ECOLOGICAL CHARACTERISTICS OF THE DIFFERENT ECOSYSTEMS in COASTAL areas OF THE ANDAMAN ISLANDS

Coastal ecosystems are well known for their higher primary and secondary productivity and support of diverse floral and faunal communities.  Especially coral reef and seagrasses create, as well as occupy, important niches in shallow water environments.  Physico- chemical characteristics of the critical habitats (Mangrove, seagrass, dead coral bed and sandy beach) of Andaman islands were studied.  Physico-chemical parameters recorded in 18 stations showed distinct variations among different ecosystems, especially chemical parameters showed notable variations in all these ecosystems. Sediment characters showed significant variations: pH of the sediments varied between 8.1 and 8.6 in all the sampling locations and the electrical conductivity of the sediments varied between 2.1 and 4.1dSm-1. Sediment nutrients varied widely: nitrogen (22-52 kg/acre), phosphorus (10-15 kg/acre) and potassium (55-73 kg/acre). Though the physico-chemical parameters showed distinct variations among different ecosystems, they are within the optimum range reported for the specific ecosystems prevailing in the area. In general, the nutrient level of water in the seagrass and mangroves was low when compared similar ecosystems of the mainland. It is important to note that, though the ambient water quality of these ecosystems is at the optimum level reported for the respective ecosystems, proper attention should be paid to maintain the subtle nature of the ecosystems of the islands, under the post-tsunamic geomorphological variations, increasing national and international tourism activity and the changing climatic conditions

Distribution and biology of seagrass resources of Lakshadweep group of Islands, India

624-634Present study explains the diversity, distribution, biomass and productivity of seagrasses in the Lakshadweep group of Islands. Seven seagrass species under five genera were recorded from nine islands and no seagrass was found at Bitra island. Out of seven seagrass species, Cymodocea serrulata was found to be dominant in the Lakshadweep group of islands whereas Halophila decipiens was found only in Kalpeni island. Biomass varied widely from 72+9 to 944+99 gfr.wt.m‑2 among all the species of seagrasses. Productivity also showed clear variation within the species and between the species at different stations. Productivity of the species varied from 2.76+0.17 mgCm-2day-1 to 95.53+10.06 mgCm-2day-1 and it was in the following order of increase: H. decipiens H. pinifolia H. uninervis< T. hemprichii< C. rotundata< S. isoetifolium The spatial cover of seagrasses in Lakshadweep Island is more and are healthy in almost all the islands

Evaluation of seagrasses for their nutritional value

105-111Biochemical and calorific contents of different species of seagrasses occurring in Palk Bay were determined: Enhalus acoroides (68.82 K cal g-1), Halophila beccarii (29.16 K cal g-1), Halophila ovalis (24.08 K cal g-1), Cymodocea rotundata (60.62 K cal g-1), Cymodocea serrulata (43.40 K cal g-1), Halodule uninervis (40.15 K cal g-1), Halodule pinifolia (28.39 K cal g-1) and Syringodium isoetifolium (38.38 K cal g-1) of leaves and in rhizome Enhalus acoroides (77.84 K cal g-1), Halophila beccarii (38.84 K cal g-1), Halophila ovalis (37.03 K cal g-1), Cymodocea rotundata (63.68 K cal g-1), Cymodocea serrulata (37.33 K cal g-1), Halodule uninervis (28.39 K cal g-1), Halodule pinifolia (28.23 K cal g-1) and Syringodium isoetifolium (30.48 K cal g-1). Calorific contents of seagrasses were equivalent to Bengal gram, Peas, Potato and Sweet potatoes.&nbsp; Present study suggests that the seagrasses could be considered as feed/food