Spatial and Temporal Diversity in the Diatom Flora of Pathanamthitta District of Kerala, India

摘要

Pathanamthitta district is located between the slopes of Western Ghats and the low-lying rice fields of Alappuzha district of Kerala state. Since a major part of the state remains unexplored, there is a need for an area wise systematic exploration for the micro-algal species belonging to various groups. The work was aimed at exploring almost all the accessible ecosystems of the Pathanamthitta district to report the diversity of diatoms in seven different taluks during the monsoon pre-monsoon and post-monsoon periods. The explored water bodies of the seven different taluks of the Pathanamthitta district has shown variations in the diatom community during different seasons. Light microscopic and Scanning Electron Microscopic observations have revealed the presence of 90 taxa of diatoms belonging to 29 genera. Out of the seven taluks of the district, maximum number of taxa was recorded during the post-monsoon season in the Pathanamthitta thaluk with a Shannon diversity index of 5.3044 and the least number of taxa was recorded during the pre-monsoon season from Ranni taluk with an index value of 2.4079. Navicula and Pinnularia were the two dominant genera represented with maximum number of species. Presence of diatoms such as Cyclotella meneghiniana, Mastogloia smithii, etc. in some of the waterbodies indicates the high level of pollution.