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541.
A. Matarrese F. Mastrototaro G. D'onghia P. Maiorano A. Tursi 《Chemistry and Ecology》2004,20(5):377-386
Side-scan sonar and underwater video camera records as well as dredging samples were used to map the bottom morphology and biocoenoses in the Taranto seas. A 1:20,000 scale chart has been produced with all the data recorded. Most of the study area consists of biocoenoses affected by the anthropogenic activities of the town of Taranto. Some native broadly tolerant species seem to benefit from these activities and become increasingly dominant. Environmental modifications also seem to favour the settlement of exotic species. 相似文献
542.
Samples of Mugil cephalus, Liza ramada, Siganus luridus, Siganus rivulatus, Epinephelus alexandrinus, Epinephelus areolatus, Epinephelus fasciatus, Epinephelus chlorostigma, Cephalopholis argus and Cephalopholis sonnerati were collected from the Mediterranean and Red Seas and their muscle and bone analyzed by AAS for some trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb). the results showed that these metals accumulate in the bones to a greater extent than in the muscle. the highest accumulated element is cobalt (4.7-20.8 times), while the lowest is lead (1.1-2.5 times). the accumulation is more pronounced in Red Sea species than in Mediterranean species. the elevated levels of lead in Mugil cephalus (2.6-3.0 mg kg-1) and Epinephelus alexandrinus (3.0-3.9 mg kg-1) were attributed to the intake in food in the polluted environment of Alexandria coastal water. the relationship between body size and concentration of trace metals using a standard linear regression technique gives a significant positive correlation for cobalt, manganese, iron and lead in the muscle, as well as for lead in the bones of Mugil species from the Red Sea, while the Mediterranean species showed little correlation.
There is a tendency for increased concentrations of the essential metals manganese, iron and copper with increasing trophic level of the fish, while the opposite is true for the toxic metals chromium and lead. Our results indicate that there is no risk from toxic metal concentrations in muscle of fish from the Mediterranean and Red Seas consumed by man even in contaminated areas. 相似文献
There is a tendency for increased concentrations of the essential metals manganese, iron and copper with increasing trophic level of the fish, while the opposite is true for the toxic metals chromium and lead. Our results indicate that there is no risk from toxic metal concentrations in muscle of fish from the Mediterranean and Red Seas consumed by man even in contaminated areas. 相似文献
543.
Sediment Flux to the Sea as Influenced by Changing Human Activities and Precipitation: Example of the Yellow River,China 总被引:9,自引:0,他引:9
Jiongxin X 《Environmental management》2003,31(3):0328-0341
Since the 1970s, the sediment flux of the Yellow River to the sea has shown a marked tendency to decrease, which is unfavorable
for wetland protection and oil extraction in the Yellow River delta. Thus, an effort has been made to elucidate the relation
between the sediment flux to the sea and the drainage basin factors including climate and human activities. The results show
that the sediment flux to the sea responds to the changed precipitation in different ways for different runoff and sediment
source areas in the drainage basin. If other factors are assumed to be constant, when the annual precipitation in the area
between Longmen and Sanmenxia decreases by 10 mm, the sediment flux to the sea will decrease by 27.5 million t/yr; when the
precipitation in the area between Hekouzhen and Longmen decreases by 10 mm, the sediment flux to the sea will decrease by
14.3 million t/yr; when the precipitation in the area above Lanzhou decreases by 10 mm, the sediment flux to the sea will
decrease by 17.4 million t/yr. A multiple regression equation has been established between the sediment flux to the sea and
the influencing factors, such as the area of land terracing and tree and grass planting, the area of the land created by the
sediment trapped by check dams, the annual precipitation, and the annual quantity of water diversion by man. The equation
may be used to estimate the change in the sediment flux to the sea when the influencing variables are further changed, to
provide useful knowledge for the environmental planning of the Yellow River drainage basin and its delta. 相似文献
544.
545.
Masanori Izumi 《Disasters》1983,7(4):244-250
A summary review of the Japan Sea (Nipponkai-chubu) earthquake of 1983 is presented. Damage to civil and building structures is explained in brief. Owing to the spread of earthquake-proof design, damage sustained was very slight for a M = 7.7 earthquake, except to those built on liquefied ground. Our next target in earthquake engineering may be to protect and maintain the functions of city-facilities against strong shaking so that citizens might not experience much disruption in their daily lives after big earthquakes. 相似文献
546.
追踪研究南黄海6-1 级地震前,松散覆盖层巨厚地区形变电阻率异常特征。探讨形变电阻率在破坏性地震前兆跟踪中的作用。 相似文献
547.
Virginia C. Welford Richard A. Block Jonathan W. Bulkley 《Journal of the American Water Resources Association》1987,23(5):803-807
ABSTRACT: The production of a documentary video in a graduate seminar offers advantages over the traditional term paper. These advantages derive from the nature of the videotape medium. The most distinct difference between a written document and a video production is the use of the video camera to record events. In using the camera, the student is required to become involved both in front of the video camera, for example, as an interviewer, and behind the camera as a camera operator. Next, as an editor, the student is required to review the events that she/he has taped for inclusion in the final product. By participating in these three roles, the student has the opportunity to learn interviewing skills while interacting with professionals in the field, to learn videotaping skills, and to see him/herself as he/she appears to others. The student can use the video feedback to improve his/her professional presentation; posture, dress, gestures, speech, and facial expressions all have an impact on how we are perceived by others. Additionally, the painstaking process of reviewing the taped material leads to an intimate knowledge of the topic, and the process of choosing portions out of entire interviews hones the ability to select the crucial or central themes and ideas from any discussion. Finally, the power of video lies in its ability to communicate information to a wide audience. Although the nature of video for the general public does not permit highly detailed or rigorous coverage of any topic, it is a major source of information. Accordingly, video is an important tool that can be used to inform the public about the importance of wise water resource management. 相似文献
548.
Charles R. Kratzer William Dritschilo Lee J. Hannah Marlene A. Broutman 《Journal of the American Water Resources Association》1985,21(4):565-572
ABSTRACT: An input-output model was developed to predict changes in Salton Sea salinity and water level until the year 2000 due to proposed water conservation efforts and geothermal and solar pond energy developments. The model SALINP provided good agreement with the observed salinities for 1960–80. While SALINP was not overly sensitive to one-year changes in any of the major inputs, a change in the historical means of the Imperial Valley runoff and evaporative loss inputs produced a significant effect on future predictions. The proposed water conservation measures caused the predicted Salton Sea salinity for 2000 to greatly exceed 40,000 ppm, the level at which adverse effects to wildlife are believed to occur. The possible geothermal development also produced predicted salinities considerably above 40,000 ppm. The salinity predictions for solar ponds by themselves and in conjunction with geothermal development were below 45,000 ppm for 2000. The solar pond and geothermal combination also resulted in a predicted lowering of the “natural” water level by 5 to 7 feet by 2000. 相似文献
549.
550.
Radiocarbon measurements were made in the water column of the Arabian Sea and the equatorial Indian Ocean during 1994, 1995 and 1997 to assess the temporal variations in bomb 14C distribution and its inventory in the region with respect to GEOSECS measurements made during 1977-1978. Four GEOSECS stations were reoccupied (three in the Arabian Sea and one in the equatorial Indian Ocean) during this study, with all of them showing increased penetration of bomb 14C along with decrease in its surface water activity. The upwelling rates derived by model simulation of bomb 14C depth profile using the calculated exchange rates ranged from 3 to 9 m a(-1). The western region of the Arabian Sea experiencing high wind-induced upwelling has higher estimated upwelling rates. However, lower upwelling rates obtained for the stations occupied during this study could be due to reduced 14C gradient compared to that during GEOSECS. 相似文献