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961.
962.
963.
在1989/1990年度南极夏季,对中山站附近麦氏贼鸥雏鸟的生长进行了观察和研究。本区麦氏贼鸥育雏期大约在每年12月中旬至翌年2月下旬,雏鸟的成活率较低,本年度为38.9%,从出雏到育成(首飞日),育期平均53.2天(范围52-55天)。雏鸟平均体重日增长率,第一雏鸟为27.42g/d,第二雏鸟为16.56g/d。雏鸟生长的逻辑斯蒂克曲线数学方程式为:W=1255.41+22.6034e-0.1518t(第一雏鸟)生长曲线渐近线为1255.4g,拐点为20.5d,第一雏鸟体重的最大日增率x=43.94±8.24(g)。影响本区麦氏贼鸥雏鸟生长和成活率的主要外部因子是天气(如暴风雪)同类自残以及食物等 相似文献
964.
南极大陆位于地球南端。地层自太主界至新生界均有出露,岩浆活动各个时代亦均有发育。南极基底是由前寒武系和寒武-奥陶系构成的双构造层基底;盖层由泥盆系三叠系组成,其中石炭纪末至二叠纪初的冰碛层对研究冈瓦纳古陆的演化具有极为重要的意义。冈瓦纳古陆的裂解,即东冈瓦纳(南极-印度-澳大利亚)与西冈瓦纳(南美-非洲)是在约150Ma之前分开的。130Ma之前,南大西洋的打开又把西冈瓦纳分割成两块,并导致Ellsworth山与南极半岛及Thurston岛相连形成威德尔古陆。 相似文献
965.
Hydroxy acids in sediments of Lakes Bonney, Fryxell, Joyce and Vanda, and unnamed ponds (B2, NF1, NF2 and L4) as well as in cyanobacterial mats from the McMurdo Sound region of southern Victoria Land in Antarctica have been studied to clarify their features and elucidate their source organisms. Normal and branched (iso and anteiso) 2-hydroxy acids were found in all the samples studied with the predominance of even- and odd-carbon numbers, respectively. The most dominant 2-hydroxy acids in the sediments were mainly short-chain components (<C20). Normal and branched 3-hydroxy acids were detectewith the predominance of even- and odd-carbon numbers, respectively, in total concentrations between 0.48 and 53 μg/g of dry sediment. (ω-1)-Hydroxy acids were all long-chains (C22, C24, C26, C28 and C30). 9,10-Dihydroxyhexadecanoic and/or 9,10-dihydroxyoctadecanoic acids were identified in all the sediments and a cyanobacterial mat. The composition of hydroxy acids differ considerably among the lakes and ponds, suggesting the difference of source organisms. These 2-, 3- and (ω-1)-hydroxy, and 9,10-dihydroxy acids may be derived from cyanobacteria and microalgae, in addition to non-photosynthetic microorganisms. Cyanobacteria and microalgae which are widely distributed in the world, may be important sources of hydroxy acids in the natural environments. 相似文献
966.
Field observations on the variability of crude oil impact on indigenous hydrocarbon-degrading bacteria from sub-Antarctic intertidal sediments 总被引:3,自引:0,他引:3
Oil pollution of the oceans has been a problem ever since man began to use fossil fuels. Biodegradation by naturally occurring populations of micro-organisms is a major mechanism for the removal of petroleum from the environment. To examine the effects of crude oil pollution on intertidal bacteria, we repeated the same contamination experiments on nine different sub-Antarctic intertidal beaches using specifically built enclosures (PVC pipe, 15 cm in inner diameter and 30 cm in height). Despite the pristine environmental conditions, significant numbers of indigenous hydrocarbon-degrading bacteria were observed in all the studied beaches. Introduction of oil into these previously oil-free environments resulted in several orders of magnitude of increase in hydrocarbon-degrading micro-organisms within a few days in some of the studied sites but has no obvious effects on two others. The physical environment of the bacterial assemblage seems to play a major role in the biodegradation capacities. After 3 months of contamination, both remaining oil concentrations and biodegradation indexes differ strongly between the different stations. Thus, chemical and biological parameters reveal a strong heterogeneity of biodegradation capacities between the different sites. 相似文献
967.
东南极格罗夫山地区晚第三纪孢粉的发现 总被引:3,自引:0,他引:3
对采自东南极格罗夫山地区的7个土壤样品、2个冰碛岩样品和1个剪切泥样品进行了孢粉分析,共获孢子花粉33个种属,乔木和木本花粉总数占94.5%,灌木和草木植物花粉总数占3.2%,蕨类植物孢子总数占2.3%,乔木和木本花粉中主要的优势种属为松属(Pinus)和桦属(Petula)以及少量的栗属(Quercus)、胡桃属(Juglans)、椴属(Tilia)和蒿属(Aretmisia)等。根据孢粉组合及形态和颜色特征,认为其时代可能为上新世。说明晚第三纪以来,东南极格罗夫山地区可能有一个暖期存在。 相似文献
968.
I. Corsi S. Bonacci G. Santovito M. Chiantore L. Castagnolo S. Focardi 《Marine environmental research》2004,58(2-5):401
Biochemical characterization of cholinesterase activity (ChE) was carried out on the Antarctic scallop Adamussium colbecki collected in winter 2000 from Campo Icaro (Ross Sea, Antarctica) in order to increase its suitability as a sentinel organism for monitoring the Antarctic environment. The digestive gland, gills and adductor muscle were investigated for substrate specificity and inhibitors sensitivity using acetylthiocholine iodide (ASCh) and butyrylthiocholine iodide (BSCh) as substrates and tetra (monoisopropyl)pyrophosphor-tetramide (Iso-OMPA), 1,5-bis(4-allyldimethylammoniumphenyl)-penthan-3-one dibromide (BW284c51) and the insecticide chlorpyrifos as inhibitors. Effect of in vivo exposure to ZnCl2 was also investigated. All the tissues expressed ChE activity (gill > adductor muscle > digestive gland) and low substrates specificity throughout the hydrolysis of both ASCh and BSCh substrates. Partial (25–29%) and total inhibition (100%) of ChE activity in gills was demonstrated following in vitro incubation with Iso-OMPA and BW284c51 (3 mM), respectively. Concentration-dependent inhibition was also evident with chlorpyrifos in the range 10−4–10−10 M (IC50 10−6) while in vivo exposure to ZnCl2 did not seem to affect ChE activity in the scallop. The potential use of ChE in the A. colbecki as biomarker for monitoring water contamination in the marine Antarctic environment is discussed. 相似文献
969.
We present a compilation of more than 45,000 km of multichannel seismic data acquired in the last three decades in the Weddell
Sea. In accordance with recent tectonic models and available drillhole information, a consistent stratigraphic model for depositional
units W1–W5 is set up. In conjunction with existing aeromagnetic data, a chronostratigraphic timetable is compiled and units
W1.5, W2 and W3 are tentatively dated to have ages of between 136 Ma and 114 Ma. The age of W3 is not well constrained, but
might be younger than 114 Ma. The data indicate that the thickest sediments are present in the western and southern Weddell
Sea. These areas formed the earliest basins in the Weddell Sea and so the distribution of Mesozoic sediments is in accordance
with the tectonic development of the ocean basin. In terms of Cenozoic glacial sediments, the largest depocenters are situated
in front of the Filchner–Ronne Shelf, i.e. at the Crary Fan, with a thickness of up to 3 km. 相似文献
970.