Spatial structure of a warm eddy which was located stably above the western side of the Yamato Rise was described in detail by examining hydrographic data, NOAA-infrared image, and current data in summer 1989. The doughnut-like flow structure surrounding a warm-core was found to play a significant role in the northward transport of warm and salin water in summer. However, it was inferred from the analysis of hydrographic data through the year that the above doughnut-like flow disappeared in winter and drastic structural variations of an eddy were brought by wintertime convection. During winter, not only the core-temperature but also the salinity decreased and the shape of an eddy became unclear, suggesting the exchange of a core water with the outer one.

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After 1977, anomalous southward intrusions of the Oyashio and subarctic circulation in the North Pacific have been observed from winter to late spring approximately every three years, while they occurred approximately every ten years before 1976. The southward intrusions has been focused as a remarkable event of the ocean phenomena. Occurrences of the southward intrusion of the Oyashio and the subarctic circulation are reviewed with reference to its relationship to the global change in atmospheric circulation. It has been demonstrated by the historical data analyses that prior to the occurrence of the anomalous southward intrusion of the Oyashio and the subarctic circulation, the southward formation of the Aleutian Low is observed and it yields southward shift of the wind stress distribution. In particular, southerly displacement of the latitude of no wind stress curl is carried out with the range of 3-5° over the wide area west to 160° W in the North Pacific. It has been also shown by numerical models that the occurrences of the southward intrusion of the Oyashio and the subarctic circulation are due to the barotropic response of the ocean to the change in wind stress distribution denoted above. The southward development of the Aleutian Low is a part of PNA pattern, which has a teleconnection with the ENSO phenomenon. It has been shown by some historical atmospheric studies that the southward development of the Aleutian Low is formed by the cold sea surface temperature due to the southward shift of subarctic circulation of the North Pacific. This indicates the positive feedback of the southward shift of the subarctic circulation for the enhancement of the PNA pattern. It is suggested that the anomalous southward intrusion of the Oyashio and subarctic circulation is one process of the coupled ocean and atmosphere disturbances that propagates to a global scale. More detailed studies by used of a combined ocean-atmosphere model are strongly needed.

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Many marine bacteria can survive long periods of low nutrient stress that exists in ocean. For example, marine psychrophilic Vibrio sp. ANT-300 has been reported to survive 2.5 years without nutrient supply. Starving cells utilize endogenous substrate for respiration, and then decrease in cell volume. However, bacteria which utilize cellular RNA cannot survive a long starvation. Bacterial species decreasing respiratory activity can survive a long starvation. Decrease of respiratory activity seems to be prerequisite for saving cellular materials and for long starvation survival. Cellular ATP of starving bacteria seems to remain at relatively higher level. Starving cells can quickly incorporate external materials without any lag periods. Starving cells appear to be not in dormant state. Many of starvation proteins which are not synthesized during growing stages are reported on Escherichia coli and marine bacteria. Synthesis of some of the starvation proteins is induced also by many other stresses like heat shock. The role of starvation proteins in long starvation survival has not been elucidated.

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