Radioonuclides in the surface sediments in special biological population dropping amended soil collecing from Antarctica have been measured with γ spectrometer. The average contents of ~(40)K,~(137)Cs,~(210Pb,)~(226)Ra,~(228)Ra,~(228)Th and ~(238)U are 143,7.56,24.1,3.65,5.36,4.15 and 6.5 Bq/kg.
Early hominids have long been considered to have evolved in response to a directional shift from forested to open habitats (e.g., woodland, savanna grassland,glaciated terrain). Long-term paleoenvironmental records during the span of hominid evolution, however, contradict the idea of a simple directional trend followed by open-habitat stability. Rather, evidence from deep ocean cores, paleovegetation, and paleolakes all suggest a high degree and erratic pace of environmental fluctuation. The degree of fluctuation...
Early hominids have long been considered to have evolved in response to a directional shift from forested to open habitats (e.g., woodland, savanna grassland,glaciated terrain). Long-term paleoenvironmental records during the span of hominid evolution, however, contradict the idea of a simple directional trend followed by open-habitat stability. Rather, evidence from deep ocean cores, paleovegetation, and paleolakes all suggest a high degree and erratic pace of environmental fluctuation. The degree of fluctuation was higher during the period of hominid evolution than any earlier time during the Cenozoic. Thus adaptation to disparity, or to the conflicting demands posed by natural selection, may provide a better explanation of hominid evoluReceived April 27, 1995Submitted for the special publication commemorating the 65th Anniversary of the IVPP, Academia Sinica, China. tion than adaptation to a single directional trend or stable environment. An example from the Pleistocene of southern Kenya illustrates how species survival and change may have been affected by environmental variability.
Acid sulfate soils (ASS) are widely distributed along the coastal areas in tropical and subtropical world. When the iron sulfides (FeS 2) in ASS are exposed to air, oxidation process and acid hazards would take place, which could result in the damages of the environment,and would be very harmful to human, animals and plants. The occurrence of acid hazards are commonly involved in four processes: 1) the formation, accumulation and deposit of FeS 2 in ASS; 2) the oxidation of FeS 2 and formation of acids; 3)...
Acid sulfate soils (ASS) are widely distributed along the coastal areas in tropical and subtropical world. When the iron sulfides (FeS 2) in ASS are exposed to air, oxidation process and acid hazards would take place, which could result in the damages of the environment,and would be very harmful to human, animals and plants. The occurrence of acid hazards are commonly involved in four processes: 1) the formation, accumulation and deposit of FeS 2 in ASS; 2) the oxidation of FeS 2 and formation of acids; 3) the neutralization to the resulting acidity by soil buffering system; 4) the dilution and transportation of the acids. The actual acidity occurring in ASS is determined by the relative intensity and comprehensive result of the four processes. The acid hazards in ASS can cause the acidification of soil, water and atmosphere and the release of harmful metal ions, especially,those of heavy metals. Commonly, in the areas of ASS, owing to the acid influences, the eco-environment is degraded and the habitats are lost, plants and animals grow abnormally with low productivity and take disease frequently, the structure and function of regional ecosystems change and biodiversity declined gradually.
Geological environment (or the uperfacical earch system) which is composed of biosphere, atmosphere, hydrosphere and lithosphere, is the substantial foundation of all living beings including human.Geological environment has some regular properties (such as space,stability, deformation, system and so on). During geological history, changes of geological environment were caused by the interaction between internal geological agent and external one. At present, the human activities resulted in deformation of earth′s...
Geological environment (or the uperfacical earch system) which is composed of biosphere, atmosphere, hydrosphere and lithosphere, is the substantial foundation of all living beings including human.Geological environment has some regular properties (such as space,stability, deformation, system and so on). During geological history, changes of geological environment were caused by the interaction between internal geological agent and external one. At present, the human activities resulted in deformation of earth′s surface form, damage of vegetation, occurrence of neo geochemical process, change of circulation and constituent of water, variation of gas composition and decrease of species, which seriously influenced quality of environment of human existence.