The balance of carbon and the efficiency of growth yield were studied using E. coli as a typical bacterium and glucose as the sole organic substance. The efficiency of growth yield to the decrease of substrate, the evolution of CO_2 and the excretion of waste products were, respectively, 0.54,0.36 and 0.11 in terms of carbon, and these values were almost constant throughout the whole growing stage. Furthermore, the amount of glucose incorporated, CO_2 evolved and the waste products excreted by one cell during its one generation time seemed to be constant throughout the whole growing stage, i.e., the unit of biomass(1.00)incorporated 1.73 glucose, evolved 0.68 CO_2 and excreted 0.19 waste products for one generation time. The growth curves of E. coli and mixed bacterial population decomposing glucose under the influence of aeration with CO_2-containing or CO_2-free air and of repeated preculture were the same in type and yield efficiencies were also the same(0.54), irrespective of the length of lag time. Different substrate gave different growth yield, but the growth yield seemed to be independent of temperature for a wide range. As a biogeochemical agent, the role of bacterial population in the turn-over of material and in the mineralization of organic compound was also discussed.
Population density, biomass and species composition of soil Collembola were investigated in the temperate forests mainly composed of Tsuga Sieboldii or Fagus crenata in Mt. Sobo, central Kyushu, Japan, in the late summers of 1961 and 1965. The Collembola community in Mt. Sobo was divided into the following three subcommunities by means of density and C_λ-index : Valley, Slope and Ridge subcommunities. The average density of Collembola on the ridges in Mt. Sobo was 48100 per m^2 and the average biomass of dry specimens was 145mg which was determined by the method described later. These figures for the density and biomass of the Collembola population were as large as those of Europe throughout. The regressions between the body length and the dry weight of the individuals in each taxonomic group of Collembola were obtained, and then the biomass of Collembola was estimated through the dry individual weights which were known from the regressions.
The breeding ecology of the Japanese great tit (Parus major minor) was observed by use of nest boxes from 1961 to 1969. Three breeding habitats were used : a mixed wood of broad-leaved trees and pines, a dense pine wood and a sparse grass-land wood. The mean number of pairs per hectare in each habitat was 1.7,1.2 and 0.3. The nesting period ranged between 5 and 12 days, and its peak varied by year between late April and early May. The incubation period was 14 to 17 days and the nestling period differed from 12 to 17 days. There was no significant difference in clutch size between the years or between the habitats, the overall mean of clutch size was 8.9. There was also no significant difference in the brood size by the years and the habitats, the mean brood size was 6.9. The rates of homing in the adults were 0,16.6,20.0 and 27.3 percent, and those in the youngs were 0 and 7.1 percent. The longest homing record was four years in the adults. There were statistically positive correlations between the egglaying dates and warmth or sunshine sum.
Along the northern coast, the peninsula borders the neck of the Ariake Sea. As the western half of the coast is rocky and is connected with the East China Sea through the strait, the rising tide of the open sea flows straightly toward the tip of the peninsula, but the eastern half is sandy and is fed by the drainage of the River Midori at its end. The chlorine-content of the sea water decreases toward the east and abruptly falls near the eastern extremity owing to dilution by the river water. As the northern half of Yatsushiro Bay is almost separated from the open sea by the Amakusa Islands and receives the water from the Kuma River, the chlorine-content of the sea water is also considerably low. Along the northern coast, the Gloiopeltis furcata-Sargassum thunbergii community is remarkable in the western half and the Enteromorpha compressa-Gracilaria verrucosa community in the eastern half. At the eastern extremity Caloglossa leprieurii grows in the muddy marsh which is separated from the sea and invaded by sea water only at high tide, but on the coast of Yatsushiro Bay it grows on the muddy shore of the bay. Along the coast of this bay, Enteromorpha compressa and Gracilaria verrucosa are generally dominant, but only a small community of Sargassum thunbergii survives around a small island near the western extremity of the bay where sea water flows from the harbour of Misumi. In the intertidal zone of Misumi, three belts are recognized which are named after their dominant species. They are from above downwards ; Gloiopeltis furcata-Monostroma nitidum belt, Ulva pertusa-Sargassum thunbergii belt and Sargassum patens belt. As the sand is deposited on the bottom of the sea toward the east, where the depth becomes shallower the community gradually changes and the lowest belt is lost first, and at last the uppermost belt is replaced by that of Enteromorpha compressa-Gracilaria verrucosa. The change of these communities is considered to be caused by the fall of salinity of sea water.