Appearance and Growth of Sargassum plagiophyllum (MERT.) C. AGARDH on a Fresh Substratum

Abstract

Species of Sargassum are very common in the subtidal and lower intertidal regions of the Indian coasts. SRTNIVASAN (1966) has enumerated s many s 70 taxa, It was pointed out by VARRIER and PILLAI (1952) that Sargassum spp. can be good sources of alginic acid. Since then a number of studies have been carried out on the alginic acid content in and methods of extraction from various species of Sargassum. The alginic acid content varies from 4.85% to 29.17% on the basis of dry weight (ΚΑΡΡΑΝΝΓΑ et al. 1962). This may also show seasonal Variation in the same species. Again plants of the same species from different regions of the coast are also said to show variations in alginic acid content. Because of these variations, it would be desirable to bring into cultivation a species which is rieh in alginic acid and harvest it in the right time to give a high grade product. Sargassum plagiophyllttm is a common species in the South Indian waters and grows submerged at a depth of about 2 to 5 fathoms (A-10 m). This species has been estimated to have an alginic acid content of 25%. Therefore, this species would be an ideal one for cultivation, As preliminary step, it was decided to plant a fresh substratum made of concrete among the plants of S. plagiophylhtm in its natural environment. By this it was thought to allow the oospores of the alga to settle on the substratum and start new plants. If large number o£ such concrete devices were planted in naturally occuring Sarg sstfw beds and these devices were to be covered by oospores shed by Sargassum^ an easy and effective method of cultivation would be the result. With the above object in view, Sargassum beds were located at three places in the Gulf o£ Mannar on the eastern side of Krusadai Island. Concrete cylinders with rough surfaces 1,5 foot high and l foot in diameter were prepared and these were lowered into the sea at preselected places. The cylinders were fixed erect to the sea bottom. The cylinders were taken out periodically and examined to note the appearance of sporelings of Sargassum and to record the growth of these sporelings into mature plants.Observations were recorded for a period of eighteen months in the first instance and again at the end of 30 months. The cylinders were planted on January, 27 1967. A month later one of the cylinders was found broken to pieces and only one small piece could be recovered. In April 1967 two other cylinders were washed away and only one cylinder could be recovered.Further observations were made wholly on this cylinder. In the first three months after planting the cylinders, there was apparently no sporelings of Sargassum or of any other seaweed on the surface o£ the cylinders, but the surface was covered by a slimy matter, presumably some benthic orgamsms. In the fourth month a number of sporelings of seaweeds other than Sargassum made their appearance, These included EnUromorpha spp,, Caulerpa sertulari tdes> Pococktella variegata, Peyssonelia obscura, Padina spp., Colpomenia sinuosa> Dictyota spp., Hypnea valentiae and Cenf...

The settlement, attachment and establishment of marine algal spores

“…and favourable bacteria-filmed surfaces. Similar relationships between bacterial films and the settlement and metamorphosis of a variety of marine invertebrate larvae have already been described (Wilson, 1955;Neumann, 1979;Kirchman et al, 1982;Weiner, 1985) and explain the apparent need for surfaces to be "conditioned" before spore and larval colonization can take place (Raju & Venugopal, 1971;Neushul et al, 1976;Foster, 1980;Ang, 1985, Peterson & Stevenson, 1989.…”

Seasonal variation in biomass and species composition of seaweeds stranded along Port Okha, northwest coast of India

“…In the present study, the seaweeds stranded ashore were negligible during December and January but suddenly increased by a factor of 6 times in February. The life history and phenology of Sargassum species and its recruitment dynamics have extensively been investigated Krishnamurthy 1967a, 1967b;Raju and Venugopal 1971;Chauhan 1972;Chauhan and Mairh 1978;Kendrick 1994;Kendrick and Walker 1995). Sargassum species are canopy-forming algae up to 120 cm tall; and commonly grow in semiexposed habitats from the intertidal to subtidal reefs (up to 30 m depths) in tropical and temperate regions (Chauhan 1972;Kirkman and Kendrick 1997).…”

Variações espaciais e temporais no desenvolvimento vegetativo e reprodutivo da macroalga Sargassum C. Agardh (Fucales, Phaeophyaceae) - síntese do conhecimento

“…As partes que persistem após a fase de senescência são o apressório, os ramos principais e os ramos laterais primários não férteis. Novos ramos laterais primários podem se diferenciar a partir dos ramos principais, ou os ramos laterais primários fragmentados podem voltar a se desenvolver, o que se denomina de regeneração (Raju & Venugopal 1971, Fletcher & Fletcher 1975b, Norton 1977a, b, Chamberlain et al 1979, Mc Court 1984, Umezaki 1984b, Umezaki 1986, Ang Jr. 1985a, b, Paula & Eston 1987, Critchley et al 1991, Vuki & Price 1994, Arenas & Fernández 1998, Gillespie & Critchley 1999. A natureza perene de Sargassum, então, é garantida pelo processo de regeneração, conhecido para várias espécies (Chauan & Krishnamurthy 1971, Chauan 1972, Fletcher & Fletcher 1975a, Fagerberg & Dawes 1976, Nabata et al 1981, Ang Jr. 1985b, Givernaud et al 1990, Hales & Fletcher 1992.…”

“…A partir do recrutamento dos propágulos, originados pela fecundação dos oogônios, novos indivíduos são incorporados às populações (Raju & Venugopal 1971, Fletcher & Fletcher 1975b, Gunnill 1980, Critchley et al 1991, Kendrick & Walker 1994.…”