The periodic variation of the barotropic components of a wind-driven circulation of sea water is discussed. Special attention is drawn to the vertical component of velocity at the sea surface which is required to fulfill the continuity of mass. Its effect is considerable only when the period is shorter than a few days, even if the wind stress varies on a scale of about 1, 200 km.

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Some inhibitory effects of the atmospheric environment on the chitinoclastic bacteria which are carried into the atmosphere and effects of ecological factors on the bacteria which are migrating in the free water of sea from substratum to substratum were examined on the chitinoclastic bacteria isolated at Aburatsubo Inlet. The results obtained are summarized as follows:
1. Although all the chitinoclastic bacteria are killed by irradiation of ultraviolet light, they show to have strong resistance for the lethal effect of ultraviolet illumination compared to Escherichia coli.
2. All types of chitinoclastic bacteria examined stop their multiplications at a sodium chloride concentration of 12 per cent, which indicates the cessation of bacterial activities in the droplets of sea water containing more than 12 per cent of sodium chloride.
3. All the chitinoclastic bacteria die within 24 hours in a solution having a sodium chloride concentration of 25 per cent.
4. The chitinoclastic bacteria die in distilled water as the result of prolonged contact in dilute environment, although they do not perish within one hour.
5. All types of the chitinoclastic bacteria die within 8 days with starvation.
6. The chitinoclastic bacteria, on the other hand, can multiply in peptone sea water medium rapidly without the supply of chitin in the medium. They also utilize inorganic nitrogen, i.e., ammonium, nitrate and nitrite, with available carbohydrates for their multiplication.
7. All the chitinoclastic bacteria multiply at 5°C. Even at 0°C they could survive in the peptone sea water for 20 days, although no multiplication was detected by the turbidimetric method.
8. Though 50 per cent reduction of the chitinoclastic bacteria is obtained at the contact to -5°C for 60 minutes, considerable survival of them is obtained even at -10°C.
9. A pressure even at 200 atm inhibits the normal growth of the chitinoclastic bacteria.

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A series of zooplankton samples was obtained by high-speed sampling at the surface, in the Bering Sea and northern North Pacific during the cruise of the Oshoro Maru from June to August 1960. The average biomass of the zooplankton in all the samples was 390g/1, 000m³ wet weight. Very high values were obtained in the northern part of the Gulf of Alaska (1, 169g/1, 000m³) and off the south of the Aleutian Islands (888g/1, 000m³). Thirty-nine species of copepods were identified from the samples. The area investigated could be divided into three regions by the composition of copepods: 1) the cold offshore water region characterized by Calanus plumchrus-C. cristatus population, 2) the warm offshore water associated with Calanus pacificus and several warm oceanic species, 3) the neritic water mass represented by Pseudocalanus minutus-Acartia longiremis population.
The relationships between the total numbers of zooplankton and phytoplankton suggest that in the offshore region the phytoplankton population is grazed down by zooplankton within a considerably short period, resulting in the poor standing crops, while sufficient phytoplankton standing crops are available in the neritic region because of less active feeding of the neritic consumer.

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