Plenty of high-resolution paleoclimate investigations of the last thousand years were carried out to potentially predict future climate changes.Mountainous ombrotrophic peatland is one of the best recorders for high-r...Plenty of high-resolution paleoclimate investigations of the last thousand years were carried out to potentially predict future climate changes.Mountainous ombrotrophic peatland is one of the best recorders for high-resolution paleoclimate studies in the forest area.Grain size analysis was carried out on ombrotrophic peat profile in the eastern mountainous region of Jilin Province,Northeast China.The peat profile lasts the past 2000 a by four radiocarbon(AMS14C)ages.The results showed that the inorganic minerals in the peat profile are mainly silt,with some contribution from clay and a minor amount of sand,which are mainly due to wind dust and suspended transportation.Two paleoclimate stages are found in this peat profile by phytolith analysis,peat cellulose isotope research and historical documents:ca.45–1550 AD,relatively cold period;ca.1550 AD–present,relatively warm period.This finding is important for the initial study of paleoclimatic changes over the last 2000 a in the mountainous area of eastern mountainous area,Jilin Province,Northeast China.展开更多
To investigate vertical changes of bacterial communities from living plants to the associated sediments and bacterial biogeo- chemical roles in peatland ecosystem, samples of different part of individual Sphagnum palu...To investigate vertical changes of bacterial communities from living plants to the associated sediments and bacterial biogeo- chemical roles in peatland ecosystem, samples of different part of individual Sphagnum palustre and the different layers of the underlying sediments were collected from Dajiuhu Peatland in central China. All samples were subject to 16S rRNA gene clone libraries and quantitative PCR analysis. Even though bacteria vary in abundance at the same order of magnitude in all samples, they show great profile difference in composition from the top part of S. palustre to the low layer of the sediments. Cyanobacteria and alpha-Proteobacteria dominate at the top part whereas Acidobacteria at the middle part of S. palustre. A1- pha-Proteobacteria and Acidobacteria are the dominant phyla at the bottom part of S. palustre and in the surface peat sediment. In contrast, bacterial communities in the subsurface sediments are dominated by Acidobacteria. These profile distributions of different bacterial communities are closely related to their ecological functions in the peatland ecosystem. Specifically, most Cyanobacteria were observed at the top green part of S. palustre, a horizon where the active photosynthesis of the moss occurs, which infers their endosymbiosis. In contrast, Acidobacteria, dominant in the subsurface sediments, are able to decompose the specific compounds on the cell wall of Sphagnum moss and thus might play an important role in the formation of the peatland, including the acidic condition. Methane oxidizing process might have been underestimated in Sphagnum peatland due to the identification of Methylocystaceae in all parts of the moss investigated here. The vertical difference in bacterial composition and bacterial ecological functions presented here sheds light on the understanding of biogeochemical processes, in particular the CH4 flux, in peat ecosystems.展开更多
以新疆石河子草滩湖湿地作为研究地点,采用化学分析手段,获取该地区4 000 a B.P.以来有机质和总氮TN等数据,并结合孢粉数据,综合探讨古气候变化特征。在500-1 080 a B.P.和2 190-3 800 a B.P.期间,有机质和TN含量较高,此时气候较为湿润...以新疆石河子草滩湖湿地作为研究地点,采用化学分析手段,获取该地区4 000 a B.P.以来有机质和总氮TN等数据,并结合孢粉数据,综合探讨古气候变化特征。在500-1 080 a B.P.和2 190-3 800 a B.P.期间,有机质和TN含量较高,此时气候较为湿润,泥炭累积;而在1 080-2 190 a B.P.期间,有机质和TN含量均处于剖面最低值,可能出现一次干旱事件,不利于泥炭堆积。湿地开垦为农田,其有机质和TN含量变化迅速减少,养分大量损失,可见开垦活动是引起湿地退化的原因之一。展开更多
为了探究过去150 a来大气粉尘沉降历史及其对季风边缘区和季风影响区的影响差异,利用长白山典型雨养泥炭灰分粒度、成岩化学元素、210Pb和137Cs年代等指标重建过去大气粉尘变化,并与大兴安岭摩天岭雨养泥炭粉尘记录进行比较。东北山地...为了探究过去150 a来大气粉尘沉降历史及其对季风边缘区和季风影响区的影响差异,利用长白山典型雨养泥炭灰分粒度、成岩化学元素、210Pb和137Cs年代等指标重建过去大气粉尘变化,并与大兴安岭摩天岭雨养泥炭粉尘记录进行比较。东北山地泥炭灰分主要以粘土颗粒和粉砂颗粒物为主。中值粒径和成岩元素特征也初步揭示东北山地泥炭中矿物灰分主要源于蒙古国和中国北方沙漠和沙地的土壤尘。大气土壤尘降通量自19世纪初至20世纪60年代表现出逐渐增加的趋势,与区域近代化、工业化和战争等人类活动强度增加一致。在过去60 a间具有减小的趋势,与区域自然尘暴的监测数据吻合较好。东北地区长距离传输的大气土壤尘降通量背景基线为(5.2±2.6) g m^(-2)a^(-1)。长白山大气土壤尘降通量(5~38 g m^(-2) a^(-1))小于大兴安岭(14~68 g m^(-2) a^(-1)),揭示了大气尘降随着与尘源区的距离增加而递减,对东北地区西部的影响要强于对东部的影响。展开更多
基金Supported by projects of National Natural Science Foundation of China(Nos.40702027,41472173)Ministry of Land and Resources Outstanding Youth Science and Technology Talent Training Program of China(No.201311111).
文摘Plenty of high-resolution paleoclimate investigations of the last thousand years were carried out to potentially predict future climate changes.Mountainous ombrotrophic peatland is one of the best recorders for high-resolution paleoclimate studies in the forest area.Grain size analysis was carried out on ombrotrophic peat profile in the eastern mountainous region of Jilin Province,Northeast China.The peat profile lasts the past 2000 a by four radiocarbon(AMS14C)ages.The results showed that the inorganic minerals in the peat profile are mainly silt,with some contribution from clay and a minor amount of sand,which are mainly due to wind dust and suspended transportation.Two paleoclimate stages are found in this peat profile by phytolith analysis,peat cellulose isotope research and historical documents:ca.45–1550 AD,relatively cold period;ca.1550 AD–present,relatively warm period.This finding is important for the initial study of paleoclimatic changes over the last 2000 a in the mountainous area of eastern mountainous area,Jilin Province,Northeast China.
基金supported by National Natural Science Foundation of China(Grant Nos.41072253,41130207)Special Funds for Basic Scientific Research of Central Colleges,China University of Geosciences(Wuhan)(Grant No.CUG120103)
文摘To investigate vertical changes of bacterial communities from living plants to the associated sediments and bacterial biogeo- chemical roles in peatland ecosystem, samples of different part of individual Sphagnum palustre and the different layers of the underlying sediments were collected from Dajiuhu Peatland in central China. All samples were subject to 16S rRNA gene clone libraries and quantitative PCR analysis. Even though bacteria vary in abundance at the same order of magnitude in all samples, they show great profile difference in composition from the top part of S. palustre to the low layer of the sediments. Cyanobacteria and alpha-Proteobacteria dominate at the top part whereas Acidobacteria at the middle part of S. palustre. A1- pha-Proteobacteria and Acidobacteria are the dominant phyla at the bottom part of S. palustre and in the surface peat sediment. In contrast, bacterial communities in the subsurface sediments are dominated by Acidobacteria. These profile distributions of different bacterial communities are closely related to their ecological functions in the peatland ecosystem. Specifically, most Cyanobacteria were observed at the top green part of S. palustre, a horizon where the active photosynthesis of the moss occurs, which infers their endosymbiosis. In contrast, Acidobacteria, dominant in the subsurface sediments, are able to decompose the specific compounds on the cell wall of Sphagnum moss and thus might play an important role in the formation of the peatland, including the acidic condition. Methane oxidizing process might have been underestimated in Sphagnum peatland due to the identification of Methylocystaceae in all parts of the moss investigated here. The vertical difference in bacterial composition and bacterial ecological functions presented here sheds light on the understanding of biogeochemical processes, in particular the CH4 flux, in peat ecosystems.
文摘以新疆石河子草滩湖湿地作为研究地点,采用化学分析手段,获取该地区4 000 a B.P.以来有机质和总氮TN等数据,并结合孢粉数据,综合探讨古气候变化特征。在500-1 080 a B.P.和2 190-3 800 a B.P.期间,有机质和TN含量较高,此时气候较为湿润,泥炭累积;而在1 080-2 190 a B.P.期间,有机质和TN含量均处于剖面最低值,可能出现一次干旱事件,不利于泥炭堆积。湿地开垦为农田,其有机质和TN含量变化迅速减少,养分大量损失,可见开垦活动是引起湿地退化的原因之一。
文摘为了探究过去150 a来大气粉尘沉降历史及其对季风边缘区和季风影响区的影响差异,利用长白山典型雨养泥炭灰分粒度、成岩化学元素、210Pb和137Cs年代等指标重建过去大气粉尘变化,并与大兴安岭摩天岭雨养泥炭粉尘记录进行比较。东北山地泥炭灰分主要以粘土颗粒和粉砂颗粒物为主。中值粒径和成岩元素特征也初步揭示东北山地泥炭中矿物灰分主要源于蒙古国和中国北方沙漠和沙地的土壤尘。大气土壤尘降通量自19世纪初至20世纪60年代表现出逐渐增加的趋势,与区域近代化、工业化和战争等人类活动强度增加一致。在过去60 a间具有减小的趋势,与区域自然尘暴的监测数据吻合较好。东北地区长距离传输的大气土壤尘降通量背景基线为(5.2±2.6) g m^(-2)a^(-1)。长白山大气土壤尘降通量(5~38 g m^(-2) a^(-1))小于大兴安岭(14~68 g m^(-2) a^(-1)),揭示了大气尘降随着与尘源区的距离增加而递减,对东北地区西部的影响要强于对东部的影响。
