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Título:
Spatial-scales and local factors influencing nanoflagellates assemblage from a floodplain fluvial system
Autor/es:
DI PASCUALE, V.; UNREIN, F.; HUBER, M. P.; METZ, S.; MAYORA, G.; SCHNEIDER, B.; DEVERCELLI, M.
Reunión:
Workshop; 18th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP); 2017
Resumen:
Nanoflagellates are functionally important in microbial food webs since they link the different path of energy flow due to their heterotrophic, autotrophic, and mixotrophic nutrition. The variability in nanoflagellates assemblage among habitats is regulated by a combination of abiotic factors, biotic interactions, and dispersal processes. In floodplain fluvial systems, the dispersal potential is mainly related to the hydrological connectivity of habitats and hence, to the spatial configuration. In this sense, the shaping of local communities depends not only on the local environmental factors, and but also on the spatial processes operating at multiple scales as it is stated in the metacommunity frame. The objective of this work was to analyse the different factors and scales intervening in the nanoflagellates assembly of the Middle Paraná floodplain. With this purpose we compare i) two geomorphological units characterised by different drainage pattern and connectivity strength (meandering and anastomosed), ii) type of environments with different hydrological influence, and iii) patches within each environment (pelagic and vegetated).A total of twenty eight lotic and lentic environments were sampled during a low water period. When it was possible, two sampling points: pelagic and vegetated were established. The morphological identification and counting of nanoflagellates assemblage was performed using an epifluorescence microscope. Measurements of spatial, physical, and chemical variables, and macrophyte coverage and composition were made. Additionally, heterotrophic and phototrophic picoplankton were counted by flow cytometry since they are considered the main food source of heterotrophic flagellates.We decomposed the variation explained by spatial (dbMEM eigenfunction) and local factors by a variance partition analysis. We performed NPMANOVA and SIMPER to compare nanoflagellates structure among geomorphological units, environments, and patches, and the assemblage divergence was analysed with PERMDISP.