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The phylogenetic diversity of culturable psychrophilic bacteria associ ated with sea ice from the high latitude regions of Canadian Basin and Chukchi S ea,Arctic,was investigated.A total of 34 psychropilic strains were isolated u sing three methods of(Ⅰ)dilution plating(at 4 ℃),(Ⅱ)bath culturing(at-1 ℃)and dilution plating,and(Ⅲ)cold shock(-20 ℃ for 24 h),bath culturin g and dilution plating under aerobic conditions.Sea-ice samples were exposed to-20 ℃ for 24 h that might reduce the number of common microorganisms and encou rag e outgrowth of psychrophilic strains.This process might be able to be introduce d to isolation psychrophilic bacteria from other environmental samples in future study.16S rDNA nearly full-length sequence analysis revealed that psychrophil i c strains felled in two phylogenetic divisions,γ-proteobacteria(in the gen era Colwellia、Marinobacter、Shewanella、Glaciecola、Marinomonas and Pseudoalt eromon as) and Cytophaga-Flexibacter-Bacteroides(Flavobacterium and Psychrof lexus).Fi fteen of bacterial isolates quite likely represented novel species(16S rDNA seq uence similarity below 98%).One of strains(BSi20002)from Canadian Basin showe d 100% sequence similarity to that of Marinobacter sp.ANT8277 isolated from the Antarctic Weddell sea ice,suggesting bacteria may have a bipolar distribution at the species level. 相似文献
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自北冰洋楚科奇海、加拿大海盆、格陵兰海和中国南极中山站近岸的海水、海冰和沉积物样品中分离的322株低温细菌中筛选出73株低温β-半乳糖苷酶产生菌,并对其中1株BCw006进行了研究。通过16S rDNA序列同源性分析表明,该菌株属于交替单胞菌属,定名为Alteromonas sp.BCw006。对该菌株研究表明:该菌最适生长和产酶温度为24℃;在pH6.0—8.0、含0%—6.O% NaCl的培养基条件下菌株能够较好地生长与产酶,其最适生长和产酶NaCl浓度分别为3%和1%,乳糖对β-半乳糖苷酶合成具有明显诱导作用,酵母粉和蛋白胨是菌株生长和产酶较适宜的氮源,酶的最适作用温度为35℃,0℃时能保持35℃下酶活的25%左右,表明其具有较好的适应低温特性。酶对热敏感,60℃时作用30min后酶活力下降了41%。 相似文献
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从中国第二次北极科学考察采集的海冰样品中分离到8种细菌,研究了盐度对其生长的影响。结果表明,8株海冰细菌对盐度有着广泛的适应性,在盐度为30-90的范围内均可较快生长,其中菌株BJ2、BJ3和BJ7的盐耐受性较强。进一步的研究表明,BJ2、BJ3和BJ7在0-150 的盐度范围内均有不同程度的生长,盐度为0-30时,菌株的生长最快;盐度为180时,这三株菌株也均有短暂的生长。随着盐度的增加,三株菌株生长的延迟期增加,到达生长稳定期的时间也相应增加。温度对菌株BJ2、BJ3和BJ7的盐耐受性也有着一定的影响,随着温度的升高, 菌株的生长速度变慢,但盐耐受性有所增加。 相似文献
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This paper presents a detailed account of the effect of shipping activity on the increasing trends of air temperatures in the Canadian Arctic region for the period of 1980–2018. Increasing trend of temperature has gained significant attention with respect to shipping activities and sea ice area in the Canadian Arctic. Temperature, sea ice area and shipping traffic datasets were investigated, and simple linear regression analyses were conducted to predict the rate of change(per decade) of the average temperature, considering winter(January) and summer(July) seasons. The results indicate that temperature generally increased over the studied region. Significant warming trend was observed during July, with an increase of up to 1℃, for the Canadian Arctic region. Such increasing trend of temperature was observed during July from the lower to higher latitudes. The increase in temperature during July is speculated to increase the melting of ice. Results also show a decline in sea ice area has a significant positive effect on the shipping traffic, and the numbers of marine vessel continue to increase in the region. The increase in temperature causes the breaking of sea ice due to shipping activities over northern Arctic Canada. 相似文献
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The role of declining Arctic sea ice in recent decreasing terrestrial Arctic snow depths 总被引：1，自引：1，他引：0
The dramatic decline in Arctic sea ice cover is anticipated to influence atmospheric temperatures and circulation patterns. These changes will affect the terrestrial climate beyond the boundary of the Arctic, consequently modulating terrestrial snow cover. Therefore, an improved understanding of the relationship between Arctic sea ice and snow depth over the terrestrial Arctic is warranted. We examined responses of snow depth to the declining Arctic sea ice extent in September, during the period of 1979–2006. The major reason for a focus on snow depth, rather than snow cover, is because its variability has a climatic memory that impacts hydrothermal processes during the following summer season. Analyses of combined data sets of satellite measurements of sea ice extent and snow depth, simulated by a land surface model (CHANGE), suggested that an anomalously larger snow depth over northeastern Siberia during autumn and winter was significantly correlated to the declining September Arctic sea ice extent, which has resulted in cooling temperatures, along with an increase in precipitation. Meanwhile, the reduction of Arctic sea ice has amplified warming temperatures in North America, which has readily offset the input of precipitation to snow cover, consequently further decreasing snow depth. However, a part of the Canadian Arctic recorded an increase in snow depth driven locally by the diminishing September Arctic sea ice extent. Decreasing snow depth at the hemispheric scale, outside the northernmost regions (i.e., northeastern Siberia and Canadian Arctic), indicated that Arctic amplification related to the diminishing Arctic sea ice has already impacted the terrestrial Arctic snow depth. The strong reduction in Arctic sea ice anticipated in the future also suggests a potential long-range impact on Arctic snow cover. Moreover, the snow depth during the early snow season tends to contribute to the warming of soil temperatures in the following summer, at least in the northernmost regions. 相似文献
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结合前人对北冰洋海冰、气候系统的研究成果和 1 999年 8月在北冰洋对海冰的现场观测 ,本文综述了海冰分布、厚度的变化 ,海冰表面特征、积雪变化及北冰洋天气、气候特征和分区。讨论了北极海冰与南极海冰的差异。文章认为 ,北冰洋与周围地区气候变化趋势的不一致 ,主要是由于夏季在北冰洋海冰与开阔水域的相间分布、海冰漂移、融化吸热 ,均衡了周围大气、海洋温度的变化。 相似文献
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To evaluate improvements in modelling Arctic sea ice, we compare results from two regional models at 1/12° horizontal resolution. The first is a coupled ice-ocean model of the Arctic Ocean, consisting of an ocean model (adapted from the Parallel Ocean Program, Los Alamos National Laboratory [LANL]) and the "old" sea ice model. The second model uses the same grid but consists of an improved "new" sea ice model (LANL/CICE) with a simple ocean mixed layer. Both models are forced with European Centre for Medium-range Weather Forecasts reanalysis data for 1979–1993. A comparison of the two sea ice models focuses on the winter of 1987 to emphasize the internal ice stress and to minimize biases towards a particular Arctic climate regime. The "new" sea ice model gives improved ice deformation and drift fields. These improvements are associated at least in part with the multi-category representation of the ice thickness distribution and more realistic parameterization of the ice strength. Long, narrow features in ice divergence and shear fields resemble those observed in SAR imagery, except that their average width is overestimated, possibly due to insufficient horizontal resolution. We also compare the mean sea ice drift and its decadal variability in two "old" sea ice models at different horizontal resolutions: 18-km and 9-km. We find no significant change in ice drift between the two models, except in areas of significant ice-ocean interactions due to more realistic ocean currents and water mass properties in the 9-km model. 相似文献
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覆盖在北极海洋上的广阔海冰为其内部生存的微生物群落提供了一个独特的生境。研究表明 ,大量海冰细菌能够分泌产生胞外酶 ,其中产蛋白或脂质水解酶细菌的比例远高于产多糖水解酶的细菌。温度、盐度是直接影响海冰细菌生存与活力的 2个主要环境因子。 76%的产酪蛋白酶海冰细菌为低温菌 ,菌株只能在 <35°C条件下生长 ;而 98%的酪蛋白酶最适作用温度≥ 35°C ,其中 62 %的酶最适作用温度≥ 45°C。几乎所有的产酪蛋白酶海冰细菌都耐盐或嗜盐 相似文献
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海冰是海洋-大气交互系统的重要组成部分,与全球气候系统间存在灵敏的响应和反馈机制。本文选用欧洲空间局发布的1992—2008年海冰密集度数据分析了南北极海冰在时间和空间上的变化规律与趋势,并结合由美国环境预报中心(National Centers for Environmental Prediction,NCEP)和美国大气研究中心(National Center for Atmospheric Research, NCAR)联合制作的NCEP/NCAR气温数据和ENSO指数探讨了南北极海冰变化的影响因素。结果表明,北极海冰面积呈明显的减少趋势,其中夏季海冰最小月的减少更快。北冰洋中央海盆区、巴伦支海、喀拉海、巴芬湾和拉布拉多海的减少最明显。南极海冰面积呈微弱增加趋势,罗斯海、太平洋扇区和大西洋扇区的海冰增加。北极海冰面积与气温有显著的滞后1个月的负相关关系(P0.01)。北极升温显著,北冰洋中央海盆区、喀拉海、巴伦支海、巴芬湾和楚科奇海升温趋势最大,海冰减少很明显。南极在南大西洋、南太平洋呈降温趋势,海冰增加。北极海冰减少与39个月之后ONI的下降、40个月之后SOI的上升密切相关;南极海冰增加与7个月之后ONI的下降、6个月之后SOI的上升存在很好的响应关系。南北极海冰变化与三次ENSO的强暖与强冷事件有很好的对应关系。 相似文献
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在过去30年间,北极气候发生了前所未有的异常变化,北极海冰变化更是经历了令人瞩目的、从平缓到突变的缩减过程,因此,北冰洋及其海冰的研究得到广泛的重视。综述当前国内外有关北极海冰快速变化的研究工作,对这些大气的现场观测和卫星遥感资料的分析,以及一些全球和区域气候模拟的结果,基本上一致地指出了近3O年来北极海冰的快速衰减趋势,尤其是夏季北极海冰正以每lO年超过10％的变化幅度快速减少。从海冰的基本物理特征、与大气海洋相互作用的物理过程、及其对全球和北极气候变化的响应和反馈机制,研究形成这种快速变化的因子--海表面气温增暖,太平洋与大西洋人流的热盐性质变化,以及大气环流模态的影响等。 相似文献
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本文用了 1 999年夏季中国首次北极科学考察队对海冰、大气和海洋进行的同步和准同步的综合立体观测所获取的资料 ,研究海冰在海 气相互作用中扮演的角色。发现海冰的种类、分布、冰厚等变化对海气热交换都有重要影响。在浮冰区海洋以潜热的形式向大气输送热量 ,潜热通量与浮冰密集度的大小密切有关 ,浮冰越少潜热通量越大 ,潜热通量约为2 1～ 2 3 .6W /m2 ,潜热通量大于感热通量 ;在冰盖和大浮冰块上 ,大气以感热的形式向冰雪面上输送热量。新生的浮冰区或冰间湖是海气热交换最激烈的地方 ,是气候最敏感的区域 ,是北冰洋蒸汽雾生成的重要条件。用层结大气整体动力学输送法 ,计算了一次大范围的蒸汽雾过程的海气热交换 ,海洋向大气输送的热量总功率约为 1 4 8亿千瓦 ,相当于中国发电能力的 69倍 ,相当于大西洋向北冰洋输送热量平均功率的 1 / 2 0。北冰洋的夏季能够形成各种类型的海雾 :辐射雾、蒸汽雾和平流雾 ,其重要原因就是因为海冰的存在 ,使下垫面的性质复杂化 ,海气交换复杂化。 相似文献
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Oil-weathering processes in ice-free subarctic and Arctic waters include spreading, evaporation, dissolution, dispersion of whole-oil droplets into the water column, photochemical oxidation, water-in-oil emulsification, microbial degradation, adsorption onto suspended particulate material, ingestion by organisms, sinking, and sedimentation. While many of these processes also are important factors in ice-covered waters, the various forms of sea ice (depending on the active state of ice growth, extent of coverage and/or decay) impart drastic, if not controlling, changes to the rates and relative importance of different oil-weathering mechanisms. Flow-through seawater wave-tank experiments in a cold room at −35°C and studies in the Chukchi Sea in late winter provide data on oil fate and effects for a variety of potential oil spill scenarios in the Arctic. Time-series chemical weathering data are presented for Prudhoe Bay crude oil released under and encapsulated in growing first-year columnar ice through spring breakup. 相似文献
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雪和海冰作为北极地区反照率最高的地表类型,可以将大部分入射辐射能量反射回天空,其表面反照率的变化对整个地表-大气辐射平衡系统和全球气候变化都会有重要影响。在2010年中国第4次北极科学考察期间用ASD光谱仪对北极太平洋扇区不同类型的海冰表面反照率进行了现场测量,观测时段为7月27日至8月23日,地理范围在72°18′-87°20′N和152°34′-178°22′W之间。观测结果表明积雪覆盖海冰的反照率最高,干雪覆盖时均值达到0.82,融化的湿雪覆盖时反照率会有一定程度地降低。夏季北极地区存在大量融池,融池海冰按颜色划分为白冰,蓝冰和灰冰,白冰的平均反照率为0.54,蓝冰的为0.31,灰冰的只有0.20,融池水的反照率只有0.16。融池是北极夏季反照率变化的重要原因。 相似文献
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利用2003年8月22日-9月3日中国北极科学考察队在北冰洋78°N浮冰站获得的近地层观测资料,采用整体输送法对北冰洋浮冰近地层特征参数进行了分析研究。结果表明,在考察期间,雪面吸收的净辐射仅为3.6 W/m2,其中以感热和潜热向大气输送的能量分别占52%和31%,向海冰深层传导的热量很少;近中性层结条件下的平均拖曳系数Cdn为1.16×10-3,略小于75°N北冰洋浮冰上近中性层结的Cdn。与1999年75°N附近冰站观测结果的对比表明,当海冰密度及冰站所在浮冰的尺度不同时,海冰与大气相互作用的热力学和动力学过程的差异显著,在研究北冰洋地区海/冰/气相互作用对气候过程影响时,应考虑这一问题。 相似文献
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The sea ice community plays an important role in the Arctic marine ecosystem. Because of the predicted environmental changes in the Arctic environment and specifically related to sea ice, the Arctic pack ice biota has received more attention in recent years using modern ice-breaking research vessels. Studies show that the Arctic pack ice contains a diverse biota and besides ice algae, the bacterial and protozoan biomasses can be high. Surprisingly high primary production values were observed in the pack ice of the central Arctic Ocean. Occasionally biomass maximum were discovered in the interior of the ice floes, a habitat that had been ignored in most Arctic studies. Many scientific questions, which deserve special attention, remained unsolved due to logistic limitations and the sea ice characteristics. Little is know about the pack ice community in the central Arctic Ocean. Almost no data exists from the pack ice zone for the winter season. Concerning the abundance of bacteria and protozoa, more studies are needed to understand the microbial network within the ice and its role in material and energy flows. The response of the sea ice biota to global change will impact the entire Arctic marine ecosystem and a long-term monitoring program is needed. The techniques, that are applied to study the sea ice biota and the sea ice ecology, should be improved. 相似文献
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海冰冰情是开发、利用北极航道的关键信息,研究利用2006—2015年北极地区逐日海冰密集度数据,根据2013年"永盛轮"首航北极东北航道时所经航线为例,提取了航线冰情要素,包括航线通航窗口、逐日海冰密集度时空分布以及海冰密集度月标准差等,对航线通航条件进行了研究。根据航线冰情要素获得了十年间航线通航窗口的基本情况,十年间航线所经水域的大体通航情况和主要冰障位置,7—10月份航线所经水域海冰密集度的变化动态。通过对航线冰情要素的分析,得出影响航线的两个关键海域,并分析了"永盛轮"航线与关键水域航线通航窗口的变化趋势。 相似文献
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为保障我国第四次北极科学考察的顺利开展,于2010年6～8月开展了北极海冰预报预测服务。预报试验基于MITgcm （麻省理工学院通用环流模式）,以NCEP GFS（美国国家环境预测中心全球预报系统）资料为大气强迫,初始化分别使用美国冰雪中心SSM/I（专用微波成像仪）或德国不莱梅大学AMSR-E（地球观测系统先进微波扫描辐射计）北极海冰密集度卫星资料。对2010年6～8月预报结果的初步评估表明,预报结果同卫星观测资料比较一致。在发生快速海冰变化的太平洋扇区,预报结果优于惯性预报,表明模式具有较好的局地海冰数值预报能力。 相似文献