房州富崎に於る〓に就て(第一報)日中の垂直分布

抄録

Since April 1931, the collection of plankton samples has been carried out by the staff of the Meteorological Station at Tomizaki, Bôsô Peninsula. Using Nansens's quantitative closing net, 19cm. in diameter, plankton hauls were made from the following layers; 0-10m., 10-20m., 20-30m., 30-50m. and 50-80m. depth. Hensen's method was adopted for counting the plankton.
Phytoplanktonic association represented by Chaetoceras, Rhizosolenia and Thalassiothrix was most abundant at all seasons of the year and indeed, at the end of July over 98% of the total number of plankton individuals was phytoplankton. And in addition to the above mentioned species in summer Bacteriastrum and Nitzschia seriata appeared in a large quantity.
As far as the present observations in the daytime were concerned, the layer between the 0-20m. depth was most densely populated by diatoms, and they suddenly decreased in the 50-80m. layer to as much as below 20% in quantity of these in the surface layer. Dinoflagellata showed maximum abundance in the layer between the 0-10m. depth and almost disappeared in the layer below 50m..
The most common species found among the zooplankton were Oithona spp., Paracalanus parvus etc.. Although phytoplankton was generally prevailing, Copepods were found crowded in the layer between 20-30m. depth while Noctiluca, Tintinnoidea, nauplius juv. of Copepod as well as pelagic fish eggs mainly existed in the uppermost layer.