With a brief introduction to the Government Information Locator Service(GILS)program,this paper gives a detailed description of GILS metadata’s structure and elements.
Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the p...Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the past one hundred years in a mangrove swamp of Maowei Sea, SW China. The sedimentation rates(0.38-0.95 cm yr^(-1)) were calculated on the basis of ln(^(210)Pb_(xs)/Al) and mass depth in the core sediments. Chemical tracers, such as δ^(13)C_(org) and C:N values, were utilized to trace the contribution of mangrove-derived organic matter using a ternary mixing model. Because of potential diagenetic alteration and / or overlap in the isotopic signatures of different components, simultaneous use of mangrove pollen diagrams can help to supplement some of these limitations. Combined with mangrove pollen, mangrove evolution was reconstructed and could be divided into three stages: flourishment(1886-1905 AD), slight degradation(1905-1949 AD) and rapid degradation period(1949-2007 AD), which was consistent with previous reports. The reclamation of mangrove swamps to shrimp ponds was the major reason for rapid degradation of mangrove ecosystems in recent years, rather than climate change in the region.展开更多
Recent studies suggest that the hydrogen and oxygen isotopic compositions of clay minerals can indicate paleoclimate.Here,we report mineralogy and stable isotopic records(d D and δ^(18)O_(OH))of a weathering profile ...Recent studies suggest that the hydrogen and oxygen isotopic compositions of clay minerals can indicate paleoclimate.Here,we report mineralogy and stable isotopic records(d D and δ^(18)O_(OH))of a weathering profile located in the Fujian Province,aiming to validate whether hydroxyl stable isotopes can indicate paleo-precipitation and paleo-temperature.Our results indicate that the d D and δ^(18)O_(OH)changes in the kaolinite hydroxyl of the weathering profile are basically determined by the isotopic composition of paleo-meteoric water and paleotemperature,respectively.Nevertheless,whether the d D and δ^(18)O_(OH)of kaolinite can quantitatively indicate paleo-precipitation and paleo-temperature needs to be verified further,and especially,the structural oxygen isotopic composition that is the essential element for the kaolinite formation temperature calculation has to be constrained in future work.展开更多
文摘With a brief introduction to the Government Information Locator Service(GILS)program,this paper gives a detailed description of GILS metadata’s structure and elements.
基金supported by the National Key Scientific Research Project on Global Climate Change (Grant No. 2010CB 951203)the National Natural Science Foundation of China (Grant Nos. 41206057, 41576067, 41376075 and 41576061)
文摘Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the past one hundred years in a mangrove swamp of Maowei Sea, SW China. The sedimentation rates(0.38-0.95 cm yr^(-1)) were calculated on the basis of ln(^(210)Pb_(xs)/Al) and mass depth in the core sediments. Chemical tracers, such as δ^(13)C_(org) and C:N values, were utilized to trace the contribution of mangrove-derived organic matter using a ternary mixing model. Because of potential diagenetic alteration and / or overlap in the isotopic signatures of different components, simultaneous use of mangrove pollen diagrams can help to supplement some of these limitations. Combined with mangrove pollen, mangrove evolution was reconstructed and could be divided into three stages: flourishment(1886-1905 AD), slight degradation(1905-1949 AD) and rapid degradation period(1949-2007 AD), which was consistent with previous reports. The reclamation of mangrove swamps to shrimp ponds was the major reason for rapid degradation of mangrove ecosystems in recent years, rather than climate change in the region.
基金funded by the National Natural Science Foundation of China(NSFC)(Grant Nos.41225020 and41376049)National Programme on Global Change and Air-Sea Interaction(GASI-GEOGE-03)
文摘Recent studies suggest that the hydrogen and oxygen isotopic compositions of clay minerals can indicate paleoclimate.Here,we report mineralogy and stable isotopic records(d D and δ^(18)O_(OH))of a weathering profile located in the Fujian Province,aiming to validate whether hydroxyl stable isotopes can indicate paleo-precipitation and paleo-temperature.Our results indicate that the d D and δ^(18)O_(OH)changes in the kaolinite hydroxyl of the weathering profile are basically determined by the isotopic composition of paleo-meteoric water and paleotemperature,respectively.Nevertheless,whether the d D and δ^(18)O_(OH)of kaolinite can quantitatively indicate paleo-precipitation and paleo-temperature needs to be verified further,and especially,the structural oxygen isotopic composition that is the essential element for the kaolinite formation temperature calculation has to be constrained in future work.
