Spring Diatom Increase in Relation to the Nutrient Salts and the Meteorological Elelnents. (Relation between the Physiological Phenomena of Plankton and its Enviroments. Part 1.)

[摘要] The present paper is the result of the observations of the water of the Ohori (castle-moat) in the spring-time of 1933 and some experimental investigation which was carried out in aquaria, using Synedra salina cultured in it as material of phgtoplankton.1. As far as the results obtained by the study of the water of the Ohori are concerned, the diatom increase in the spring-time is fairly accelarated by the rise of water-temperature and by the increase of solar radiation, provided the necessary nutrient salts are available. 2. Even if other conditions be suitable, when the water-temperature is above 14°C. the multiplication of Synedra salina is greatly checked. 3. Synedra sinks down into the bottom layer to avoid the too strong solar radiation when the weather is fine and vice versa. 4. The average amount of salts consumed by Sunedra salina of 10, 000per c. c. in the layer of 15cm to 25cm. in depth are 1.45mg/L. in SiO2, 0.006mg. in P2O5 and 0.017mg. in N2O5-N, when the solar radiation is calculated 1, 000gr. cal./cm2., while in the surface layer no consumption of nutrient salts oceurred, as there was too strong solar radiation and so there no multiplication of Sunedra occurred. 5. In the place where there was no direct sunlight the consumption of nutrient salts by Synedra did not occur at all.

[学科分类] 大气科学