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Advisor(s)
Abstract(s)
This research aimed at monitoring and characterizing the zooplankton
community of Aguieira reservoir (40.33 N; 8.19 W). Aguieira trophic state, nutrient
concentration (the highest amounts were observed in summer) and ultimately
water quality can be explained by the internal disturbance induced by the intense
water level fluctuations. This indeed leads to an increase in suspended particulate
material in the water column. Besides, the exposure of littoral sediments to cycles
of drying and wetting also increases nutrient availability, preventing macrophytes
establishment. These phenomena with the input of allochthonous nutrients originated
from human activities in the catchment area lead to the increase of phytoplankton
biomass (mainly Cyanobacteria) during summer. When Cyanobacteria were
dominating the phytoplankton assemblage, zooplankton community was clearly
dominated by the rotifer, Keratella cochlearis and by the caldoceran, Chydorus
sphaericus. In the absence of Cyanobacteria, Copidodiaptomus numidicus and
Daphnia longispina subsisted as the most representative species. Canonical
correspondence analysis (CCA) identified two main environmental gradients that
shape zooplankton community: one being temporal mainly related to temperature,
and the other, a trophic gradient associated to chlorophyll a concentration, water
transparency, nitrates and nitrites. Variance partitioning using CCA revealed that
the largest portion (45%) of the total variation explained (70%) was attributed to
the interaction between lake and environmental variables.
Description
Keywords
Zooplankton community Seasonal trends Deep reservoir Environmental variables
Pedagogical Context
Citation
Geraldes, Ana Maria; Silva-Santos, Pedro; Pasupuleti, Rajeev (2016). Zooplankton community structure in a deep reservoir: seasonal trends and structuring variables? In International Zoological Congress of “Grigore Antipa” Museum. Bucharest. ISSN 2457-9777