BIODIVERSITY, ULTRASTRUCTURE AND SCANNING ELECTRON MICROSCOPY WITH ENERGY DISPERSIVE SPECTROSCOPIC STUDIES OF FRESHWATER MICROALGAE

K. SIVAKUMAR

Volume : IX, Issue : II, February - 2019

BIODIVERSITY, ULTRASTRUCTURE AND SCANNING ELECTRON MICROSCOPY WITH ENERGY DISPERSIVE SPECTROSCOPIC STUDIES OF FRESHWATER MICROALGAE

K. Sivakumar

Abstract :

Studies were made on the seasonal variation of phytoplankton in the Perumal lake for a period of one year from 2017–2018. The physico–chemical parameters such as atmospheric temperature, water temperature, pH, salinity, dissolved oxygen, electrical conductivity and total dissolved solids were at the ranges of 28.1–36.5°C, 27.0–34.4°C, 7.9– 8.7, 1.2–2.5 mg/l, 2.62.4.34 mg/l and 2.5–5.2 mg/l, respectively. Totally 213 species of phytoplankton belonging to Bacillariophyceae (76 species), Chlorophyceae (63 species), Cyanophyceae (60 species) and Euglenophyceae (14 species) were recorded. Transmission electron microscopic studies on Euglena, The outer cell wall layer is more electron dense than the inner layer, the inner layer is translucent. The outer component of the cell comprises the euglenoid pellicular complex, composed of a plasmamemane and a proteinaceous pellicle. The chloroplasts are numerous and scattered randomly or arranged radially, and they lack pyrenoids mitochondria, golgibodies were frequently observed and vacuole is absent. Species of Fragillaria, Mastogloia, Navicula, Cymbella and Nitzschia (Bacillariophyceae); Chiorella, Scenedesmus, Pediastrum, Closterium and Spirogyra (Chlorophyceae) and Chrococcus, Aphancapsa, Spirulina, Oscillatoria, Anabaena and Nostoc (Cyanophyceae) were found in all the seasons. The phytoplankton density was high (1672 cells/I) during the summer season and low (1200 cells/l) during the monsoon season. Bacillariophyceae formed the dominant group. Commonly occurred genera, Oscillatoria (Cyanophyceae), Navicula (Bacillariophyceae) and Scenedesmus (Chlorophyceae), were subjected to energy dispersive spectroscopic analysis (EDS). They were found to accumulate different elements such as Zn, P, S, Ca, Mg, Fe, N, Si, Cl and Mn. Among these the member cyanophyceae contained Zn, P, Mg, Ca, Mn, S and N. Bacillariophyceae Si, Zn, Mg, Cl, N, Fe and Ca. Chlorophyceae Ca, Mg, N, Fe, Cl, Zn, Si and Mn. Thus these observations would determine the chemical dialogue between the cell structures and role of the elements. Further, it gives the clue about the phytoplankton growth requirements