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91.
92.
Chemical and X-ray analyses were performed on the fifteen manganese nodules collected from the Pacific Ocean floor. The results
were discussed compared with the previous data on the manganese nodules. Minerals were found to be todorokite, δ-MnO2 and other silicates, montmorillonite, illite, phillipsite and α-SiO2. Average composition shows that copper is concentrated on the deep sea nodules more than the shallow ones, and that the todorokite
rich nodules contain more copper and nickel than the δ-MnO2 rich ones. The analyses of fresh water iron-manganese precipitates by bacterial activity suggest that biological process
is one of the important factors on the genesis of the sedimentary iron-manganese deposits, including the manganese nodule.
The Institute of Physical and Chemical Research 相似文献
93.
Using ichthyoplankton samples collected in the Kuroshio Subgyre during early summer cruises, we examined spatial distributions
of scyllarid phyllosoma larvae in the Subgyre, particularly of the genus Scyllarus. The present study has two objectives: (1) to reveal species composition of Scyllarus phyllosoma larvae in the Kuroshio Subgyre, and (2) to examine larval recruitment of Scyllarus species as contrasted with that of Panulirus, particularly P. japonicus, the larval recruitment of which has been examined in detail. A total of 218 phyllosoma larvae collected in the present study
belonged to two families (Palinuridae and Scyllaridae) representing 5 genera and 11 species. Phyllosoma larvae of two Scyllarus species (S. cultrifer and Scyllarus sp. c) were abundant among the collected larvae, and were found mainly in the following three regions located within the
Kuroshio-Counter Current region south of Kuroshio Current: the water east of Okinawa Is., the water far east of Okinawa Is.
(or far south of Shikoku Is.), and the water around Hachijojima Is. Larvae of each of the above two Scyllarus species collected in the three regions may belong to different populations: larvae collected in the water around Hachijojima
Is. may come from their benthic populations along the Pacific coast of Honshu and Shikoku Is., central Japan, while larvae
collected in the other two regions may come from their benthic populations of the Ryukyu Archipelago and Taiwan. Judging from
their shorter larval period and current systems within the Kuroshio Subgyre, these Scyllarus larvae may be destined for death.
An erratum to this article is available at . 相似文献
94.
Chattonella antiqua (Raphidophyceae), which causes heavy red tides in the Seto Inland Sea, Japan, was placed in axenic clonal culture by micropipette washing. The effects of temperature, salinity, light intensity and pH on growth were monitored. Maximum growth occurred at 25°C, at salinities between 25 and 41‰, under light intensities above 0.04 ly min?1. The pH effect was not significant in the pH range from 7.6 to 8.3. Comparisons of our results with those from field observations suggest that the development of theC. antiqua red tide is strongly temperature dependent. 相似文献
95.
Abstract. On the subtidal rocky shore of Akkeshi Bay, Hokkaido, Japan, the congeneric phytal gastropods, Lacuna uchidai and L. decorata , inhabit the multispecific vegetation consisting of the surfgrass, Phyllospadix iwatensis and the brown alga, Cystoseira hakodatensis . We studied the phenologies of Phyllospadix and Cystoseira , host utilization patterns and life histories of Lacuna spp. to examine how these gastropods accommodate the seasonal fluctuations of the habitat. The preferences for macrophyte by Lacuna spp. were examined by laboratory experiments. The phenologies of macrophytes, the seasonal and between-substrata variations of Lacuna spp. were examined by monthly sampling from Phyllospadix and Cystoseira beds between May 1999 and May 2000. Lacuna uchidai showed significant preference for Phyllospadix , whereas L. decorata had no preference for a particular substratum. Most L. uchidai were collected from the Phyllospadix bed, however L. decorata appeared in both Phyllospadix and Cystoseira beds. The peak of new recruit of L. uchidai coincided with that of Phyllospadix biomass. The synchronization of life cycle with the phenology of the host may be adaptive for using the limited habitat. Seasonal variation in density of L. decorata coincided with neither patterns for Phyllospadix nor Cystoseira . Seasonal variation in density and size frequency distribution suggested L. decorata migrated among adjacent macrophytes. Although it was a little vague, this hypothesis was probably the best explanation of our results. Our study shows that two co-occurring Lacuna species utilize the macrophytes as habitats by the different life histories and utilization patterns and, may be alternatively accommodated to the seasonal fluctuations of their habitats. 相似文献
96.
Hodaka Kawahata Mayuri Inoue Masato Nohara Atsushi Suzuki 《Journal of Oceanography》2006,62(4):405-412
The δ18O, δ13C and trace element composition of pearls collected from Ago Bay, Japan, were investigated in order to evaluate biomineralization
in the cultured pearl oyster (Pinctada fucata martensii). The oxygen isotopic data suggest that the pearls were produced around 23–24°C, mainly in June to early July, which is consistent
with their occurrence in the field. Therefore the pearls were produced under or close to isotopic equilibrium conditions,
although they showed high calcification rates (higher than 0.2–1.0 g cm− 2yr−1) under which, for example, coral skeletons (calcification rate ∼0.28 g cm− 2yr−1) often show non-equilibrium isotope partitioning. The δ13C values were ∼− 2.9‰ lower than those calculated for offshore waters under equilibrium conditions. This may be due to low-δ13C bottom waters resulting from the degradation of organic matter (OM) or to a contribution of low-δ 13C food. In the latter case, a simple mass balance calculation gives a respiration component of 14%. Twelve trace elements
of bulk pearl samples were classified into four groups on the basis of their enrichment/depletion patterns relative to seawater
and inter-element relationships: group 1, Co, Cr, Pb; group 2, Ba, Cs, U; group 3, Cu, Sn, V, and group 4, Mn, Rb, Mo. Comparison
with coral skeletons suggests that Ba and Mn (groups 2 and 4) were definitely much enriched in proteinaceous OM relative to
aragonite crystals in pearls and that V (group 3) in pearls showed only slight enrichment in the organicrich layer. By contrast,
the other elements showed small differences between both layers (enrichment factor of <3), suggesting that these elements
occur largely in aragonite crystals. 相似文献
97.
Some behavior ofSergestes lucens by day was observed by underwater camera with an electronic flash. A number of species was snapped at about 2–60 m above the steep continental slope where the bottom ranged between 341 and 437 m depths. They were often abundant from 3–4 to 10 m above the bottom. It suggests that the shrimps scatter widely along the continental slope by day. The maximum concentration of the shrimp was 1.2 individuals/m3. None of the shrimps was found on the bottom, and the majority were swimming in horizontal position. 相似文献
98.
A numerical experiment on the sedimentation processes in the Yellow Sea and the East China Sea 总被引:6,自引:0,他引:6
Sedimentation processes of suspended matter supplied from the Huanghe (Yellow River) and the Changjiang are investigated with the use of a three-dimensional numerical model of the Yellow Sea and the East China Sea which includes the tidal current, residual flow and wind waves. Suspended matter supplied from the Huanghe mainly deposits in the Bohai Sea and that from the old river mouth of the Huanghe and from the Changjiang in the central part of the Yellow Sea or south of Cheju Island. The calculated results well reproduce the observed sedimentation pattern qualitatively except for the offshore area of the southeastern coast of China. 相似文献
99.
Diatoms represent the major part of the microfossils preserved in the subarctic Pacific sediments. During the warm climate
intervals the diatom accumulation rate (DAR) tended to increase, whereas it tended to decrease during the cold intervals.
Principal component (PC) analysis of the fossil diatom assemblages in Piston Core KH99-3 ES samples from the subarctic Pacific
was carried out to investigate the paleoceanographic conditions of the area. PC1 (59.9% of the total variance) was represented
by Neodenticula seminae, a characteristic species representing the high nutrient concentrations, which dominated during the interglacial periods.
The DAR and PC changes can be attributed to a global origin that is influenced by the nutrient change due to intermediate
water change and to a local one that is explained by the change of upwelling region. The analysis of PC2 (17.1% of the total
variance) indicates the change of water mass in the western subarctic Pacific. During Marine Isotope Stages (MIS) 2 and 3,
the western subarctic Pacific region was significantly influenced by the sea-ice, which may have been derived from the coastal
region or a proximal marginal sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
100.
Spatial Variability of Living Coccolithophore Distribution in the Western Subarctic Pacific and Western Bering Sea 总被引:1,自引:0,他引:1
Hiroshi Hattori Makoto Koike Kenichi Tachikawa Hiroaki Saito Kazuya Nagasawa 《Journal of Oceanography》2004,60(2):505-515
Vertical distributions of coccolithophores were observed in the depth range 0–50 m in the western subarctic Pacific and western
Bering Sea in summer, 1997. Thirty-five species of coccolithophores were collected. Overall, Emiliania huxleyi var. huxleyi was the most abundant taxon, accounting for 82.8% of all coccolithophores, although it was less abundant in the western Bering
Sea. Maximum abundance of this species was found in an area south of 41°N and east of 175°E (Transition Zone) reaching >10,000
cells L−1 in the water column. In addition to this species, Coccolithus pelagicus f. pelagicus, which accounted for 4.2% of the assemblage, was representative of the coccolithophore standing crop in the western part
of the subarctic Pacific. Coccolithus pelagicus f. hyalinus was relatively abundant in the Bering Sea, accounting for 2.6% of the assemblage. Coccolithophore standing crops in the top
50 m were high south of 41°N (>241 × 106 cells m−2) and east of 170°E (542 × 106 cells m−2) where temperatures were higher than 12°C and salinities were greater than 34.2. The lowest standing crop was observed in
the Bering Sea and Oyashio areas where temperatures were lower than 6–10°C and salinities were less than 33.0. From the coccolithophore
volumes, the calcite stocks in the Transition, Subarctic, and the Bering Sea regions were estimated to be 73.0, 9.7, and 6.9
mg m−2, respectively, corresponding to calcite fluxes of 3.6, 0.5, and 0.3 mg m−2d−1 using Stoke's Law.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献