Abstract
Marine plants are considered as a source of bioactive compounds as they are able to produce a great variety of secondary metabolites characterized by a broad spectrum of biological activities. Compounds with antioxidant, antiviral, antifungal and antimicrobial activities have been detected in mangroves, seaweeds and seagrasses. Marine plants are the source of amino acids, terpenoids, phlorotannins, steroids, phenolic compounds, halogenated ketones and alkanes and cyclic polysulphides. In this study, the antibacterial activity of flowering seagrass species viz., Syringodium isoetifolium and Cymodocea serrulata and non-flowering seaweeds viz., Amphiroa anceps, Gracilaria corticata, Sargassum wightii, Padina pavonica, Ulva lactuca, and Valaniopsis pachynema were tested. Interestingly it is found that, most of the ethanolic algal extracts controls all the pathogens of antibiotic resistant organism, fish pathogens, poultry pathogens and human ophthalmic pathogens. The antibacterial activity of halophytic plant extracts were evaluated by the well diffusion assay and the zone of inhibition ranged between 6mm to 14mm. The maximum activity was recorded with the marine algal ethanolic extract of V. pachynema against almost to all the pathogens selected for the study.

1503022.Antimicrobial activity of marine flowering and non-flowering halophytic plants…pdf.

Abstract
Trichodesmium erythraeum is a filamentous cyanobacteria which forms dense algal bloom along the Pudhumadam coast in the Gulf of Mannar during the pre monsoon season 14th September, 2014. At the time of bloom totally 25 zooplankton species were observed of which four species were considered as most abundant viz. Corycaeus danae (19.28 %), Acrocalanus gracilis and Microsetella norvegica (7.23%) and Gastropod veliger (6.02%). Although the T. erythraeum occurred in high concentration (75,000/m3), it did not cause any unusual mortality to the marine large fish and shellfish and disrupt the marine environment.

1503021.Occurrence of Trichodesmium erythraeum bloom in the Gulf of Mannar…pdf.