| dc.description.abstract | To study the effects of total solar eclipse of 16th Feb. 1980, on the behaviour and metabolic activities of intertidal invertebrates - nematodes, gastropods and bivalves - having different habitat preference a set of relevant observations, covering the pre-eclipse, eclipse and post-eclipse period, were carried out in the natural environment of Dias beach, Goa (Lat. 15 degrees 25'N; Long. 73 degrees 45'E). Environmental factors considered are tidal amplitude, atmospheric temperature and the sand column temperature. Results indicate that the stratification of nematodes which usually was maximum (57 to 80%) in the top 1 cm layer of the sand column at all the tide levels, during pre- and post-eclipse period, showed low population density of 11 to 40% on the day of the total solar eclipse. Similarly, the metabolite contents in S. cucullata and L. intermedia, as assessed from the variations in water and carbohydrate composition, indicated a sudden fall of 10% and 16%, respectively, almost coinciding with the planetary events of 16th Feb. 1980. An attempt is made to analyze the magnitude of exogenous and endogenous factors in influencing the observed changes, coinciding with the total solar eclipse. On prima facie, the observed changes in the behavioural activity of interstitial nematodes and in the metabolite composition of the rock oyster and the periwinkle, appear to be a consequence of the total solar eclipse. However, the possibilities of these observed changes, being an event of the persisting "biological clock" or "circadian rhythm", which reportedly controls the activities of intertidal animals, cannot totally be overruled | |
