Annual hydrological cycle of environmental variables in astatic soda pans (Hungary)

Abstract

In order to examine temporal patterns and the hydrological cycle of shallow soda pans, six pans in Hungarian Great Plain were sampled at monthly intervals over a period of 2.5 years. Water chemistry and physical parameters (temperature, pH, dissolved oxygen, conductivity, light, water color - Pt color -, turbidity, phosphorous and nitrogen forms, silica, alkalinity, chloride, sulfate content, chemical oxygen demand) were measured both in the field and laboratory and analyzed using multivariate statistical methods. It was possible to distinguish the pans on the basis of water color, separating them into two groups: G1, consisting of colored pans characterized by low turbidity and high Pt color, and G2, consisting of turbid pans characterized by high turbidity and low Pt color. Both groups displayed temporal (seasonal, as well as annual) trends, and their hydrological cycles followed regular cyclical patterns. Three hydrological phases (filling, drying, and desiccated) were described in the case of the colored pans, and five for the turbid (filling, diluted, drying, concentrated, desiccated). Regarding the recommendation that there be a reduced time interval in the sampling to determine the typical chemical characterization of the pans.