Calcification in a solitary coral, Fungia scutaria Lamarck in relation to environmental factors

Typescript.Thesis (Ph. D.)--University of Hawaii, 1966.Bibliography: leaves [124]-130.xiv, 130 leaves illWith the ultimate purpose of clarifying the role of zooxanthellae in calcification in corals, a study was conducted (1) to analyze the effects of some environmental factors on the rate of calcium uptake by Fungia scutaria and (2) to obtain a clear picture of the uptake and release of phosphorus by the same animal under various conditions. The effect of the factors investigated on the rate of calcium uptake was strikingly different in the light and in the dark. In the dark, the rate increased linearly with increase in temperature (15° - 32° C) and, also, with increase in the ambient calcium concentration from 0 to 200 mg Ca/l. A steady state was maintained for calcium concentrations from 200 to 600 mg/l. A drastic decrease occurred in solutions of 75 to 25% sea water, and a lesser decrease in 125% sea water. The rate decreased linearly with the logarithmic increase in the .ambient phosphate concentration from 10^-7 (natural sea water) to 10^-2 M. In the light, the rate of calcium uptake was maximum at 24°C, and in natural and 75% sea water. Deviations from either of these conditions resulted in decrease in the rate of calcium. uptake. Uptake rates increased linearly with increase in the ambient calcium concentration from 0 to 400 mg Ca/l and with a steeper slope from 400 to 600 mg Ca/l. The effect of the ambient phosphate concentration on calcium uptake was not clear but there was a general trend of decrease in the uptake rate with increasing concentration of phosphate. The greatest difference in the rate of calcium uptake between the dark and light conditions was observed at the lower phosphate concentrations. Dinitrophenol completely inhibited calcium uptake at concentrations of 10^-4 M and higher both in the light and in the dark. At a concentration of 10^-5 M a complete 'inhibition was observed in the dark but not in the light. The removal of zooxanthellae from the animal caused a decrease in the rate of calcium uptake to 1/12 the control value in the light and to 1/8 in the dark. These ratios were unaltered in the polyps devoid of zooxanthe11ae kept in the same container with the normal polyps. The rate of phosphorus uptake from sea water supplemented with phosphate (2.7 μg-at. P/1) was approximately two times greater in the light than in the dark. Net uptake occurred both in the light and in the dark at this phosphate concentration, while net release occurred in the light and in the dark in natural sea water (0.27 μg-at. P/1). In the light, the polyps devoid of zooxanthe11ae absorbed phosphorus at the rate 1/8 that of the normal polyps; in the dark this ratio was about 1/6. Some indication of interaction between the normal and zooxanthel1afree polyps in the same container was observed. The effect of temperature on phosphorus uptake was about the same as that on calcium uptake. Approximately the same quantity of organic phosphorus (particulate and dissolved) was released in the light as in the dark, while nine times more inorganic phosphorus was released in the dark than in the light. More organic P-32 was released by the normal polyp than by the zooxanthella-free polyps under both light and dark conditions

REPRODUCTIVE CYCLE IN A ZOANTHID PALYTHOA TUBERCULOSA ESPER

From the study on the reproductive cycle exhibited by thirteen colonies of P. tuberculosa a previous proposal by KIMURA et al. (1972) that this species is a protogynous hermaphrodite was confirmed. It was further elucidated that there are two types of hermaphroditic colonies, one with both functional female and hermaphroditic polyps along with functional males and the other with non-functional female and without hermaphroditic polyps. In addition the third type of colony, the male was also recognized. Among the three types of colonies, the first was regarded as the basic while the other two as derived from the first by a successive loss of the female phase

A coral spawning calendar for Sesoko Station, Okinawa, Japan

info:eu-repo/semantics/publishe