南沙岛礁的建港选址及其开发利用     

宋朝景 《海洋信息》1992,(3):27-32

  相似文献   

Correlative changes in metabolism and DNA damage in turbot (Scophthalmus maximus) exposed to benzo[a]pyrene     

Telli-Karakoç F  Ruddock PJ  Bird DJ  Hewer A  Van Schanke A  Phillips DH  Peters LD 《Marine environmental research》2002,54(3-5):511-515

Juvenile turbot (Scophthalmus maximus) were injected intraperitoneally with either corn oil or 5 mg/kg benzo[a]pyrene (BaP) dissolved in corn oil and sampled I and 3 days after injection. After 1 day, no elevation of 7-ethoxyresorufin O-deethylase (EROD) activity was observed, however bile metabolites (BaP-7,8 dihydrodiol representing 70% of the total metabolites) and a single hepatic DNA adduct spot (0.47 adducts/10(8) nucleotides) identified by 32P-postlabelling were formed. No BaP metabolites or DNA adducts were observed in either control or carrier control fish. Fish sampled after 3 days reported 5-fold higher (P < 0.05) levels of EROD activity, a shift in the bile metabolite profile towards BaP phenol formation (1OH and 30H BaP comprising up to 60% of total metabolites detected) and the formation of two adduct spots (0.86 and 0.71 adducts/10(8) nucleotides). These results show that BaP can be metabolised and form hydrophobic DNA adducts in turbot without EROD elevation. Following EROD elevation, a shift in the profile of both BaP metabolites and BaP metabolite-DNA interactions occurs indicative of other oxidative processes.  相似文献   

An Experi mental Study on Wave-Induced Dynamic Stresses in Seabed     

S.C.Chang  L.K.Chien  J .G.Lin  Y.F.Chiu 《中国海洋工程》2006,20(1)

1 .IntroductionEvery year ,Taiwanis subjectedtotwo or three typhoonintrusions in average which always causedisasters . Most of the disasters which occur around the coastal zone are due to seabed instability andcoastal structure destruction caused bytyphoo…  相似文献   

Oxidative stress responses in two populations of Laeonereis acuta (Polychaeta, Nereididae) after acute and chronic exposure to copper     

Geracitano LA  Bocchetti R  Monserrat JM  Regoli F  Bianchini A 《Marine environmental research》2004,58(1):1-17

Acute (4 days) and chronic (14 days) effects of copper were evaluated on the antioxidant defenses of Laeonereis acuta (Polychaeta) collected in unpolluted (UP) and polluted (P) sites. In the acute assay (125 and 250 micro g Cu/l) superoxide dismutase (SOD) and glutathione S-transferase (GST) activities did not change, whereas catalase (CAT) increased in worms from both the sites. Lipid peroxidation was higher in copper exposed worms from the P site. In the chronic assay (62.5 micro g Cu/l) polychaetes from the P site showed enhanced activities of SOD, GST and CAT and higher contents of metallothionein-like proteins and sulfhydrils compared to worms from UP. Differences in responses between polychaetes from UP and P sites suggest that organisms from the polluted site, P, are more susceptible to oxidative stress conditions.  相似文献   

The concentration and distribution of dimethyl sulfide in the marine atmospheric boundary layer near the equator     

Li Xingsheng  Li Zhe  F. Parungo  C. Nagamoto 《海洋学报(英文版)》1995,14(3):355-369

Ｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎａｎｄｄｉｓｔｒｉｂｕｔｉｏｎｏｆｄｉｍｅｔｈｙｌｓｕｌｆｉｄｅｉｎｔｈｅｍａｒｉｎｅａｔｍｏｓｐｈｅｒｉｃｂｏｕｎｄａｒｙｌａｙｅｒｎｅａｒｔｈｅｅｑｕａｔｏｒ￥ＬｉＸｉｎｇｓｈｅｎｇ；ＬｉＺｈｅ；Ｆ．Ｐａｒｕｎｇｏ...  相似文献   

Evaluating the effects of protection on fish predators and sea urchins in shallow artificial rocky habitats: a case study in the northern Adriatic Sea     

Guidetti P  Bussotti S  Boero F 《Marine environmental research》2005,59(4):333-348

Man-made defence structures (e.g., breakwaters, jetties) are becoming common features of marine coastal landscapes all around the world. The ecology of assemblages of species associated with such artificial structures is, however, poorly known. In this study, we evaluated the density and size of fish predators of echinoids (i.e., Diplodus sargus, Diplodus vulgaris, Sparus aurata), and the density of sea urchins (i.e., Paracentrotus lividus) at defence structures (i.e., breakwaters) inside and outside the marine protected area of Miramare (northern Adriatic Sea) in order to: (1) assess possible differences in fish predator density and size between protected and fished breakwaters; (2) assess whether fish predation may have the potential to affect sea urchin density in artificial rocky habitats. Surveys were carried out at four random times over a period of two years. Total density, and density of medium- and large-sized individuals of the three predatory fishes were generally greater at the protected than at the fished breakwaters, whereas no differences were detected in the density of small-sized individuals. Density of the sea urchin P. lividus did not show any difference between protected and fished breakwaters. The results of this study suggest that: (1) protection may significantly affect predatory fishes in artificial rocky habitats; (2) differences in predatory fish density, and size may be unrelated with the density of the sea urchin P. lividus; (3) protected artificial structures such as breakwaters, originally planned for other purposes, could represent a potential tool for fish population recovery and enhancement of local fisheries.  相似文献   

Irish on the move     

King R  Mcgrath F  Shuttleworth I  Strachan A 《Geography review》1989,3(3):23-27

Trends in emigration from Ireland over time are reviewed. "During the eighteenth and nineteenth centuries overseas migration to the United States and seasonal harvest migration to Britain were the main types of movement, but over the past 100 years the Irish have developed a special affinity for settling in British towns. Although the outflow was halted for a time during the 1970s, when return migration took over, the 1980s have seen a renewal of the exodus. This time, however, the character of the flow has changed from predominantly low-skill construction and factory workers to embrace better-educated emigrants, including many graduates. This shift reflects Ireland's changing position in the international market for labour."  相似文献   

华北克拉通东南缘约1.8 Ga高压麻粒岩相变质作用:岩石学和锆石U-Pb年代学证据     

刘贻灿  王安东  李曙光  F.Rolfo  C.Groppo  古晓锋  宋彪 《矿物岩石地球化学通报》2008,27(Z1)

华北克拉通北邻中亚造山带,南接秦岭-大别-苏鲁造山带.它通常被认为是约18亿年固结形成的陆块.其基底的形成与演化,一直受到广泛关注(Zhao et al.,1998,2000,2005;Zhai et al.,2000,2005;Wilde et al.,2002,2005;Guo et al.,2005;Kroner et al.,2005,2006;Lu et al.,2008).大多数研究者都注重于华北克拉通内部、北部和东西陆块结合带(中间带),较少关注东南缘基底的形成与演化研究.  相似文献   

Theoretical infrared spectra of some model polycyclic aromatic hydrocarbons: effect of ionization     

De Frees DJ  Miller MD  Talbi D  Pauzat F  Ellinger Y 《The Astrophysical journal》1993,408(2):530-538

In order to test the hypothesis of ionized polycyclic aromatic hydrocarbons (PAHs) as possible carriers of the UIR bands, we realized a computational exploration on selected PAHs of small dimension in order to identify which changes ionization would induce on their IR spectra. In this study we performed ab initio calculations of the spectra of neutral and positively ionized naphthalene, anthracene, and pyrene. The results are significantly important. The frequencies in the cations are slightly shifted with respect to the neutral species, but no general conclusion can be reached from the three molecules considered. By contrast, the relative intensities of most vibrations are strongly affected by ionization, leading to a much better agreement between the calculated CH/CC vibration intensity ratios and those deduced from observations.  相似文献   

Interstellar water in meteorites?   总被引：1，自引：0，他引：1  

Deloule E  Robert F 《Geochimica et cosmochimica acta》1995,59(22):4695-4706

D/H ratios of two meteorites (Renazzo CR and Semarkona LL3), which are known to exhibit the largest departures from the terrestrial hydrogen isotopic ratios, have been determined with the CRPG Nancy ion microprobe. Correlations between the D/H ratios and the chemical compositions (H2O, K, Si, C/H) of plausible hydrogen carriers were observed. From these correlations, it is possible to show that, contrary to previous interpretations, phyllosilicates are the carriers of the deuterium-rich hydrogen in Semarkona and Renazzo: 870 x 10(-6) > or = D/H > or = 670 x 10(-6) (+4600 > or = deltaD > or = 3300%) and > or = 320 x 10(-6) (deltaD > or = 1050%), respectively. Hydrogen is also present in the chondrules of these two deuterium-rich meteorites. The large differences in D/H ratios between matrix (up to 700 x 10(-6), deltaD up to +3500%) and chondrules (from 120 x 10(-6) (deltaD = -230%) to 230 x 10(-6) (deltaD = +475%)) show that hydrogen in chondrules cannot originate from the matrix by simple contamination or diffusion processes. The high D/H ratios measured in water-bearing minerals could not have been produced thermally within a dense solar nebula. Chemical reactions (i.e., involving ions or radicals), taking place in interstellar space or in the outer regions of the nebula at 110-140K are presently the only conceivable mechanisms capable of yielding such isotopic enrichments. Water in these meteorites should no longer be considered as a simple product of nebular condensation under equilibrium thermodynamic conditions at T > or = 160K.  相似文献