Sediments of core YSJD-86GC(referred to as86GC)collected from the southern South China Sea were selected for environmental magnetic studies.Combined with the published chronological framework,sediment magnetic propert...Sediments of core YSJD-86GC(referred to as86GC)collected from the southern South China Sea were selected for environmental magnetic studies.Combined with the published chronological framework,sediment magnetic properties were revealed for the study area since the MIS3 stage.The rock magnetic results indicate that low-coercivity magnetite is the main magnetic mineral within the sediments.Also,a certain amounts of hematite are present.The King plot and Day plot,which reflect the magnetic particle size,show that fine-grained pseudo-single-domain phase magnetic particles dominate the magnetic minerals in the sediments.Comparison of magnetic parameters and geochemical indicators show that magnetic properties of core 86GC sediments reflect a terrigenous input.Simultaneously,magnetic characteristics of the studied sediment are influenced by the quantity of terrigenous sediment input,oxidation-reduction conditions of the provenance area,and the transportation environment and distance.Sea level fluctuation caused by global climate change was the main factor for variation in concentration of magnetic minerals and magnetic particle size of thestudied core sediments.Thus,variation of sediment magnetic properties in the study area can be used as an indirect indicator of sea level fluctuation.展开更多
The multiple,complex and systemic problems of the agriculture-food-water-environment nexus(“Nexus”)are among the most significant challenges of the 21st century.China is a key site for Nexus research amidst profound...The multiple,complex and systemic problems of the agriculture-food-water-environment nexus(“Nexus”)are among the most significant challenges of the 21st century.China is a key site for Nexus research amidst profound socio-environmental problems.The policy implications of these problems have been authoritatively summarized elsewhere.This study presents discussions at an international workshop in Guangzhou that asked instead“What science is needed to deliver the growing policy commitments regarding these challenges?And,What changes are needed to the science itself?”Understanding and effective intervention regarding the Nexus calls for a paradigm shift:to a new kind of science of(capacity for)international,interdisciplinary,and impactful research working with and within complex socio-natural systems.We here argue that science must become proactive in approach,striving only for“minimal harm”not“silver bullet”solutions,and adopting an explicitly long-term strategic perspective.Together,these arguments lead to calls for reorienting science and science policy in three ways:from short-term remediation to longer-term optimization;from a focus on environmental threats to one on the opportunities for international collaborative learning;and toward supporting new forms of scientific career.We bring these points together by recommending a new form of scientific institution:a global network of collaborative Nexus Centres,under the umbrella of a global Food Nexus Organization akin to those of the human genome and proteome.展开更多
基金supported by the National Natural Science Foundation of China(41272384,40930106)the National Basic Research Program of China(2010CB833400)+2 种基金‘‘TuGuangchi’’ Talents Funds of Guangzhou Institute of Geochemistry,CAS(GIS-08-0301)the China Geological Survey Bureau(GZH200900504)Project of Youth Innovation Promotion Association,CAS
文摘Sediments of core YSJD-86GC(referred to as86GC)collected from the southern South China Sea were selected for environmental magnetic studies.Combined with the published chronological framework,sediment magnetic properties were revealed for the study area since the MIS3 stage.The rock magnetic results indicate that low-coercivity magnetite is the main magnetic mineral within the sediments.Also,a certain amounts of hematite are present.The King plot and Day plot,which reflect the magnetic particle size,show that fine-grained pseudo-single-domain phase magnetic particles dominate the magnetic minerals in the sediments.Comparison of magnetic parameters and geochemical indicators show that magnetic properties of core 86GC sediments reflect a terrigenous input.Simultaneously,magnetic characteristics of the studied sediment are influenced by the quantity of terrigenous sediment input,oxidation-reduction conditions of the provenance area,and the transportation environment and distance.Sea level fluctuation caused by global climate change was the main factor for variation in concentration of magnetic minerals and magnetic particle size of thestudied core sediments.Thus,variation of sediment magnetic properties in the study area can be used as an indirect indicator of sea level fluctuation.
基金the funding of the European Union EuropeAid for the SEW-REAP project(ECRIP 348-010)that has sponsored the work behind this article.
文摘The multiple,complex and systemic problems of the agriculture-food-water-environment nexus(“Nexus”)are among the most significant challenges of the 21st century.China is a key site for Nexus research amidst profound socio-environmental problems.The policy implications of these problems have been authoritatively summarized elsewhere.This study presents discussions at an international workshop in Guangzhou that asked instead“What science is needed to deliver the growing policy commitments regarding these challenges?And,What changes are needed to the science itself?”Understanding and effective intervention regarding the Nexus calls for a paradigm shift:to a new kind of science of(capacity for)international,interdisciplinary,and impactful research working with and within complex socio-natural systems.We here argue that science must become proactive in approach,striving only for“minimal harm”not“silver bullet”solutions,and adopting an explicitly long-term strategic perspective.Together,these arguments lead to calls for reorienting science and science policy in three ways:from short-term remediation to longer-term optimization;from a focus on environmental threats to one on the opportunities for international collaborative learning;and toward supporting new forms of scientific career.We bring these points together by recommending a new form of scientific institution:a global network of collaborative Nexus Centres,under the umbrella of a global Food Nexus Organization akin to those of the human genome and proteome.
