With the rapid economic development in the surrounding coastal zone, more and more wastewater has been discharged into the Bohai Bay. And with the scale of coastal exploitation being expanded year by year, the eco-env...With the rapid economic development in the surrounding coastal zone, more and more wastewater has been discharged into the Bohai Bay. And with the scale of coastal exploitation being expanded year by year, the eco-environment of the Bohai Bay has been confronted with great pressure. In this paper, the main problems in the eco-environment of the Bohai Bay were summarized firstly. Red tides occurred more frequently and more seriously; salinity rose in inshore area, the fishery resources degenerated; all the above indicate that the eco-environment of the Bohai Bay is under a severe situation Next, to make a concrete study of the existing status of the Bohai Bay, the eco-environment index system was set up. Then the principal components analytic method and grey relation method were adopted to carry on a comprehensive analysis on the status. The results show that serious pollution of inorganic nitrogen and active phosphate, and poor species diversity are the main presentations of the bad quality of the inshore aquatic eco-environment of the Bohai Bay, which is mainly induced by the massive discharge of pollutant from land and the overexploitation in the surrounding coastal zone. At last, the variations of hydrodynamic characteristics and the pollutant transport caused by coastal exploitations such as reclamation and seawater desalination are analyzed. The results show that reclamation in coastal water not only decreases the tidal prism and weakens the tidal current action, but also influences the pollution distribution in the coastal water. The seawater desalination project would cause tremendous influence to the aquatic eco-environment of the Bohai Bay as the pollutant＇s pulse impact. Much more attention would be paid to the reasonable use of the coastal zone resources and the control of pollution from land-based sources.展开更多
A quite severe degradation was found in all seven types of grasslands in the study area involving 12counties of the northwestern Qinghai Province. The slightly, moderately and severely degraded grasslandsoccupied 49.7...A quite severe degradation was found in all seven types of grasslands in the study area involving 12counties of the northwestern Qinghai Province. The slightly, moderately and severely degraded grasslandsoccupied 49.7%, 32.0% and 18.3% of the area respectively. The major factors resulting in the degradationwere overgrazing, the damages from mice and grasshopper and blown sands, and improper use of grasslands.The measures to deal with these problems should be: 1) to make livestock development in accordancewith grassland carrying capacity for animals; 2) to build more artificial grasslands with a stable and highergraas yield; 3) to put more widely the rotation grazing system into practice; 4) to clear up the poisonousgrass species; and 5) to adopt more effective measures to deal with the damages to grasslands by mice andgrasshoppers.展开更多
Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers （indigenous to them） to adjacent ones with b...Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers （indigenous to them） to adjacent ones with better attributes. The extent of and determinants of inter-port competition in the West Africa＇s coast are of interest to port administrators/operators who risk losing significant portion of their domestic generated cargo traffic to competing neighbouring ports. In this paper, we explore the question of what port specific attributes serve as competitive basis for West Africa＇s coastal ports operating in proximity to the other. Through a survey, users of these ports were asked to identify port specific attributes which they consider when deciding which port to use for shipments making. To enrich our empirical model, data collected from the survey were augmented with secondary data （on the identified attributes） obtained from the respective ports. Statistical evidence from data analysis suggests that ports operating in proximity in the West Africa＇s coast compete on the basis of attributes that minimise costs for port users, viz： ships＇ pre-berthiig time, ship turnround time, crane efficiency and availability of cargo spaces （proxied by frequency of ship calls）. Policy implications of the findings were discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant No:50479049)the Support Plan of Science and Technology of Tianjin(Grant No.07ZCGYSH01700)+1 种基金the Natural Science Foundation of Tianjin(Grant No.07JCZDJC10700)Global Environmental Foundation(Grant No.TF053183)
文摘With the rapid economic development in the surrounding coastal zone, more and more wastewater has been discharged into the Bohai Bay. And with the scale of coastal exploitation being expanded year by year, the eco-environment of the Bohai Bay has been confronted with great pressure. In this paper, the main problems in the eco-environment of the Bohai Bay were summarized firstly. Red tides occurred more frequently and more seriously; salinity rose in inshore area, the fishery resources degenerated; all the above indicate that the eco-environment of the Bohai Bay is under a severe situation Next, to make a concrete study of the existing status of the Bohai Bay, the eco-environment index system was set up. Then the principal components analytic method and grey relation method were adopted to carry on a comprehensive analysis on the status. The results show that serious pollution of inorganic nitrogen and active phosphate, and poor species diversity are the main presentations of the bad quality of the inshore aquatic eco-environment of the Bohai Bay, which is mainly induced by the massive discharge of pollutant from land and the overexploitation in the surrounding coastal zone. At last, the variations of hydrodynamic characteristics and the pollutant transport caused by coastal exploitations such as reclamation and seawater desalination are analyzed. The results show that reclamation in coastal water not only decreases the tidal prism and weakens the tidal current action, but also influences the pollution distribution in the coastal water. The seawater desalination project would cause tremendous influence to the aquatic eco-environment of the Bohai Bay as the pollutant＇s pulse impact. Much more attention would be paid to the reasonable use of the coastal zone resources and the control of pollution from land-based sources.
文摘A quite severe degradation was found in all seven types of grasslands in the study area involving 12counties of the northwestern Qinghai Province. The slightly, moderately and severely degraded grasslandsoccupied 49.7%, 32.0% and 18.3% of the area respectively. The major factors resulting in the degradationwere overgrazing, the damages from mice and grasshopper and blown sands, and improper use of grasslands.The measures to deal with these problems should be: 1) to make livestock development in accordancewith grassland carrying capacity for animals; 2) to build more artificial grasslands with a stable and highergraas yield; 3) to put more widely the rotation grazing system into practice; 4) to clear up the poisonousgrass species; and 5) to adopt more effective measures to deal with the damages to grasslands by mice andgrasshoppers.
文摘Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers （indigenous to them） to adjacent ones with better attributes. The extent of and determinants of inter-port competition in the West Africa＇s coast are of interest to port administrators/operators who risk losing significant portion of their domestic generated cargo traffic to competing neighbouring ports. In this paper, we explore the question of what port specific attributes serve as competitive basis for West Africa＇s coastal ports operating in proximity to the other. Through a survey, users of these ports were asked to identify port specific attributes which they consider when deciding which port to use for shipments making. To enrich our empirical model, data collected from the survey were augmented with secondary data （on the identified attributes） obtained from the respective ports. Statistical evidence from data analysis suggests that ports operating in proximity in the West Africa＇s coast compete on the basis of attributes that minimise costs for port users, viz： ships＇ pre-berthiig time, ship turnround time, crane efficiency and availability of cargo spaces （proxied by frequency of ship calls）. Policy implications of the findings were discussed.
