排序方式: 共有14条查询结果,搜索用时 15 毫秒
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北方沼泽地水位下降对全球气候变暖的影响 总被引:4,自引:0,他引:4
钱云 《Ambio-人类环境杂志》1996,25(3):179-184
自从最后一次冰川消退以来,北方沼泽地(3.46亿hm^2)积存了300-500Pg了300-500Pg碳。这些沼泽地在分离二氧化碳(CO2)的同时,释放了相当数量的甲烷(CH4)到大气中,正如对高纬地区预报的那样,如果夏季变得更热,更干,未来沼泽地温室气体的平衡将发生变化,随之而来CH4排放将减少,而CO2和N2O的排放将增加。北部沼泽地水位下降预计将增强温室效应的影响。我们分别在不同营养水平的水 相似文献
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Spatial variations in daily average CO2 concentrations above wetland surface of Xianghai National Nature Reserve, China 总被引:1,自引:0,他引:1
Horizontal and vertical variations of daily average CO2 concentration above the wetland surface were studied in Xianghai National Nature Reserve of China in August, 2000. The primary purpose was to study spatial distribution characteristics of CO2 concentration on the four levels of height(0.1 m, 0.6 m, 1.2 m and 2 m) and compare the differences of CO2 concentration under different land covers. Results showed that daily average CO2 concentration above wetland surface in Xianghai National Natural Reserve was lower than that above other wetlands in northeast China as well as the worldwide average, suggesting that Xianghai wetland absorbed CO2 in August and acted as“sink” of CO2. The horizontal variations on the four levels of height along the latitude were distinct, and had the changing tendency of“decreasing after increasing” with the increase of height. The areas with obvious variations were consistent on different levels of height,and those with the highest variations appeared above surface of shore, sloping field, Typha wetland and Phragmites wetland; the vertical variations were greatly different, with the higher variations in Phragmites wetland and Typha wetland, and the lands near the shore and the sloping field with the lower variations. Spatial variations of daily average CO2 concentrations above wet!and surface were affected by surface qualities and land covers. 相似文献
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黑雁,也称北极雁,是法国北部濒临灭绝的一种珍稀大雁,这种候鸟每年都要从法国北部迁徙一万多里到西班牙南部沼泽地过冬。然而,随着黑雁的栖息地被不断开发破坏,黑雁一天天减少。一群生来就没有父母的黑雁孤儿丧失了飞翔的技能,就在它们的生命岌岌可危时,法国男子克里斯蒂安·穆莱克和妻子保拉担起了重任,他们成了黑雁孤儿的"鸟爸""鸟妈",并发明了一种滑翔机充当"头鸟",带领这些幼雁学习飞翔,不远万里带领他们到南方过冬。 相似文献
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李忠波 《辽宁城乡环境科技》2003,23(1):39-41
由于保护区工农业活动频繁,使丹顶鹤的栖息地形成分割不连片的岛的化,其原因是人们打井采油,毁苇造田,过渡捕捉鱼虾,使水生动植物遭到毁灭性打击。进而断绝水禽的饵料,拯救丹顶鹤及赖以生存的湿地生态环境非常必要。 相似文献
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甘南尕海泥炭沼泽地退化过程土壤特征和水源涵养功能的变化 总被引:2,自引:0,他引:2
由于气候变化、过度放牧、沟蚀及修路等人为影响,尕海泥炭沼泽地出现退化现象。为了查明尕海泥炭沼泽地退化过程土壤性质和水源涵养功能的变化趋势,采用空间序列代替时间序列的方法,对该区域4 种不同退化阶段泥炭沼泽地土壤性质和水源涵养功能进行了调查研究。结果表明: 随着尕海泥炭沼泽地退化程度的加剧,0~40 cm层土壤平均容重逐渐增大,总孔隙度逐渐减小,且容重和孔隙度在土壤剖面自然分布规律发生变化;土壤有机质、全氮、速效钾和水解氮含量呈逐渐降低趋势,铵态氮呈增大趋势,全磷、全钾无明显变化规律,但均沿土壤剖面分布呈波动性变化;土壤自然含水量、最小蓄水量和毛管蓄水量均为未退化最大,中度退化最小;方差分析结果表明不同退化阶段泥炭沼泽地土壤容重、总孔隙度、有机质、氨态氮及其土壤蓄水性能均存在显著差异。土壤饱和蓄水量和毛管蓄水量与有机质之间存在显著正相关,并受植被盖度和泥炭层厚度的影响。研究结果表明地下水位、植被盖度、土壤有机质含量及泥炭层厚度的下降是导致尕海泥炭沼泽地退化过程土壤性质和水源涵养功能变化的主要原因。 相似文献
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小时候,在松花江边上,初春和深秋总能看到成群结队的大雁在天空排成长长的“人”字队型,展示着生命的和谐之美,偶尔留下长空雁鸣。当地人给大雁起了一个很不雅的名字——长脖老。大雁飞来的时候,我们小朋友也会结伴去江边的沼泽地里看大雁。这大概就是现如今许多城里人“时尚而 相似文献