Ecologia do fitoplâncton de um rio tropical (rio São Mateus, ES)

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2012-02-15
Autores
Mamão, Mônica Alves
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Universidade Federal do Espírito Santo
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The multiple uses of river ecosystems can lead to disruption of its natural continuous gradient. Policies biomonitoring and/or detection of human impacts are needed to maintain the water quality of rivers. This study was conducted in São Mateus river, located in the northern state of Espirito Santo, Brazil, and aimed: 1) to evaluate the gradient of continuity of a lotic tropical environment through the limnological variables in a section with multiple uses; 2 ) to assess the connectivity between the sampling stations throughout the structure of the phytoplankton community and see note abiotic variables most influenced the community, 3) to evaluate the use of functional groups as indicators of ecological quality of São Mateus river. Six sampling stations along a stretch of São Mateus river were determined: two upstream of the city (SM01, SM02), two over the city (SM03 and SM04) and two immediately downstream of the city (SM05 and SM06). Water samples were collected in the sub-surface water column for physical, chemical, physico-chemical and phytoplankton community. Stations SM05 and SM06, subject to the influence of intensive fish farming and the release of large volumes of effluent, respectively, showed higher values of most limnological variables and were analyzed and considered mesotrophic, while other stations were considered oligotrophic. The Principal Component Analysis (PCA) separated the stations SM05 and SM06 of the others stations relating them with high values of limnological variables and trophic state index.The sampling stations SM05 and SM06 had the highest biomass and dominance of Polymyxus coronalis Bailey. Furthermore, these two stations had a higher floristic similarity. We identified nine functional groups: X1, X2, Y, LO, D, TB, TD, W2 and C. The canonical correspondence analysis (CCA) separated stations SM05 and SM06 relating them to high biomass of Bacillariophyceae and Cryptophyceae, total biomass, with the functional group D and variables such as total nitrogen, electrical conductivity, total suspended solids, orthophosphate and trophic state index. Thus, it can be concluded that mainly the release of domestic and industrial sewage and intensive farming have resulted in the disruption of continuity in the São Mateus.
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MAMÃO, Mônica Alves. Ecologia do fitoplâncton de um rio tropical (Rio São Mateus, ES). 2012. 117 f. Dissertação (Mestrado em Biodiversidade Tropical) - Universidade Federal do Espírito Santo, Centro Universitário Norte do Espírito Santo, São Mateus, 2012.
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