Sediment environmental capacity of pollutants is very important for marine environmental management.Based on the methodology of a study on water,soil environmental capacity,and mass conservation theory in a system,the...Sediment environmental capacity of pollutants is very important for marine environmental management.Based on the methodology of a study on water,soil environmental capacity,and mass conservation theory in a system,the concept and model on sediment environmental capacity for 137Cs in Daya Bay were developed.The static capacity for 137Cs in the upper sediment near the shore at a shallow area was calculated,and the annual dynamic capacity and total dynamic capacity were also calculated through determination of the typical biomass in the sediment.The results showed that the estimated environmental capacity for 137Cs in sedi-ments was approximately equal to the current input of 137Cs into the sediments.Controlling the input of 137Cs in the sedi-ments within the environmental capacity guarantees the sus-tainability of the current situation of the Daya Bay ecosystem and avoidance of a significant degradation of the system.展开更多
The alpine treeline ecotone is defined as a forest-grassland or forest-tundra transition boundary either between subalpine forest and treeless grassland,or between subalpine forest and treeless tundra.The alpine treel...The alpine treeline ecotone is defined as a forest-grassland or forest-tundra transition boundary either between subalpine forest and treeless grassland,or between subalpine forest and treeless tundra.The alpine treeline ecotone serves irreplaceable ecological functions and provides various ecosystem services.There are three lines associated with the alpine treeline ecotone,the tree species line(i.e.,the highest elevational limit of individual tree establishment and growth),the treeline(i.e.,the transition line between tree islands and isolated individual trees)and the timber line(i.e.,the upper boundary of the closed subalpine forest).The alpine treeline ecotone is the belt region between the tree species line and the timber line of the closed forest.The treeline is very sensitive to climate change and is often used as an indicator for the response of vegetation to global warming.However,there is currently no comprehensive review in the field of alpine treeline advance under global warming.Therefore,this review summarizes the literature and discusses the theoretical bases and challenges in the study of alpine treeline dynamics from the following four aspects:(1)Ecological functions and issues of treeline dynamics;(2)Methodology for monitoring treeline dynamics;(3)Treeline shifts in different climate zones;(4)Driving factors for treeline upward shifting.展开更多
基金This work was supported by the Key Science and Technology Project of Guangdong Environmental Protection Bureau(Grant No.YUEHUAN 1999-31).
文摘Sediment environmental capacity of pollutants is very important for marine environmental management.Based on the methodology of a study on water,soil environmental capacity,and mass conservation theory in a system,the concept and model on sediment environmental capacity for 137Cs in Daya Bay were developed.The static capacity for 137Cs in the upper sediment near the shore at a shallow area was calculated,and the annual dynamic capacity and total dynamic capacity were also calculated through determination of the typical biomass in the sediment.The results showed that the estimated environmental capacity for 137Cs in sedi-ments was approximately equal to the current input of 137Cs into the sediments.Controlling the input of 137Cs in the sedi-ments within the environmental capacity guarantees the sus-tainability of the current situation of the Daya Bay ecosystem and avoidance of a significant degradation of the system.
基金The National Natural Science Foundation of China(41901361)The Six Talent Peaks Project of Jiangsu Province(TD-XYDXX-006)+1 种基金The Natural Science Foundation of Jiangsu Province(BK20180769)The Major Basic Research Project of the Natural Science Foundation of theJiangsu Higher Education Institutions(18KJB180009).
文摘The alpine treeline ecotone is defined as a forest-grassland or forest-tundra transition boundary either between subalpine forest and treeless grassland,or between subalpine forest and treeless tundra.The alpine treeline ecotone serves irreplaceable ecological functions and provides various ecosystem services.There are three lines associated with the alpine treeline ecotone,the tree species line(i.e.,the highest elevational limit of individual tree establishment and growth),the treeline(i.e.,the transition line between tree islands and isolated individual trees)and the timber line(i.e.,the upper boundary of the closed subalpine forest).The alpine treeline ecotone is the belt region between the tree species line and the timber line of the closed forest.The treeline is very sensitive to climate change and is often used as an indicator for the response of vegetation to global warming.However,there is currently no comprehensive review in the field of alpine treeline advance under global warming.Therefore,this review summarizes the literature and discusses the theoretical bases and challenges in the study of alpine treeline dynamics from the following four aspects:(1)Ecological functions and issues of treeline dynamics;(2)Methodology for monitoring treeline dynamics;(3)Treeline shifts in different climate zones;(4)Driving factors for treeline upward shifting.
