COMUNIDADE DE ALGAS EPIFÍTICAS (COM ÊNFASE EM DIATOMÁCEAS) EM 23 VEREDAS DO ESTADO DE GOIÁS SOB DIFERENTES IMPACTOS AMBIENTAIS / Epiphytic algae community (with emphasis on diatoms) of Palm swamps of Goias State

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

(Epiphytic algae community of (with emphasis on diatoms) of Palm swamps of Goias State). The present study is the first to evaluating epiphytic algae community structure of in the subsystem Palm swamps in the Cerrado. The general hypotheses of this study were: impacted Palm swamps are under greater influence of allochthonous material, causing changes in limnological characteristics, as the record of increased nutrient levels and turbidity; the structure of ephiphytic algae community is influenced by environmental characteristics, and impacted Palm swamps have diatom as dominant group of epiphyton due to the adaptive cytomorphological characteristics. The overall objective was to analyze the spatial variation of limnological (physical, chemical and biological) and climatological characteristics of 23 Palm swamps in the Goias State under different environmental impacts and to evaluate epiphytic algae community structure of in relation to environmental characteristics of Palm swamps. This dissertation was structured in a general introduction and two chapters in the form of articles: (Article 1) Spatial variation of limnological and climatic characteristics of Palm swamps under different environmental impacts in the Goias State; (Article 2) Relationship between the structure epiphytic algal community (with emphasis on diatoms) and Palm swamps under different environmental impacts in the Goias State. Sampling was conducted in August and September 2008, in the cities of Caldas Novas, Catalan, Cidade de Goiás, Goiânia, Ipameri, Morrinhos and Piracanjuba. Environmental data of Palm swamps were analyzed: morphometric, climatological and limnological characteristics (pH, water temperature, conductivity and turbidity), nutrients (total nitrogen, total phosphorus and silica), chlorophyll-a and the attributes of epiphytic algae community structure (composition, richness, density, biovolume, diversity and evenness). The abiotic data were collected simultaneously to the biotic data. Epiphytic material was obtained from grasses (Poaceae). Environments showed great variation in the values of electric conductivity, turbidity, total nitrogen and epiphytic biomass, low pH and total phosphorus, and high concentrations of silica. Palm swamps groups under different environmental impacts were discriminated mainly by pH and turbidity. Among the environments preserved only 50% showed oligotrophic characteristics for total nitrogen content, a situation caused by contamination by agricultural activities and urban impacts. It was noted that the acidic water was related to the dystrophic soils of these environments, which showed the pH as an important variable in structuring communities. Greater richness, diversity, density and biovolume of epiphytic algae were recorded in Palm swamps impacted. Zignemafíceas were the most representative in species richness followed by diatoms. Palm swamps impacted had greater density and biovolume of epifiton. Eunotia bilunaris (Ehrenberg) Mills was predominant in the Palm swamps with the highest density of epiphytic algae. Tapinothrix bornetii Sauvageau had higher biovolume in the community. Two taxa (Gomphonema sp.2 and Oedogonium sp.4) were indicator species to impacted by agriculture Palm swamps. This study reported great features for development of several taxa of Bacillariophyceae, manly to Eunotia Ehrenberg. The epiphytic community of Palm swamps showed less expressive than Veredas impacted, probably related to characteristics such as low light, given the preservation of vegetation cover of arboreal and low concentrations of nutrients.

ASSUNTO(S)

ecologia environmental impacts limnology community structure impactos ambientais 1. epifíton. 2. diatomáceas. 3. estrutura de comunidade; 4. limnologia limnologia epifíton diatoms epiphyton diatomáceas estrutura de comunidade

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