Diatom community structure in relation to physico-chemical factors in a tropical soda Lake Shala and inflowing hot-springs, Ethiopia


October 25, 2022


Diatoms are highly diverse and versatile, with members growing under different environmental conditions including extreme environments. Although diatom communities in some extreme environments have been investigated recently, little is known about their community structure within the hot springs of soda lakes in Ethiopia. The study aimed to assess the diversity and distribution of diatoms from Lake Shala and inflowing hot springs in relation to physico-chemical variables. Water and diatom samples were collected from Lake Shala and three inflowing hotsprings. The mean pH, temperature, EC, salinity, TDS, DO, NO3-+NO2-, NH3+NH4+, SRP, TP and SiO2 were significantly different among the stations. The significant variations in these factors could be attributed to their heterogeneous geological characteristic and the hydrology of the study area.  A total of 45 diatom taxa were identified, with the highest species observed in Shala Hora Mid Hotspring sites (37) and the lowest in Shala Gike Hotspring (29). Diatom community structure was also examined and it was found that the diatom community of Lake Shala and inflowing hotsprings are highly influenced by environmental water conditions. Characteristic taxa including Anomoeoneis sphaerophora, Nitzschia spp., Rhomboids gibberula, R. gibba, R. acuminata, R. operculata, Navicula spp. and Frustulia rhomboids, showed a wide tolerance to pH, salinity, EC, TDS, temperature, nitrogen and phosphate. RDA analysis found a number of discriminating taxa and salinity, conductivity, pH, DO SRP and temperature were key factors that accounted for a significant variation in the diatom community structure.