Chlorophyll a Biomass of Netplankton in Surface Waters of the Northern North Pacific Ocean and the Adjacent Seas from Summer to Autumn

Chlorophyll a concentrations of net (retained on 30 m mesh net) and total plankton in surface waters were determined along cruise tracks in an area of the northern North Pacific Ocean and the adjacent Bering Sea and the Gulf of Alaska from summer to autumn. Total chlorophyll a concentrations were high with a great areal and temporal variations in the western northern North Pacific compared to the eastern part. Chlorophyll a concentrations of netplankton varied from 0.001 to 0.230 g chl a l^–1 (average, 0.029 ± 0.040 g chl a l^–1), and showed a positive relation but a weak regression coefficient (r ² = 0.551) against the "average total chlorophyll a" (average of total chlorophyll a at the beginning and at the end during sampling of netplankton). However there were several data points showing high "average total chlorophyll a" but low netplankton and vice versa. Average percentage share of netplankton in the total chlorophyll a was estimated to be as large as 4.26%.     

High Ash Content in Net-Plankton Samples from Shallow Coastal Water: Possible Source of Error in Dry Weight Measurement of Zooplankton Biomass

Annual examination of net-plankton biomass in dry weight, ash-free dry weight, organic carbon, and nitrogen weight at the Manazuru harbor, central Japan revealed that net-plankton samples from shallow coastal water contained considerable amount of ash (53±13% of dry weight) which would be caused by contamination of inorganic materials from re-suspendion of sediments, terrestrial runoff and chain-forming diatoms. Therefore, in coastal water, dry weight is inadequate fro determination of zooplankton biomass in volving the possibility of over-estimation. Practical estimation of net-plankton biomass in shallow coastal waters, ash-free dry weight, organic carbon, and/or nitrogen are more adequate.     

Photosynthetic pigment system of picophytoplankton of cyanophytes isolated from subsurface water in the Kuroshio area

Photosynthetic pigment system of picophytoplankton of cyanophytes was examined with five strains isolated from the Kuroshio water at the depth of 70 m. Examination was made for the absorption spectra of intact cells of each strain. Analysis of pigment composition was also made withSynechococcus NIBB 1059 and 1071, which were isolated from surface waters of the Gulf Stream and Kuroshio area, respectively. Results indicated that (1) all strains contain phycoerythrin with a very high concentration, and (2) the phycoerythrin in these strains contains two chromophores, phycoerythrobilin and phycourobilin, and (3) a large abundance of phycoerythrin and phycourobilin in the phycoerythrin enablesSynechococcus picophytoplankton to absorb effectively the light in the blue-green region at the subsurface depth. These characteristics suggest that cyanophytes in the subsurface water can collectt the blue-green light and perform actively photosynthesis even at the bottom of euphotic layer.     

Distribution of the subsurface chlorophyll maximum and its nutrient-light environment in and around the Euroshio off Japan

Continuous distribution of the subsurface chlorophyll maximum (SCM) was confirmed in the Kuroshio and neighbouring areas in observations at 15 to 40 km intervals. Chlorophyll amounts occurring in and immediately around the SCM constituted 60 to 80% of the total chlorophyll in the water column above the 1% light level. The SCM zone received 1 to 10% of the surface irradiance at its center and contained sufficient macronutrients to support approximately one doubling of the existing phytoplankton biomass at most stations. There were several stations where there were higher nutrient concentrations that would support more than one doubling of the existing biomass around the SCM zone, and this was interpreted as resulting from uplift of the SCM zone due to upwelling.     

Wind Fields over Funka Bay and Their Effect on Water Circulation in the Bay

Horizontal wind fields over Funka Bay during cold air outbreaks were simulated using a 3-D meso-scale atmospheric model. The simulated wind fields over the bay have a positive curl in the north and a negative curl in the south. These wind fields were used to simulate the current in Funka Bay using a barotropic ocean model. The simulated current pattern was composed of two vortices—one with anti-clockwise vorticity in the north and the other with clockwise vorticity in the south—and was in the opposite direction to that simulated by the uniform wind fields. This is because the wind stress curl effect on the vorticity production in Funka Bay opposes and overwhelms the bathymetry torque effect during cold air outbreaks. These results show that the non-uniformity of the wind fields caused by the land topography around a shallow lake or bay cannot be neglected in simulating its currents.     

A pump-sampler as a method of collecting plankton and its preliminary operation

A pump-sampler was designed to study the distribution of marine plankton and its possible relationship with the temperature and salinity of the water. Sea water was pumped up through a 2 inch diameter hose and plankton contained in it was collected on a filter cup (2 inches in diameter, 139 meshes/inch) without being damaged. The filter cup, when clogged by plankton organisms, was washed by spraying with about 100 cu. cm of water. The differences between two continuous with an interval of more than 3–4 seconds could be detected.A preliminary operation along a 2.82 km course in Maizuru Bay was carried out simultaneously with temperature-salinity measurements at sampling intervals of 30 m. Temperature was measured by a thermistor resistance thermometer, and salinity was measured by a salinometer with a subsample of water which was collected from an additional opening of the pump-sampler. The temperature-salinity record showed that four zones of water were characterized.It was found that wide variation of plankton counts indicated dense concentrations of particular species or group of species, and on the mesoscale it was possible to examine the size of the aggregation.     

Noble gases in oxidized residue prepared from the Saratov L4 chondrite and Raman spectroscopic study of residues to characterize phase Q

We analyzed noble gases in an oxidized residue prepared from a HF‐HCl residue of the Saratov L4 chondrite. The Ar, Kr, and Xe concentrations in the oxidized residue are two orders of magnitude lower than those in the HF‐HCl residue, and they are close to concentrations in the bulk. The He and Ne concentrations are similar in the three samples. The Ne isotopic ratios are almost purely cosmogenic, indicating absence of presolar diamonds (the carrier of the HL component). Thus, Saratov contains phase Q without presolar diamond. A study of the Raman spectroscopic parameters for the HF‐HCl residue and the oxidized residue shows large changes due to oxidation. The directions of these changes are the same as observed in Allende, except oxidation increased the I_D/I_G (intensity ratio of the D band to the G band) in Saratov but decreased in Allende. This difference may be attributed to the different crystalline stages of carbon in both meteorites. The shifts in the Raman parameters to a discrete and/or more expanded region suggest that (1) oxidation changes the crystalline condition of graphitic carbon, (2) phase Q is not a dissolved site, and (3) the release of Q‐gas is simply related to the rearrangement of the carbon structure during oxidation.     

南极中山站午后极光强度与太阳风参数的关系

本文利用1997年和1998年南极中山站多通道扫描光度计的地面观测数据和WIND卫星在弓激波上游对太阳风参数的观测数据，对午后高纬极光强度与太阳风等离子体密度、动压以及太阳风速度之间的相关性进行了定量研究。研究表明，午后极光630．0nm的强度与太阳风等离子体参数之间有较好的相关，630．0nm的强度表现出随太阳风等离子体密度、动压和速度的增大而增加的趋势，其相关系数分别为0．84、0．88和0．61；而557．7nm极光的强度与太阳风等离子体参数之间的相关较差。午后557．7nm极光的强度与太阳风等离子体参数之间的相关较差。午后557．7nm和630．0nm对太阳风参数的不同响应表明太阳风对630．0nm影响更直接，而557．7nm受到了磁层动力学过程的影响。     

Study of metal contents of elasmobranch fishes: part 1—metal concentration in the muscle tissues of a dogfish, squalus mitsukurii

Concentrations of Hg, Zn, Fe, Cd and Cu in the muscle tissues of a dogfish, Squalus mitsukurii, were determined by atomic absorption spectrometry and found to be in the ranges of f0·019–2·13, 1·8–3·6, 1·5–5·7, 0·001–0·018 and 0·12–0·70 μg/g wet weight, respectively. The frequency distributions of concentrations, with the exception of mercury, were found to be log-normal. The correlation coefficient between mercury content and total length was positive and large and statistically highly significant. For other metals negative correlations were observed. Mercury concentration in the muscle was found to increase in proportion to the total length cubed. Regression of mercury concentration on age of sharks was shown to be linear. Analysis of covariance showed that the difference between sexes was not statistically significant, either in slope or in height. The concentration of mercury in the muscle tissues of embryos was considerably lower, Cd roughly the same and Zn and Fe higher than those of mothers. The concentrations of Zn, Fe and Cu are higher in the embryonic stage and immediately after birth than in later stages of growth.