Variação sazonal e sucessional da comunidade de algas perifíticas em substrato natural em um reservatório mesotrófico tropical

Abstract

RESUMO(Variação sazonal e sucessional da comunidade de algas perifíticas em substrato natural em um reservatório mesotrófico tropical). A colonização e sucessão da comunidade de algas perifíticas em substrato natural (Nymphaea spp.) foi avaliada em um reservatório raso (Lago das Ninféias, PEFI, SP). O estudo avaliou as fontes de variabilidade da estrutura da comunidade perifítica em dois períodos climáticos, contribuindo para o maior entendimento da dinâmica da comunidade em região tropical. A amostragem das variáveis abióticas e bióticas foi realizada a cada três dias até o 12º dia e cada cinco dias até completar 30 dias no período seco e chuvoso. Os pecíolos de Nymphaea spp. foram aleatoriamente selecionados e limpos. A estrutura do perifíton foi analisada através da clorofila-a, densidade de espécies algais, biovolume, riqueza e diversidade de espécies. O período chuvoso caracterizou-se pelos maiores valores de temperatura e disponibilidade de nutrientes e o período seco pela maior disponibilidade de luz. Os maiores valores de biomassa, densidade e biovolume algal foram observados no período seco. Fases e trajetórias sucessionais distintas foram identificadas em cada período climático. As condições limnológicas mudaram sazonalmente no interior dos bancos de macrófitas e, consequentemente, influenciaram a estrutura da comunidade de algas perifíticas. Concluiu-se que a estrutura da comunidade de algas perifíticas foi sensível às alterações autogênicas (sucessão), mas a escala sazonal foi a principal fonte de variabilidade da estrutura da comunidade.Palavras-chave: biomassa, diversidade, Nymphaea spp., perifíton ABSTRACT (Seasonal and successional variation of a periphytic algal community on natural substrate in a tropical mesotrophic reservoir). Colonization and succession of a periphytic algal community on a natural substrate (Nymphaea spp.) was evaluated in a shallow reservoir (Lago das Ninféias, PEFI, SP). This study aimed to evaluate the environmental factors responsible for the structural variability of a periphytic algal community. Samplings of abiotic and biological variables were carried out every three days up to the 15th day, and later at five days intervals for 30 days in the dry (4/07 to 08/03/2007) and rainy (9/01 to 02/08/2008) seasons. The petioles of Nymphaea spp. were randomly selected and cleaned. Periphytic algal structure was analyzed by measuring chlorophyll-a, algal density, biovolume, species richness and diversity. The rainy season was characterized by high temperature and nutrient availability and the dry season had the highest light availability. Periphyton biomass, algal density and biovolume were higher in the dry season than in rainy season. Different successional phases and trajectories were identified in each climatic period. Limnological conditions inside macrophyte stands changed seasonally, and consequently influenced the periphytic algal structure. The final conclusion is that the periphytic algae structure was sensitive to autogenic changes (succession), but the seasonal scal...

Functional diversity and functional traits of periphytic algae during a short-term successional process in a Neotropical floodplain lake

“…The higher biomass (density and biovolume) in both periods was related to the 12th and 16th days of colonization, similar to that recorded in Brazil by Felisberto and Rodrigues (2012) for a subtropical lotic system in the northwest of Paraná and by Pellegrini and Ferragut (2012) for a mesotrophic tropical reservoir. For the functional diversity, the highest values corresponded to peaks in biomass in both periods.…”

Periphyton biomass on artificial substrates during the summer and winter

“…Regardless of the substrate used, it was observed a cumulative increase in the periphytic biomass production in all substrates in the summer period. The spatial sequence which is presented by the periphyton community (FRANÇA et al, 2011) and its relationship with the substrates available for development (PELLEGRINI and FERRAGUT, 2012) can be infl uenced in the composition and, therefore, in the periphytic community biomass.…”

“…It was still observed during the winter that the black plastic and wood substrates presented the best cumulative periphyton production results, highlighting the differences between the substrate's performances in the summer and winter. These differences are closely related to climatic conditions, such as temperature, photoperiod, and the rainy season (GUARIENTO et al, 2009;FRANÇA et al, 2011) which altogether interfere directly in the predominance of species (FELISBERTO & ROFDRIGUES, 2010), and hence, their favorable habitat conditions (PELLEGRINI & FERRAGUT, 2012). The periphytic biomass is directly related to the characteristics and composition of the substrate used for their development (ZHANG et al, 2012), the water fl ow (PELLEGRINI & FERRAGUT., 2012), the brightness, physical, and chemical characteristics of the water (AZIM et al, 2002) such as the concentration of chemical compounds (FELISBERTO & RODRIGUES, 2010).…”

“…This condition may be related to changes in the predominant species attached to the substrates that has an infl uence in the species throughout its development (PELLEGRINI & FERRAGUT, 2012). Since the species in the periphytic community were not evaluated, it is only assumed that the changes in species occurred along the experiment.…”

Criptógamos do Parque Estadual das Fontes do Ipiranga, São Paulo, SP. Algas 36: Bacillariophyceae (Cymbellales)

“…Estes incluem apenas as citações e só eventualmente se fizeram acompanhar de ilustração e/ou medidas dos materiais identificados (ex. Marinho 1994, Vercellino 2001, Fermino 2006, Costa 2008, Ferrari 2010, Borduqui & Ferragut 2012, Costa-Böddeker et al 2012, Pellegrini & Ferragut 2012.…”