The phytoplankton of the Upper Parana River. Seasonal variation and distribution related to environmental faetors
Structure, population density and distribution of the phytoplankton of the Upper Paraná River (between Corpus and Ita Ibate) as well as its variations to climatic and hydrologic cycles, were studied from 1976 to 1978. Qualitative and quantitative sub-superficial samples were obtained by monthly samp...
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| Autores principales: | , |
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| Formato: | Artículo revista |
| Lenguaje: | Español |
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Centro de Ecología Aplicada del Litoral (Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de Nordeste)
2025
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| Acceso en línea: | https://revistas.unne.edu.ar/index.php/eco/article/view/8580 |
| Aporte de: |
| Sumario: | Structure, population density and distribution of the phytoplankton of the Upper Paraná River (between Corpus and Ita Ibate) as well as its variations to climatic and hydrologic cycles, were studied from 1976 to 1978. Qualitative and quantitative sub-superficial samples were obtained by monthly sampling in the middle of the river. Counts were done by the Utermóhl method with an inverted microscope. Population density of phytoplankton ranged between 33 and 1 397 ind/ml, increasing downstream. Structural composition of this community was uniform through the studied area. The prevailing group were Diatomophyceae. Among them, Melosira granulata and M.pseudogranulata were the most abundant. Occasionally, Synedra prevailed. The Cyanophyceae occurred more frequently during summer, being Lyngbya limnetica, Raphidiopsis mediterránea and Anabaena spiroides the most numerous. These groups could even exeeed the number of Diatomophyceae in summer time. Among Chlorophyceae, Monoraphidium, Scenedesmus and Schroederia were the dominant. Fluctuations in phytoplankton were related to water transparency and hydrometric level of the river. Phytoplankton concentration was low in high turbidity conditions of flood periods, increasing in low water phases and higher water transparency. |
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