查看更多>>摘要：Ecosystem service flow is essential for transporting,transforming,and maintaining ecosystem services and connecting supply and demand.This study attempted to quantitatively assess the supply and demand flows of ecosystem services in the Yangtze River Basin in 2000,2010,and 2020;assess the evolution of the spatial patterns of ecosystem service flow at the provincial,watershed and urban agglomeration scales;and design a zoning standard for ecosystem service flow.The results showed as follows.1)Between 2000 and 2020,the Yangtze River had a progressive drop in its freshwater supply,water conservation service and carbon sequestration service flows.The decline rates for these services were measured at 10.90％,11.11％,and 5.17％,respectively.The climate regulation service flow exhibited a pattern of initial fall followed by a subsequent increase,characterized by a decline rate of 35.53％.2)The lowest was the ecosystem service flow in the lower reaches of the Yangtze River and the Yangtze River Delta urban agglomeration.Freshwater supply service flow and water conservation service flow were the highest in the upper reaches of the Yangtze River and the Chengdu-Chongqing urban agglomeration.Carbon sequestration service flow and climate regulation service flow were the highest in the middle reaches of the Yangtze River Basin and the urban agglomeration in the middle reaches of the Yangtze River.3)From 2000 to 2020,the change ratios of the area proportion of the confluence,flow,and outflow areas in the Yangtze River Basin were 1.06,3.17,and 0.86,respectively.The results of this research could offer decision support for regulating ecosystem services in the Yangtze River Basin,promoting sustainable regional development and achieving rational use of the basin resources.
查看更多>>摘要：The accurate determination of geological age is a key to understanding the history and process of paleolake evolution and oil and gas exploration in continental lake basin.However,improving the accuracy of geological age has always been a difficult scientific problem.A 609-m-thick,continuous lacustrine mudstone and sandstone succession in Chezhen Sag(eastern China)provides an ideal middle Eocene sedimentary record for establishing a high-resolution stratigraphic chronology framework.Based on spectrum analysis and sliding window spectrum analysis of the natural gamma(GR)logging data of well Che 271(C271)in Chezhen Sag,the periods of 405 kyr and 40.1 kyr were filtered by a Gaussian bandpass filter,and a"floating"astrochronological time scale(ATS)was established.The total number of 405 kyr eccentricity cycles were 13.6 and 40.1 kyr obliquity cycles were 138 which recorded from the upper member 4(Es4U)to the member 3(Es3)of the Eocene Shahejie Formation,and the depositional duration was 5.53 Myr.Correlation Coefficient(COCO)analysis and evolutionary Correlation Coefficient(eCoCo)analysis found that the optimal sedimentary rate of different strata.Sedimentary noise simulation revealed the history of paleolake water changes in the Middle Eocene in the Chezhen Sag,according to which four sequences are divided.The study shows that the lake level change of Chezhen Sag in the middle Eocene shows prominent 1.2 Myr cycles and an antiphase well-coupled relationship with obliquity modulation.Finally,we propose a model to explain the relationship between the orbital cycle and lake level change in the continental lake basin.When the obliquity of the earth increases,the middle and high latitudes of the earth will be closer to the sun,the direct sunlight will be higher,and the meridional sunshine will increase,thus accelerating the evaporation process of lake basin water.When the seasonal changes are obvious(maximum period of 1.2 Myr ultra-long obliquity),this effect is more significant.The relative lake level change based on the restoration of high-precision ATS has significant scientific and economic value for understanding the vertical evolution of continental stratigraphic sequences and the formation and distribution of oil and gas resources.
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