绿洲演化与自然和人为因素的关系初探——以克里雅河下游地区为例

以位于塔里木盆地的克里雅河下游地区绿洲为例 ,论述了自然环境要素演变及人类活动对绿洲发育的重要作用。克里雅河下游地区的现代绿洲包括沿河岸分布的带状绿色走廊和河流终端干三角洲上的扇形牧业绿洲。依据对河流沉积物及古河道分析得出的结论是 ,在末次冰期晚期时 ,由于来自昆仑山的大量消融水的出现 ,克里雅河的绿色走廊横穿塔克拉玛干沙漠。类似的情况在距今约2 0 0 0年和小冰期时都出现过。这种大的变化是自然环境演变的结果。但是 ,近百年来特别是近 5 0年克里雅河下游牧业绿洲的严重退化是中游地区集中发展农业绿洲而增加引水量及下游地区过度砍伐所造成的。     

小兴安岭黑大公路沿线多年冻土分布及退化状态

黑大公路沿线多年土主要分布于黑河－北安段，属小兴安岭岛状多年冻土区，该区存在的多年冻土是晚全新世寒冷时期的产物，现处于欧亚多年冰土南界边缘，多年冻土发育在低洼、地表积水、塔头草生长茂密、草炭和泥炭发育的沼泽化湿地当中，沼泽湿地独特的热交换特性决定了其中发育的多年冻土处于退化的最晚阶段，冻土的退化在自然条件下可能依赖于由于至上的地下热流。多年冻土的地温剖面表现为零梯度曲且冰土温度接近于0℃，由此决定了多年冻土对人为活动干扰的敏感性。     

1994年西太平洋副高异常变化及其成因分析

对１９９４年副高的异常气候特征及其原因进行了分析，结果表明，１９９４年副高强度异常强，季节性北跳早，盛夏位置稳定北，副高的这些特点除了气候背景的影响外，主要与海气相互作用有关。同也，也讨论了副高异常对海温距平场的影响。     

红壤退化中的土壤质量评价指标及评价方法

土壤质量评价与监测是评价土壤退化的重要工作,也是重新设计持续性的土壤管理系统的基础。目前缺乏统一的评价指标以及将各项土壤性质与土壤管理措施结合起来的评价方法。本文首先提出了选择红壤质量评价指标的原则,并从化学、物理学和生物学三个方面初步探讨了评价红壤质量动态变化可资采用的指标体系,综述了国内在南方丘陵区红壤质量演化的研究中应用的指标;最后从土地评价方法中选择了可用于红壤质量评价的方法,并简要综述了国际上最新的土壤质量评价方法。     

Characteristics and formation causes of Qingdao Cold Water Mass

In this work,the main characteristics of the Qingdao Cold Water Mass were studied by using“the comparison analysis method”based on 1980 temperature,salinity and dissolved oxygen data on the western South Yellow Sea.The formation cause of the water mass was analyzed based on February of 1959 temperature and salinity data for this area and on some other authors’studies.The results showed that the Qingdao Cold Water Mass has growing and vanishing processes：appears in the last ten days of March;has stable pattern in April;is biggest in its area in May;becomes small in its area in June;vanishes in July.It comes from the northem Shandong Coastal Water and is characterized by low temperature and salinity and high disolved oxygen.The mass is formed under the joint effects of anticyclonic circulation and solar radiation.     

Hydrocarbon degraders from tropical marine environments

Analysis of 20 samples of marine mud and water around Mumbai resulted in the isolation of 17 bacteria and yeasts all of which were able to degrade more than 10% of the supplied crude oil. The yeasts strains were important degraders of the aliphatic fraction of crude. All the isolated yeasts belonged to the genus Candida. Using biochemical tests these were identified as Candida parapsilosis, C. albicans, C. guilliermondii, Yarrowia lipolytica, C. tropicalis and C. intermedia. Y. lipolytica was the best degrader utilizing 78% of the aliphatic fraction of Bombay High crude oil. None of these isolates degraded the aromatic or ashphaltene fractions. All the isolates required aeration, nitrogen and phosphate supplementation for optimal degradation. Four out of the six yeasts are human pathogens.     

Relationship between structures of substituted indolic compounds and their degradation by marine anaerobic microorganisms

Degradation of selected indolic compounds including indole, 1-methylindole, 2-methylindole, and 3-methylindole was assessed under methanogenic and sulfate-reducing conditions using the serum-bottle anaerobic technique and marine sediment from Victoria Harbour, Hong Kong as an inoculum. Our results showed that indole degradation was achieved in 28 days by a methanogenic consortium and 35 days by a sulfate-reducing consortium. During degradation under both conditions, two intermediates were isolated, purified and identified as oxindole and isatin (indole-2,3-dione) suggesting that both methanogenic and sulfate-reducing bacteria use an identical degradation pathway. Degradation processes followed two steps of oxidation accomplished by hydroxylation and then dehydrogenation at 2- and then 3-position sequentially prior to the cleavage of the pyrrole ring between 2- and 3-positions. However, none of 1-methylindole or 2-methylindole was degraded under any conditions. 3-Methylindole (3-methyl-1H-indole, skatole) was transformed under methanogenic conditions and mineralized only under sulfate-reducing conditions. It is clear that methyl substitution on 1- or 2-position inhibits the initial attack by hydroxylation enzymes making them more persistent in the environment and posing longer toxic impact.     

回忆父亲点滴

父亲是世纪同龄人 ,从 50岁到 80岁是他生命的春天。他以常人在这个年龄难以迸发的热情、智慧、不懈努力和顽强开拓的精神 ,在地质战线上为新中国建设辛勤耕耘 ,是一位在地学领域涉足宽广、具有科学预见能力、富有领导组织才能的科学家和领导者。他总是关注未来 ,特别热心于培养年轻人 ,对建立一支高水平、有解决问题能力的地质队伍下了很大功夫。父亲沉静善思、富有哲学头脑 ,他的许多预见性学术观点和开创性思维都源于他宁静淡泊的心态。没有浮华和功利 ,这便是他智慧的源泉。     

近31年登陆北上台风特征及其成因分析

为探讨对我国产生严重影响的登陆北上台风的成因，利用1975—2005年台风资料及NCEP／NCAR逐日再分析等资料，分析了登陆北上台风的气候特征及其大尺度环流和物理量分布特征。结果发现，不仅西北太平洋副热带高压位置和强度变化对台风登陆北上起决定性作用，而且西风带系统和南亚高压活动有利于台风登陆后北折和持续北上也有不可忽视的影响。总结归纳台风登陆北上的预报着眼点，希望有助于提高此类台风的预报预警能力。     

河西走廊春季强冻害成因及防御对策

应用酒泉、张掖、武威实况资料,从作物的各个生长发育期进行了对比分析,结果表明强冷空气爆发是造成冻害的直接原因,前期气温异常偏高使农作物生育期提前、气温和地温较低加剧了冻害程度。并提出了防御冻害发生的有效措施。