太湖全新世沉积物有机联同位素的分布及其古气侯意义

通过太湖两个钻孔岩芯有机碳同位素（１３Ｃ／１２Ｃ）的分析,发现δ１３Ｃ的垂直分布与太湖地区１６０００ａＢ．Ｐ．以来古气候波动相关。根据δ１３Ｃ垂直分布曲线可推测,大约在１１０００—６０００ａＢ．Ｐ,太湖地区处于温暖湿润期,气温高于现在平均温度。另一方面,根据太湖两岩芯沉积物的δ１３Ｃ值的对比发现,大约在１１０００—６０００ａＢ．Ｐ,西太湖（Ｗ１Ｂ）岩芯沉积物的δ１３Ｃ平均值明显高于东太湖（Ｅ２Ｂ）。据此可认为,在这一期间西太湖很可能有过海水侵入。     

太湖全新世沉积物有机碳同位素的分布及其古气候意义

通过太湖两个钻孔岩芯有机碳同位素（＾１３Ｃ／＾１２Ｃ）的分析,发现δ＾１３Ｃ的垂直分布与太湖地区１６０００ａＢ．Ｐ．以来古气候波动相关。根据δ＾１３Ｃ垂直分布曲线可推测,大约在１１０００－６０００ａＢ．Ｐ．,太湖地区处于温暖湿润期,气温高于现在平均温度,另一方面,根据太湖两岩芯沉积物的δ＾１３Ｃ值的对比发现,大约在１１０００－６０００ａＢ．Ｐ．,西太湖（Ｗ１Ｂ）岩芯沉积物的δ＾１３Ｃ平均值明显高于     

11000年以来太湖地区的植被与气候变化

根据太湖盆地３个钻孔、约自１１０００年以来的孢粉分析结果将其划分为３个阶段：１）１１０００—９０００ａＢ．Ｐ,该段虽以Ｐｉｎｕｓ为主的针叶植物占有一定的优势,但起主导作用的仍以壳斗科为主的阔叶乔木种类,尤其是其间尚含有不少的亚热带成分,推测当时该区地带性植被已为亚热带落叶常绿阔叶林,鉴于植被中尚含有少量耐寒的Ａｂｉｅｓ和Ｐｉｃｅａ,推测当时气温可能较今略低;２）９０００—５０００（５４００）ａＢ．Ｐ,该段为常绿阔叶林大发展时期,气候温暖适宜,为全新世最佳期,气温约较今高１—２Ｃ;３）５０００？ａＢ．Ｐ．－现在,孢粉组合特征显示,阔叶木本植物就总的来说呈下降趋势,尤其是亚热带成分,与其相反,针叶和一些暖温带成分的含量则略有上升,表明该段气温较前一阶段有所下降,但该阶段的植被受人类活动的影响较大。     

11000年以来太湖地区的植被气候变化

根据太湖盆地３个钻孔,约自１１０００年以来的孢粉分析结果将其划分为３个阶段;１）１１０００－９０００ａＢ．Ｐ．该段虽以Ｐｉｎｕｓ为主的针叶植物占有一定的优势,但起主导作用的仍以壳斗科为主的阔叶乔木种类,尤其是其间尚含有不少的亚热带成分,推测当时该区地带性植被已为亚热带落叶常绿阔叶林,鉴于植被中尚含有少量耐寒的Ａｂｉｅｓ和Ｐｉｃｅａ,推测当时气温可能较今略低;２）９０００－５０００（５４００）ａＢ．     

太湖16000年来沉积环境的演变

通过对太湖钻孔岩芯岩性,结构,构造的剖析及粒度,磁化率的测试,发现冰后期东太湖形成于跑今６５００年前,在距今６５００－５８００年,为一水深约２－３ｍ的,经常受到流水作用影响的浅水湖泊,距今约５８００－５７００年,东太湖曾一度干枯或接近于干枯,距今５７００年以来湖泊变浅,平均水深只有１ｍ左右,由于湖泊变浅,湖底经常遭受波浪的扰动,形成波状层理或透镜状层理。西太湖局部洼地集水成湖的时间比东太湖早,并且     

高密度网围养鱼对水生植被的影响及生态对策探讨

研究了东太湖高密度网围养鱼实验区周围水生植被退化情况,影响范围半径＞６００ｍ,在中心带优势种微齿眼子菜为黑藻、金鱼藻和穗花狐尾藻所代替,并引起水绵严重发生,丧失了饲料生产能力．养鱼污染可导致水生植被退化,１４．３ｈｍ２网围面积上年Ｎ、Ｐ污染负荷量分别达２４２ｇ·ｍ（－２）·ａ（－１）和２７．４ｇ·ｍ（－２）·ａ（－１）．网围对风浪、水流的作用和水草收割的障碍效应是水生植被退化的另一重要原因．应对湖泊中网围养鱼的规模进行严格限制,并通过网围的小型、分散和短期化来减弱其环境效应的时空叠加,加强对网围周围水草的收割管理以防止植被退化和湖泊营养化．     

渤海晚冰期以来环境变化的化石介形类证据

对渤海中央盆地Ｂ９２－３孔（芯长４２０ｃｍ）、Ｂ９２－１孔（芯长４２０ｃｍ）以及莱州湾Ｂ９２－２孔（芯长３３０ｃｍ）柱状样进行了介形类属种、丰度和分异度分析,并将Ｂ９２－３孔和Ｂ９２－１孔的介形类划分出６个组合带。根据渤、黄海地区不同沉积环境中现代介形类的分布,将剖面中的介形类分成滨岸－河口区的Ｓｉｎｏｃｙｔｈｅｒｉｄｅａ组合和近岸区的Ｍｕｎｓｅｙｅｌｌａ组合。按照地层１４Ｃ年代以及剖面中Ｓｉｎｏｃｙｔｈｅｒｉｄｅａ组合分子和Ｍｕｎｓｅｙｅｌｌａ组合分子的相对丰度变化,讨论了渤海晚冰期后期以来的古环境演化历史：晚冰期为河流、湖沼环境;大约１００００ａＢ．Ｐ．开始海侵,早全新世属滨岸－河口沉积;８７００ａＢ．Ｐ．前后开始水深加大,盐度提高;２４００ａＢＰ以后水深逐渐降低。     

血管紧张素Ⅱ对大鼠心肌肌浆网Ca~(2+),Mg~(2+)-ATPase基因转录调节的影响

观察血管紧张素Ⅱ（ＡｎｇⅡ）对心肌肌浆网Ｃａ２＋,Ｍｇ２＋－ＡＴＰａｓｅ基因（ＳＥＲＣＡ２ａ）转录调节的影响,评价ＤＭＰ８１１对此效应的干预作用．６周龄雄性ＳＤ大鼠随机分为３组,每组６只．组１：生理盐水输注;组２：ＡｎｇⅡ输注＋ＤＭＰ８１１管饲（３ｍｇ·ｄ－１·ｋｇ－１）;组３：ＡｎｇⅡ输注（２００ｎｇ·ｍｉｎ－１·ｋｇ－１．１周后称其体重,取心脏并称重,提取心脏总ＲＮＡ后采用Ｎｏｒｔｈｅｒｎｂｌｏｔ的方法检测ＳＥＲ－ＣＡ２ａ的转录水平,采用ＲＴ－ＰＣＲ检测ＡｎｇⅡ１型受体（ＡＴ１）ｍＲＮＡ水平．实验后,组３心重（ＣＷ）、心重／体重（Ｃ／Ｂ）、ＡＴ１受体转录水平均高于组１（分别增加４．７±０．４％,４．９±０．９％和２４．７±３．５％;Ｐ＜０．０１）,而ＳＥＲＣＡ２ａ基因转录水平显著低于组１（降低２０．１±３．０％,Ｐ＜０．０１）,并且ＳＥＲＣＡ２ａｍＲＮＡ水平与ＡＴ１受体ｍＲＮＡ水平呈负相关（ｒ＝－０．７４,Ｐ＜０．０１）．ＡｎｇⅡ导致的上述改变能被ＤＭＰ８１１完全阻断．ＡｎｇⅡ通过其Ⅰ型受体的介导,诱导了ＳＥＲＣＡ２ａ的转录下调     

猪产仔数性状基因效应与有效基因数的研究

利用太湖猪（Ｐ１）、长白猪（Ｐ２）、杂交一代（Ｆ１）、杂交二代（Ｆ２）、杂交三代（Ｆ３）;和回交一代（Ｂ２）等６个世代产仔数的材料,分析了猪产仔性状的基因效应和基因数。结果表明上位效应不显著,猪产仔数性状符合加性－显性遗传模式,受一个有效基因控制。太湖猪产仔数性状基因加性值比长白猪高１．３９头,太湖猪高产仔数基因对长白猪等位基因呈显性,显性度为０．８１。     

猪产仔数性状基因效应与有效因数的研究

利用太湖猪（Ｐ１）、长白猪（Ｐ２）、杂交一代（Ｆ１）、杂交二代（Ｆ２）、杂交三代（Ｆ２）和回交一代（Ｂ２）等６个世代产仔数的材料,分析了猪产仔性状的基因效应和基因数,结果表明上位效应不显著,猪产仔数性状符合加性－显性遗传模式,受一个有效基因控制。太湖猪产仔数性状基因加性值比长白猪高１．３９头,太湖猪高产仔在因对长白猪等位基因呈显性,显性度为０．８１。     

晚更新世以来呼伦湖地区孢粉植物群发展与环境变迁

呼伦湖是我国纬度最高的湖泊。晚更新世以来,由于气候冷暖干湿的多次波动,湖相及河流,风成为主的水上沉各佼替变化。通过对该区东露天煤矿沉积剖面１１３块样品进行系统孢粉百分比及浓度分析,划分出８个孢粉组合带。结合＾１４Ｃ测年数据,确定了该区２００００年以来的气候演变序列。     

大小兴安岭泥炭的孢粉记录及演变过程研究

根据３个高位泥炭剖面孢粉分析,揭示大注兴安岭分别于５０００ａＢ．Ｐ．、２７００ａＢ。．Ｐ．以来孢粉组合特征和植物群与气候演变过程。小兴安岭北部山地森林疲宣传早分为２个时期,５０００－３０００ａＢ．Ｐ．桦为主落叶阔叶林;３０００ａＢ．Ｐ．－－现今为红松、云冷杉为主,混有少量桦寒温必殖阔叶混交林。气候由温凉偏干向冷偏湿方向发展大兴安岭北部山地,２７００～１８００ａＢ．Ｐ．以来,已构成针叶林为主（樟子松     

太湖东部平原平望孔全新世环境演变地层记录

通过对太湖东部平原平望钻孔的年代、有孔虫和孢粉分析,探讨了该区域全新世植被变化与环境特征。结果显示全新世(11.5 kaBP)以来,太湖东部平原未受到广泛海侵的影响,主要是以淡水湖泊-沼泽沉积为主。该区域在4 kaBP以后,才有大面积的水稻种植。11.0—9.1 kaBP,以常绿-落叶阔叶林为主,花粉浓度较小,木本植物和水生湿生植物花粉含量增加,整体环境温凉偏干,但湿度逐渐增大,指示东亚季风逐渐加强。9.1—5.8 kaBP,花粉浓度最大,木本植物花粉含量略有减小,草本植物含量明显增加,主要是水生、湿生花粉的含量增加明显,平均达到32%,藻类含量为整个钻孔最大,其中在8—7 kaBP前后常绿类花粉含量较大,水生湿生花粉、淡水藻类的含量达到整个剖面最大,推测此时区域湿度最大,东亚夏季风最为强盛。5.8—1.3 kaBP常绿阔叶林百分比含量增加,落叶阔叶花粉含量减少,陆生草本植物的含量增加,水生湿生草本的含量减小,主要以常绿-落叶阔叶林为主,环境较前一带略干,东亚夏季风减弱。     

河西走廊西部全新世气候环境变化的元素地球化学记录

通过河西走廊西部地区条湖剖面沉积物元素地球化学分析, 结合高精度AMS-14C测年, 探讨研究区~11400-1060 cal BP期间的气候环境演变过程。研究结果显示, ~11400-9400 cal BP期间, 条湖处于高水位且流域内化学风化作用较强, 气候条件相对温暖湿润; ~9400-8100 cal BP期间, 湖泊水位下降, 化学风化作用减弱, 指示了干旱的气候条件; ~8100-5800 cal BP气候相对湿润, 其中最湿润时段出现在~8100-7200 cal BP之间; ~5800-4800 cal BP期间, 气候转干。~4800 cal BP以后人类活动增强, 导致区域荒漠化加剧。     

A mid-Holocene environmental change in Amazonian savannas

Aim The main goal of this study was to investigate how climate and human activities may have influenced ecotonal areas of disjoint savannas within Brazilian Amazonia. Location Eastern Brazilian Amazonia, Amapá State. Methods The fossil pollen and charcoal records of two lakes in Amapá (Marcio and Tapera) were used to provide a Holocene palaeoecological history of eastern Amazonian savannas. Detrended correspondence analysis was used to enhance the patterns of sample distribution along the sediment core. Results Even though sedimentary hiatuses were recognized in the sediment cores from both lakes, a marked change in vegetation from closed forests with swamp elements to open flooded savanna at c. 5000 yr bp was evident from the pollen record. Charcoal analysis revealed a pattern of increased accumulation of charred particles coincident with the establishment of savanna vegetation, suggesting higher fire frequency near the lakes. Because the timing of the sedimentary hiatus overlapped with the highest Holocene sea level, which would have increased the local water table preventing the lakes from drying out, we infer that both lakes used to depend heavily on flood waters, and the sedimentary gap was caused by reduced discharge from the Amazon River, due to a dry period in the Andes, when precipitation levels markedly decreased between 8000 and 5000 yr bp . The lack of Andean pollen (probably river transported) in the sediment record after this event and the existence of similar records near the study site make this interpretation more appealing. The resumption of sedimentation in Lake Marcio, contemporaneous with falling sea level and increasingly wet conditions in the Andes after 5000 yr bp , indicates that Holocene sea‐level variation did not play an important role in maintaining lake levels. Main conclusions The study site recorded long‐term occupation by pre‐Columbian peoples. However, it is still unclear whether these disjoint savannas have an anthropogenic origin. Even though locally dry environmental conditions were inferred from both records, there is no evidence of a mid‐Holocene dry climate in eastern Amazonia. Instead, the Amapá record indicates a connection between Andean climate and eastern Amazonia, demonstrating the need for a better understanding of the impacts and magnitude of climate changes.     

The Dry Holocene Megathermal in Inner Mongolia

The paleoclimate since 14 kyr BP (¹⁴C age) was reconstructed based on a 16.22-m-long sediment core collected from Lake Yanhaizi, a saline lake located near the northern limit of the East Asian summer monsoon in Inner Mongolia. Coarse sediments were deposited there during a shrinkage phase of the lake when sand dunes reactivated. These sediments have low organic carbon contents but high maturity indices, indicating that they were deposited in an arid environment. By contrast, based on high organic contents and low maturity indices, fine sediments were deposited during periods of high lake stand in a humid environment. It was in general dry between 8.0 and 4.3 kyr BP. The above dry and wet phases are consistent with those recovered from the arid-semiarid transition zone elsewhere, but are unlike the widely perceived humid Holocene Megathermal reported in east China and the newly reconstructed record in the alpine Retreat Lake in Taiwan. The discrepancy may be due to a relative insensitivity to humidity changes in these two areas since they have both been under the total influence of the summer monsoon. On the other hand, much enhanced evaporation over higher monsoon precipitation at Lake Yanhaizi reduces the effective humidity in the warm climate near the northern boundary of the summer monsoon. This also accounts for the fact the high-temperature Holocene Megathermal, as revealed in the Okinawa Trough and the northern South China Sea, is correlated to the dry phases at Lake Yanhaizi. Conversely, the 4-2-kyr BP coldest period in the Holocene corresponds to a wet phase at Lake Yanhaizi.     

根据孢粉分析论青藏高原西部和北部全新世环境变化

通过对青藏高原西部班公湖钻孔和北部中昆仑山３个湖相剖面的孢粉研究,揭示青藏高原西部和北部地区全新世１万年期间植被的演替和气候变化,西部在全新世早期９９００－７８００ｙｒ．Ｂ．Ｐ．植被由荒漠转为草原,气候好转;中期７８００－３５００ｙｒ．Ｂ．Ｐ．,草原发展,气候较适宜,以７２００－６３００ｙｒ．Ｂ．Ｐ．为高温湿期,５５００ｙｒ．Ｂ．Ｐ．和３５００ｙｒ．Ｂ．Ｐ．出现干旱,晚期从３５００ｙｒ．Ｂ．Ｐ．至今植被为荒漠,气候干旱,其中７００ｙｒ．Ｂ．Ｐ．气候恶化。北部地区全新世时期为荒漠植被,当气候温湿时,蒿和禾本科,莎草科成份增加,藜科减少,气候干旱时则相反,北部全新世的气候分期和干湿波动与西部相近,两地在晚期气候朝干旱化发展。