Studies on ecology, chemical constituents and culture of marine macroalgae of Minicoy Island, Lakshadweep

The Union Territory of Lakshadweep is situated in the Arabian Sea about 200 to 400 km off the Kerala coast. This archipelago consists of 36 islands and five s.ubmerged banks with a total area of 32 sq. km .The islands lie between 08° 00 - 12° 30' N latitude and 71 ° 00 - 74° 00 E longitude. These islands consist of coral formation built on submerged ridge raising steeply from a depth of about 1500 to 4000 m in the Arabian Sea. The Lakshadweep, Maldives and Chagos archipelagos foon an uninterrupted chain of coral atolls and reefs on a submarine bank covering a distance of over 2000 km. Most of these islands have sandy beaches with gentle slope on the lagoon side and on the seaward side there is a steep slope with boulders, coral rocks, living corals and debris. Corals cannot grow very deep in the oceans and what is seen at present depicts millennia of interaction between the submarine bank, tectonic activity and the level of the oceans, particularly during the Pleistocene period (Jones, 1986). Coral reef ecosystems are the most diverse and colourful of any communities with the most complex interrelationship between species. Corals grow where the mean sea temperature is at least 20 °C throughout the year, preferably more than 23 °C. They also need clean sea water and are wlable to grow where rivers dilute the sea or bring in mud. Coral reef communities may be very old and their foonation is a result of persistent accumulation of calcareous deposits over long periods, extending from hundred to thousands of years (Qasim, 1998). Coral reefs are of three types: (I) Barrier reefs along continents (2) Fringing reefs around islands (3) Atolls, broken fringes of reef and islands around a central lagoon. The IndoPaci fic region is particularly rich in corals. The Australian Great Barrier Reef is an intermittent series of reefs stretching over 1900 km along the coast of Queensland. Other coastal reefs lie off East Africa and in the Red Sea. The Pacific and the Indian Oceans have thousands of atolls. In the West Atlantic, coastal reefs extend 200 km. southwards from Yucatan and many Caribbean islands are fringed with coral reefs. The corals are coelenterate polyp animals which extent their tentacles at night to feed on zooplankton washed over the reefs. Their tissues house symbiotic green algae (zooxanthillae). Zooxanthillae and other algae living in or on their calcareous skeleton conduct photosynthesis in the sunlight. Many reefs are in trade wind belts, the windward side being exposed to wave action, the leeward side being sheltered. Reef systems are often bioenergeticaly more or less self maintaining, complete ecosystem in themselves, beautifully adapted to use, hoard or recycle any inputs from the surroundings

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कृपया पूरा लेख पढे

Productivity of the coral reef alga Halimeda gracilis Harv. ex. J.Ag. Minicoy island, Lakshadweep

The present investigation deals with the morphology and productivity of Halimeda gracilis from 3 locations of Minicoy Island. The estimated percentage cover of H. Gracilis were 32.6% on the reef, 10.9% on the shore reef and 17.3% on the seagrass beds. Halimeda in scagrass beds had the highest biomass of 1339.2 g/m2 followed by the shore reef with 1256.0 g/m2 and the lowest biomass at the reef (420.8 g/m2). The length of Halimeda gracilis varied between 4.5 cm at the reef and 8.5 cm in scagrass beds but the weight showed only slight variation. Length weight reintionship of Halimeda gracilis indicated least variable morphology at reef and lagoon. Plants collected from seagrass beds in the lagoon showed highest productivity of 0.64 g C/m2 / day while the lowest production of 0.08 gC/m2/day was recorded from the shore reef. Environmental parameters such as temperature salinity dissolved oxygen and nutrients were monitored at the three stations

Domestic waste and its impact on production of Caulerpa racemosa (Forssk.) Weber v. Bosse at Minicoy Island, Lakshadweep

The present study deals with the impact of domestic waste on Caulerpa recemosa collected from a densely populated village of Minicoy Island. Length of erect foliar portion of C. racemosa collected from the polluted site was only 2.15 cm while at control site it was 6.16 cm. Similarly weight of the plant was also low (0.26 g) when compared to unpolluted site (0.95 g). Length – weight relationship indicated wider variability in the size of the plant at polluted site with lower values. Net primary production values showed 7.2 fold more production at control site than that of polluted site. Environmental parameters such as temperature, salinity, turbidity and nutrients were monitored

Distribution and abundance of seaweeds on a coral reef at Minicoy Island, Lakshadweep

Macroalgal distribution and abundance in different regions of a coral reef was studied for a period of one year in 1998 at Minicoy Island, Lakshadweep. The biomass distribution of algac on the seaward side of the reef varied from 620.2 g wet wt/m2 in September to a maximum of 2800.6 g wet wt/m2 in August. Reef flat had a minimum in July (251 g wet wt/m2) and a maximum in December (2074.9 g wet wt/m2). Significant seasonal differences were noticed in the three regions with maximum biomass during monsoon on the seaward side and in the postmonsoon at reef flat and lagoon side of the reef. Laurencia ceylanica ornate (32.0%) were major algae of he reef flat and lagoon side of the reef. Minor algae observed on the reef were Gelidiella acerasa. Bocrgesenia forbesil, Sargassum duplicatum and Cladophoropsis zollingeri. Hydrographical parameters such as water temperature, salinity, nutrients, rainfall and hours of exposure of algac were monitored

Not Available

Not AvailableA green turtle was washed ashore on 10-8-98 about 1 km south of the Lakshadweep Harbour Works at Minicoy Information on the landings and bleaching of turtles from Lakshadweep are rare. Out of the four species of turtles found in Lakshadweep, Chelonia mydas is common. At Minicoy this species is reported to have nested in thousands in the past. Presently the nesting area has been reduced due to human inhabitation.Not Availabl

On a green turtle Chelonia mydas washed ashore at Minicoy Island,Lakshadweep

A green turtle was washed ashore on 10-8-98 about 1 km south of the Lakshadweep Harbour Works at Minicoy Information on the landings and bleaching of turtles from Lakshadweep are rare. Out of the four species of turtles found in Lakshadweep, Chelonia mydas is common. At Minicoy this species is reported to have nested in thousands in the past. Presently the nesting area has been reduced due to human inhabitation

Not Available

Not AvailableA green turtle was washed ashore on 10-8-98 about 1 km south of the Lakshadweep Harbour Works at Minicoy Information on the landings and bleaching of turtles from Lakshadweep are rare. Out of the four species of turtles found in Lakshadweep, Chelonia mydas is common. At Minicoy this species is reported to have nested in thousands in the past. Presently the nesting area has been reduced due to human inhabitation.Not Availabl

Not Available

Not AvailableThe present investigation deals with the morphology and productivity of Halimeda gracilis from 3 locations of Minicoy Island. The estimated percentage cover of H. Gracilis were 32.6% on the reef, 10.9% on the shore reef and 17.3% on the seagrass beds. Halimeda in scagrass beds had the highest biomass of 1339.2 g/m2 followed by the shore reef with 1256.0 g/m2 and the lowest biomass at the reef (420.8 g/m2). The length of Halimeda gracilis varied between 4.5 cm at the reef and 8.5 cm in scagrass beds but the weight showed only slight variation. Length weight reintionship of Halimeda gracilis indicated least variable morphology at reef and lagoon. Plants collected from seagrass beds in the lagoon showed highest productivity of 0.64 g C/m2 / day while the lowest production of 0.08 gC/m2/day was recorded from the shore reef. Environmental parameters such as temperature salinity dissolved oxygen and nutrients were monitored at the three stations.Not Availabl

Not Available

Not AvailableMacroalgal distribution and abundance in different regions of a coral reef was studied for a period of one year in 1998 at Minicoy Island, Lakshadweep. The biomass distribution of algac on the seaward side of the reef varied from 620.2 g wet wt/m2 in September to a maximum of 2800.6 g wet wt/m2 in August. Reef flat had a minimum in July (251 g wet wt/m2) and a maximum in December (2074.9 g wet wt/m2). Significant seasonal differences were noticed in the three regions with maximum biomass during monsoon on the seaward side and in the postmonsoon at reef flat and lagoon side of the reef. Laurencia ceylanica ornate (32.0%) were major algae of he reef flat and lagoon side of the reef. Minor algae observed on the reef were Gelidiella acerasa. Bocrgesenia forbesil, Sargassum duplicatum and Cladophoropsis zollingeri. Hydrographical parameters such as water temperature, salinity, nutrients, rainfall and hours of exposure of algac were monitored.Not Availabl