Diversity and ecology of freshwater diatoms as pollution indicators from the freshwater Ponds of Kanyakumari district, Tamilnadu

The present study explores the diversity and ecology of freshwater diatom in the Kanyakumari district, Tamilnadu. Six freshwater ponds namely, Thuckalay pond, Eraniel pond, Pampanvilai pond, Villukuri pond, Erachakulam and Thottiyodu pond were selected from Kalkulam Taluk in Kanyakumari district. A total of 27 taxa of 17 genera were recorded from these freshwater ponds. Among the freshwater diatom species, Gomphonema montanum was found to be the predominant species in all stations except St- 2. The correlation analysis between diatom density and physico-chemical parameters revealed a significant positive correlation of diatoms (Nitzschia sp., Navicula sp., Cyclotella meneghiniana and Stauroneis sp) with nitrate, phosphate and lead at sampling statins St- 2 and 6. CCA analysis revealed that the concentration of calcium, chloride, pH, alkalinity, silica, and ammonia were found to favor the occurrence of dominant species such as Cymbella turgiduta, Gomphonema sp., Rhopalodia sp., in St-3 and St-4. Among all ponds, certain parameters like total alkalinity, nitrite, phosphate, sodium, cobalt, potassium perhaps reflect the influence of agricultural waste, sewage waste, or anthropogenic activities. The statistical indices in coherence with the dominance of pollution indicator species such as Nitzschia palea, Melosira granulata and Cyclotella meneghiniana revealed that the stations St-2, 4 and 6 were heavily polluted, whereas St- 1, 3 and 5 were less polluted.