科尔沁沙地生态环境脆弱,对气候变化反应敏感,明确沙地演化规律及其对气候变化的响应对于未来沙地保护和管理具有重要理论指导意义。以科尔沁沙地东北缘一处风沙古土壤剖面为研究对象,利用粒度、烧失量、植硅体指标系统重建了科尔沁沙...科尔沁沙地生态环境脆弱,对气候变化反应敏感,明确沙地演化规律及其对气候变化的响应对于未来沙地保护和管理具有重要理论指导意义。以科尔沁沙地东北缘一处风沙古土壤剖面为研究对象,利用粒度、烧失量、植硅体指标系统重建了科尔沁沙地中晚全新世以来的气候变化和沙地演化。结果表明:5700~2400 cal a BP期间,科尔沁沙地经历了2次固定期和2次扩张期。第一次固定期为5700~4800 cal a BP,东亚夏季风强烈,气候温暖湿润,沙地大部分为固定沙丘;第一次扩张期为4800~3900 cal a BP,此时夏季风不断衰退,气候开始变得冷干,导致沙地逐渐扩张;第二次固定期为3900~3300 cal a BP,气候转暖湿,土壤发育,沙地面积减少;第二次扩张期为3300~2400 cal a BP,气候转冷干,沙地再次扩张,古土壤层普遍被风沙覆盖。总之,东亚夏季风驱动的气候变化驱动了科尔沁沙地中晚全新世沙地演化,沙地管理政策的制定需要特别关注未来气候变化趋势。展开更多
嫩江流域孕育的昂昂溪文化是新石器时代中国北方"渔猎文化"的代表文化。文章对昂昂溪文化的典型代表遗址——洪河遗址附近3 m的自然沉积物剖面进行植硅体分析、粒度分析和烧失量测定,探讨了新石器时代以来嫩江流域人类活动的...嫩江流域孕育的昂昂溪文化是新石器时代中国北方"渔猎文化"的代表文化。文章对昂昂溪文化的典型代表遗址——洪河遗址附近3 m的自然沉积物剖面进行植硅体分析、粒度分析和烧失量测定,探讨了新石器时代以来嫩江流域人类活动的环境背景及昂昂溪"渔猎文化"走向衰亡的原因。结果表明,洪河剖面植硅体主要来自于禾本科植物,并以早熟禾亚科(C3植物)为主,剖面沉积物主要由嫩江冲积砂经风力吹扬、搬运、堆积而成。嫩江流域文化的空间分布和时间演替,在受到人类活动影响的同时,也与自然环境有密切的关系。在7024~3820 cal. a B.P.期间,嫩江流域气候温暖湿润,适宜人类生存繁衍,孕育了典型的昂昂溪"渔猎文化";在4000 cal. a B.P.左右,气候呈现逐渐变冷干的趋势,同时昂昂溪文化也逐渐衰落;3820~1000 cal. a B.P.期间,气候持续冷干,导致部分居民离开昂昂溪地区沿嫩江逐渐向更加温暖的下游迁移以寻找更为适宜的栖息地,昂昂溪文化逐渐被取代;1000 cal. a B.P.以来,人类活动频繁,土地沙漠化日趋严重。展开更多
本文提取大兴安岭中段红水泡泥炭地中晚全新世以来泥炭沉积中所含的硅藻化石,在82个样品中共发现32属94种硅藻。结合硅藻化石中优势种类生态特征,通过主成分分析发现,水位为控制该区域硅藻组合变化的最主要因素。其中,Meridion circular...本文提取大兴安岭中段红水泡泥炭地中晚全新世以来泥炭沉积中所含的硅藻化石,在82个样品中共发现32属94种硅藻。结合硅藻化石中优势种类生态特征,通过主成分分析发现,水位为控制该区域硅藻组合变化的最主要因素。其中,Meridion circulare,Meridion criculare var.constrictum等硅藻百分含量的升高指示水位的上升,Hantzschia amphioxys,Pinnularia spp.等硅藻百分含量的升高伴随水位的下降。根据主成分得分建立的红水泡泥炭地古水位曲线发现,中晚全新世以来当地气候经历了数次干湿交替变化,在总体上趋于干旱。其中5 000-3 300 cal a BP为相对湿润期,优势种类为M.circulare,M.criculare var.constrictum;3 300-1 900 cal a BP为气候转干期,H.amphioxys,C.meneghiniana,Pinnularia spp.成为该带中的优势种类;1 900-600 cal a BP,该段内红水泡泥炭地水位较上一阶段进一步下降,气候继续转干;600-200 cal a BP为气候转湿期,红水泡泥炭地水位迅速上升,Achnanthes lanceolata含量迅速增加成为该段优势种;200 cal a BP至今,红水泡泥炭地水位迅速下降,Pinnularia spp.成为该带中的绝对优势种。通过与季风区边缘其他研究区的古气候变化特征对比发现,红水泡泥炭地气候变化与多数研究区气候变化特征具有良好的一致性,因而推断其主要受东亚季风活动控制,泥炭沉积中硅藻化石组合记录可作为反映东亚季风变迁历史的良好指标。展开更多
大兴安岭阿尔山地区位于东亚季风边缘区,对气候变化响应敏感,是研究全球气候变化的理想区域。在该区的红水泡泥炭地,采集了3个泥炭芯,通过测定其腐殖化度和总有机碳含量,重建大兴安岭阿尔山地区约5 ka BP的古气候演变信息,进一步阐述东...大兴安岭阿尔山地区位于东亚季风边缘区,对气候变化响应敏感,是研究全球气候变化的理想区域。在该区的红水泡泥炭地,采集了3个泥炭芯,通过测定其腐殖化度和总有机碳含量,重建大兴安岭阿尔山地区约5 ka BP的古气候演变信息,进一步阐述东北地区气候变化规律,进而预测该区未来的气候变化趋势。研究结果表明,大兴安岭阿尔山地区红水泡泥炭地的泥炭腐殖化度高,指示气候相对温暖潮湿,泥炭腐殖化度低,指示气候相对清凉干燥;泥炭中的总有机碳含量高,指示气候相对温暖潮湿,泥炭中的总有机碳含量低,指示气候相对清凉干燥;根据泥炭记录的古气候特征,将该地区5.07~0.18 ka BP期间的古气候分为4个主要阶段,5.07~4.55 ka BP阶段为气候暖湿阶段,4.55~3.27 ka BP阶段为气候由暖湿转向凉干再转向暖湿阶段,该阶段在4.14 ka BP左右发生了一次全球较为普遍的冷事件,3.27~1.16 ka BP阶段为气候由暖湿转向凉湿后再转为凉干阶段;1.16~0.18 ka BP阶段为气候转向暖湿阶段。红水泡泥炭的腐殖化度和总有机碳含量可以指示区域古气候变化。展开更多
长白山拥有亚洲目前保存较为完好的温带山地森林生态系统,由于近年来无火事件发生而积累了大量可燃物,火灾隐患逐年增加,重建古火历史找出火事件发生规律有助于现代火灾的有效防控。本文以长白山区孤山屯泥炭剖面的68个样品为研究载体,...长白山拥有亚洲目前保存较为完好的温带山地森林生态系统,由于近年来无火事件发生而积累了大量可燃物,火灾隐患逐年增加,重建古火历史找出火事件发生规律有助于现代火灾的有效防控。本文以长白山区孤山屯泥炭剖面的68个样品为研究载体,选取炭屑作为主要指标反演了长白山全新世以来的火事件演化历史;并结合前人利用孢粉、植硅体等代用指标重建的古环境、古气候特征,分析了火事件的成因机制。在11 686-10 883 cal aBP、7 336-2 624 cal aBP、2 624-1 189 cal aBP,炭屑浓度较高,古火事件发生频繁,强度较大;在10 883-7 336 cal aBP、1 189 cal aBP至今,炭屑浓度较低,古火事件发生频率较小,强度相对较弱。气候和植被对于火事件的影响贯穿了整个全新世时期,火事件多发生在寒冷干燥气候时期且以区域性火事件为主;近千年以来,人类活动与火山喷发对火事件的影响显著,局域性火事件比例逐渐增多。展开更多
Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songn...Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.展开更多
Deposited in plant cells and their intercellular space,phytoliths,a special form of silica,could be used to determine information on plant structure and physiology especially their size and content.With the hypothesis...Deposited in plant cells and their intercellular space,phytoliths,a special form of silica,could be used to determine information on plant structure and physiology especially their size and content.With the hypothesis that phytolith in plant would change under variable climate and environment,the dominant plant species in Songnen grassland,guinea grass(Leymus chinensis),was treated by an open-top chamber(OTC) to elevate CO2 concentration,infrared heaters,and artificial nitrogen(N) addition for three years from 2006–2008.Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on.We found that the responses to elevated CO2 are complicated,and warming is positive while N addition is negative to the deposition of phytoliths in L.chinensis leaves.Especially,warming could reduce the negative impact of N addition on phytolith in L.chinensis.The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes.The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration,warming,and N addition,and could become some new indicators for environmental changes.In conclusion,different phytolith types have various responses to simulated warming,N addition and elevated CO2 concentration.展开更多
文摘科尔沁沙地生态环境脆弱,对气候变化反应敏感,明确沙地演化规律及其对气候变化的响应对于未来沙地保护和管理具有重要理论指导意义。以科尔沁沙地东北缘一处风沙古土壤剖面为研究对象,利用粒度、烧失量、植硅体指标系统重建了科尔沁沙地中晚全新世以来的气候变化和沙地演化。结果表明:5700~2400 cal a BP期间,科尔沁沙地经历了2次固定期和2次扩张期。第一次固定期为5700~4800 cal a BP,东亚夏季风强烈,气候温暖湿润,沙地大部分为固定沙丘;第一次扩张期为4800~3900 cal a BP,此时夏季风不断衰退,气候开始变得冷干,导致沙地逐渐扩张;第二次固定期为3900~3300 cal a BP,气候转暖湿,土壤发育,沙地面积减少;第二次扩张期为3300~2400 cal a BP,气候转冷干,沙地再次扩张,古土壤层普遍被风沙覆盖。总之,东亚夏季风驱动的气候变化驱动了科尔沁沙地中晚全新世沙地演化,沙地管理政策的制定需要特别关注未来气候变化趋势。
文摘嫩江流域孕育的昂昂溪文化是新石器时代中国北方"渔猎文化"的代表文化。文章对昂昂溪文化的典型代表遗址——洪河遗址附近3 m的自然沉积物剖面进行植硅体分析、粒度分析和烧失量测定,探讨了新石器时代以来嫩江流域人类活动的环境背景及昂昂溪"渔猎文化"走向衰亡的原因。结果表明,洪河剖面植硅体主要来自于禾本科植物,并以早熟禾亚科(C3植物)为主,剖面沉积物主要由嫩江冲积砂经风力吹扬、搬运、堆积而成。嫩江流域文化的空间分布和时间演替,在受到人类活动影响的同时,也与自然环境有密切的关系。在7024~3820 cal. a B.P.期间,嫩江流域气候温暖湿润,适宜人类生存繁衍,孕育了典型的昂昂溪"渔猎文化";在4000 cal. a B.P.左右,气候呈现逐渐变冷干的趋势,同时昂昂溪文化也逐渐衰落;3820~1000 cal. a B.P.期间,气候持续冷干,导致部分居民离开昂昂溪地区沿嫩江逐渐向更加温暖的下游迁移以寻找更为适宜的栖息地,昂昂溪文化逐渐被取代;1000 cal. a B.P.以来,人类活动频繁,土地沙漠化日趋严重。
文摘本文提取大兴安岭中段红水泡泥炭地中晚全新世以来泥炭沉积中所含的硅藻化石,在82个样品中共发现32属94种硅藻。结合硅藻化石中优势种类生态特征,通过主成分分析发现,水位为控制该区域硅藻组合变化的最主要因素。其中,Meridion circulare,Meridion criculare var.constrictum等硅藻百分含量的升高指示水位的上升,Hantzschia amphioxys,Pinnularia spp.等硅藻百分含量的升高伴随水位的下降。根据主成分得分建立的红水泡泥炭地古水位曲线发现,中晚全新世以来当地气候经历了数次干湿交替变化,在总体上趋于干旱。其中5 000-3 300 cal a BP为相对湿润期,优势种类为M.circulare,M.criculare var.constrictum;3 300-1 900 cal a BP为气候转干期,H.amphioxys,C.meneghiniana,Pinnularia spp.成为该带中的优势种类;1 900-600 cal a BP,该段内红水泡泥炭地水位较上一阶段进一步下降,气候继续转干;600-200 cal a BP为气候转湿期,红水泡泥炭地水位迅速上升,Achnanthes lanceolata含量迅速增加成为该段优势种;200 cal a BP至今,红水泡泥炭地水位迅速下降,Pinnularia spp.成为该带中的绝对优势种。通过与季风区边缘其他研究区的古气候变化特征对比发现,红水泡泥炭地气候变化与多数研究区气候变化特征具有良好的一致性,因而推断其主要受东亚季风活动控制,泥炭沉积中硅藻化石组合记录可作为反映东亚季风变迁历史的良好指标。
文摘大兴安岭阿尔山地区位于东亚季风边缘区,对气候变化响应敏感,是研究全球气候变化的理想区域。在该区的红水泡泥炭地,采集了3个泥炭芯,通过测定其腐殖化度和总有机碳含量,重建大兴安岭阿尔山地区约5 ka BP的古气候演变信息,进一步阐述东北地区气候变化规律,进而预测该区未来的气候变化趋势。研究结果表明,大兴安岭阿尔山地区红水泡泥炭地的泥炭腐殖化度高,指示气候相对温暖潮湿,泥炭腐殖化度低,指示气候相对清凉干燥;泥炭中的总有机碳含量高,指示气候相对温暖潮湿,泥炭中的总有机碳含量低,指示气候相对清凉干燥;根据泥炭记录的古气候特征,将该地区5.07~0.18 ka BP期间的古气候分为4个主要阶段,5.07~4.55 ka BP阶段为气候暖湿阶段,4.55~3.27 ka BP阶段为气候由暖湿转向凉干再转向暖湿阶段,该阶段在4.14 ka BP左右发生了一次全球较为普遍的冷事件,3.27~1.16 ka BP阶段为气候由暖湿转向凉湿后再转为凉干阶段;1.16~0.18 ka BP阶段为气候转向暖湿阶段。红水泡泥炭的腐殖化度和总有机碳含量可以指示区域古气候变化。
文摘长白山拥有亚洲目前保存较为完好的温带山地森林生态系统,由于近年来无火事件发生而积累了大量可燃物,火灾隐患逐年增加,重建古火历史找出火事件发生规律有助于现代火灾的有效防控。本文以长白山区孤山屯泥炭剖面的68个样品为研究载体,选取炭屑作为主要指标反演了长白山全新世以来的火事件演化历史;并结合前人利用孢粉、植硅体等代用指标重建的古环境、古气候特征,分析了火事件的成因机制。在11 686-10 883 cal aBP、7 336-2 624 cal aBP、2 624-1 189 cal aBP,炭屑浓度较高,古火事件发生频繁,强度较大;在10 883-7 336 cal aBP、1 189 cal aBP至今,炭屑浓度较低,古火事件发生频率较小,强度相对较弱。气候和植被对于火事件的影响贯穿了整个全新世时期,火事件多发生在寒冷干燥气候时期且以区域性火事件为主;近千年以来,人类活动与火山喷发对火事件的影响显著,局域性火事件比例逐渐增多。
基金supported in a part by Chinese National Key Project of Basic Research (No G2000048703)the Grant-in-Aid for Scientific Research (No 16310008,18403002) from the Ministry of Education, Culture,Sports, Science and Technology, Japan
文摘Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.
基金Under the auspices of National Natural Science Foundation of China(No.40971116,41471164,31170303,31270366)Ministry of Environmental Protection Foundation for Public Welfare Project(No.201109067)National Undergraduate Training Programs for Innovation and Entrepreneurship(No.201410200074)
文摘Deposited in plant cells and their intercellular space,phytoliths,a special form of silica,could be used to determine information on plant structure and physiology especially their size and content.With the hypothesis that phytolith in plant would change under variable climate and environment,the dominant plant species in Songnen grassland,guinea grass(Leymus chinensis),was treated by an open-top chamber(OTC) to elevate CO2 concentration,infrared heaters,and artificial nitrogen(N) addition for three years from 2006–2008.Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on.We found that the responses to elevated CO2 are complicated,and warming is positive while N addition is negative to the deposition of phytoliths in L.chinensis leaves.Especially,warming could reduce the negative impact of N addition on phytolith in L.chinensis.The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes.The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration,warming,and N addition,and could become some new indicators for environmental changes.In conclusion,different phytolith types have various responses to simulated warming,N addition and elevated CO2 concentration.
