A 41-year Antarctic sea ice concentration (SIC) dataset derived from satellite passive microwave radiometers during the period of 1979–2019 has been used to analyze sea ice changes in recent decades. The trends of SIC and sea ice extent (SIE) are calculated during the periods of 1979–2019, 1979–2013, and 2014–2019. The trends show regionally dependent features. The SIC shows an increasing trend in most of the regions except the Bellingshausen Sea and Amundsen Sea (BA) during 1979–2019 and 1979–2013. The SIE trend shows a decreasing or decelerating trend in the period of 1979–2019 ((6 835±2 210) km²/a) compared with the 1979–2013 period ((18 600±2 203) km²/a). In recent years (2014–2019), the SIC and SIE have exhibited decreasing trends (–(34 567±3 521) km²/month), especially in the Weddell Sea (WS) and Ross Sea (RS) during summer and autumn. The trends are related to regionally dependent causes. The analyses show that the SIC and SIE decreased in response to the warming trend of 2 m air temperature (T_a-2m) and have exhibited a good relationship with T_a-2m in summer and autumn in recent years. The sea ice decrease in the Antarctic is mainly caused by increases in absorbed energy and southward energy transportation in recent years, such as the increase in gained solar radiation and moist static energy from the south, which demonstrate notable regional characteristics. In the WS region, the local positive feedback from the additional absorbed solar radiation, resulting in warmer air and reduced sea ice, is the main reason for the sea ice decrease in recent years. The increase in southward energy transport has also favored a decrease in sea ice. In the RS region, the increase in southward-transported moist static energy has contributed to the decrease in sea ice, and the increases in cloud cover and longwave radiation have prevented sea ice growth.

好氧不产氧光合(AAP)细菌因其具有利用溶解性有机物及光能的能力,在海洋碳循环及能量流动中发挥着重要的作用。该类细菌广泛分布在海洋环境中,其在不同生境中的多样性已被调查。但到目前为止,人们对于高纬度地区好氧不产氧光合细菌的认识还较为缺乏。有鉴于此,本研究基于编码光反应复合物上一个色素结合蛋白亚基的pufM基因,对北极王湾及南极乔治王岛近岸水体中夏季好氧不产氧光合细菌的多样性进行了检测。针对2个王湾站位和2个南极麦克斯维尔湾站位构建了4个pufM基因克隆文库,获得674个阳性克隆子。北极克隆子全部由α-变形细菌组成,而南极克隆子则包括α-变形细菌及β-变形细菌。来源于类似红细菌科的pufM基因在所有样品中皆占据优势。此外,与一株滴状亚硫酸盐杆菌中质粒编码的pufM基因存在亲缘关系的序列,在南、北极样品中均占优势。结果表明海洋环境中的pufM基因存在跨极甚至是环球分布。与此同时,南、北极序列之间的差异,也表明了极地地方种的存在。这些结果显示,作为好氧不产氧光合细菌的红细菌科在两极的近岸水体中具有重要的地位。

The importance of the Atlantic Multidecadal Oscillation (AMO) and Interdecadal Pacific Oscillation (IPO) in influencing zonally asymmetric changes in Antarctic surface air temperature (SAT) has been established. However, previous studies have primarily concentrated on examining the combined impact of the contrasting phases of the AMO and IPO, which have been dominant since the advent of satellite observations in 1979. This study utilizes long-term reanalysis data to investigate the impact of four combinations of +AMO+IPO, –AMO–IPO, +AMO–IPO, and –AMO+IPO on Antarctic SAT over the past 115 years. The +AMO phase is characterized by a spatial mean temperature amplitude of up to 0.5℃ over the North Atlantic Ocean, accompanied by positive sea surface temperature (SST) anomalies in the tropical eastern Pacific and negative SST anomalies in the extratropical-mid-latitude western Pacific, which are indicative of the +IPO phase. The Antarctic SAT exhibits contrasting spatial patterns during the +AMO+IPO and +AMO–IPO periods. However, during the –AMO+IPO period, apart from the Antarctic Peninsula and the vicinity of the Weddell Sea, the entire Antarctic region experiences a warming trend. The most pronounced signal in the SAT anomalies is observed during the austral autumn, whereas the combination of –AMO and –IPO exhibits the smallest magnitude across all the combinations. The wavetrain excited by the SST anomalies associated with the AMO and IPO induces upper-level and surface atmospheric circulation anomalies, which alter the SAT anomalies. Furthermore, downward longwave radiation anomalies related to anomalous cloud cover play a crucial role. In the future, if the phases of AMO and IPO were to reverse (AMO transitioning to a negative phase and IPO transitioning to a positive phase), Antarctica could potentially face more pronounced warming and accelerated melting compared to the current observations.

南极适冷菌菌株G中参与温度适应的关键功能基因是通过转录组测序确定的。我们分析了在冷激条件（0℃）和热激条件（30℃）下菌株G的转录情况，并把最适生长温度20℃作为对照组。冷激/热激后，转录组情况发生了很大的变化，与对照组相比，分别有11和12个基因表达显著上调，同时有47和42个基因显著下调。热激条件下编码酶和转录调控因子的基因，包括PfpI和TetR家族转录调节因子以及冷激条件下编码DEAD/DEAH解旋酶和IclR家族转录调节因子的基因，其表达量均显著上升。另外一些基因的表达，主要是与Ton-B依赖性受体和铁载体受体有关的基因，其表达量无论在冷激还是热激条件下，均显著下降。许多与脂肪酸代谢和ABC运输有关的基因在不同温度条件下的表达情况有所不同。对转录组和温度胁迫相关基因的调查结果有助于我们了解南极细菌的抗逆力机制。

本文对海洋二号（HY-2A）微波散射计极地海冰识别算法进行了研究。该算法以后向散射系数、STD阈值和APR作为海冰识别的指标，首先利用后向散射系数阈值和极化比的海冰识别，在此基础上分别进行方差滤波和空间滤波，最终得出海冰分布结果。以美国雪冰中心发布的微波辐射计海冰分布产品为参考，对本文的海冰识别结果进行验证，结果表明，本文算法所得海冰识别结与SSMI海冰结果在海冰发展趋势，季节变化、面积分布和外缘线分布上都具有很好的一致性，其海冰面积识别的准确率相对SSMI海冰结果优于91%。

Sea-ice concentration is a key item in global climate change research. Recent progress in remotely sensed sea-ice concentration product has been stimulated by the use of a new sensor, advanced microwave scanning radiometer for EOS (AMSR-E), which offers a spatial resolution of 6 km×4 km at 89GHz. A new inversion algorithm named LASI (linear ASI) using AMSR-E 89GHz data was proposed and applied in the antarctic sea areas. And then comparisons between the LASI ice concentration products and those retrieved by the other two standard algorithms, ASI (arctic radiation and turbulence interaction study sea-ice algorithm) and bootstrap, were made. Both the spatial and temporal variability patterns of ice concentration differences, LASI minus ASI and LASI minus bootstrap, were investigated. Comparative data suggest a high result consistency, especially between LASI and ASI. On the other hand, in order to estimate the LASI ice concentration errors introduced by the tie-points uncertainties, a sensitivity analysis was carried out. Additionally an LASI algorithmerror estimation based on the field measurements was also completed. The errors suggest that themoderate to high ice concentration areas (>70%) are less affected (never exceeding 10%) than those in the low ice concentration. LASI and ASI consume 75 and 112 s respectively when processing the same AMSR-E time series thourghout the year 2010. To conclude, by using the LASI algorithm, not only the seaice concentration can be retrieved with at least an equal quality as that of the two extensively demonstrated operational algorithms, ASI and bootstrap, but also in a more efficient way than ASI.

二甲基巯基丙酸内盐（DMSP）主要是由海洋浮游植物生成，可作为胞内渗透调节剂、抗氧化剂、捕食者威慑物、或抗冻剂。DMSP对于海洋细菌而言也是一种重要的碳源和硫源。细菌可以通过涉及DMSP脱甲基酶基因（dmdA）的脱甲基途径、或涉及7种DMSP裂解酶基因的裂解途径对DMSP进行分解代谢。释放到海水中的大多数DMSP是被细菌通过脱甲基途径降解。在主要的海洋细菌种类中存在着较高的dmdA基因频率，这可能部分归功于该基因的水平基因转移（HGT）行为。为了验证这一假设，课题组从北极王湾分离获得了31株细菌。16S rRNA基因序列分析结果表明，除了菌株BSw22118、BSw22131、以及BSw22132分别属于科尔韦尔氏菌属、假单胞菌属、以及冰川菌属之外，其余细菌都属于假交替单胞菌属。在5株亲缘关系较远的不同细菌株中，包括分离自北极的假交替单胞菌BSw22112、科尔韦尔氏菌BSw22118、假单胞菌BSw22131、冰川菌BSw22132和分离自南极的玫瑰柠檬形菌ZS2-28，均检测到dmdA基因。这些dmdA基因与来自温带近岸海水中的鲁杰氏菌DSS-3的dmdA基因具有很高的序列相似性（97.7 %–98.3 %）。此外，在南极玫瑰柠檬形菌ZS2-28中检测到的基因转移因子（GTA）核衣壳蛋白基因g5与鲁杰氏菌DSS-3的g5基因也具有很近的亲缘关系。在这5株极地分离菌中，只有假单胞菌BSw22131能够以DMSP作为唯一碳源进行生长。本次研究的结果支持了不同种类的浮游细菌中存在dmdA基因的水平基因转移这一假说，同时也表明在全球海洋环境中存在如dmdA等功能基因的广泛分布。

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and β-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSw10175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus Shewanella dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria (>99%), but also between polar marine bacteria and bacteria from other aquatic environments (≥ 98.8%), including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.

In this paper, on the basis of the Antarctic sea ice data from 1972 to 1989 issued by the America Joint Ice Center, the distribution features of the Antarctic sea ice is analyzed, the net sea ice area indexes are calculated. and the long-range variation periods of the sea ice area index are analyzed with the maximum entropy spectrum, finally the distribution pattern of the Antarctic sea ice and its variation features are obtained.
According to its spatial distribution feature, the Antarctic Sea ice is divided into three large regions. Region Ⅰ (0°-120°E) is a zonal area which includes the Prydz Bay area, and sea ice area extending from the Weddell Sea, Region Ⅰ (120°E-120°W) mainly includes the Ross Sea area, and Region Ⅱ(120°W-0°) mainly the Weddell Sea area. Of all the regions, the ice area in Region,is the largest, and that in Region Ⅰ is the smallest.

The characteristic low-frequency oscillation of the sea surface temperature anomaly (SSTA) of ENSO related regions, Niño 1+2, Niño 3, Niño 4 and Niño West, and the Southern Oscillation index (SOI) is analyzed with the method of maximum entropy spectrum.Antarctic sea ice is divided into 4 regions, i.e.East Antarctic is Region Ⅰ (0°-120°E), the region dominated by Ross Sea ice is Region Ⅱ (120°E-120°W), the region dominated by Ross Sea ice is Region Ⅲ (120°W-0°), and the whole Antarctic sea ice area is Region Ⅳ.Also, the month-to-month correlation series of the sea ice with ENSO from contemporary to 5-years lag is calculated.The optimum correlation period is selected from the series.The characteristics and the rules obtained are as follows.1.There are a common 4-years main period of the SSTA of Niños 1+2, 3 and 4, a rather strong 4-years secondary period and a quasi-8-years main period of that of Niño West.