Growth inhibition of a red tide flagellate,Chattonella antiqua by copper

Journal of Oceanography - Copper toxicity inChattonella antiqua (Raphidophyceae) was examined using an artificial seawater medium. The growth rate (Μ) was found to be a unique function of...     

A pycnostad on the bottom of the ventilated portion in the central subtropical North Pacific: Its distribution and formation

A water mass characterized by the pycnostad on the bottom of the ventilated portion in the central subtropical North Pacific is described through the comparison with the Subtropical Mode Wate (STMW). In this paper, this water mass is called the North Pacific Central Mode Water (CMW), because of its vertical homogeneity. The distribution of CMW is examined based on the climatological maps of annual mean potential vorticity. On the other hand, its formation area is examined based on the climatological winter temperature data set and the STD sections across the Kuroshio Extension in early spring of individual years. The main results are summarized as follows: 1) STMW is formed in the deep winter mixed layer south of the main path of the Kuroshio Extension (termed 12°C Front in this paper). On the other hand, CMW is formed in the deep winter mixed layer in the east-west band surrounded by a branch of the Kuroshio Extension (termed 9°C Front in this paper) and the boundary of two water masses representing the subtropical and subpolar gyres. 2) The winter mixed layer between the 12°C Front and the 9°C Front is shallower than that in the CMW and STMW formation areas. 3) These geographical features of the winter mixed layer depths near the subarcticsubtropical transition zone result in two pycnostads (STMW and CMW) in the main thermocline of the subtropical North Pacific through the advection caused by the subtropical gyre.     

Experimental analysis of recruitment patterns of coral reef fishes in seagrass beds: Effects of substrate type, shape, and rigidity

Habitat choice of reef fish larvae at settlement is one of the mechanisms proposed to explain spatial patterns in the distribution of fishes and the corresponding spatial structure of communities. Field experiments using Pomacentridae were conducted at Iriomote Island, southern Japan, in order to determine if rare recruitment of coral reef fishes in seagrass beds is due to larval settlement preference. When three types of natural patch treatments (branching coral patch, seagrass patch, and control without patches) were established in cleared seagrass squares in the center of a seagrass bed, four pomacentrid species, Amblyglyphidodon curacao, Dischistodus prosopotaenia, Cheiloprion labiatus, and Dascyllus aruanus, recruited exclusively onto the coral patches, indicating that larvae distributed in the seagrass bed may have preferred a coral rather than seagrass substrate as a settlement habitat. The effects of differences in physical shape (grid structure for branching coral vs. vertical structure for seagrass leaves) and rigidity (rigid substrate for coral vs. flexible substrate for seagrass) between coral and seagrass substrates on such recruitment patterns were investigated using artificial coral and seagrass units. When artificial habitat units with predator exclusion cages were established in the cleared seagrass squares as above, high densities of A. curacao and D. prosopotaenia recruits were observed on the rigid rather than flexible habitat units (both unit types having similar shape), whereas differences in recruit numbers of the two species were unclear in differently shaped units. These results demonstrated that even though pomacentrid larvae are distributed in the seagrass bed, they do not settle on the seagrass substrate owing to their habitat choice being partially based on a preference for substrate rigidity. Moreover, non-recruitment of C. labiatus and D. aruanus on artificial habitat units suggested that the presence of living coral substrates rather than physical shape/rigidity of substrates are an important cue for habitat choice of these fishes.     

Comparison of upper ocean thermal conditions in the western North Pacific between two pentads: 1938–42 and 1978–82

In order to understand long-term changes in the temperature structure of the upper western North Pacific, we compared thermal conditions in two pentads, 1938–42 (P34) and 1978–82 (P78). The 1938–42 data were taken mostly by the Japanese Imperial Navy in a series of hydrographic surveys. The 1978–82 data were mostly XBT data taken as part of the TRANSPAC program. For each pentad, the data were interpolated to a set of standard depths, put through quality control procedures and averaged on a 1^o×1^o grid. A large area of the central subtropical gyre was warmer during P78, while the southern subtropical gyre, in the area of the North Equatorial Current was warmer during P34. This suggests that the transports of the Kuroshio and North Equatorial currents were larger during P78. Properties of North Pacific subtropical mode water (NPSTMW) were compared between pentads. It was found that NPSTMW was thicker, more uniform in temperature and more confined geographically during P34. A greater thickness is shown to result from stronger wintertime cooling during P34. Changes in the geographic extent of NPSTMW probably result from reduced advection by the Kuroshio current system during P34. The reason for the reduced advection maybe the Kuroshio was in a large meander state for a larger fraction of the earlier pentad, which can cut off advection west of the Izu Ridge.     

Long nonlinear topographic planetary waves in a rotating stratified ocean

Long nonlinear topographic waves in a continuously stratified ocean with a linear bottom slope are investigated. It is shown that odd cross-channel modes are governed by the Korteweg-de Vries (K-dV) equation. The solitary waves are those of a low pressure type. The long waves are shown to be modulationally stable because of the nonlinear effect due to irrotational motion. All these results are missed if the conventional quasi-geostrophic approximation is adopted.     

239, 240Pu,137Cs and90Sr in the central North Pacific

^{239, 240}Pu,¹³⁷Cs and⁹⁰Sr concentrations were determined in sea waters from the central and western North Pacific in 1980 and 1982. The results are consistent with those reported earlier for North Pacific waters. The profiles of⁹⁰Sr and¹³⁷Cs show a monotonic decrease with depth, whilst^{239, 240}Pu shows a distinct subsurface maximum at a depth between 400 and 1,000 m. The calculated inventories of these nuclides significantly exceed the global mean fallout inputs for these latitudes. This may be due to local fallout input to the ocean at times of large-scale nuclear weapon tests in the equatorial North Pacific. The existence of measurable amounts of¹³⁷Cs and^{239, 240}Pu in deep waters suggests that these nuclides are transported by sinking particulate matter from the surface to the deep ocean.     

Four Decadal Ocean-Atmosphere Modes in the North Pacific Revealed by Various Analysis Methods

Various statistical methods (empirical orthogonal function (EOF), rotated EOF, singular value decomposition (SVD), principal oscillation pattern (POP), complex EOF (CEOF) and joint CEOF) were applied to low-pass filtered (>7 years) sea surface temperature (SST), subsurface temperature and 500 hPa geopotential height in order to reveal standing and propagating features of decadal variations in the North Pacific. Four decadal ocean-atmosphere covariant modes were found in this study. The first mode is the well-known ENSO-like mode associated with the “Pacific-North American” atmospheric pattern, showing SST variations reversed between the tropics and the extratropics. In the western tropical Pacific, subsurface temperature variations were found to be out of phase with the SST variations. The other three modes are related to the oceanic general circulation composed of the subtropical gyre, the Alaskan gyre and the subpolar gyre, respectively. The 1988/89 event in the northern North Pacific was found to be closely associated with the subtropical gyre mode, and the atmospheric pattern associated with this mode is the Arctic Oscillation. An upper ocean heat budget analysis suggests that the surface net heat flux and mean gyre advection are important to the Alaskan gyre mode. For the subpolar gyre mode, the mean gyre advection, local Ekman pumping and surface net heat flux play important roles. Possible air-sea interactions in the North Pacific are also discussed. The oceanic signals for these decadal modes occupy a thick layer in the North Pacific, so that accumulated heat content may in turn support long-term climate variations. This revised version was published online in July 2006 with corrections to the Cover Date.     

The idea of nature in the east in comparison with the west

Conclusion — Contemporary Implications According to Buddhist philosophy, men constitute just one class of living beings. As such, they have no right to unlimited use of natural resources. Also men have no right to unlimited exploitation of animal and plant life, which forms part of Nature. Until recently, Westerners or moderns tended to think that men were quite separate and different from the natural world. This assumption is ungrounded and unreasonable. It has brought about devastation. Men incur retaliation by nature.In order to deal with the difficult situation that has come about, we must seek a solution that is both objective and subjective. On the objective side, we must discard the arrogance of supposing that men are entitled to exploit the natural world at their own will, without limit and regardless of the consequences. It is not appropriate to maintain the idea of conquering nature. Nature should be met with affection. In this connection, we emphasize that the world of nature should not be monopolized by a few countries. The whole natural world should be shared by all mankind. We cannot but feel angry at the small, limited number of countries which totally control the reserves of a limited energy supply, and which are extravagantly wasting what nature has entrusted to them. Just as individual egoism must be curtailed and placed under control, so national and ethnic egoism also should be restrained in the name of justice and respect for nature.On the subjective side, there is need for correction of the opinion of moderns that the progress of mankind consists in the unlimited satisfaction of human desire for material objects. Buddhism taught satisfaction with what is given to men. To know being satisfied was thought to be the way to spiritual happiness. The key to the relationship between man and the environment may very well lie in the control of our desires according to this concept of satisfaction. For that purpose our desire should be scaled to the possibilities of nature conceived as supporting human existence. Nature is not an entity to confront us as if it were quite different from us; it is something to embrace, as we might think it as that from which we cannot separate ourselves. Admitting the disinction between man and nature, we have to think how to live with the knowledge that nature is necessary to us.     

CaseA evolution of massive close binary systems

The caseA evolution of close binary systems with total mass of 20.4M is investigated by following the evolution of both components simultaneously. The evolution is followed up to the stage at which a system overflows the outer critical surface or evolves into the phase of modeBr mass-transfer. It is found that the evolution of the systems can be classified into six types. The ranges of initial parameters which lead systems to each type of evolution are shown on the initial-parameter plane. The evolutionary features of each evolution type are described in detail.