Composição e abundância do fitoplâncton do sudoeste da reserva biológica do lago Piratuba (Amapá, Brasil)
The present study was done on the southwest of the Lago Piratuba Biological Reserve, on Araguari river floodplain, Amapá coast region, Brazil. The environments were the lakes Comprido de Cima, Bacia, Lodão, Ventos, Grande and Comprido de Baixo and the Araguari River downstream. This region is sub...
| Autor principal: | Dias, Maxley Barbosa |
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| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/11231 http://lattes.cnpq.br/8849680489061524 |
| Resumo: |
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The present study was done on the southwest of the Lago Piratuba Biological Reserve, on
Araguari river floodplain, Amapá coast region, Brazil. The environments were the lakes
Comprido de Cima, Bacia, Lodão, Ventos, Grande and Comprido de Baixo and the Araguari
River downstream. This region is submitted to an influence of the semidiurnal tide from the
Amazon River sediments plume and the periodical local rain regime. The ecological
characterization of the phytoplankton community was done by to seasonal samples (rainy and
less rainy season). Information from physical and chemical factors (pH, electrical conductivity,
turbidity, water transparency, water temperature, salinity), climatological (precipitation) and
hydrological (hydrometric level and river discharge). Phytoplankton was represented by 178 taxa.
Although, these ecosystems are located in a great ecotone, they present a low specific diversity in
contrast to the high specific diversity from other Amazonian environments. Lakes presented
higher specific richness and diversity than the River. On both seasonal periods, lakes and
Araguari River presented low phytoplankton composition complexity, described by C-strategists
species, represented predominantly by cryptophytes and chrysophytes. These species are
characteristic of shallow and turbid environments. The presence of estuarine species increases the
diversity in some lakes and in Araguari River. They also contribute to the complexity increase of
the phytoplanktonic community. The spatial uniformity between lakes probably is related to the
low variation between the physical and chemical conditions. However, the river phytoplankton
composition changed with the horizontal gradient observed for the physical and chemical factors
when it comes near the delta. The environmental characteristics favoured the dominance of
species form the functional groups S, X 1 , X 3 and Y in distinct points of the lakes and the Araguari
River. They were also linked with the low significant incidence of desmids. The relevant
regulatory factors on the phytoplankton population composition and abundance on these
environments were the conspicuous variation on the water column between both seasonal
periods, the water from the daily tide in the river and some lakes estudied, the presence of
currents on lakes, the constant mixture on the water column and the low water transparency,
especially on the less rainy season. |