Seasonal studies of limnological aspects of a wetland forest fragment in the Araguaia Plains, Tocantins, Brazil / Estudos sazonais de aspectos limnólogicos de um fragmento florestal inundado na Planície do Araguaia, Tocantins, Brasil

Abstract

Ipucas are ecosystems of natural forest fragments, occurring particularly in the Araguaia plain. It has great influence of flood pulses that occur during the rainy season because they remain flooded during this period and as terrestrial environments in the dry season. The study aimed to evaluate the temporal variation of limnological factors in a Ipuca in the district of the Lagoa da Confusao, Tocantins, through monthly collections between December/2014 and August/2015. The variables measured were: transparency by Secchi disk, turbidity (NTU), dissolved oxygen (mg/L), temperature (°C), hydrogen potential - pH, total dissolved solids (ppm), electrical conductivity (µS/cm) ammonia - NH3 (mg/L) nitrite - NO2 (mg/L) nitrate - NO3 (mg/L), orthophosphate - P (mg/L) ?-chlorophyll (mg/L) and depth of the water blade (cm). The total water transparency and low turbidity values demonstrate the importance of the precipitation of these parameters, as well as the structure of the forest Ipuca supports the values found. The water temperature of Ipucas was influenced by the seasons. The dissolved oxygen was directly related to chlorophyll-?. The concentration of nutrients analyzed showed big swings, probably due to the rapid incorporation of the aquatic communities. However, a homogenization of physical and chemical parameters during the sampling time was observed.