Showing papers by "Annamalai University published in 1984"

The nature of biodegradation of vegetation in mangrove ecosystem

Abstract: Experiments were carried out in situ and in the laboratory for 45 and 90 day periods respectively to study the nature and process of biodegradation of leaves/cladodes of 9 species of halophytes with special reference to mangrove vegetation. The leaching rate of chlorophylls a, b, bacteriochlorophylls a, c, d, phaeopigments, organic carbon and micronutrients such as Zinc, Copper. Iron and Manganese were studied at different intervals (10, 30, 90 days) and in varying salinity media (0.30, 16.60, 33.30%°S). The organisms involved in fragmentation, decomposition and biodeterioration have been listed. Total litter production in the wooded mangrove area was 7,457.07 tonnes/year (leaf litter alone 5,834.4 tonnes/year). The mangroves export substantial organic material to the neighbouring estuarine and sea waters and the values were estimated at 261 tonnes C/year and 1,566 tonnes C/year respectively. Only 783 tonnes C/year were utilised and retained for use within the mangrove ecosystem.

Burrowing behavior and ecology of the crab-eating Indian snake eel Pisoodonophis boro

Abstract: The snake eel Pisoodonophis boro burrows, causing leaks in the embankments and damaging the paddy fields and salt pans near estuaries. Field observations and laboratory experiments were made to study this behavior. P. boro was burrowing to eat the fiddler crab Uca annulipes in the mud flats. The eel showed a patchy distribution within the Uca zone. Salinity and the physical nature of the deposits controlled the distribution of the eel. Eel population density was low when the estuary was completely filled with neritic waters during the summer and fresh water during the monsoon period. The region of greatest abundance contained a good mixture of sand, silt and clay. Eels were not found where medium and fine sand formed the bulk of the substratum. The laboratory experiments showed that P. boro preferred loam soil although it could invariably burrow into hard substratum like sand for protection. The eel adapted itself to the experimental substrates ranging from sand to fine clay. However, their natural distribution was determined by Uca distribution. As U. annulipes is not found either in salt pans or in paddy fields P. boro rarely occurs in these habitats.

A modified method of analysis of gut content of carnivorous fish

Abstract: A modified comparative feeding index (CFI), as applicable to carnivorous fish, is described.

Effect of substituents on the oxidation of some alkyl-aryl sulphoxides by chloramine-T

Abstract: The oxidation rates of some substituted phenyl methyl sulphoxides with chloramine-T have been studied in alkaline and neutral media. OsO4 is used as catalyst in alkaline medium where the meta and para substituents show no effect on the reaction rate. This is explained on the basis of isokinetic relationship. In both the media, the orthosubstituents show steric effect.

Fin rot and other diseases in marine fishes

Abstract: A survey was conducted on the incidence of diseases, by superficial appearance, in common fish species of Portonovo coast. Approximately 46,484 marine and 22,150 estuarine fishes were examined. Marine fishes alone were observed with fin rot and neoplasm while estuarine fishes were free from such abnormalities. Fin rot was recorded among seventeen species of marine fish and tumour in cat fish. Fin necrosis accompanied with haemorrhage, ulceration and loss of scales was consistent external sign of the disease. Species of cat fish, grunter, queen fish and pikes were mostly affected by fin rot at high level and the maximum peak was recorded in April. Cat fishes alone had tumour. More than 80% of the tumour bearing specimen had fin necrosis.