首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
Bird observations were made as part of a preliminary biological survey of the southern half of the Mawson Escarpment in the southern Prince Charles Mountains, Mac.Robertson Land between 26 January and 4 February 1998. A new breeding colony of snow petrels (Pagodroma nivea) is described, together with details of individual snow petrel sightings. At 440 km from the coast, the snow petrel colony is the furthest inland of any confirmed breeding site for this species. Accepted: 1 May 2000  相似文献   

2.
Adélie penguins Pygoscelis adeliae in Enderby Land, Antarctica feed mainly on Euphausia superba during the chick rearing season in shelf areas where fast sea-ice remains: indicating that E. superba is abundant under the fast sea-ice in these areas. The shelf areas in Enderby Land, therefore, are unique since the previous studies of Adélie penguin diet in Ross Sea, Adélie Land and Prydz Bay show that E. crystallorophias is the most abundant krill species in shelf areas in general.  相似文献   

3.
An albinistic penguin of Pygoscelis adeliae, found in the colony located in the southwestern part of the Mt. Riiser-Larsen area, Amundsen Bay, Enderby Land, was incubating a single egg. Accepted: 18 September 1999  相似文献   

4.
为揭示呼伦贝尔沙地樟子松人工林土壤细菌群落结构和功能特征,以3种林龄(25 a、34 a和43 a)沙地樟子松人工林为研究对象,沙质草地为对照,采用野外调查、Illumina Miseq高通量测序和PICRUSt功能预测相结合的研究方法,鉴定分析土壤细菌群落结构,阐明土壤理化因子对土壤细菌群落结构的影响,预测土壤细菌功能特征。研究结果显示:(1)呼伦贝尔沙地樟子松人工林共获得土壤细菌35门92纲109目210科267属,主要细菌优势门为变形菌门(Proteobacteria)(24.29%±3.39%)、放线菌门(Actinobacteria)(23.72%±4.10%)和酸杆菌门(Acidobacteria)(23.40%±2.55%)。人工林与沙质草地的变形菌门和酸杆菌门相对丰度存在显著差异(P<0.05),人工林间土壤细菌多样性指数不存在显著差异(P>0.05)。(2)研究区土壤细菌群落的主要影响因子是速效钾、全磷和全氮。(3)PICRUSt功能预测共获得5个一级功能层和31个二级功能层,主要涉及环境信息处理、代谢和遗传信息处理等功能。43 a人工林土壤细菌代谢功能活跃,有利于植物对养分的吸收和利用。在呼伦贝尔沙地种植樟子松人工林有助于改善土壤细菌群落结构,促进土壤细菌代谢功能,且表层土壤细菌群落对土壤环境变化更为敏感。  相似文献   

5.
The available ecological and palaeoecological information for two sea ice-related marine diatoms (Bacillariophyceae), Thalassiosira antarctica Comber and Porosira glacialis (Grunow) Jørgensen, suggests that these two species have similar sea surface temperature (SST), sea surface salinity (SSS) and sea ice proximity preferences. From phytoplankton observations, both are described as summer or autumn bloom species, commonly found in low SST waters associated with sea ice, although rarely within the ice. Both species form resting spores (RS) as irradiance decreases, SST falls and SSS increases in response to freezing ice in autumn. Recent work analysing late Quaternary seasonally laminated diatom ooze from coastal Antarctic sites has revealed that sub-laminae dominated either by T. antarctica RS, or by P. glacialis RS, are nearly always deposited as the last sediment increment of the year, interpreted as representing autumn flux. In this study, we focus on sites from the East Antarctic margin and show that there is a spatial and temporal separation in whether T. antarctica RS or P. glacialis RS form the autumnal sub-laminae. For instance, in deglacial sediments from the Mertz Ninnis Trough (George V Coast) P. glacialis RS form the sub-laminae whereas in similar age sediments from Iceberg Alley (Mac.Robertson Shelf) T. antarctica RS dominate the autumn sub-lamina. In the Dumont d'Urville Trough (Adélie Land), mid-Holocene (Hypsithermal warm period) autumnal sub-laminae are dominated by T. antarctica RS whereas late Holocene (Neoglacial cool period) sub-laminae are dominated by P. glacialis RS. These observations from late Quaternary seasonally laminated sediments would appear to indicate that P. glacialis prefers slightly cooler ocean–climate conditions than T. antarctica. We test this relationship against two down-core Holocene quantitative diatom abundance records from Dumont d'Urville Trough and Svenner Channel (Princess Elizabeth Land) and compare the results with SST and sea ice concentration results of an Antarctic and Southern Ocean Holocene climate simulation that used a coupled atmosphere–sea ice–vegation model forced with orbital parameters and greenhouse gas concentrations. We find that abundance of P. glacialis RS is favoured by higher winter and spring sea ice concentrations and that a climatically-sensitive threshold exists between the abundance of P. glacialis RS and T. antarctica RS in the sediments. An increase to > 0.1 for the ratio of P. glacialis RS:T. antarctica RS indicates a change to increased winter sea ice concentration (to >80% concentration), cooler spring seasons with increased sea ice, slightly warmer autumn seasons with less sea ice and a change from ~ 7.5 months annual sea ice cover at a site to much greater than 7.5 months. In the East Antarctic sediment record, an increase in the ratio from <0.1 to above 0.1 occurs at the transition from the warmer Hypsithermal climate into the cooler Neoglacial climate (~ 4 cal kyr) indicating that the ratio between these two diatoms has the potential to be used as a semi-quantitative climate proxy.  相似文献   

6.
Abstract:Thalli of the lichens Buellia frigida and Xanthoria elegans were collected from five different locations each 5–15 km apart in the Vestfold Hills, Princess Elizabeth Land, eastern Antarctica. A further collection was made from Mawson Station, Mac Robertson Land, eastern Antarctica, 660 km away. DNA was extracted from whole thalli and the ribosomal ITS region amplified by PCR using fungal specific primers. Resulting products were sequenced to gain an indication of whether or not variation was present within populations of lichen-forming fungi from continental Antarctica, and therefore of the availability of genetic resources to react to pressures such as climate change. Three genotypes ofB. frigida and two of X. elegans were detected in the Vestfold Hill collections. However, these differed by only one nucleotide position suggesting the presence of relatively little genetic variation, if the ITS region is indicative of the overall genome. Buellia frigida collected from Mawson Station had an identical ITS region sequence to the most common Vestfold Hills genotype, indicating that this species may have a low level of genetic variation across much of eastern Antarctica. In contrast, X. elegans collected from Mawson showed considerable genetic variation from the Vestfolds thalli, differing at 14·2% of nucleotide positions and had an identical ITS region sequence to an isolate from maritime Antarctica 4960 km away. Samples from the Vestfold Hills formed a distinct cluster in a phylogenetic analysis of ITS sequences from a worldwide collection of X. elegans isolates.  相似文献   

7.
Psychrooligotrophic fungi from Arctic soils of Franz Joseph Land   总被引:1,自引:1,他引:0  
Microfungi isolated from soil samples collected in Franz Joseph Land by means of the soil dilution and soil washing methods were screened for their ability to grow at low temperatures. The oligotrophic ability of the psychrotrophic strains was then determined on silica gel. A total of 40 taxa from 21 genera were isolated. Most isolates were species of Acremonium, Geomyces, Mortierella, Phialophora, Phoma, Thelebolus and sterile fungi. Eutypella scoparia, Hyphozyma variabilis and Ovadendron sulphureo-ochraceum are new records as soil and Arctic fungi. Most fungal isolates were psychrotrophic. The few psychrooligotrophs were species of Geomyces, Phoma, Thelebolus and Mortierella. Overall, our results suggest that the major component of an Arctic soil mycoflora should be active in one or more short growing seasons interspersed with periods of prolonged dormancy. Only a minor component, such as the small group of psychrooligotrophic fungi found in this study, may be expected to show continuous slow growth. Accepted: 22 November 1998  相似文献   

8.
Fungi isolated from Antarctic material   总被引:1,自引:1,他引:0  
Summary Fungi isolated from samples of soil, penguin, skua and petrel dung and bird feathers in the Victoria Land, Antarctica, from Inexpressible Island to Cape King, were studied. All material was collected in December 1987–January 1988. Fungi occurred prevalently in bird dung and in soil, especially when mosses were present. The main species isolated were: the keratinophilic Chrysosporium verrucosum and Geomyces pannorum var. pannorum, Phoma herbarum and Thelebolus microsporus. A variety of filamentous fungi and yeasts were also encountered in soil, dung and bird feathers samples in different localities: Acremonium strictum, Cladosporium herbarum, Scolecobasidium salinum, Mortierella antarctica, Paecilomyces farinosus, Phialophora fastigiata, the thermophilic Scytalidium thermophile and Thermomyces lanuginosus, Verticillium sp., Mycelia sterilia and Cryptococcus albidus and Torulaspora delbrueckii. Most of the fungal isolates appeared to be cold-tolerant. Results from this study are discussed in conjuction with data from previous Antarctic studies in this area.  相似文献   

9.
降水格局是影响陆地生态系统结构和过程的重要环境要素,尤其对于干旱/半干旱地区,降水变化是植物生长驱动的关键生态因子。目前,针对降水变化对陆地生态系统C、N、P等元素生物地球化学循环过程影响开展了大量研究。然而,关于沙地樟子松重要引种地科尔沁沙地自然降水梯度下沙地樟子松人工林土壤、植物生态化学计量特征的研究未见报道。因此,本研究以樟子松原产地红花尔基和引种地科尔沁沙地自然降水梯度下4个典型沙地樟子松人工林为对象,研究樟子松引种地降水变化对土壤(0—10,10—20 cm和20—40 cm)和植物(1年和2年生叶)生态化学计量特征的影响。研究结果发现:(1)与红花尔基原产地樟子松人工林相比,科尔沁沙地引种的樟子松人工林土壤C、N、P元素含量显著降低;(2)科尔沁沙地自西向东,随降水量增加,沙地樟子松人工林土壤C、N、P含量以及C∶P和N∶P表现为逐渐增加趋势,而土壤C∶N呈减少趋势;(3)随着降水量增加,樟子松叶C含量呈下降趋势,叶N含量和N∶P比值呈增加趋势,植物叶P含量无一致性规律;(4)樟子松叶片P含量与土壤C、N、P含量呈极显著正相关关系,而叶片C和N含量与土壤C、N、P含量无显著相关性。研究表明,沙地樟子松引种地科尔沁沙地土壤C、N、P养分比较缺乏,且随着降水增加土壤N养分限制降低,而土壤P养分限制增加。本研究从生态化学计量特征角度,为今后开展科尔沁沙地不同降水梯度条件下引种樟子松人工林提供理论依据。  相似文献   

10.
周正虎  王传宽  张全智 《生态学报》2015,35(20):6694-6702
土地利用方式的改变打破森林生态系统原有的碳氮磷平衡,从而显著地影响森林生态系统的生物地球化学循环过程。以地段相邻、林龄相同(10年生)、原始植被一致但土地利用方式不同(无土壤翻动的天然次生林[NS]、间作大豆而土壤翻动中等的人工林[MS]、间作人参而土壤翻动严重的次生林[SS])的温带幼龄林为对象,探索土地利用变化对土壤碳、氮、磷含量及相互关系的影响。结果显示:(1)土地利用方式显著改变表层和深层土壤碳含量,各土壤层次碳含量均呈现NSMSSS;而氮含量仅在0—20 cm具有显著性差异(P0.05);不同土地利用类型之间磷含量无显著差异(P0.05);表明碳氮磷对土地利用变化敏感程度不同。(2)SS土壤碳氮比(C/N)和碳磷比(C/P)低于NS和MS,而NS和MS之间C/N和C/P因土壤层次而异。不同土壤层次氮磷比(N/P)均随土壤翻动强度的增加而显著减小(NSMSSS,P0.05),且随土层加深而降低;表明N/P相对于C/N和C/P可能对土地利用变化具有更优生态指示功能。(3)土地利用变化显著改变土壤碳-氮、碳-磷、氮-磷的耦合关系。土壤碳-氮(C-N)之间存在极显著(P0.001)的线性关系,其中3种土地利用方式的土壤C-N关系的斜率差异不显著(P=0.458,共同斜率为11.1),但截距差异显著(P0.001)。结合本地区和全球文献数据分析指出,森林土壤碳氮关系既有大尺度上的普适性,又有小尺度上对土地利用方式响应的局域分异性。  相似文献   

11.
The purpose of this study was to isolate yeast (Candida) from the quarter milk of cow udders from 37 dairy farms in Brazil and to identify the different species involved in mastitis. The samples were collected between October 2002 and February 2003. Two-hundred-and-sixty milk samples from cows with clinical and subclinical mastitis were examined. Milk samples were plated onto Blood agar, Mac Conkey agar and Sabouraud dextrose agar. Forty-five (17.3%) samples were positive for the genus Candida. The Candida species isolated were C. krusei (44.5%), C. rugosa (24.5%), C. albicans (8.9%), C. guilliermondii (8.9%), and others (13.2%). We also isolated Escherichia coli (26.5%), coagulase-positive Staphylococcus (25.0%), Streptococcus spp. (8.1%), Enterobacter spp. (8.1%), and other fungi (8.1%), among others.  相似文献   

12.
P. samsonii, n.sp., isolated from apples damaged by indeterminate insects, P. rademirici, n.sp., isolated from air, and P. pittii, n.sp., isolated from clayed soil, were found to be different from previously described species and therefore are proposed as new taxa.  相似文献   

13.
Thirty-five strains of microfungi, isolated from various sites in Victoria Land, Antarctica, were grown at eight temperatures ranging from 0 to 45°C. Only 1 strain (Chaetomium sp. from hot soil) was a thermotolerant mesophile; other strains were psychrophilic (2 strains) or psychrotrophic (32 strains). The fitness of different species to thermal instability is discussed, based on the width of the growth rate curves.  相似文献   

14.
Two bacterial species (isolates N and O) were isolated from a paddy soil microcosm that had been artificially contaminated with diesel oil to which extrinsic Pseudomonas aeruginosa strain WatG, had been added exogenously. One bacterial species (isolate J) was isolated from a similar soil microcosm that had been biostimulated with Luria–Bertani (LB) medium. Isolates N and O, which were tentatively identified as Stenotrophomonas sp. and Ochromonas sp., respectively, by sequencing of their 16 S rRNA genes had no ability to degrade diesel oil on their own in any liquid medium. When each strain was cocultivated with P. aeruginosa strain WatG in liquid mineral salts medium (MSM) containing 1% diesel oil, isolate N enhanced the degradation of diesel oil by P. aeruginosa strain WatG, but isolate O inhibited it. In contrast, isolate J, which was tentatively identified as a Rhodococcus sp., degraded diesel oil contained not only in liquid LB and MSM, but also in paddy soil microcosms supplemented with LB medium. The bioaugmentation capacity of isolate J in soil microcosms contaminated with diesel oil was much higher than that of P. aeruginosa strain WatG. The possibility of using isolate J for autochthonous bioaugmentation is discussed.  相似文献   

15.
The purpose of this study was to isolate fungi from the quarter milk of cow udders in 9 dairy farms. The samples were collected between May 1996 and April 2000 in the Lublin region. Six hundred and four milk samples collected from the quarters of 172 cows with clinical and subclinical mastitis were examined. Milk samples were plated as soon as possible on blood agar (BA), Mac Conkey agar, aesculin-tallium acetate-crystal violet blood agar, and Sabouraud agar with chloramphenicol and gentamicin. Fifty eight (9.6%) of the samples were positive for fungi. All of the fungal isolates were yeasts of the genera Candida, Rhodotorula and Trichosporon. We also isolated Streptococcus agalactiae (4.9%), Str. spp.(6.4%), Staphylococcus aureus (10.4%), coagulase-negative staphylococci-CNS (36.6%), Escherichia coli (3.5%), other microorganisms (2.6%) and no growth (25.8%). This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

16.
Potato golden cyst nematode is an important causal agent of potato disease. Nematode cysts were isolated and identified by phenotypic and genotypic characteristics. Biocontrol activity of 120 isolated bacteria from rhizosphere towards Globodera rostochiensis, were evaluated. Nematode cysts were exposed to root extracts and released juveniles (J2) subjected to cultural filtrate of isolated bacteria and their mortality were recorded after 24 and 48 h. In total, 33 strains showed inhibitory activities which they caused mortality ranged from 61.10% to 78.74%. Five representatives of inhibitory strains were applied on potato cultivar Marfona under greenhouse conditions using tuber coating and soil drenching in a complete randomised block design with three replicates. The active bacterial strains were identified as Bacillus subtilis, Bacillus megaterium, Pseudomonas fluorescens bv. I, P. fluorescens bv. II and P. putida bv. B. In the greenhouse, significant differences were observed among the tested strains, where the highest disease severity reduction was 42.31%.  相似文献   

17.
Ninety-five species and seven varieties which belong to thirty-nine genera were isolated from 74 soil samples from salt marshes. At 28°C, on 30% sucrose Czapek's agar, ninety species and four varieties which belong to thirty-six genera were encountered, from which A. niger, A. fumigatus A. terreus and P. notatum were the most frequent. On 60% sucrose Czapek's agar, sixty-three species and three varieties were recovered which belong to twenty-five genera, from which A. niger, A. fumigatus, Cladosporium herbarum and A. terreus were the most frequent.At 45°C, on 30% sucrose, sixteen species and four varieties were identified, but on 60% sucrose, fourteen species and three varieties were isolated. A. fumigatus and A. niger were the most frequent on both sucrose concentrations.The results reveal that the soil samples poor in total osmophilic fungi (at 28°C) were significantly higher in their content of total soluble salts, Na and K and significantly lower in the average number of species per soil samples than the rich ones; the difference was nonsignificant in case of organic matter.  相似文献   

18.
Sparkill (25% Cypermethrin) and Tafaban (48% Chlorpyrifos) insecticides were used in the treatment of maize plants in the field to investigate the effect of these compounds on fungi associated with roots and shoots of maize as well as on soil fungi. Generally, the two insecticides exhibited an inhibitive effect on the total and individual counts of glucophilic fungi after different periods of treatment except in some cases the counts were not affected or promoted compared with the control samples. Fungal genera and species associated with roots and shoots of maize plants were isolated from untreated plants as control and then compared with those isolated from plants treated with different doses of insecticides. The most common fungal species recovered from soil and different parts of plants were Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Cochliobolus spicifer, Emericella nidulans, E. nidulans var. lata, Fusarium oxysporum, Gibberella fujikuroi, Nectria haematococca, Penicillium chrysogenum, P. funiculosum, P. oxalicum and Rhizopus stolonifer.  相似文献   

19.
The prevalence of selected tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae (n = 80) isolated from dairy farm soil and nondairy soils was evaluated. Among 56 bacteria isolated from dairy farm soils, 36 (64.3%) were resistant to tetracycline, and 17 (30.4%) were resistant to streptomycin. Lower frequencies of tetracycline (9 of 24 or 37.5%) and streptomycin (1 of 24 or 4.2%) resistance were observed in bacteria isolated from nondairy soils. Bacteria (n = 56) isolated from dairy farm soil had a higher frequency of tetracycline resistance genes including tetM (28.6%), tetA (21.4%), tetW (8.9%), tetB (5.4%), tetS (5.4%), tetG (3.6%), and tetO (1.8%). Among 24 bacteria isolated from nondairy soils, four isolates carried tetM, tetO, tetS, and tetW in different combinations; whereas tetA, tetB, and tetG were not detected. Similarly, a higher prevalence of streptomycin resistance genes including strA (12.5%), strB (12.5%), ant(3″) (12.5), aph(6)-1c (12.5%), aph(3″) (10.8%), and addA (5.4%) was detected in bacteria isolated from dairy farm soils than in nondairy soils. None of the nondairy soil isolates carried aadA gene. Other tetracycline (tetC, tetD, tetE, tetK, tetL, tetQ, and tetT) and streptomycin (aph(6)-1c and ant(6)) resistance genes were not detected in both dairy and nondairy soil isolates. A higher distribution of multiple resistance genes was observed in bacteria isolated from dairy farm soil than in nondairy soil. Among 36 tetracycline- and 17 streptomycin-resistant isolates from dairy farm soils, 11 (30.6%) and 9 (52.9%) isolates carried multiple resistance genes encoding resistance to tetracycline and streptomycin, respectively, which was higher than in bacteria isolated from nondairy soils. One strain each of Citrobacter freundii and C. youngae isolated from dairy farm soils carried class 1 integrons with different inserted gene cassettes. Results of this small study suggest that the presence of multiple resistance genes and class 1 integrons in Enterobacteriaceae in dairy farm soil may act as a reservoir of antimicrobial resistance genes and could play a role in the dissemination of these antimicrobial resistance genes to other commensal and indigenous microbial communities in soil. However, additional longer-term studies conducted in more locations are needed to validate this hypothesis.  相似文献   

20.
孔华忠  齐祖同 《菌物学报》1988,7(Z1):107-114
本文报导青霉属的三个新种,它们不同于此属已发表的诸种.异型青霉(Penicillium heteromorphum Kong et Qi),根据帚状枝的结构和分生孢子的某些特征,近于两型孢青霉(Penicillium dimorphosporum Swart),但此种在查氏琼脂上生长很稀疏,并有两种大小的分生孢子,大分生孢子直径可达10 pm,壁光滑,在观察菌落期间,有时大分生孢子落在基质上,很快萌发生长成简单的分生孢子结构,这些特征易于与后者区分.结节青霉(Penicillium nodulum Kong et Qi)在某些方面类似纠缠青霉(Penicilliumimplicatum Biourge),此新种的菌落特征,柄顶端膨大似顶囊,呈结节状膨大的营养菌丝等特征而不同于纠缠青霉.神农架青霉(Penicillium shennong jianum Kong et Qi)和毡毛青霉(Penicillium velutinum van Heyma)相近,而新种在多种培养基上生长都局限,菌落面呈带褐的橄榄色,分生孢子壁光滑等特征可与毡毛青霉区分开来.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号