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On the behavior of symmetric waves in stratified shear layers
Oceanographic Abstracts
395
in cracks by ground water. Thus, the origin of differential corrosion in these structures is not always the same, and slight disparities in petrological constitution can sometimes result in large differences in morphological behaviour. The differences in morphological evolution between parts of the same platform standing at different heights come perhaps from contrasts in corrosion by crystallizing salt. Since observations in temperate and cold areas are not yet numerous, other investigations would be necessary to determine the influence of temperature on coastal corrosion forms in volcanic rocks. The Subantarctic Islands, Jan Mayen, and Aleutian Islands, might be interesting research fields in this respect. GUILLARD R. R. L. and J. H. RYTHER,1962. Studies of marine planktonic diatoms. I. Cyclotel/a nana Hustedt, and Detonula confervacea (Cleve) Gran. Canad. J. Microbiol., 8 (2): 229-240. Bacteria-free clones of the Small centric diatom Cyclotella nana Hustedt were isolated, three from estuarine localities, one from Continental Shelf waters, and one from the Sargasso Sea. Detonula confervacea was isolated from Narrangansett Bay. Morphology of all crones was studied with the light and electron microscopes. Morphological differences between clones of C. nana do not at present warrant separating any as distinct species. Clones of C. nana require only vitamin Blz; D. confervacea has no vitamin requirement. Growth of the estuarine clones of C. nana was unaffected by salinity down to 0"5~ and increased with temperature to 25°C. The Shelf clone grew more rapidly at salinities above 8 ~ and at temperatures between 10~ and 20~C. The Sargasso Sea clone did not survive below 15°C or 17.5~, while D. confer~acea did not survive at temperatures above 15° or at salinities below 8 ~ . The physiological differences between clones correspond roughly to the conditions obtaining in nature where each was collected. HASLE G. R., 1961 (1962). The morphology of Thalassiosira fluviatilis from the polluted inner Oslofjord. Nytt Mag. Botanikk, 9: 151-154. The centric diatom Thalassiosira fluviatilis Hustedt has been recorded from a marine environment, presumably for the first time. The valve structure of the diatom has been studied in the light and the electron microscopes. The details of the structure vary with the size of the valve and with the degree of silicification. HIDAKA K., 1961. Equatorial upwelling and sinking in a zonal ocean with lateral mixing. Geophys. Notes, Tokyo Univ., 14 (2) (22): reprint originally published in: Geophys. ,1., Astr. Soc. 4: 359-371. The two-dimensional dynamical equations were solved and an expression for the vertical motion was derived by assuming a balance between the pressure gradient, Coriolis and frictional forces. The frictional forces consist of terms of both vertical and lateral mixing. Isovels of the upwelling and sinking in a meridional section were obtained, assuming the magnitude of the coefficients of the horizontal and vertical viscosities to be 10 s and 10z c.g.s, respectively. The resulting vertical motion of water seems to be more intense than expected. But the result is quite flexible and reasonable values of vertical motion may be obtained by a proper choice of both the horizontal and vertical viscosity coefficients. HIRST D. M., 1962. The geochemistry of modern sediments from the Gulf of Paria. 1. The relationship between the mineralogy and the distribution of major elements..Geochim, et Cosmochim. Acta, 26: 309-334. The distribution of the major elements in some recent sediments from the Gulf of Paria has been determined. In interpreting the variation in the major element contents across the basin of deposition, consideration is given to such factors as rate of deposition, physico-chemical environment, salinity and facies. The majority of the major elements are already present within the lattices of various clay minerals when they enter the basin of deposition, and the variations in their contents in the different sediments reflect variation in the clay mineralogy is thought to be due to variation in weathering conditions in the source area of the sediments. HOLMBOE J., 1962. On the behavior of symmetric waves in stratified shear layers. Geofys. Publik., Geophysica Norvegica, 24: 67-114. The physical mechanism of hydrodynamical instability is examined in cases where an upper warm layer of air is moving relative to a lower cold layer. The two layers are separated by a shear layer where the wind has a continuous variation with height. Three models with different distribution of temperature in the shear layer are considered, namely: (i) The entire temperature change is located at the centre of the shear layer, in Chapter I. (ii) The shear layer has a constant potential temperature equai to the arithmetic mean of the outer temperatures, in Chapter II. (iii) The wind shear and temperature stratification have continuous (hyperbolic tangent) variations in the shear layer, in Chapter HI. The results represent generalisations of earlier results by HELMFIOLITZ,RAYLEIGH,TAYLORand GOLDSTEIN: The model ( i ) h a s overstability, i.e. oscillations with growing amplitudes, in a spectral band which shifts toward shorter waves with increasing static stability. The kinematic structure and overstable growth mechanism of these waves are discussed in Section 9. This system has no neutral waves
396
Oceanographic Abstracts
which are stationary with reference to the air at the central temperature interface. The transition waves from stability to overstability perform stable oscillations with no growth rate. The model (ii) has instability, i.e. stationary wave-tilt with exponential growth, in a spectral band which shifts toward shorter waves with increasing static stability. The transition waves from stability to instability are non-tilting neutral waves which are stationary relative to the air at the centre of the shear layer. These transition waves have a very simple structure (Section 12) which gives the key to the interpretation of the growth mechanism of the unstable waves (Section 16). The model (iii) has stationary neutral waves which are similar in kinematic structure to the transition waves in the discontinuous model (ii). However the waves are significantly different near the centre of the shear layer and their behaviour is accounted for by this difference. It is possible to construct quasi-stationary waves in model (iii) which are quite similar in all respects to the transition waves in model (ii). Professor VlLHELMBJERKNES'famous circulation theorem in 1898 opened the door to the physical hydrodynamics of large scale baroctinic motions in the atmosphere. The (ollowing art icle is an attempt to extend some of B.IERKNES'ideas in a limited area of this field of science. It is the author's hope that it may reflect a little of the inspiration that he received in his youth under the influence and guidance of his great teacher and benefactor. ITO T. and T. IWAI, 1960. Studies on the ' Mizukawari' in eel-culture ponds. 19. The effect of the sea water supply upon the plankton in mixohaline eel-culture pond. Rept. Fac. Fish. Prefi Univ. Mie, 3 (3): 649-655. It is sometimes necessary to supply a large quantity of sea water into the eel-culture pond tO control Lernaea, the parasite of the cultured eels there. This study, aiming to make clear the influence of the sea water supply on the plankton, the water quality and on the feeding activity of the cultured eels and to find what the relation is between the sea-water supply and ' Mizukawari ', has been carried out in a mixohaline eel-culture pond area 46 a, depth l m in Tsu City, Mie Prefecture, Middle Japan. Through the sea water supply in the period September 13-17, the salinity of the pond water showed the sudden increase from Cl 2'3~o to 5"3%°. Further, by the supply of groundwater it decreased to Cl 3 ~ . The supply of sea water has caused the perishments of freshwater phytoplankters, Chroococcus minutus, Merismopedia tenuissima, Microcystis aeruginosa, and Scenedesmus quadricauda. But no influence was observed at all on Chroococcus dispersus, Ch. limneticus, Dactylococcopsis rhaphidioides, Nitzschia closterium and Cyclotella glomerata. After the supply of sea water, Chaetoceros Muelleri and Euglena sp. were found considerably increased. On the other side, Microcystis aeruginosa, once seemed to have p:rished, reappeared to be observed when the salinity lessened to Cl 3%0 (Fig. 1). No effects of the sea water supply were observed on such mixohaline zoo-plankters as Pseudodiaptomus inopinus, Brachionus plicatilis and Hexarthra fennica, but some freshwater zooplankters as Moina dubia and Br. calyciflorus f. amphiceros were found perished. The latter two species, however, reappeared when the salinity was down to C1 3 ~ , as Microcystis aeruginosa did. The two species, Br. quadridentatus vat. clunioribicularis and Br. angularis, showed considerable increase in spite of the sea water supply (Fig. 2). The water colour of the pond, after the supply of sea water, has changed in the order from green, brown, dark drown in bluish green; this change of water colour is caused by that of plankton flora there. At that time, the transparency rose from 20 cm to 47 cm, pH lowered from 9'0 to 7'3, and dissolved oxygen decreased from 6"9 cc/l. to 2-4 cc/l., NH4 N and NOz-N have also remarkably increased after the sea water supply (Fig. 3). The feeding activity of the cultured eels much more weakened, but such an extraordinary phenomenon as surfacing was not observed at all. Consequently, it can be said here that through the sudden supply of sea water, part of freshwater algae perished, the dissolved oxygen decreases, a kind of ' Mizukawari' phenomenon is observed; but even in that case no damage is observed on the cultured eels. ITO T., T. IWAIand Y. AKAMINE,1960. Studies on t h e ' Mizukawari ' in eel-culture ponds. 20. The effect of winter drainage upon the plankton and formation of the plankton community after the water-renewed in eel-culture ponds (English resume). Rep. Fac. Fish, Prefi Univ. Mie, 3 (3): 656-679. All eel-culture ponds are dried up in the winter and the eels are gathered. Sometimes the bottom mud is cleaned out and the pond filled with ground water, surface water or the old water from other ponds. This is called' Ikega6 '. The questions posed as a consequence of the changes are : how will the plankton form and when will the first ' Mizukawari' come. To resolve these, research was undertaken in six eel-culture ponds in Tsu City, Mie Prefecture, during the period December 1956June, 1957. With such various conditions for the water-renewal as mentioned, the following conclusions can be deduced. The dominant species of phytoplankton in the winter time are the micron algae Synechococcus sp., Chroococcus dispersus, Selenastrum gracile and Chaetoceros Muelleri; and those of the zooplankton are represented by the copepods as Sinocalanus tenellus, Pseudodiaptomus inopinus and Paracyclopina nana; and by the ciliates as Didinium sp., Paramecium sp. and Strobilidium sp. After the water-renewal, in phytoplankton, the dominant species show a remarkable increase within a week, and in zooplankton, no conspicuous difference was found with the water-renewal.
395
in cracks by ground water. Thus, the origin of differential corrosion in these structures is not always the same, and slight disparities in petrological constitution can sometimes result in large differences in morphological behaviour. The differences in morphological evolution between parts of the same platform standing at different heights come perhaps from contrasts in corrosion by crystallizing salt. Since observations in temperate and cold areas are not yet numerous, other investigations would be necessary to determine the influence of temperature on coastal corrosion forms in volcanic rocks. The Subantarctic Islands, Jan Mayen, and Aleutian Islands, might be interesting research fields in this respect. GUILLARD R. R. L. and J. H. RYTHER,1962. Studies of marine planktonic diatoms. I. Cyclotel/a nana Hustedt, and Detonula confervacea (Cleve) Gran. Canad. J. Microbiol., 8 (2): 229-240. Bacteria-free clones of the Small centric diatom Cyclotella nana Hustedt were isolated, three from estuarine localities, one from Continental Shelf waters, and one from the Sargasso Sea. Detonula confervacea was isolated from Narrangansett Bay. Morphology of all crones was studied with the light and electron microscopes. Morphological differences between clones of C. nana do not at present warrant separating any as distinct species. Clones of C. nana require only vitamin Blz; D. confervacea has no vitamin requirement. Growth of the estuarine clones of C. nana was unaffected by salinity down to 0"5~ and increased with temperature to 25°C. The Shelf clone grew more rapidly at salinities above 8 ~ and at temperatures between 10~ and 20~C. The Sargasso Sea clone did not survive below 15°C or 17.5~, while D. confer~acea did not survive at temperatures above 15° or at salinities below 8 ~ . The physiological differences between clones correspond roughly to the conditions obtaining in nature where each was collected. HASLE G. R., 1961 (1962). The morphology of Thalassiosira fluviatilis from the polluted inner Oslofjord. Nytt Mag. Botanikk, 9: 151-154. The centric diatom Thalassiosira fluviatilis Hustedt has been recorded from a marine environment, presumably for the first time. The valve structure of the diatom has been studied in the light and the electron microscopes. The details of the structure vary with the size of the valve and with the degree of silicification. HIDAKA K., 1961. Equatorial upwelling and sinking in a zonal ocean with lateral mixing. Geophys. Notes, Tokyo Univ., 14 (2) (22): reprint originally published in: Geophys. ,1., Astr. Soc. 4: 359-371. The two-dimensional dynamical equations were solved and an expression for the vertical motion was derived by assuming a balance between the pressure gradient, Coriolis and frictional forces. The frictional forces consist of terms of both vertical and lateral mixing. Isovels of the upwelling and sinking in a meridional section were obtained, assuming the magnitude of the coefficients of the horizontal and vertical viscosities to be 10 s and 10z c.g.s, respectively. The resulting vertical motion of water seems to be more intense than expected. But the result is quite flexible and reasonable values of vertical motion may be obtained by a proper choice of both the horizontal and vertical viscosity coefficients. HIRST D. M., 1962. The geochemistry of modern sediments from the Gulf of Paria. 1. The relationship between the mineralogy and the distribution of major elements..Geochim, et Cosmochim. Acta, 26: 309-334. The distribution of the major elements in some recent sediments from the Gulf of Paria has been determined. In interpreting the variation in the major element contents across the basin of deposition, consideration is given to such factors as rate of deposition, physico-chemical environment, salinity and facies. The majority of the major elements are already present within the lattices of various clay minerals when they enter the basin of deposition, and the variations in their contents in the different sediments reflect variation in the clay mineralogy is thought to be due to variation in weathering conditions in the source area of the sediments. HOLMBOE J., 1962. On the behavior of symmetric waves in stratified shear layers. Geofys. Publik., Geophysica Norvegica, 24: 67-114. The physical mechanism of hydrodynamical instability is examined in cases where an upper warm layer of air is moving relative to a lower cold layer. The two layers are separated by a shear layer where the wind has a continuous variation with height. Three models with different distribution of temperature in the shear layer are considered, namely: (i) The entire temperature change is located at the centre of the shear layer, in Chapter I. (ii) The shear layer has a constant potential temperature equai to the arithmetic mean of the outer temperatures, in Chapter II. (iii) The wind shear and temperature stratification have continuous (hyperbolic tangent) variations in the shear layer, in Chapter HI. The results represent generalisations of earlier results by HELMFIOLITZ,RAYLEIGH,TAYLORand GOLDSTEIN: The model ( i ) h a s overstability, i.e. oscillations with growing amplitudes, in a spectral band which shifts toward shorter waves with increasing static stability. The kinematic structure and overstable growth mechanism of these waves are discussed in Section 9. This system has no neutral waves
396
Oceanographic Abstracts
which are stationary with reference to the air at the central temperature interface. The transition waves from stability to overstability perform stable oscillations with no growth rate. The model (ii) has instability, i.e. stationary wave-tilt with exponential growth, in a spectral band which shifts toward shorter waves with increasing static stability. The transition waves from stability to instability are non-tilting neutral waves which are stationary relative to the air at the centre of the shear layer. These transition waves have a very simple structure (Section 12) which gives the key to the interpretation of the growth mechanism of the unstable waves (Section 16). The model (iii) has stationary neutral waves which are similar in kinematic structure to the transition waves in the discontinuous model (ii). However the waves are significantly different near the centre of the shear layer and their behaviour is accounted for by this difference. It is possible to construct quasi-stationary waves in model (iii) which are quite similar in all respects to the transition waves in model (ii). Professor VlLHELMBJERKNES'famous circulation theorem in 1898 opened the door to the physical hydrodynamics of large scale baroctinic motions in the atmosphere. The (ollowing art icle is an attempt to extend some of B.IERKNES'ideas in a limited area of this field of science. It is the author's hope that it may reflect a little of the inspiration that he received in his youth under the influence and guidance of his great teacher and benefactor. ITO T. and T. IWAI, 1960. Studies on the ' Mizukawari' in eel-culture ponds. 19. The effect of the sea water supply upon the plankton in mixohaline eel-culture pond. Rept. Fac. Fish. Prefi Univ. Mie, 3 (3): 649-655. It is sometimes necessary to supply a large quantity of sea water into the eel-culture pond tO control Lernaea, the parasite of the cultured eels there. This study, aiming to make clear the influence of the sea water supply on the plankton, the water quality and on the feeding activity of the cultured eels and to find what the relation is between the sea-water supply and ' Mizukawari ', has been carried out in a mixohaline eel-culture pond area 46 a, depth l m in Tsu City, Mie Prefecture, Middle Japan. Through the sea water supply in the period September 13-17, the salinity of the pond water showed the sudden increase from Cl 2'3~o to 5"3%°. Further, by the supply of groundwater it decreased to Cl 3 ~ . The supply of sea water has caused the perishments of freshwater phytoplankters, Chroococcus minutus, Merismopedia tenuissima, Microcystis aeruginosa, and Scenedesmus quadricauda. But no influence was observed at all on Chroococcus dispersus, Ch. limneticus, Dactylococcopsis rhaphidioides, Nitzschia closterium and Cyclotella glomerata. After the supply of sea water, Chaetoceros Muelleri and Euglena sp. were found considerably increased. On the other side, Microcystis aeruginosa, once seemed to have p:rished, reappeared to be observed when the salinity lessened to Cl 3%0 (Fig. 1). No effects of the sea water supply were observed on such mixohaline zoo-plankters as Pseudodiaptomus inopinus, Brachionus plicatilis and Hexarthra fennica, but some freshwater zooplankters as Moina dubia and Br. calyciflorus f. amphiceros were found perished. The latter two species, however, reappeared when the salinity was down to C1 3 ~ , as Microcystis aeruginosa did. The two species, Br. quadridentatus vat. clunioribicularis and Br. angularis, showed considerable increase in spite of the sea water supply (Fig. 2). The water colour of the pond, after the supply of sea water, has changed in the order from green, brown, dark drown in bluish green; this change of water colour is caused by that of plankton flora there. At that time, the transparency rose from 20 cm to 47 cm, pH lowered from 9'0 to 7'3, and dissolved oxygen decreased from 6"9 cc/l. to 2-4 cc/l., NH4 N and NOz-N have also remarkably increased after the sea water supply (Fig. 3). The feeding activity of the cultured eels much more weakened, but such an extraordinary phenomenon as surfacing was not observed at all. Consequently, it can be said here that through the sudden supply of sea water, part of freshwater algae perished, the dissolved oxygen decreases, a kind of ' Mizukawari' phenomenon is observed; but even in that case no damage is observed on the cultured eels. ITO T., T. IWAIand Y. AKAMINE,1960. Studies on t h e ' Mizukawari ' in eel-culture ponds. 20. The effect of winter drainage upon the plankton and formation of the plankton community after the water-renewed in eel-culture ponds (English resume). Rep. Fac. Fish, Prefi Univ. Mie, 3 (3): 656-679. All eel-culture ponds are dried up in the winter and the eels are gathered. Sometimes the bottom mud is cleaned out and the pond filled with ground water, surface water or the old water from other ponds. This is called' Ikega6 '. The questions posed as a consequence of the changes are : how will the plankton form and when will the first ' Mizukawari' come. To resolve these, research was undertaken in six eel-culture ponds in Tsu City, Mie Prefecture, during the period December 1956June, 1957. With such various conditions for the water-renewal as mentioned, the following conclusions can be deduced. The dominant species of phytoplankton in the winter time are the micron algae Synechococcus sp., Chroococcus dispersus, Selenastrum gracile and Chaetoceros Muelleri; and those of the zooplankton are represented by the copepods as Sinocalanus tenellus, Pseudodiaptomus inopinus and Paracyclopina nana; and by the ciliates as Didinium sp., Paramecium sp. and Strobilidium sp. After the water-renewal, in phytoplankton, the dominant species show a remarkable increase within a week, and in zooplankton, no conspicuous difference was found with the water-renewal.