共查询到20条相似文献，搜索用时 15 毫秒
1.
Temporal relationships of carbon cycling and ocean circulation at glacial boundaries 总被引：2，自引：0，他引：2
Piotrowski AM Goldstein SL Hemming SR Fairbanks RG 《Science (New York, N.Y.)》2005,307(5717):1933-1938
Evidence from high-sedimentation-rate South Atlantic deep-sea cores indicates that global and Southern Ocean carbon budget shifts preceded thermohaline circulation changes during the last ice age initiation and termination and that these were preceded by ice-sheet growth and retreat, respectively. No consistent lead-lag relationships are observed during abrupt millennial warming events during the last ice age, allowing for the possibility that ocean circulation triggered some millenial climate changes. At the major glacial-interglacial transitions, the global carbon budget and thermohaline ocean circulation responded sequentially to the climate changes that forced the growth and decline of continental ice sheets. 相似文献
2.
北方森林生态系统对全球气候变化的响应研究进展 总被引：1，自引：1，他引：1
北方森林是地球上第2大生物群区,约占陆地森林面积的30%,提供了从局地到全球的生态系统服务功能。1850年以来,全球性持续升温不断显现,2000—2050年全球至少升高2 ℃,甚至更高。预计到2100年,北方森林区冬季平均温度将升高1.3~6.3 ℃。与此同时,几乎所有的北方森林生态系统功能都将会受到影响,尤其是近几十年来,该区域发生了很多与温度升高相关的潜在生态响应。本文从碳循环、生物多样性、干旱化和林火发生频率以及冻土变化等方面具体综述了北方森林生态系统对于全球气候变化的响应。响应结果如下:1)气候变化对于北方森林碳循环动态的影响是极其复杂的,迄今为止并没有达成共识, 分解对于温度的反应敏感程度至今仍存在很多不确定性。2)动物、植物和微生物(真菌)均对气候变化产生了一定的响应,表现为动物和植物的分布区进一步北移,但真菌的多样性和生产力响应机制尚无法确定。3)北方森林区随气候变化表现为进一步的干旱化和林火发生明显增加。4)北方森林区与冻土伴生,冻土随气候变暖表现出了面积缩小和活动层扩大的趋势。可见,北方森林对气候变化响应明显,尽管到目前为止有些响应机制尚不清楚,但变化趋势十分明显。本文旨在为北方森林的经营和管理提供基础数据和技术支持,实现北方森林的可持续经营。 相似文献
3.
小兴安岭典型温带森林土壤呼吸对强降雨的响应 总被引：3，自引：1，他引：2
森林土壤呼吸是全球碳循环的重要组成部分,其对降雨格局的变化如何响应,是当前全球变化研究中的热点问题。本研究以小兴安岭地区原始温带森林(云冷杉红松林)为研究对象,使用SF-3000土壤气体通量自动测量系统,对雨季不同时期4次强降雨前后的土壤呼吸速率、土壤呼吸的组分和相关环境因子进行了连续观测。结果表明:1)土壤温度和含水量协同影响土壤呼吸强度。降雨是影响甚至改变控制土壤呼吸(Rs)的关键环境因子,强降雨使土壤含水量激增,并对土壤温度也有不同程度的影响。雨季初期强降雨对Rs的扰动作用相对较小,雨季中期强降雨可抑制Rs,在雨季结束后强降雨可促进Rs。2)在雨季不同时期的强降雨均不同程度的影响了土壤异养呼吸(Rh)与土壤呼吸的比例(Rh/Rs),相对于土壤自养呼吸(Ra),短时极强降雨对Rh的抑制作用更强。3)加入水分修正系数c的Rs与T5、W5指数关系模型可更好的表征土壤含水量和土壤温度对土壤呼吸的影响,不同雨季时期的强降雨均对土壤的温度敏感系数(Q10)有着显著的影响。强降雨使得土壤对水分的敏感性降低,处于雨季不同时期的土壤水分敏感性表现为:在雨季的开始和结束后,土壤呼吸的水分敏感性较高,而雨季中期的水分敏感性较低。 相似文献
4.
Cronin TM 《Science (New York, N.Y.)》1985,227(4682):60-63
Morphologic and paleozoogeographic analysis of Cenozoic marine Ostracoda from the Atlantic, Caribbean, and Pacific indicates that climatic change modulates evolution by disrupting long-term stasis and catalyzing speciation during sustained, unidirectional climatic transitions and, conversely, by maintaining morphologic stasis during rapid, high-frequency climatic oscillations. In the middle Pliocene, 4 to 3 million years ago, at least six new species of Puriana suddenly appeared as the Isthmus of Panama closed, changing oceanographic circulation and global climate. Since then morphologic stasis has characterized ancestral and descendant species during many glacial-interglacial cycles. The frequency and duration of climatic events have more impact on ostracode evolution than the magnitude of climatic changes. 相似文献
5.
Estimates of glacial-interglacial climate change in tropical Africa have varied widely. Results from a process-based vegetation model show how montane vegetation in East Africa shifts with changes in both carbon dioxide concentration and climate. For the last glacial maximum, the change in atmospheric carbon dioxide concentration alone could explain the observed replacement of tropical montane forest by a scrub biome. This result implies that estimates of the last glacial maximum tropical cooling based on tree- line shifts must be revised. 相似文献
6.
Sandel B Arge L Dalsgaard B Davies RG Gaston KJ Sutherland WJ Svenning JC 《Science (New York, N.Y.)》2011,334(6056):660-664
The effects of climate change on biodiversity should depend in part on climate displacement rate (climate-change velocity) and its interaction with species' capacity to migrate. We estimated Late Quaternary glacial-interglacial climate-change velocity by integrating macroclimatic shifts since the Last Glacial Maximum with topoclimatic gradients. Globally, areas with high velocities were associated with marked absences of small-ranged amphibians, mammals, and birds. The association between endemism and velocity was weakest in the highly vagile birds and strongest in the weakly dispersing amphibians, linking dispersal ability to extinction risk due to climate change. High velocity was also associated with low endemism at regional scales, especially in wet and aseasonal regions. Overall, we show that low-velocity areas are essential refuges for Earth's many small-ranged species. 相似文献
7.
A deep-sea sediment core underlying the Benguela upwelling system off southwest Africa provides a continuous time series of sea surface temperature (SST) for the past 4.5 million years. Our results indicate that temperatures in the region have declined by about 10 degrees C since 3.2 million years ago. Records of paleoproductivity suggest that this cooling was associated with an increase in wind-driven upwelling tied to a shift from relatively stable global warmth during the mid-Pliocene to the high-amplitude glacial-interglacial cycles of the late Quaternary. These observations imply that Atlantic Ocean surface water circulation was radically different during the mid-Pliocene. 相似文献
8.
[目的]太阳辐射是森林生态系统最主要的能量来源,同时是影响森林生态系统区域气候与环境的最重要因素之一.探讨森林辐射长期变化特征,以期为气候变化、热带地区森林生产力、辐射能量平衡的研究以及辐射模型的建立和验证等建立研究基础.[方法]利用西双版纳热带季节雨林14年(2003-2016)辐射实测数据,对不同时间尺度的辐射各分... 相似文献
9.
温室气体排放剧增引起全球变暖,已成为全球高度关注的生态环境问题。一氧化二氮(N2O)是大气中仅次于二氧化碳(CO2)和甲烷(CH4)的第三大温室气体,森林土壤氮矿化过程伴随着硝化和反硝化的发生,能够导致N2O的产生,进而引起大气N2O浓度的升高。森林土壤氮矿化是生物与非生物环境因素共同调控的复杂生态学过程,探明森林土壤氮矿化的影响因素及其调控机制,有助于丰富人们对森林土壤氮循环过程的认识,在全球变化研究中具有重要的地位与作用。本研究揭示森林土壤氮矿化的时空变化及影响因素,阐明非生物因素以及森林植被覆盖、森林凋落物、土壤微生物与土壤动物等生物因素对森林土壤氮矿化的影响特征及作用机制。目前,森林土壤氮矿化研究存在结果可比性不强;内容多集中于氮矿化单因素影响研究,缺乏多因子尤其是微生物-动物协同调控研究;缺乏不同气候类型及不同土地利用方式森林土壤氮矿化特征及影响机制研究;缺乏氮矿化对全球变化的响应研究等一系列问题。土壤氮矿化研究应该探索统一高效的测定方法,加强土壤微生物-动物-环境因子多因素耦合对森林土壤氮矿化影响机制研究,探讨不同气候类型及不同利用方式森林土壤氮矿化调控机制,重点阐明全球变化背景下森林土壤氮矿化的过程与机理。旨在为准确理解不同气候区森林土壤氮矿化的时空格局及其对全球气候变化的影响提供理论支撑。参69 相似文献
10.
青海高寒区5种典型林分土壤呼吸季节变化及其影响因素 总被引：4，自引：3，他引：1
土壤呼吸是陆地生态系统碳循环的重要环节,也是影响全球气候变化的重要因素。研究土壤呼吸及其对环境因素的响应,对准确估计全球碳循环系统的收支平衡有重要意义。高寒区是陆地生态系统的重要组成部分,研究该区域环境因素对土壤呼吸的影响有助于深刻了解高寒区的土壤碳循环过程。本研究采用动态密闭气室红外CO2分析法,以青海高寒区的5种典型林分(华北落叶松林、云杉林、云杉-华北落叶松混交林、云杉-白桦混交林、白桦林)为对象,研究不同林分类型生长季土壤呼吸的变化规律及其与环境因子的关系。结果表明:5种林型土壤呼吸速率的大小为云杉林白桦林云杉-华北落叶松混交林华北落叶松林云杉-白桦混交林。土壤呼吸具有明显的季节变化,并在7月份达到最大值。云杉-华北落叶松混交林的土壤呼吸季节间变化幅度最大,华北落叶松林的变化幅度最小,最大土壤呼吸分别是最小土壤呼吸的17.36和1.83倍。华北落叶松林的土壤呼吸与土壤温度没有相关关系,与大气温度正相关(R2=0.75)且呈幂函数模型,与土壤水分含量负相关,其他4种林型的土壤呼吸与大气温度和土壤温度均呈现很好的正相关关系(R2=0.80~0.94),且与大气温度和土壤温度均呈幂函数模型,与土壤水分含量不相关。土壤呼吸对凋落物量的增加产生正响应,且凋落物呼吸在混交林内所占的比重大于纯林。 相似文献
11.
Secord R Bloch JI Chester SG Boyer DM Wood AR Wing SL Kraus MJ McInerney FA Krigbaum J 《Science (New York, N.Y.)》2012,335(6071):959-962
Body size plays a critical role in mammalian ecology and physiology. Previous research has shown that many mammals became smaller during the Paleocene-Eocene Thermal Maximum (PETM), but the timing and magnitude of that change relative to climate change have been unclear. A high-resolution record of continental climate and equid body size change shows a directional size decrease of ~30% over the first ~130,000 years of the PETM, followed by a ~76% increase in the recovery phase of the PETM. These size changes are negatively correlated with temperature inferred from oxygen isotopes in mammal teeth and were probably driven by shifts in temperature and possibly high atmospheric CO(2) concentrations. These findings could be important for understanding mammalian evolutionary responses to future global warming. 相似文献
12.
东亚是温带植物种丰度的热点地区,它与北美东部具有相似的气候和植物组成,但是物种丰度是北美东部的2倍。第四纪冰期和间冰期反复的气候变动形成了当今北半球温带物种的分布格局与遗传结构,反复的气候波动导致海平面的反复升降,为东亚地区物种扩张提供了路线,导致种群不断的分开和连接,从而促进了进化的发生和异域物种的形成。介绍了森林树种的群体遗传学研究及分子系统地理学研究情况,阐述了东亚地区森林树种迁移扩散研究概况,包括物种迁移扩散模式及森林树种天然种群在东亚的迁移扩散情况,最后展望了该研究领域的发展趋势。 相似文献
13.
Dynamic global vegetation models (DGVMs) have shown that forest dynamics could dramatically alter the response of the global climate system to increased atmospheric carbon dioxide over the next century. But there is little agreement between different DGVMs, making forest dynamics one of the greatest sources of uncertainty in predicting future climate. DGVM predictions could be strengthened by integrating the ecological realities of biodiversity and height-structured competition for light, facilitated by recent advances in the mathematics of forest modeling, ecological understanding of diverse forest communities, and the availability of forest inventory data. 相似文献
14.
15.
Ocean salinities reveal strong global water cycle intensification during 1950 to 2000 总被引：3，自引：0，他引：3
Fundamental thermodynamics and climate models suggest that dry regions will become drier and wet regions will become wetter in response to warming. Efforts to detect this long-term response in sparse surface observations of rainfall and evaporation remain ambiguous. We show that ocean salinity patterns express an identifiable fingerprint of an intensifying water cycle. Our 50-year observed global surface salinity changes, combined with changes from global climate models, present robust evidence of an intensified global water cycle at a rate of 8 ± 5% per degree of surface warming. This rate is double the response projected by current-generation climate models and suggests that a substantial (16 to 24%) intensification of the global water cycle will occur in a future 2° to 3° warmer world. 相似文献
16.
Global change and the ecology of cities 总被引：18，自引：0，他引：18
Grimm NB Faeth SH Golubiewski NE Redman CL Wu J Bai X Briggs JM 《Science (New York, N.Y.)》2008,319(5864):756-760
Urban areas are hot spots that drive environmental change at multiple scales. Material demands of production and human consumption alter land use and cover, biodiversity, and hydrosystems locally to regionally, and urban waste discharge affects local to global biogeochemical cycles and climate. For urbanites, however, global environmental changes are swamped by dramatic changes in the local environment. Urban ecology integrates natural and social sciences to study these radically altered local environments and their regional and global effects. Cities themselves present both the problems and solutions to sustainability challenges of an increasingly urbanized world. 相似文献
17.
[目的]分析我国不同区域气候变化类型对当地生态系统植被长势的长期影响。[方法]利用1981—2010年中国陆地生态系统植被指数NDVI与气温及降水之间的响应关系,定量识别植被与气候的相互作用机制,结合中国气候变化区划,完成气候变化背景下的中国陆地植被覆盖度预测。[结果]我国东北大小兴安岭、长白山、云贵高原等地区植被更适应当地气候暖干化趋势,西北地区大部、东南地区(长江下游除外)植被更适应当地气候暖湿化趋势,为气候变化利于植被生长区;我国内蒙古东部及北部沙漠化严重地区植被不适应当地气候暖干化趋势,为气候变化不利于植被生长区。我国其他大部分区域植被长势与气候变化无显著响应关系。[结果]该研究成果可为我国不同区域生态系统的差异化管理提供参考。 相似文献
18.
森林资源变化遥感监测技术研究进展 总被引：11，自引：0，他引：11
森林资源的变化对于全球碳循环、气候变化、生物多样性和生态环境有重要影响.及时、准确地获取森林资源变化信息,对于森林经营科学决策与可持续发展具有重要意义.本文对森林资源变化遥感监测技术进行了系统总结与分析,指出了各类方法的优缺点和应用范围,对影响森林资源变化遥感监测结果的因素进行了讨论,并给出了结论和建议. 相似文献
19.
大气CO_2增加对森林生态系统影响研究综述 总被引：3，自引：0，他引：3
本文针对大气ＣＯ２逐年增加的现状，分别从受控实验室模拟、历史时期冷暖期演变、气候变化后森林迁移、气候变化后林木生长潜力预测模拟四个方面，对大气ＣＯ２增加对森林生态系统影响的研究进行综述，指出了大气ＣＯ２增加导致全球气候变化的严重后果及其今后的研究对策，概述了ＣＯ２增加对森林生态系统影响研究的最新进展． 相似文献
20.
经济林产业建设是我国林业产业体系建设的重要组成部分,对于兴林富民产业的发展有着重要的意义。近年来,随着全球气候的变化和经济林产业的快速发展,经济林病虫害的发生日益加剧,严重影响着我国经济林产业的发展。阐述了我国经济林资源的发展现状,分析了经济林病虫害的特征,并针对经济林有害生物的防治提出了战略对策。 相似文献