Consulta: subjectFacets:"Diel variation"
Registros recuperados: 4
Data/hora: 06/06/2024 06:32:26

Diel density variation of amphipods associated with Sargassum beds from two shores of Ubatuba, Southeastern, Brazil
Provedor de dados: 76
Autores: Leite,Fosca P. P.; Tanaka,Marcel O.; Sudatti,Daniela B.; Gebara,Raquel S.
Densities of mobile epifaunal assemblages associated with macrophytes are very variable during the day and the activity of visually-oriented predators is thought to have an important influence on this pattern. Here we compared densities of amphipods associated with a common brown alga, Sargassum stenophyllum (Phaeophyceae), at sites contrasting in water turbidity. We expected that diel variation of amphipods would occur in a shore with clear waters (Perequê), whereas no variation was expected in a shore with turbid waters (Lamberto). Amphipod density varied during the day at both shores, with no indication of a larger variation at Perequê. Most species showed two density peaks, one at night and the other in the afternoon. These peaks occurred close the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Diel variation; Amphipods; Sargassum.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212007000400007

Spatial-temporal variation in coiled and straight morphotypes of Cylindrospermopsis raciborskii (Wolsz) Seenayya et Subba Raju (Cyanobacteria)
Provedor de dados: 39
Autores: Dantas,Ênio Wocyli; Bittencourt-Oliveira,Maria do Carmo; Moura,Ariadne do Nascimento.
This study reports the spatial and temporal behavior of straight and coiled morphotypes of C. raciborskii in a reservoir in Brazil's semi-arid region as well as the main factors responsible for the variability. Two set of samples were collected from the subsurface and bottom in the central region of a reservoir in two seasonal periods (dry - January 2005; rainy - June 2005) over 20-hour sampling periods during daylight (8 am, 12 pm and 4 pm) and dark (8 pm, 12 am and 4 am) hours. Measurements of abiotic parameters were determined concurrently to the sampling of biotic variables. Two C. raciborskii morphotypes were found in the reservoir: straight and coiled. There was no difference in density of the straight and coiled C. raciborskii morphotypes between...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cylindrospermopsis raciborskii; Semi-arid; Diel variation; Vertical variation.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062010000200028

Considerações limnológicas sobre um lago da planície de inundação amazônica (lago Catalão – Estado do Amazonas, Brasil) - DOI: 10.4025/actascibiolsci.v31i4.4641
Provedor de dados: 3
Autores: Almeida, Fabiane Ferreira de; Instituto Nacional de Pesquisas da Amazônia - Programa de Pós-Graduação em Biologia de Água Doce e Pesca Interior; Melo, Sérgio; Instituto Nacional de Pesquisas da Amazônia.
Este estudo aborda a variação temporal (sazonal, semanal e nictemeral) e espacial de algumas variáveis limnológicas na região limnética do lago Catalão, um lago da planície de inundação do rio Amazonas. Foram analisados os valores de temperatura, zona eufótica, zona de mistura, condutividade elétrica, oxigênio dissolvido, transparência, nitrogênio e fósforo total, amostrados em quatro estações, em escala semanal, durante um mês no período de seca de 2006 e um mês no período de cheia de 2007. Regressões simples foram realizadas para testar a hipótese da homogeneização de ambientes aquáticos em função da inundação. Foram analisados, também, os valores de temperatura, oxigênio dissolvido e condutividade elétrica em um perfil vertical ao longo de um ciclo...
Palavras-chave: 2.05.02.00-1 variáveis limnológicas; Variação nictemeral; Planície de inundação; Variação sazonal; Pulso de inundação; Amazônia Brasileira Ecologia de Ecossistemas (Limnologia) limnological variables; Diel variation; Flood plain lake; Seasonal variation; Flood pulse; Brazilian Amazon.
Ano: 2009
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/4641

Metabolism and Gaseous Exchanges in Two Coastal Lagoons from Rio de Janeiro with Distinct Limnological Characteristics
Provedor de dados: 52
Autores: Thomaz,Sidinei M.; Enrich-Prast,Alex; Gonçalves Jr.,José F.; Santos,Anderson M. dos; Esteves,Francisco A.
The global metabolism and exchange of gases with the atmosphere were measured during a diel cycle in two tropical coastal lagoons, using the curves of carbon dioxide and dissolved oxygen. Heterotrophic metabolism (net CO2 production and net O2 consumption) was observed in a black water lagoon (Comprida), and autotrophic metabolism (net O2 production and net CO2 consumption) in a clear water lagoon (Imboassica). These differences were attributed to the limnological characteristics of both ecosystems, especially to dissolved organic carbon and the attenuation coefficient of light, which are much higher in the first environment. During the diel cycle analyzed there was a net release of carbon dioxide into the atmosphere in the first lagoon and a net uptake by...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coastal lagoon global metabolism heterotrophic activity microbial respiration; Diel variation.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132001000400015