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1.
以双功能褐藻胶裂解酶 (Pseudoalteromonas sp.strain No. 2 72 )分别降解均聚古罗糖醛酸(PG)和均聚甘露糖醛酸 (PM) ,经 Bio- Gel- P6和 POROS- HQ2 0分离得到 2种三糖纯品 ,经 ESI- MS,1 H- NMR,1 3 C- NMR,1 H- 1 H COSY,1 H- 1 3 C HMQC确定其结构为 Δ4,5-古罗糖醛酸 - α(1→ 4 ) - L-古罗糖醛酸 -α(1→ 4 ) - L -古罗糖醛酸 (简写为Δ GG)和Δ4,5-甘露糖醛酸 -β (1→ 4 ) - D-甘露糖醛酸 -β (1→ 4 ) - D-甘露糖醛酸 (ΔMM) ,为进一步从事构效关系研究提供结构信息。 相似文献
2.
Ken Ikehara 《Journal of Oceanography》2003,59(5):585-593
The Late Quaternary sea-ice history of the northeastern Japan Sea is discussed on the basis of the occurrence of dropstones
and ice-rafted debris (IRD) in fine sediment cores. IRD was found in all strata except those from the Holocene and oxygen
isotope stage 5.5. The largest expansion of sea ice was recognized at the last glacial maximum (LGM; oxygen isotope stage
2), when the southern margin of seasonal sea ice was probably located in the vicinity of the Matsumae Plateau. The margin
might occasionally have expanded further southward to off the Oga Peninsula. Sea ice expanded southward from mid-stage 5 to
the LGM in response to global cooling, but with much fluctuation. Sea ice remained during deglaciation until around 10 ka,
but after 10 ka it retreated northward rapidly in response to global warming and changes in surface water conditions. Greater
fluctuations in IRD were found in core GH95-1208 collected from off Rumoi, Hokkaido, Japan. More IRD was found in sediments
from late stage 3, late stage 5, and early stage 6. The fluctuations were not concordant with global climate changes (based
on the standard oxygen isotope curve), and may have been controlled by regional climate factors such as the strength of the
winter monsoon, which is related in turn to high-latitude atmospheric circulation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Tatsuya?IwataEmail author Yoshiko?Shinomura Yuta?Natori Yasumasa?Igarashi Rumi?Sohrin Yoshimi?Suzuki 《Journal of Oceanography》2005,61(4):721-732
We investigated the water structure and nutrient distribution in the Suruga Bay from April 2000 to July 2002, especially the Offshore Water, which occupies a large part of the bay. The maximum salinity in the upper 200 m varied between 34.49 and 34.71, indicating a temporal change in the influence of Kuroshio Water on the Offshore Water. Seasonal variation in nutrient concentrations was largest from surface to 50 m. On the other hand, the variance in nutrient concentrations within each season was largest in the subsurface layer of 100–300 m in spring, summer and fall. In the Offshore Water, the change of nutrients was negatively correlated with that of salinity in each season. This suggests that an increasing intrusion of saline water brings about a lower nutrient concentration in the Offshore Water. Likewise, negative correlations were observed between the change of the maximum salinity and chlorophyll a (Δ [chl.a-int])/nutrients integrated in the upper 200 m. Δ[chl.a-int] was significantly correlated with the changes of nitrate and phosphorus, but there were no significant correlations between Δ[chl.a-int] and the change of silicate. These results suggest that the concentrations of chlorophyll a and nutrients in the Offshore Water were decreased due to the increasing intrusion of Kuroshio Water. The Offshore Water is likely to be related to the regulation of primary production by nitrate. 相似文献
4.
Yusuke Okazaki Osamu Seki Takeshi Nakatsuka Tatsuhiko Sakamoto Minoru Ikehara Kozo Takahashi 《Journal of Oceanography》2006,62(5):639-648
Cycladophora davisiana, a radiolarian species dwelling at mesopelagic depths, is known as a representative glacial fauna due to its unique distribution
during glacial periods. In the present ocean, abundant production of C. davisiana is only observed in the Okhotsk Sea, indicating an adaptation of C. davisiana for seasonal sea-ice covered conditions. We found pronounced abundant production of C. davisiana during the early to middle Holocene in the Okhotsk Sea, suggesting more favorable conditions for C. davisiana than the present Okhotsk Sea. In order to clarify the reason, oceanographic conditions during the Holocene were reconstructed
based on biomarkers, lithogenic grains including ice-rafted debris (IRD), biogenic opal, and total organic carbon (TOC) in
two sediment cores from the Okhotsk Sea. These indicators suggest that the pronounced C. davisiana production may be attributed to: 1) a supply to mesopelagic depths under intensified stratification of fine organic particles
derived from coccolithophorids, bacteria, and detrital materials; and 2) cold, well-ventilated intermediate water formation. 相似文献
5.
There is the natural habitat of polyps of the common jellyfish Aurelia aurita in the Taniyama area, Kagoshima Bay. We examined the attachment substrata, density, colony structure and strobilation of
the polyps. The polyps were observed only on the horizontal undersurface of floating piers. They attached specifically to
Mytilus shells, solitary ascidians, calcareous polychaete tubes, muddy amphipod tubes and the gap space that fouling animals peeled
off the substrata. The polyp colonies were distributed in patches. Spatial distribution patterns of the polyps within their
colonies were uniform. Strobilation occurred during late December to March, when water temperatures were 16–17°C, and a large
number of ephyrae were released. An increase in man-made structures such as floating piers in coastal areas may lead to bloomings
of Aurelia aurita medusae.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Yoshiko Kawabata Hiroyuki Nakahara Yukio Katayama Norio Ishida 《International Journal of Salt Lake Research》1997,6(1):5-16
The Aral Sea, Lake Balkhash, and Lake Kamyslybas are closed lakes in Central Asia. They range from oligosaline to metasaline.
The salinity of the Aral Sea has increased by more than 30 g L−1 since widespread irrigation began in its catchment area. Few studies of the phytoplankton have been conducted on these lakes
since extensive irrigation started. The investigation reported here compares the flora of phytoplankton in these saline lakes.
In the Small Aral Sea, phytoplankton density gradually decreased with increasing electrical conductivity (EC) (∼ salinity),
but there was no such relation in Lake Balkhash and Lake Kamyslybas. In the Aral Sea, Dinophyceae and Bacillariophyceae were
frequently observed in most areas of high EC value, and Cyanophyceae were most conspicuous in the area of medium and lower
EC values. In Lake Balkhash, Cyanophyceae were most conspicuous, but Chlorophyceae were also noticeable. Most Cyanophyceae
in Aral Sea formed filaments with heterocysts. The distinct characteristic of the phytoplankton of the Lake Balkhash was that
all dominant species form colonies covered with a gelatinous film. Siliceousplankton diversity gradually decreased with increasing
EC values in the Aral Sea and Lake Balkhash. 相似文献
7.
The use of microstructures for discriminating turbiditic and hemipelagic muds and mudstones 
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下载免费PDF全文 The microstructures of turbiditic and hemipelagic muds and mudstones were investigated using a scanning electron microscope to determine whether there are microstructural features that can differentiate turbiditic from hemipelagic sedimentary processes. Both types of muddy deposits are, in general, characterized by randomly‐oriented clay particles. However, turbiditic muds and mudstones also characteristically contain aggregates of ‘edge‐to‐face’ contacts between clay particles with long‐axis lengths of up to 30 μm. Based on observations of the clay fabric of the experimentally‐formed muds settled from previously agitated muddy fluids, these types of aggregates, hereafter referred to as ‘aggregates of clay particles’, are interpreted as having been formed by the collision of component flocs in turbulent fluids. Furthermore, some aggregates of clay particles have ‘face‐to‐face’ contacts between clay particles; this is similar to face‐to‐face aggregates characteristically developed in fluid‐mud deposits that are commonly recognized only in turbiditic mudstones, indicating the possibility of a final stage of deposition under highly‐dense conditions, such as temporary fluid muds. In conjunction with earlier proposed lithofacies‐based and ichnofacies‐based criteria, aggregates of clay particles should be useful for the differentiation of turbiditic and hemipelagic muddy deposits, particularly with limited volumes of non‐oriented samples from deep‐water successions. 相似文献
8.
9.
Ohkura Y 《Marine pollution bulletin》2003,47(1-6):237-245
This paper looks at Japanese newspaper coverage of environmental issues, focusing on the case of the controversy over the Isahaya Bay land reclamation project. This project was first planned in the early 1950s and construction began in 1989. Local activists groups began raising questions about the project in the 1970s, focusing on the environmental degradation that would result, but they did not succeed in having their opinions discussed widely in the media until it was too late to prevent completion. Only after the dramatic images of the last slab of the seawall falling into place, was there intense media coverage of the project.The attention paid to the project by the media did much to inform the public about the effects of large-scale public works projects on the environment. Yet an analysis of the newspaper coverage shows that the media played mostly a "spectator" role in the controversy, merely reacting to events. A more active, "watch-dog" role would be necessary for the media to uncover threats to the environment in time for the public to be educated about such issues and have a chance to influence crucial official decisions. 相似文献
10.
Koji Kameo Makoto Okada Moamen El-Masry Toshio Hisamitsu Saneatsu Saito Hiroomi Nakazato Naohiko Ohkouchi Minoru Ikehara Hisato Yasuda Hiroshi Kitazato Asahiko Taira 《Island Arc》2006,15(3):366-377
Abstract A continuous, well-preserved core was obtained from the Choshi area, on the Pacific side of Japan, to investigate paleoceanographic and paleoclimatic changes around the northwestern Pacific region during the middle Pleistocene. Siliciclastic sequences in the core are divided into five formations – the Obama, Yokone, Kurahashi and Toyosato Formations in the Inubo Group and the Katori Formation, in ascending order. Examination of calcareous nannofossils and magnetic polarities detected four datums in the core sediments of the Inubo Group: the top of Reticulofenestra asanoi , the base of Helicosphaera inversa , the top of Pseudoemiliania lacunosa and the Brunhes–Matuyama boundary. Fourteen marine isotope stages (MIS24–MIS11) were identified in the δ18 O and δ13 C records based on detected datums and the graphic correlation with the standard stack oxygen isotope curve. Magnetic susceptibility and gamma-ray attenuation porosity evaluator density were also measured and low values characterize the glacial intervals. Biogenic sedimentation by primary production may be larger during the glacial periods because of invasions of nutrient-rich northern surface-waters related to the southward shift of the Kuroshio front in the Choshi area. 相似文献