depth, substrate type, temperature, oxygen saturation, conductivity, pH and turbidity. The abundance of E. pulvinata was considered high (X = 26.7%), with more development (22-46%) during autumn/winter. The low values (0-0.08) of niche width and the few associations with environmental variables shows that the population evaluated is a generalist with regards to the environment in which it occurs. Factors most strictly related were the water flow and the particle size of the substrate, which positively correlated to the seasonal pattern of the population investigated.
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The damselfish, Stegastes fuscus Cuvier, 1830 (Osteichthyes: Perciformes: Pomacentridae), is abundant in the coastal reefs of Búzios Beach, Rio Grande do Norte, Brazil and they play an important role in the reef community ecology. The present study investigated the feeding strategy of this species considering the food habits and morfo-histology of the digestive tract. Influence of the environmental correlates such as temperature, rainfall and luminosity in the tidal rock pools were studied. The fish were captured on a monthly basis from September 2004 to August 2005, during which period 842 individuals of S. fuscus were captured, 125 males, 437 females and 280 individuals without sex identification. The sex ratio observed was 1 M : 3,5 F. The total body length of males varied from 3.6 to 11.3 cm, with a mean of 7.77 cm; that of females varied from 2.9 to 11.4 cm, with a mean of 7.85 cm, and that of sex grouped individuals varied from 2.9 to 11.4 cm, with a mean of 7.83. However, there was no difference between males and females in total body length. This species presented a positive alometric growth and the equations obtained for the relation between body mass and total body length were: Wt =0,0174Lt 3,1123 for males; Wt =0,0137Lt 3,2294 for females and Wt = 0,0148Lt 3.1928 for sex grouped individuals. The relation between total body length and standard length was L t = 1 ,3223Ls + 0,1527 for sex grouped individual s. February to August was associated to a long period of gonadal resting. The fish spawned during January and in September -October. The frequency of fish with empty stomachs occurred during August to December, whereas frequency of fish with food contents i n stomachs occurred during January to July. This species is considered as a preferential herbivore based on the volume of macroalgae in its diet composition. The morfo -histological aspects of S. fuscus confirm herbivory. Among the environmental factors con sidered only rainfall showed a correlation with the feeding habits of this species
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In northeastern Brazil, the extraction of agar has increased considerably in recent decades mainly using macroalgae of the genus Gracilaria. The pressure of the harvest of seaweed of this genus has compromised the sustainability of this natural resource. Given the current framework of decline in production of algae in the state of Rio Grande do Norte, it is necessary the deployment of crops that will assist in the development of coastal areas. This research aimed to develop studies on growth, productivity, efficiency and quality of agar of G. birdiae so as to provide subsidies for crops on commercial scale. The study was carried out in dry and rainy periods using rafts of cultivation. Algal biomass and the physical and chemical parameters of water were measured every fifteen days. In laboratory, the resistance and quality of agar were analyzed. The relative growth rate (TCR) was determined by the formula: RGR = ln (final weight / weight initial). 100 / interval time of sampling. During the study, environmental factors as salinity and temperature remained relatively constant (around 35 PSU and 28°C, respectively). The mean values of biomass ranged around 1952.67 ± 576g in the rainy period and 1925.67 ± 450g in the dry period, and they presented no significant variations. The maximum value of growth (TCR) was recorded in the dry season (7.45%.day-1), with an average over the study of 4.35%.day-1. The yield of agar ranged from 22% to 15%, and its resistance ranged from 850 to 650g. cm². The average obtained for the two periods was approximately 750 g cm². These results demonstrate the great potential of Gracilaria birdiae for mariculture can be used as an sustainable activity for coastal communities
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Macroalgas são organismos tipicamente bentônicos, constituídos por um talo maduro, discreto e reconhecível a olho nu, cuja identificação microscópica é necessária. Diversos estudos foram realizados visando o conhecimento taxonômico em riachos brasileiros, no entanto, são raros os trabalhos que abordam as algas que se desenvolvem nas nascentes destes riachos. de fevereiro a setembro/2007 coletas mensais foram realizadas em nascentes e em suas imediações (solos úmidos dos afloramentos d'água) de quatro riachos na região noroeste do estado de São Paulo. O levantamento taxonômico resultou na identificação de 13 espécies, sendo 54% dos táxons pertencentes a Cyanophyta e 46% a Chlorophyta. Cylindrospermum gorakhpurense, Mougeotia gotlandica, Spirogyra gallica e S. taftiana são registradas pela primeira vez para o Brasil. A flora aquática encontrada diferiu da regional devido à presença de organismos da família Zygnemataceae (Chlorophyta) em estágio reprodutivo. Este tipo de hábitat mostrou-se especialmente favorável à reprodução das Zygnemataceae.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
