Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature

1　IntroductionInthedeepseawithawatertemperaturelowerthan5℃andtheseabottom ,theor ganicmattersareoxidizedmainlybytheaerobicbacteria (BenderandHeggie 1 984;Her bert 1 986) ,whichmeansthattheaerobicbacteriainthisenvironmentareratherabun dant.Thearcticseaareaisanareawhereenvironmentispermanentlycold ,butsomere searchresults (Sahmetal.1 998)indicatethattherearedominantbacteria eubacteriainthearcticseawaterandsediment,andtheiradaptationtotemperaturehasnosubstantialdifferenceincomparisonwiththatof…     

极区冰下海洋自动剖面观测系统及其应用

中国第25次南极考察期间,于2008年12月,首次将国内研制的冰下海洋自动剖面观测系统用于南大洋考察,在普里兹湾沿岸海冰上开展冰下海洋观测,获得了连续数日的冰下上层海洋温盐剖面数据,为研究浮冰区次表层暖水提供了连续现场观测资料。文中简单介绍了自动剖面系统的技术特点和布放方法以及在南极海域的应用,为以后开展极区冰下海洋观测项目提供参考。     

Spatial distribution of Ice Shelf Water in front of the Amery Ice Shelf,Antarctica in summer

As a unique low-temperature water mass in Antarctic coastal region, the Ice Shelf Water (ISW) is an important component for the formation of the Antarctic Bottom Water (AABW). In this paper, we present a criterion for ISW identification based on freezing point at the sea surface, and we study spatial distribution of ISW in front of the Amery Ice Shelf (AIS) and its flow path in Prydz Bay by analyzing hydrographic data from Australian cruises in 2001 and 2002, as well as Chinese cruises in 2003, 2005, 2006, and 2008, all being made in the austral summer. The relatively cold and fresh ISW occurred as several discrete water blocks with cold cores in front of the AIS, within the depth range of 100?600 m, under the seasonal thermocline. ISW had obvious temporal and spatial variations and the spatial distribution pattern changed greatly after 2005. Most of ISW was concentrated west of 73°E during 2001 to 2003 and 2006, but it was widespread to east in 2005 and 2008. In all observation years, a small amount of cold ISW always occurs at the west end of the AIS front section, where the coldest ISW in the whole section also occurred in 2001, 2003 and 2006. Considering general cyclonic circulation pattern under the AIS, the ISW flowing out from west end of the AIS front might have experienced the longest cooling period under ice shelf, so it would have the lowest temperature. Analysis of data from meridian sections in Prydz Bay in 2003 implied that ISW in the west could spread north to the continental break along the east flank of the Fram Bank near 70.5°E, mix with the upwelling Circumpolar Deep Water and possibly contribute to the formation of AABW.     

南极威德尔-斯科舍汇流区上层湍流混合特征及其与水团和环流的联系

利用中国第32次南极科学考察队于2015年12月至2016年1月在南极威德尔-斯科舍汇流区获得的湍流微结构、温盐深仪和下放式声学多普勒海流计观测资料,分析了该海域上层海洋(30～500 dbar)的湍流混合空间分布特征.结果显示,湍动能耗散率(ε)和湍扩散系数(Kρ)分布呈现明显的区域性特征,与当地的水团和环流分布密切...     

埃默里冰架前缘水的特性和海流结构

本文利用中国第19次南极科学考察普里兹湾内埃默里冰架前缘水域观测的LADCP、 CTD资料,研究并分析了普里兹湾内埃默里冰架前缘水域水的温、盐特性和海流结构。资料显示,在冰架前缘的水域中存在着四种典型的夏季水团;流速分布显示出东进西出的特征。此外在普里兹湾内的上层和中层海洋中还存在着逆时针和顺时针方向的涡旋:逆时针涡旋西侧是普里兹湾向冰架入流的位置所在;入流的源地是普里兹湾东侧的沿岸西向流。这些特征涉及到夏季普里兹湾内的环流形式、冰架底部的消融速率和冰架水的生成规模以及冰架区域与冰架外普里兹湾内的水交换形式。     

白令海和楚科奇海总好气异养细菌丰度和对温度的适应性

用平皿培养计数法测定了白令海和楚科奇海测区水和沉积物中的总好气异养细菌(GAB)的丰度 ,并进行了比较。分析了不同海区、测点、不同层次沉积物中GAB丰度及在不同温度中的适应性。结果表明 ,水中GAB检出率大于沉积物 ,但丰度仅为后者的 0 .0 7% ;表层沉积物中GAB检出率高于其它层次 ;白令海GAB检出率、丰度及变幅均高于楚科奇海。所有站点沉积物中GAB含量平均约为 31 66.3× 1 0 2 CFU·g- 1 (湿 ) ;沉积物GAB丰度大致显出低纬度区大于高纬度区之势。温度试验结果表明所试GAB中多数为适冷菌 ,少数可能为中温菌 ,显示出北极海洋细菌对温度有较强的适应性     

南极普里兹湾海域不同水团的D含量

研究了南极普里兹湾海域不同水团的D含量，按照温盐指标划分的水团，给出表层水，陆架水，深层水和底层水的δD值分别为-2--5，-3--5.6,0.4--2.0和-1--2.7。     

夏季北冰洋海冰边缘区海水温盐结构及其形成机理

利用1999年北极科学考察期间在海冰边缘区的三次考察数据，研究了北冰洋海冰边缘区的温度和盐度结构。将海冰边缘区分为机制不同的两大类，一类是暖水海冰边缘区，主要热源是外部暖水进入海冰边缘区携带的热量；另一类是冷水海冰边缘区，主要热源是太阳辐射加热。文中主要对冷水海冰边缘区进行了研究。虽然两个冷水海冰边缘区(R区与T区)温度结构不尽相同，但都存在表层以下水体中的温度极大值现象，R区的温度极大值位于20m左右，T区的位于40—50m左右的深度，可以认为是海冰边缘区的典型温度特征。作者认为，次表层暖水的热源是太阳辐射的直接加热，为此，建立了太阳加热引起海水次表层增暖的物理模型和简单的数学模型，获得了冰下海水在太阳辐射的作用下增暖的解析解。结果表明，部分太阳辐射能穿过海冰加热冰下海水，加热之初温度的极大值出现在近表层，随着时间的推移，海温极大值的位置向下移动，最终可以达到40m左右，证明了仅仅依靠太阳的短波辐射就可以形成中间暖的水层。文中阐明，开阔海水更多的是上混合层和跃层结构，冰下海水主要是次表层暖水结构；冷水海冰边缘区的海水主要带有冰下海水的特征。由于次表层暖水的形成与海冰厚度关系很大，近十几年北冰洋海冰厚度的显著减少势必加强次表层暖水，可能是北冰洋增暖的又一个重要现象，对全球气候变化有意义深远的影响。     

2011/2012年夏季南极半岛北端周边海域的水团与水交换

通过分析中国第28次南极考察队于2011年12月至2012年1月在南极半岛北端周边海域获得的5条断面CTD观测温盐剖面数据, 进一步认识了该海域的水团组成和水交换情况。观测区域南部的鲍威尔海盆及周边深海区, 可以观测到保持了较显著高温核心的威德尔深层水、密度大于28.27 kg·m^-3的威德尔海深层水以及温度低于－0.7 ℃的威德尔海底层水。周边陆坡上的威德尔海深层水则表现出因与周围水体发生混合而核心性质减弱的特征。在菲利普海岭、埃斯佩里兹海槽等复杂地形处, 观测到的对应于威德尔海深层水深度的混合与热盐入侵过程更为显著。威德尔海深层水能够到达南设得兰群岛以北的象岛东北面海域, 但是高盐核心加深至1 500 db, 并上覆温度基本不变但盐度随深度显著增大的较暖水体, 表明威德尔海深层水经历了不同的路径和变性过程。布兰斯菲尔德海峡中没有绕极深层水大规模侵入的迹象, 但是乔治王岛周边陆架上可能存在涡旋等中尺度过程, 会影响德雷克海峡与布兰斯菲尔德海峡之间的水交换。     

融池热力学模式以及它在2010年夏季北极中央区的应用研究

A one-dimensional thermodynamic model of melt pond is established in this paper.The observation data measured in the summer of 2010 by the Chinese National Arctic Research Expedition(CHINARE-2010) are used to partially parameterize equations and to validate results of the model.About 85% of the incident solar radiation passed through the melt pond surface,and some of it was released in the form of sensible and latent heat.However,the released energy was very little(about 15%),compared to the incident solar radiation.More than 58.6% of the incident energy was absorbed by melt pond water,which caused pond-covered ice melting and variation of pond water temperature.The simulated temperature of melt pond had a diurnal variation and its value ranged between 0.0°C and 0.3°C.The melting rate of upper pond-covered ice is estimated to be around two times faster than snow-covered ice.At same time,the change of melting rate was relatively quick for pond depth less than 0.4 m,while the melting rate kept relatively constant(about 1.0 cm/d) for pond depth greater than 0.4 m.