Distribuição espacial da comunidade zooplanctônica em um lago raso: importância das macrófitas aquáticas como fator de heterogeneidade ambiental

Abstract

Several ecological studies seek to understand the factors that structure aquatic communities, such as abiotic characteristics and the presence of aquatic macrophytes, which increase spatial heterogeneity. This study aimed to analyze the spatial distribution and structuring factors of the zooplankton community of a shallow lake located at the Federal University of Goiás – Samambaia Campus. Collections were carried out at 11 points in the Samambaia lake in July 2023, during the dry season. At each sampling point, some environmental parameters were measured, such as water temperature, electrical conductivity, turbidity, pH, dissolved oxygen, and nutrient concentrations (total phosphorus, orthophosphate, nitrate, and ammonia nitrogen). Simultaneously, we also collected samples of zooplankton organisms. A total of 80 zooplankton taxa were recorded, represented mainly by testate amoebae (41.25%), rotifers (38.75%), cladocerans (18.75%) and copepods (1.25%). We observed greater richness and density of testate amoebae taxa in the littoral region, while rotifers predominated in the limnetic region. The sampling points located in the littoral region presented changes in the composition and density of taxa, compared to the limnetic region, mainly when the points were colonized by aquatic macrophytes. Despite a difference in abiotic conditions between the littoral and limnetic regions, the main factor that explained the change in the structure of the zooplankton communities was the presence of aquatic macrophytes, increasing the spatial heterogeneity of the lake.