Abstract

Seagrass meadows are valuable habitats having economic and ecological importance in coastal ecosystem. The major seagrass meadows in India exist along the southeast coast of India, particularly in Palk Bay region. The dominant seagrass species of this region was Cymodocea serrulata andSyringodium isoetifolium and these two species were taken for the survey. In this study, a survey was carried out for a period of two years from August 2009 to November 2011 on the seasonal and spatial variability of these two seagrass species. There was a distinct seasonal and spatial variation in the total biomass, productivity and above ground biomass, leaf canopy height and shoot density of these two species between the stations. The seasonal variation in the biomass, productivity, leaf canopy height and shoot density could be influenced by the abiotic variables and the nutrient factors.  Results conclude that the particulate organic carbon, inorganic phosphate and total organic nitrogen (p>0.001 level) influenced the enhancement of biomass, productivity, leaf canopy height and shoot density. Increase in seagrass growth was observed in the monsoon season, due to optimum temperature, low salinity, pH and addition of nutrients.

Key words: Seagrasses, seasonal changes, biomass, productivity, leaf canopy height.