Monitoring the concentration of N2O in the Fildes Peninsula, maritime Antarctica

Gases in the marine boundary layer in Fildes Peninsula, maritime Antarctica were sampled and analyzed for the first time. Sampling sites included areas covered by moss and lichen growth, penguin colonies and an area where scientific research stations are located. A total of 211 samples were analyzed for N₂O concentrations, with an average of (321.33±3.07) nL/L. This is above the global average value of 314 nL/L. It is found that the N₂O concentrations evidently increase during the summer months. Concentrations around the research stations are higher than at remote areas, indicating a potential source from human activities on the island. N₂O concentrations at a large penguin colony on Barton Peninsula are the highest among the sampled areas. This may explain why N₂O concentrations in Fildes Peninsula are higher than the global average. Our preliminary conclusions are that human activities and emissions from penguin dropping-amended soil and vegetation soil constitute the major sources of N₂O in the maritime Antarctic atmosphere.     

Atmospheric nitrous oxide observations above the oceanic surface during CHINARE-18

The gas samples in the marine boundary layer were collected from the track for research ship Xuelong during the 18th Chinese Antarctic Research Expedition (CHINARE-18) and nitrous oxide measurements were made by HP5890ECD-GC in the laboratory. The results represent the shipboard N2O data set obtained within the lower troposphere with the average concentration of (313.5±2.6)nL*L-1 from 31°N to 69°S. The results showed a latitudinally weighted, mean interhemispheric difference of 0.61 nL*L-1. The latitudinal distribution of atmospheric N2O concentration was analyzed from northern midlatitudes to Southern Ocean around the Antarctic continent and it was showed that N2O concentration in the current confluences was higher than that in other oceanic areas. This indicated that strong N2O emissions occurred there. The longitudinal distribution of N2O concentrations in the Southern Ocean also showed similar situation. According to the interhemispheric difference of atmospheric N2O concentrations and the two-box model, we estimated that 2/5 of the global flux of N2O into the atmosphere is derived from the sources in the southern hemisphere.     

Variation of Antarctic seal population in response to human activities in 20th century

A sediment core was collected from the Fildes Peninsula of Antarctica, which contained numerous seal hairs and was identified to be seal excrement deposition. By analyzing its total organic carbon (TOC) and concentrations of bio-elements, the seal population changes of the past century were reconstructed. The variation of seal population in the last century on the Fildes Peninsula is primarily controlled by human activities. The sealing industry in the early 20th century caused the dramatic decline of seal ...     

南极乔治王岛菲尔德斯半岛土壤发生类型及其诊断特性

在综合分析研究成土环境，成土过程及土壤诊断特性的基础上，提出了亚南极海洋性气候区（无冰区）土壤地理发生分类系统，并将菲尔德斯半岛地区的土壤划归为３个土纲，４个亚钢和１３个土类，然后分析了土壤分布与环境的关系。     

近10年全球水土保持研究热点问题述评

为科研人员了解水土保持学科研究前沿与发展,有针对性地开展研究提供科学依据,采用国际通用的4个引文数据库的数据,基于情报计量学理论,对2006—2015年全球水土保持学科研究领域进行分析。统计发现,2006—2015年全球水土保持研究的文献产出相对集中在美国和中国这两个该学科研究发达的国家,内容主要集中在环境科学与生态学、农业、水资源、地质学、工程和自然地理6个研究领域。其中,全球气候变化、人类活动、荒漠化及相互关系研究,土壤侵蚀建模与土壤侵蚀所造成的环境与生态影响评估是研究的热点。中国黄土高原是水土保持研究的区域重点热点。荒漠化是全球气候变化与人类活动共同影响的结果,旱地发展范式(DDP)正在兴起。与气候、水力、风成、泥石流、植被覆盖相关的土壤侵蚀模型是土壤侵蚀研究预测及治理的主要研究模型与重要方法。基于模型、指标阈值、现代化技术与设备的评估方法是土壤侵蚀所造成的环境与生态影响评估的主要方法     

森林土壤温室气体通量对森林管理和全球大气变化的响应

森林土壤是温室气体重要的源和汇。探讨不同森林管理和全球大气变化下土壤温室气体通量特征,为有效减少温室气体排放及森林可持续管理等提供参考。笔者从森林土壤温室气体(forest soil green house gases)、森林管理(forest mangement)和全球大气变化(global atmospheric change)3个关键研究点,查阅近年来相关研究成果,归纳森林管理和全球大气变化下土壤温室气体通量的一般性模式。CO₂、CH₄和N₂O是3种重要温室气体,其通量间存在协同、消长和随机型耦合关系。森林管理如火烧、采伐和造林等显著影响土壤温室气体通量。一般情况下,火烧导致土壤N₂O通量降低,CH₄吸收量增加,CO₂通量因火烧类型、火烧强度、生态系统类型不同出现增加、减低和无影响3种结果; 采伐通常导致土壤CO₂、CH₄和N₂O排放增加; 造林可使土壤CO₂排放减少,对N₂O和CH₄通量的影响随生态系统类型、造林树种等而改变。全球大气变化如CO₂浓度升高、氮沉降和气温升高影响森林土壤温室气体通量。通常,CO₂浓度升高导致土壤CO₂和N₂O排放量增加,CH₄吸收量降低; 氮沉降促进土壤N₂O排放、抑制CH₄吸收。气温升高导致土壤CO₂和N₂O排放增加。森林管理和全球大气变化对土壤温室气体通量的综合影响是非叠加的,有效的森林管理可能改变土壤温室气体通量对全球大气变化的响应。     

广西北部湾近岸海域营养盐与富营养化状态研究

为全面了解广西北部湾近岸海域营养盐与富营养化程度,于2021年8月和2022年1月在珍珠湾、钦州湾、廉州湾、铁山港和涠洲岛海域共27个站位采集表层水,分析营养盐浓度,并运用营养盐限制因素评价方法和富营养化指数法分析营养盐结构特征和富营养化状况。结果表明：广西北部湾近岸海域夏季表层水体溶解态无机氮(DIN)、磷酸盐(PO₄^3--P)和硅酸盐(SiO₃^2--Si)均值分别为0.177 mg/L、0.019 mg/L和0.578 mg/L,冬季三者分别为0.162 mg/L、0.021 mg/L和0.324 mg/L,营养盐浓度均为SiO₃^2--Si>DIN>PO₄^3--P;其中DIN和SiO₃^2--Si平均值在夏季高于冬季,而PO₄^3--P为夏季略低于冬季。各海湾营养盐浓度大小依次为铁山港和钦州湾>廉州湾>...     

基于横波分裂方法的海南地幔柱研究

利用横波分裂方法,对北京大学、南方科技大学及桂林理工大学在广东和广西布设的宽频带流动台阵以及国家地震台网在广东、广西和海南的固定台站记录的XKS震相进行计算,得到海南及邻近地区的上地幔各向异性参数,分裂延迟时间在0.35～1.90s之间.综合研究区域内前人发表的和本文的横波分裂结果,认为自新生代以来,伴随东部太平洋板块...     

鄱阳湖湿地泗洲头洲滩浅层土壤氮素的时空特征

湿地是全球氮循环的N源、N汇和N转化器,自然湿地氮的研究对于揭示生态系统氮循环的规律具有重要意义.以鄱阳湖湿地泗洲头为研究区域,根据湿地海拔高程梯度(10～17 m)采取表层土壤0～20 cm土层样品,分析了土壤全氮、铵态氮、硝态氮、碱解氮的空间分布特征.结果表明:鄱阳湖湿地泗洲头表层土壤氮含量空间分布较为复杂,0～10 cm土层的氮含量和10～20 cm土层的氮含量呈现相似的梯度特征,0～10 cm土层的土壤氮含量要高于10～20 cm土层的土壤氮含量,其中0～10 cm土层和10～20 cm土层的全氮、铵态氮、碱解氮含量最高均值出现在高程13～14 m,硝态氮最高均值出现在高程16～17 m.利用SPSS双变量中的pearson相关性检验表层土壤全氮、铵态氮、硝态氮、碱解氮与地上生物量、土壤pH值、土壤含水量、年均淹水时间、高程之间的相关性,结果表明:土壤氮素与地上生物量的相关性在统计学意义上最为显著,而与其他环境因素的相关性并不明显.这反映了鄱阳湖泗洲头表层土壤氮含量的空间分布与积累过程受干扰的因素比较复杂.     

祁连山北麓出山径流对气候变化的响应

祁连山是甘肃省河西走廊的地表径流发源地,每年平均从其北麓向南部的河西绿洲输送68．86％10^8m^3的径流量,因此,祁连山区北麓出山径流的变化对河地区的社会和经济发展有着举足轻重的作用,根据祁我与河西走廊平原区有关水文气象台站最新的降水、气温和径流观测资料,分析了该区域近50年来气候变化的特征及与全球气候变暖的关系、出山径流对抉变化的响应以及其未来的变化趋势,结果表明,祁连山区与河西走廊平原区近几十年来气温变化总的呈上升趋势,与全球增温存在着某种程度的一致性,但山区气温的变化幅度一般大于走廊平原区,其中又以祁连山中段地区温度升幅为最大,全球增温对河西内陆干旱区气候与出山径流的影响有着明显的地域性差异。受此影响,祁连山北麓东部地区出山径流呈明显的下降趋势;中部地区出山径流的增加趋势不是十分明显;西部出山径流在降水量与气温同时上升的情况下,呈明显的上升趋势。     

基于CALIOP资料的中国及周边地区云出现概率时空分布特征分析

云垂直结构是影响大气辐射的重要参数,其时空分布是影响全球气候变化的关键组成部分.本文利用星载激光雷达CALIOP的1 km云层产品,计算了中国及周边地区（0-55°N,70-140°E）云的出现概率,对不同地区、不同季节、不同高度单层云的出现概率做了对比分析.结果表明：云的出现概率表现出明显的地区差异,蒙古高原和印度半岛北部少云,热带海域和中国南方多云,多数地区夜间云出现概率略高于白天;除蒙古高原和印度半岛北部以外,多数地区单层云比多层云更常见;多数地区高云占单层云的比例最大,而中国大陆南部单层的中云较常见,西太平洋北部海域常被单层的低云覆盖;夏秋两季云出现概率普遍大于春冬两季,尤其印度半岛北部的云主要出现在夏季;蒙古高原和印度半岛北部单层云少于多层云,冬季尤其明显,而中国西南地区东部全年单层云更常见;夏季单层的高云占全年单层云的比例最大,青藏高原部分地区超过35%,这与其地形特征和夏季对流活动旺盛有关.     

南极长城站地区企鹅的种群数量与分布

１９９３－１１－１９９４－０３对南极长城站地区的企鹅种群的数量和分布进行了调查，共记录到６种企鹅即阿德利企鹅巴布亚全鹅，南级企鹅，长冠企鹅，王企鹅和帝企鹅。其中前３种企鹅在本地区繁殖，后３种企鹅为本地区鸟类分布的新记录。在长城站地区繁殖的企鹅总数约为１．１万只，繁殖成功率为１．３０－１．５７只／对。     

Paleoecological implications of the nitrogen isotope signatures in the sediments amended by Antarctic seal excrements

The nitrogen isotope signatures in the sediments amended by seal excrements, from Fildes Peninsula of King George Islands, Antarctica, were examined for their paleoecological application potential. The contents of total organic carbon (TOC) and total nitrogen (TN) and the atomic C/N ratios in the sediments show that the organic carbon and nitrogen are predominantly of marine origin and derived from seal excrements. The remarkably high δ15N values in the sediments may be related to at least two important factors of trophic enrichment and NH3 volatilization, which requires further studies. The large variations in the seal hair abundances and the determinedδ15N values in the sediments signify similar changes of the historical seal populations around the study site. A significant negative correlation between the δ15N values and seal hair abundance was observed, and this suggests that the δ15N values, like the number of seal hairs,can be used as a paleoecological proxy for the historical seal populations. The time-integrated δ15N signatures in the sediments with predominantly animal-derived nitrogen source thus provide a new tool for estimating historical populations of seals and penguins and interpretlng the underlying paleoecological processes.     

Changes in tropospheric ozone levels over the Three Representative Regions of China observed from space by the Tropospheric Emission Spectrometer (TES), 2005–2010

Tropospheric ozone observations over China from 2005 to 2010 at three pressure levels (484,681 and 825 hPa) from the Tropospheric Emission Spectrometer on board the NASA Aura satellite have been analyzed.Fourier Transform analysis revealed the trends and seasonality of regionally-averaged,monthly-mean ozone concentrations over western,northern and southern China.Significant increases in ozone levels are found over all three regions at 464 hPa and the rate of increase is fastest over northern China,reaching 0.89±0.059 nL/(La).At 681 hPa,ozone shows increases over northern and western China,at a rate of 0.57± 0.065 nL/(La) and 0.41±0.041 nL/(La) respectively,but is constant over southern China.At 825 hPa,ozone increases at a rate of 0.36±0.074 nL/(La) over northern China,while decreasing over southern China at a rate of 0.21±0.061 nL/(La).Over the three regions,ozone levels are generally higher in summer and lower in winter.Over southern China at all three pressure levels and northern China at the 825 hPa level,ozone shows double peaks occurring in spring and autumn as a result of the combined effects of atmospheric chemistry and global transport.This work provides a useful observational dataset and tools for future analysis of changes in tropospheric ozone over China.     

CO2 background concentra-tion in the atmosphere over the Chinese mainland

Based on the long-term monitoring data on CO2 concentration, variation trend and characteristics of CO2 background concentration in the atmosphere over the Chinese mainland are analyzed. Results show that the increasing trend of CO2 background concentration in the atmosphere over the Chinese mainland has appeared during the period of 1991-2000. The average annual CO2 growth increment is 1.59 μL/L, and the average annual CO2 growth rate is 0.44%. Distinct seasonal variations of CO2 background concentration are observed, and the averaged amplitude of CO2 seasonal variations is 10.35 μL/L. Regional variation characteristics of CO2 background concentration in the atmosphere and possible impact of human activities on these variations over the Chinese mainland are discussed as well.     

蛇床子总香豆素的杀螺活性研究

研究蛇床子总香豆素的杀螺效果,及对钉螺酯酶同工酶以及糖原的影响,以探究其杀螺机理.用不同浓度(1.25、2.50、5.00、10.00、20.00、40.00mg/L)蛇床子总香豆素处理液处理钉螺,发现10mg/L以上浓度处理3~4d可100%杀死钉螺,且处理液浓度和处理时间与钉螺的死亡率显著的正相关.用浸杀48h的LC50浓度(4.64mg/L)蛇床子总香豆素药液浸泡钉螺,于浸泡后24、48、72、96h挑选活螺,检测钉螺酯酶同工酶活性及软体组织糖原的变化情况.结果表明:浸泡的96h内,钉螺酯酶活性先升高,后降低,最后几乎完全丧失;体内糖原含量则随浸泡时间的延长而降低,浸泡96h后糖原含量下降30.06%.     

基于代数等价路径的一类线性约束凸规划问题的内点算法

对于满足尺度李谱希茨条件的一类线性约束凸规划问题,提出了一种基于代数等价路径的原始-对偶内点算法,并讨论了计算复杂性.该算法可以在任一内部可行点启动,并且全局收敛,当初始点靠近中心路径时,此算法便成为中心路径跟踪算法,总迭代次数为O(nL),其中L是问题的输入长度,数值实验结果表明算法是有效的.     

人类活动对长江径流量特性的影响

随着长江流域水资源开发利用程度的提高以及全球气候的变化,长江径流特性在一定程度上发生了变化.为分析人类活动对长江径流特性的影响,以万县、宜昌、汉口、大通、白河、仙桃6个水文站为研究对象,以丹江口、葛洲坝及三峡水库关闸蓄水时间划分研究时段,利用各站近50 a的日流量资料对比分析了各研究时段长江年、汛期、非汛期、月径流量变化特性.结果表明,水库对河流径流量的影响与水库库容大小、水库运行方式以及测站与水库的距离远近有关.     

地磁太阴日变化L的O1分量的变化特征

 用Winch提出的地磁太阴日变化分析方法确定佘山地磁台的地磁太阴日变化的O₁分量L(O₁).首先把佘山台 196 0～1988年D,H和Z各分量的时均值资料做为整体分析年平均变化,然后按季节和太阳活动性细分后进行计算分析.讨论了L(O₁)的基本特征和季节变化、电离层和海洋发电机效应对L(O₁)的影响以及太阳活动对L(O₁)的贡献,并与国外一些地磁台的结果进行了对比分析.     

嫌气培养下砷酸盐和氮肥种类对土壤中微生物呼吸作用和反硝化作用的影响(英文)

在土壤生态系统中,砷污染和氮肥过量所引起的氮素污染越来越普遍．但至今仍很少了解砷污染对土壤中温室气体（Ｎ２Ｏ和ＣＯ２）产生和有关微生物过程的影响．本文通过土壤泥浆的嫌气培养试验,研究了添加砷酸盐和改变氮肥种类（氮素形态）对反硝化作用（Ｎ２Ｏ产生量）和呼吸过程（ＣＯ２产生量）的影响．试验结果表明,不同氮素形态对ＣＯ２产生量没有明显的影响．供应ＮＯ－３－Ｎ作为氮源时,无论是否添加砷酸盐,其Ｎ２Ｏ产生量没有明显的差异;但当供应ＮＨ＋４－Ｎ和尿素作为氮源时,其Ｎ２Ｏ产生量稍有增加．添加砷酸盐会使Ｎ２Ｏ量增加,但使ＣＯ２产生量降低．因此,砷污染可能会导致微生物呼吸作用和反硝化作用受到抑制．