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1.
1980s-2010s中国陆地生态系统土壤碳储量的变化 总被引：6，自引：2，他引：4
土壤作为陆地生态系统有机碳库的主体,在全球碳循环中起着重要作用。然而,当前区域土壤有机碳储量的变化情况及其碳源/汇功能仍然不清楚。利用中国1980s （1979-1985年）第二次土壤普查数据,同时收集整理2010s（2004-2014年）已发表的有关中国土壤有机碳储量（0~20 cm和0~100 cm）的文献数据,综合评估了1980s-2010s中国土壤有机碳储量的变化情况,并分析森林、草地、农田和湿地等生态系统土壤碳源/汇功能;同时结合现有的中国植被碳储量变化研究,进一步探讨了1980s-2010s中国陆地生态系统的碳源/汇效应。研究发现：① 1980s-2010s中国土壤（0~100 cm）有机碳储量净增长3.04±1.65 Pg C,增长速率为0.101±0.055 Pg C yr-1,其中表层土壤（0~20 cm）的碳汇效应明显;② 森林土壤是固碳主体,净增长2.52±0.77 Pg C,而草地和农田土壤增长有限,分别为0.40±0.78和0.07±0.31 Pg C;③ 湿地有机碳储量净减少0.76±0.29 Pg C;④ 中国陆地生态系统的碳汇效应较强,总碳汇量相当于同期（1980-2009年）化石燃料和水泥生产排放CO2总量的14.85%~27.79%。随着中国森林和草地生态系统植被和土壤的进一步保护、恢复和重建,中国陆地生态系统具有较大的碳汇潜力,在未来全球碳平衡中将发挥更大的作用。 相似文献
2.
1980s-2010s内蒙古草地表层土壤有机碳储量及其变化 总被引：1，自引：1，他引：0
以我国内蒙古草原为研究区域,结合1982-1988年第二次土壤普查资料以及2011-2012年实地考察数据,构建了基于遥感数据和土壤数据的区域表层土壤有机碳储量估算方法,对研究区1980s和2010s表层土壤有机碳储量、空间分布特征及其变化进行研究,结果表明：(1) 1980s、2010s内蒙古草地表层土壤 (0~20 cm) 有机碳储量分别为2.05 Pg C、2.17 Pg C,土壤有机碳密度约为3.48 kg C·m-2、3.69 kg C·m-2,其空间分布上呈现从草甸草原、典型草原、荒漠草原逐渐降低的特征;(2) 1982-2012年间,内蒙古草地表层土壤有机碳储量略有增加,但增加幅度较小,其中草甸草原和典型草原表层土壤有机碳储量增加,荒漠草原则表现为减少。研究结果将为研究区因地制宜地采取固碳措施,实现草地可持续管理提供科学参考。 相似文献
3.
Detecting the storage and change on topsoil organic carbon in grasslands of Inner Mongolia from 1980s to 2010s 总被引：2，自引：2，他引：0
Soil carbon sequestration and potential has been a focal issue in global carbon research. Under the background of global change, the estimation of the size as well as its change of soil organic carbon（SOC） storage is of great importance. Based on soil data from the second national soil survey and field survey during 2011–2012, by using the regression method between sampling soil data and remote sensing data, this paper aimed to investigate spatial distribution and changes of topsoil（0–20 cm） organic carbon storage in grasslands of Inner Mongolia between the 1980 s and 2010 s. The results showed that：（1） the SOC storage in grasslands of Inner Mongolia between the 1980 s and 2010 s was estimated to be 2.05 and 2.17 Pg C, with an average density of 3.48 and 3.69 kg C·m–2, respectively. The SOC storage was mainly distributed in the typical steppe and meadow steppe, which accounted for over 98% of the total SOC storage. The spatial distribution showed a decreased trend from the meadow steppe, typical steppe to the desert steppe, corresponding to the temperature and precipitation gradient.（2） SOC changes during 1982–2012 were estimated to be 0.12 Pg C, at 7.00 g C·m–2·yr–1, which didn＇t show a significant change, indicating that SOC storage in grasslands of Inner Mongolia remained relatively stable over this period. However, topsoil organic carbon showed different trends of carbon source/sink during the past three decades. Meadow steppe and typical steppe had sequestered 0.15 and 0.03 Pg C, respectively, served as a carbon sink; while desert steppe lost 0.06 Pg C, served as a carbon source. It appears that SOC storage in grassland ecosystem may respond differently to climate change, related to vegetation type, regional climate type and grazing intensity. These results might give advice to decision makers on adopting suitable countermeasures for sustainable grassland utilization and protection. 相似文献
4.
Afforestation in China’s subtropics plays an important role in sequestering CO2 from the atmosphere and in storage of soil carbon (C). Compared with natural forests, plantation forests have lower soil organic carbon (SOC) content and great potential to store more C. To better evaluate the effects of afforestation on soil C turnover, we investigated SOC and its stable C isotope (δ13C) composition in three planted forests at Qianyanzhou Ecological Experimental Station in southern China. Litter and soil samples were collected and analyzed for total organic C, δ13C and total nitrogen. Similarly to the vertical distribution of SOC in natural forests, SOC concentrations decrease exponentially with depth. The land cover type (grassland) before plantation had a significant influence on the vertical distribution of SOC. The SOC δ13C composition of the upper soil layer of two plantation forests has been mainly affected by the grass biomass 13C composition. Soil profiles with a change in photosynthetic pathway had a more complex 13C isotope composition distribution. During the 20 years after plantation establishment, the soil organic matter sources influenced both the δ13C distribution with depth, and C replacement. The upper soil layer SOC turnover in masson pine (a mean 34% of replacement in the 10 cm after 20 years) was more than twice as fast as that of slash pine (16% of replacement) under subtropical conditions. The results demonstrate that masson pine and slash pine plantations cannot rapidly sequester SOC into long-term storage pools in subtropical China. 相似文献
5.
以20世纪50年代中期以来崇明岛东部盐沼6个钻孔潮坪层段为研究对象,根据柱样粒度特征、碳/氮元素含量、有机碳稳定同位素组成（δ13C）和C/N比,结合长江入海泥沙通量的变化,研究20世纪50年代中期以来崇明岛东部盐沼发育与长江入海泥沙的响应关系。结果表明：长江入海泥沙通量及组成是20世纪50年代中期以来崇明岛东部盐沼物质粗细变化的主控因素;崇明岛东部盐沼沉积物δ13C与C/N比的相关程度、有机质含量与各粒径区间颗粒含量的相关性在不同时期均存在差异;20世纪60年代,长江入海泥沙量达到顶峰,流域不同侵蚀区域的泥沙相互混合,有机质含量与各粒径区间颗粒含量的相关性及δ13C与C/N比的相关程度均很差;20世纪90年代以来,崇明岛东部地区进行了高强度的围垦活动,δ13C与C/N比的相关程度下降。这表明20世纪50-80年代崇明岛东部盐沼发育受长江入海泥沙控制,20世纪90年代以来崇明岛东部盐沼发育除受长江入海泥沙控制外,还受围垦等人类活动的显著影响。 相似文献
6.
Y. Olvera-Carrillo J. Márquez-Guzmán M.E. Sánchez-Coronado V.L. Barradas E. Rincón A. Orozco-Segovia 《Journal of Arid Environments》2009,73(4-5):421-427
Opuntia tomentosa seeds have physiological dormancy and a permeable but hard funicular envelope that restricts water uptake and embryo growth. Dormancy break, germination, and changes in the funiculus were compared in laboratory-stored seeds and in those buried for 7 months at different microsites and later exhumed and stored in the laboratory. The funicular envelopes of both lots were examined with a scanning electron microscope (SEM). Seeds in both lots were: scarified with H2SO4 (0, 45, 60 and 90 min), treated with gibberellins (0, 1000 and 2000 ppm) and germinated at the same ages (0, 2, 4, 7, and 10 months after exhumation) at 24 °C. Light effect was determined at 24 °C and 20–35 °C. In laboratory-stored seeds germination was low. Exhumed seeds germinated in ～50%, the remaining ones required scarification and gibberellins, but lost dormancy two months later. Gibberellins reduced germination heterogeneity, and scarification reduced germination; the adverse effect of scarification was offset by gibberellins. Exhumed seeds germinated mainly in darkness at 20–35 °C and partially in far red light at both temperatures. SEM showed that fungi eroded the funiculus reducing its resistance. O. tomentosa could form a seed bank, ensuring its survival under heterogeneous environments. 相似文献
7.
Bjarne Kjøllmoen & Gunnar Østrem 《Geografiska Annaler: Series A, Physical Geography》1997,79(3):195-200
When the Norwegian State Power Board decided to plan an extensive water power development in the mountainous areas southeast of Narvik in northern Norway, a large mapping project was started. Detailed maps were constructed at a scale of 1:10 000 from aerial photographs taken in 1960. Several hydrometric stations were installed, and three glaciers were selected for mass balance observations. Storsteinsfjellbreen was the largest of these, and a special glacier map with 10 m contours was printed in four colours, to be used in the field work. Mass balance studies were carried out initially during one 5-year period (1964–68), and also later during another 5-year period (1991–95).
Results from these periods are compared with similar data from the Swedish glacier Storglaciären, about 45 km to the southeast. For all the years except one (1968), the net balance of these glaciers shows a similar pattern: positive years and negative years are synchronous.
A new glacier map was made from a special aerial survey in 1993 at the same scale and of similar accuracy as the first map, so a comparison could be made to calculate the change in glacier volume from 1960 to 1993. From digital terrain models it could be shown that the glacier surface had dropped more than 60 m vertically on the tongue, while the thickness increased above the equilibrium line by up to 20 m. The overall mass loss amounted to 16.8×106 m3 water during 33 years, which corresponds to an extra 2.6 l·s−1 ·km−2 (litres per sec. per sq. km) delivered to the river, in addition to the "normal" discharge
due to annual precipitation, which is 36 l·s−1 ·km−2 in the area.
A copy of the new glacier map is enclosed with this article. 相似文献
Results from these periods are compared with similar data from the Swedish glacier Storglaciären, about 45 km to the southeast. For all the years except one (1968), the net balance of these glaciers shows a similar pattern: positive years and negative years are synchronous.
A new glacier map was made from a special aerial survey in 1993 at the same scale and of similar accuracy as the first map, so a comparison could be made to calculate the change in glacier volume from 1960 to 1993. From digital terrain models it could be shown that the glacier surface had dropped more than 60 m vertically on the tongue, while the thickness increased above the equilibrium line by up to 20 m. The overall mass loss amounted to 16.8×10
due to annual precipitation, which is 36 l·s
A copy of the new glacier map is enclosed with this article. 相似文献
8.
FU Jiafeng A Rouna WANG Meng KONG Shanshan GAO Qingxian 付加锋 阿柔娜 王蒙 孔珊珊 高庆先 《资源与生态学报(英文版)》2013,4(4):293-303
中国作为最大的发展中国家,已经成为二氧化碳第一排放大国,因此,国际社会开始敦促中国在后京都时期承担更多减排责任。现阶段,《联合国气候变化框架条约》使用生产型二氧化碳排放清单,这就意味着它将减排责任分配给了污染制造者。本文比较并分析了中国的生产型和消费型二氧化碳排放清单,并认为消费型的二氧化碳排放清单更为公平合理,产品的消费者应该为他们所购买的产品中隐含的碳排放付费。此外,为了考虑公平问题,政府应采取全面的经济政策和行政手段扶持经济落后的省份进行减排。 相似文献
9.
The National Forest Inventory (NFI) is an important resource for estimating the national carbon balance (These data were unpublished data, and we could only obtain the data before 2008 through data search by now). Based on the data from sample plots, the literature, and NFI, as well as the relationships between volume, biomass, annual litterfall and soil respiration of different forest types, the net ecosystem production (NEP), changes in forest biomass carbon storage (△Cbiomass) and non-respiratory losses (NR) of China’s forests during 1999-2008 were estimated, and the forest soil carbon sequestration (△Csoil) was assessed according to the carbon balance principle of the forest ecosystem (△Csoil = NEP - NR - △Cbiomass). The results showed that the total NEP, △Cbiomass, NR and △Csoil values for China’s forests were 157.530, 48.704, 31.033 and 77.793 Tg C yr-1 respectively, and average NEP, △Cbiomass, NR, and △Csoil values were 101.247, 31.303, 19.945 and 49.999 g C m-2 yr-1 respectively. There were large spatial differences in forest soil carbon sequestration in different parts of China. The forest soil in Jiangxi, Hunan, Zhejiang, Fujian, Anhui, Shanxi, Shaanxi, Guangxi and Liaoning served as carbon sources and the carbon released was about 25.507 Tg C yr-1. The other 22 provinces served as carbon sinks and the average carbon sequestration by forest soil came to 103.300 Tg C yr-1. This research established a method for evaluating soil carbon sequestration by China’s forests based on the NFI, which is a useful supplement to current statistical data-based studies on the forest ecosystem carbon cycle, and can promote comparable studies on forest soil carbon sequestration with consistent research methods at the regional scale. 相似文献
10.
11.
Rohan G. Clark 《The Australian geographer》1989,20(1):65-73
Australian road funding in the 1970s and 1980s has been characterised by conflict between federal and state governments over control of spending. This has influenced both total funds made available and spending priorities between national, arterial and local roads. Having the constitutional responsibility for roads, state governments have refused to discuss priorities with the Commonwealth, have not stated policies, have given the Australian government as little public acknowledgement as possible, have spent money on markedly different priorities, and yet are changing their means of determining priorities to reflect changing community wishes. Interestingly, at neither state nor federal level is there evidence of pursuance of a single, dominant policy objective. 相似文献
12.
13.
Nufar Avni 《Urban geography》2019,40(4):488-505
In the last decade, justice has been revived as a primary criterion for the analysis and evaluation of planning policies. This paper continues this line of research by examining a proposed redevelopment project in Washington, D.C. that sets equitable development as its goal . The proposed 11th Street Bridge Park would be a top-notch elevated park, physically and symbolically connecting D.C’s wealthy west with the disadvantaged east. The project is managed by a nonprofit organization and seemingly stands out in its progressive vision: An Equitable Development Plan has been developed in an attempt to secure the future of the local residents in light of the neighborhood's anticipated gentrification. However, preliminary findings show that despite explicit commitment to equity, the planning of the park also resurfaces racial and class tensions . The analysis of procedural and substantive aspects of justice in this case suggests that issues of recognition, power and representation are instrumental to fully understand urban (in)justices. 相似文献
14.
15.
M. T. Daly 《The Australian geographer》1988,19(1):149-161
The growth of Australian cities was the most prominent aspect of Australia's development during the boom years from the end of World War Two. As the nation pursued a policy of import substitution, the economies of the cities became firmly based on manufacturing. Mass production methods and mass consumption dictated the pattern of urban development. Such growth was premissed on very special conditions that enabled the system to accommodate the fluctuations that inevitably occur within the capitalist mode of production in general, and mass production methods in particular. A nation which had always been highly urbanised and open to international influences became even more deeply enmeshed in the fluctuating fortunes of the global economy. As the special factors supporting the postwar prosperity broke down through the 1970s and 1980s, Australian cities have faced a number of critical problems of adapting to the new environment. 相似文献
16.
以中国286个地级城市C2C（Consumer to Consumer,个人与个人之间的电子商务）网购指数为基础,尝试从宏观尺度分析中国居民网络消费的空间特征,并对技术扩散假说和效率假说在中国的适用性进行验证。结果表明：① 中国城市居民的网络消费水平表现出明显的由东部沿海向西北内陆逐渐递减的等级式空间分异规律。② 年轻人口比例、收入水平以及实体商业发展水平对城市居民的网络消费具有显著的促进作用,但城市交通可达性对其具有显著的抑制作用。③ 技术扩散假说和效率假说对中国城市居民网络消费水平的空间特征均有一定的解释力。发达城市居民的网络消费水平更高,这表明技术扩散假说在中国更具解释力。 相似文献
17.
1965年以来我国对外贸易及其 地域格局的演变态势 总被引：2，自引：0，他引：2
本文总结了我国不同尺度地域单元近40年不同阶段对外贸易总量增长、对外依存度不断提高的基本特点及其地域格局演变的基本态势,分析了出口商品结构变化的基本趋势,并初步探讨了我国对外贸易特点及其地域格局形成的基本成因。研究发现:(1)从时间尺度看,40年来,我国不同尺度的不同区域对外贸易总量和对外依存度均呈长期增长态势,外贸年均增长速度长期高于GDP年均增长速度;(2)从空间尺度看,东、中、西地带对外贸易的区域差异格局没有根本改变,相反中、西地带的相对地位随着市场经济的发展呈下降趋势。我国进/出口位居前四位的省市绝大部分位于东部地区,随着市场经济的进一步发展,呈现出由北向南演变的趋势。在国际上,我国对亚洲的进/出口占绝对优势,但相对地位逐渐下降。 相似文献
18.
Timothy G. Fisher Walter L. Loope William Pierce Harry M. Jol 《Journal of Paleolimnology》2007,37(3):365-382
We reconstruct postglacial lake-level history within the Lake Michigan basin using soil stratigraphy, ground-penetrating radar
(GPR), sedimentology and 14C data from the Silver Lake basin, which lies adjacent to Lake Michigan. Stratigraphy in nine vibracores recovered from the
floor of Silver Lake appears to reflect fluctuation of water levels in the Lake Michigan basin. Aeolian activity within the
study area from 3,000 years (cal yr. B.P.) to the present was inferred from analysis of buried soils, an aerial photograph
sequence, and GPR. Sediments in and around Silver Lake appear to contain a paleoenvironmental record that spans the entire
post-glacial history of the Lake Michigan basin. We suggest that (1) a pre-Nipissing rather than a Nipissing barrier separated
Silver Lake basin from the Lake Michigan basin, (2) that the Nipissing transgression elevated the water table in the Silver
Lake basin about 6,500 cal yr. B.P., resulting in reestablishment of a lake within the basin, and (3) that recent dune migration
into Silver Lake is associated with levels of Lake Michigan.
This is the fourth in a series of ten papers published in this special issue of Journal of Paleolimnology. These papers were
presented at the 47th Annual Meeting of the International Association for Great Lakes Research (2004), held at the University
of Waterloo, Waterloo, Ontario, Canada. P.F. Karrow and C.F.M. Lewis were guest editors of this special issue. 相似文献
19.
Records of terminus positions for the 1960s to 1980s have been obtained for 51 glaciers in the Greater Caucasus Mountains between the Black Sea and Caspian Sea, between latitude 40° and 44° N and longitude 40° and 49° E. These records have been analyzed as percentage of glaciers observed retreating, advancing, and stationary, displayed as a five-year moving average. The main result is the absence of the clear trend towards glacier advance found in the Alps between the 1960s and 1980s by both Patzelt (1985) and Wood (1988), suggesting a phase difference in the climates of the Alps and the Caucasus. [Key words: glaciers, glaciology, Greater Caucasus Mountains, Alps.] 相似文献
20.
Detailed understanding of global carbon cycling requires estimates of CO 2 emissions on temporal and spatial scales finer than annual and country. This is the first attempt to derive such estimates for a large, developing, Southern Hemisphere country. Though data on energy use are not complete in terms of time and geography, there are enough data available on the sale or consumption of fuels in Brazil to reasonably approximate the temporal and spatial patterns of fuel use and CO 2 emissions. Given the available data, a strong annual cycle in emissions from Brazil is not apparent. CO 2 emissions are unevenly distributed within Brazil as the population density and level of development both vary widely. 相似文献