Seagrass ecology microbial association and bioactivity profiles with special reference to halodule pinifolia miki hartog and syringodium isoetifolium asch dandy occurring along the south indian coast

Abstract

Seagrasses are a unique group of angiosperms that have adapted to exist fully submersed in the sea. They profoundly influence the physical, chemical and biological environments in coastal waters, acting as ecological engineers (Wright and Jones, 2006). There are relatively a few species globally (60 species) and these are grouped in 10 genera and 5 families (Short and Coles, 2001). Generally they are divided into five temperate and five tropical genera. The family Zosteraceae includes genera Zostera and Phyllospadix. Hydrocharitaceae notably includes Enhalus, Thalassia and Halophila. The family Potamogetonaceae includes Cymodoceae, Halodule and Syringodium and Posidoniaceae includes genus Posidonia. Additionally, a fifth family Ruppiaceae is sometimes accepted as a family of seagrass. They are common in brackishwater and the species Ruppia is a very important seagrass in parts of the Mediterranean region, particularly in the Black, Aral and Caspian Seas. In India, seagrass comprises 15 species and is dominated by Cymodocea rotundata Ehrenb. and Hempr. ex Asch., Cymodocea serrulata (R.Br.) Asch. and Magnus., Thalassia hemprichii (Ehrenb.) Asch., Halodule uninervis (Forsk.) Asch., H. pinifolia (Miki) Hartog, H. beccarii Asch., Halophila ovalis (R.Br.) Hook F. and H. ovata Gaud. (Jagtap et al., 2003). The structural components of leaves, rhizomes and roots of seagrasses modify currents and waves, and trap and store both sediments and nutrient inputs of the coastal ocean. So the biodiversity in seagrass meadows is greater than in adjacent unvegetated areas and faunal densities are orders of magnitude higher inside the meadows. newline