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1.
N2O是一种重要的温室气体,土壤是全球N2O的重要排放源。通过测定土壤源N2O中N、O同位素值,可以有效识别N2O的来源途径。本文采集了南极法尔兹半岛两个地点的海豹粪土（HS和GS）、阿德雷岛两个地点的企鹅粪土(AB和AF)以及东南极的帝企鹅粪土(DQ和DQT),在室内对所采集的样品分别在有氧和厌氧条件下进行冻融培养实验。结果表明：土壤在厌氧条件下比有氧条件下排放了更多的N2O。土壤排放的N2O与当地大气N2O相比普遍贫15N和18O。除DQT和HS外, δ15N和δ18O在有氧和厌氧培养下均呈现很好的正相关性。N2O排放量下降的同时伴随着培养瓶内剩余N2O中δ15N和δ18O 值的增加,证实N2O还原为N2的过程会引起重同位素富集。高的水分含量有利于土壤反硝化作用的进行,使释放的N2O气体富集重同位素;pH值也会影响N2O的同位素组成,低pH会引起δ15N值增加。 相似文献
2.
以南极阿德雷岛苔原沼泽为研究区域,2016年12月至2017年1月南极夏季期间观测研究了温室气体CH_4、CO_2和N_2O通量的变化规律及其对环境因子的响应关系。结果表明:光照条件下干旱苔原沼泽表现为CH_4吸收,通量为(–5.4±4.3)μg CH_4·m~(–2)·h~(–1),半干旱苔原与淹水苔原沼泽表现为净排放;三个类型苔原沼泽观测点均表现为N_2O净吸收,最高吸收通量出现在淹水苔原,为(–2.6±2.4)μg N_2O·m~(–2)·h~(–1);黑暗条件下苔原沼泽一致表现为CH_4和N_2O净排放。光照与土壤水分减少增加了苔原CH_4有氧氧化吸收,同时促进了反硝化作用对N_2O的还原转化。观测期间所有观测点均表现为CO_2的汇,最高CO_2净交换量与光合作用强度都出现在淹水苔原区,分别为(–40.1±17.6)μg CO_2·m~(–2)·h~(–1)和(91.2±26.5) mg CO_2·m~(–2)·h~(–1);而最高苔原沼泽呼吸速率出现在干旱苔原观测点,为(73.1±17.6)μg CO_2·m~(–2)·h~(–1)。夏季适宜的温度、降水条件促进了苔原植被的光合作用,增加了苔原沼泽CO_2吸收量。CO_2、N_2O、CH_4通量随时间变化的相互关系规律不显著(P0.05),但在降水与温度波动下,N_2O与CH_4通量都随CO_2通量呈现相似的波动。三种温室气体与各种环境因子之间的响应关系值得进一步研究;不同光照条件对CH_4、N_2O排放量的估算有重要影响。 相似文献
3.
海洋动物粪土是南极陆地生态系统养分的重要来源,粪土层细菌群落对南极苔原碳、氮循环过程起重要作用,但目前对南极海洋动物粪土层中细菌群落的变化特征却鲜有报道。本文采集了东南极四个企鹅、海豹粪土剖面样品,通过酶活性、微生物量碳、微生物熵、土壤呼吸和DNA浓度测定以及16 S r DNA-DGGE分析,探讨了粪土层中细菌群落变化特征及其与环境因子的关系。土壤转化酶、脲酶和磷酸酶活性、微生物量碳、土壤呼吸和微生物熵随深度增加而递减,而代谢熵增加,表明随深度增加,微生物生存环境恶劣,造成细菌丰度和酶分泌量减小,需更多有机碳进行能量代谢。土壤DNA浓度与pH、含水率、TOC、TN、微生物量碳、土壤呼吸以及酶活性呈高度正相关,表明这些因子对粪土层中细菌种群的丰度有重要影响。DGGE图谱分析证实：东南极海洋动物粪土中含丰富的细菌群落结构,随深度增加泳道带型数量和亮度递减,表明细菌多样性和丰度递减。聚类分析表明：四个剖面随深度泳道带型差异明显,细菌遗传相似性为46%,企鹅、海豹粪土细菌群落差异性尤为明显;发现四个粪土剖面中,细菌丰度与企鹅、海豹粪的相对含量呈协调一致性变化,且表层5cm粪土层细菌丰度最高,表明东南极企鹅和海豹排泄物对土壤中细菌群落多样性变化起重要作用。 相似文献
4.
Three-year summertime surface atmospheric N2O concentrations were observed for the first time on the Fildes Peninsula, maritime Antarctica, and the relationships among the N2O concentration, total atmospheric O3 amount, and sunspot number were analyzed. Solar activity had an important effect on surface N2O concentration and total O3 amount, and increases of sunspot number were followed by decreases in the N2O concentration and total O3 amount. A corresponding relationship exists between the N2O concentration and total atmospheric O3, and ozone destruction was preceded by N2O reduction. We propose that the extended solar activity in the Antarctic summer reduces the stratospheric N2O by converting it into NOx, increases the diffusion of N2O from the troposphere to the stratosphere, decreases the surface atmospheric N2O, and depletes O3 via the chemical reaction between O3 and NOx. Our observation results are consistent with the theory of solar activity regarding the formation of the Antarctic O3 hole. 相似文献
5.
Atmospheric nitrous oxide observations above the oceanic surface during the first Chinese Arctic Research Expedition 总被引：1，自引：0，他引：1
339 gas samples above oceanic surface were collected on the cruise of "Xuelong" expeditionary ship and nitrous oxide concentrations were analyzed in the laboratory. Results showed that Atmospheric average N2O concentration was 309 ±3. 8nL/L above the surface of northern Pacific and Arctic ocean. N2O concentrations were significantly different on the northbound and southbound track in the range of the same latitude, 308.0 ±3.5 nL/L from Shanghai harbor to the Arctic and 311.9 ±2.5 nL/L from the Arctic to Shanghai harbor. N2O concentration had a greater changing magnitude on the mid- and high-latitude oceanic surface of northern Pacific Ocean than in the other latitudinal ranges. The correlation between the concentrations of the compositions in the aerosol samples and atmospheric N2 O showed that continental sources had a great contribution on atmospheric N2 O concentration above the oceanic surface. Atmospheric N2O concentration significantly increased when the expeditionary ship approached Shanghai h 相似文献
6.
1999与 2 0 0 0年夏季对南极菲尔德斯半岛不同地点大气中 N2 O浓度进行了监测 ,分析了苔藓植被区 N2 O浓度季节变化特征 ;2 0 0 0年夏季该植被区 N2 O浓度均值为 ( 31 0 .7± 4.4)×1 0 - 9(体积百分比 ) ,比 1 999年的 ( 32 1 .9± 3.3)× 1 0 - 9约低 1 1× 1 0 - 9;阿德雷岛企鹅滩及其沙坝处N2 O浓度变化趋势与苔藓植被区相一致 ,浓度均值分别为 ( 31 2 .4± 5 .1 )× 1 0 - 9和 ( 31 2 .7± 5 .3)× 1 0 - 9,比 1 999年约低 9× 1 0 - 9;另外 ,不同地点大气中 N2 O浓度普遍比 1 999年低 ,但整体变化规律相似 :各考察站区 N2 O浓度普遍高于无人区 ;唯一例外的是企鹅聚集区 N2 O浓度却高于各考察站区 ,暗示了企鹅及其排泄物、人为源是南极大气中 N2 O主要的源。本文初步探讨了 N2 O浓度异常降低的原因 相似文献
7.
The identification and comparison of the bio-elements of the penguin ornithogenic sediments sample from Davis Station and Great Wall Station 
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下载免费PDF全文 During CHINARE-22 in austral summer of 2005-2006,a lake sediment core named DG4,which is impacted by penguin droppings,was retrieved from a lake catchment in Gardner Island of Vesffold Hills,East Antarctica.In this study,the concentrations of characteristic elements in the core,local bedrocks and fresh penguin guanos were determined.P,Se,F,S,As,Sr and Cu in DG4 were identified as the bio-element assemblage by R-clustering analysis and compared with those in the local bedrocks and fresh guanos,the results are similar to Y2 in Ardley Island,Antarctic Peninsula.On this basis,P and Se were identified as the optimum bio-elements in DG4 and F,P and S were identified in Y2,respectively.This work will provides the foundation for reconstructing the past penguin populations in Gardner Island of Vest- fold Hills,East Antarctica and comparing the penguin population dynamics between East Antarctica and Antarctic Peninsula. 相似文献
8.
The elemental and isotopic signatures in the sediments influenced by seal excrement on Antarctic Fildes Peninsula are examined for their potential palaeoecologlcal applications. The seal hair abundance in sediments exhibits remarkable fluctuation versus depth, indicating similar changes in historical populations of the seals visiting the marine terrace. The combination of δ^13 C, total organic carbon concentration （TOC）, total nitrogen concentration （TN） and atomic C/N ratio shows that the organic matters in sediments with numerous seal hairs have a marine origin and are predominantly derived from seal excrements. The large δ15 N values in sediments are attributed to trophic enrichment and NH3 vollatilization processes. The large variations in the δ^15 N values and the negative correlation between the δ15 N values and the seal hair abundances seem to be the results of changes in the paleoclimates and the volatilization rates of the ammonia produced in the seal excrements. The 87 Sr/86 Sr ratios in the acid-soluble fraction of sediments are interpreted as a mixture of the ones from the seal excrements （30%-50%） and the chemically weathered local bedrocks （70%-50%）. The calculated proportion of seal-derived Sr based on the ^87 Sr/^86 Sr ratios has a significant correlation with seal hair abundances in sediments. These results suggest that δ15 N values and the ^87 Sr/^86 Sr ratios in the acid-soluble fraction of sediments were influenced by seal excrements, similar to seal halt numbers, and thus can potentially be used to estimate the historical seal population in the Antarctic region. 相似文献
9.
During CHINARE-22 in austral summer of 2005-2006, a lake sediment core named DG4, which is impacted by penguin droppings, was retrieved from a lake catchment in Gardner Island of Vestfold Hills, East Antarctica. In this study, the concentrations of characteristic elements in the core, local bedrocks and fresh penguin guanos were determined. P, Se, F, S, As, Sr and Cu in DG4 were identified as the bio-element assemblage by R-clustering analysis and compared with those in the local bedrocks and fresh guanos, the results are similar to Y2 in Ardley Island, Antarctic Peninsula. On this basis, P and Se were identified as the optimum bio-elements in DG4 and F, P and S were identified in Y2, respectively. This work will provides the foundation for reconstructing the past penguin populations in Gardner Island of Vest- fold Hills, East Antarctica and comparing the penguin population dynamics between East Antarctica and Antarctic Peninsula. 相似文献
10.
在中国第22次南极科学考察期间,采集了东南极米洛半岛不同地点近地面大气样品,在室内分析了样品中CH4浓度及其δ13C值,结果表明:该半岛近地面大气CH4平均浓度为(1.87±0.12)ppm,略高于全球大气甲烷平均浓度;白天10:00和夜间22:00大气CH4浓度的夏季变化呈现较大波动,与气温存在响应关系;其δ13C值变化范围为-39.31‰--37.56‰,平均值为(-38.26±0.52)‰。对米洛半岛及周边不同地点大气CH4浓度及其δ13C的分析结果表明:大气CH4浓度的空间变化范围为1.74-2.56ppm,δ13C值的变化范围为-39.31‰--31.25‰;CH4的δ13C值随其浓度的增加而增加。本文还讨论了影响米洛半岛大气CH4浓度及其δ13C值的因素。 相似文献