南极洲东方湖的融化和冻结

至今在南极洲的冰盖之下发现了 77个湖泊。其中最大的一个 (面积近 2万km2 )是前苏联科学家在“东方”站附近 4km厚的冰层之下发现的 ,并命名东方湖。这个呈半月形弯曲的淡水湖具有强烈切割的湖底 ,局部深度可达 10 0 0m。在 2 0 0 0年 ,英国布里斯托尔大学的MSiegert及其同事们对湖泊进行了 3次无线电测量工作。结果显示 ,在湖泊的西部和北部边缘 ,尽管温度很低 ,每年要融化几乎 1 0cm厚的冰层 (融解温度低于正常是由于上覆冰盾的巨大压力 )。由于融解水在冰盖底部重新冻结 ,使它的底部增厚 ,但这发生在相反的岸边。就这样 ,湖水缓慢地环…     

南极洲古老冰川研究的动向

研究冰川和冰川盖层的迫切性未引起任何人的怀疑。一层层堆积下来的冰成为区域性的或全球性的周围环境状态的特殊档案。     

普里兹湾是研究南极洲冰川史的关键地点

具有巨厚冰盾和周围海洋的南极洲大陆是形成地球气候及全球性大洋环流的最重要因素。环抱南极洲的环南极洋流造成了大陆的热隔离和明显的纬向温度梯度 ,因此在南半球产生了大气和海洋环流。南极洲周围海冰的广泛分布促使形成了充填世界海洋广大深水部分和保证其通气及给海洋生物提供营养元素的南极洲洋底水体。一般认为 ,反映气候波动的冰盾容积的变化回答了过去地质年代海平面的强烈变化。在大陆和南大洋的多年研究表明 ,中生代和新生代初期 ,南极洲的气候要比今日暖和得多 ,当时它被茂盛的植被覆盖 ,这一点局部反映在白垩纪煤层的形成中。…     

全球变暖，为什么南极洲冰层变厚？

今年我们听到最多的关于天气的评价就是这样几个词“热”、“波动”。 2010年的夏天据信是最近几十年来最热的一年，炎热的天气使北冰洋上的冰层融化、变薄，引发了诸多的担忧。就在不久之前，科学家还观察到一个260平方千米的冰块脱离了格陵兰冰川。     

南极洲的恐龙类

古生物学家在南极洲发现了两个恐龙类新种。一组科研人员在罗斯岛上发现了属于霸王龙和вецочраиторы属的食肉恐龙类古生物残骸。在白垩纪末（约70Ma前）爬虫类在这里生活。     

南极洲冰盾的演化

尽管在地面考察、陆地固定测站以及海洋科学研究钻探船“JOIDES Resolution”号的诸多航次中 ,对南极洲有着长期的研究历史 ,但对巨厚冰盾的演化的研究仍然几乎为零。显然 ,它的形成和冰体积变化对整个新生代发展时期的地球气候起了决定性的影响。有关南极洲冰盖的生长起伏 ,通常是根据底栖有孔虫介壳中氧同位素的变化以及按照低纬度大陆水下边缘沉积物的组分和剖面结构重建的海平面升降来判断的。但是这个重建由于以下原因而复杂化 ,即碳酸盐介壳在海底的溶解歪曲了其中重、轻氧同位素的原始比例关系 ,这样就导致对获得结果的解释不一致…     

南极洲的恐龙类

以古生物学家W.Hammer为首的美国极地工作者在离南极点500km的南极横断山脉中发现了属于蜥脚亚目、翼龙类的大型食草恐龙类和若干小型食尸恐龙类以及至今完全未知的“装备了”角和脊的大型食肉恐龙类残骸的化石。     

联合国“无权”管辖的南极洲

很多人都知道,南极洲不属于任何国家所有。但是大多数人却不知道,南极洲并不是全人类的共有财产,甚至联合国也无权直接管辖。而与南极情况近似同样也不属于任何国家的外空空间、外空天体以及大洋洋底却属于全人类共同财产,管辖权归联合国。那南极洲归谁管呢?     

海岛奇岩怪石风景旅游资源形成的地质地貌分析——以福建平潭县的千礁百岛为例

我国东南沿海,无论海岸和岛屿,绝大部分由花岗岩所构成,花岗岩在热带、亚热带的气候环境下,经受以海水为主的长期侵蚀,塑造出无数动人心魄的地表形胜景观,它们在大海的衬托下,构成我国东南一隅独具特色的海岛奇岩怪石造型的地貌旅游资源,如海南岛的天涯海     

Shell damage and shell repair in the Antarctic limpet Nacella concinna from King George Island

Nacella concinna is the most conspicuous macroinvertebrate in the intertidal of King George Island. An important predator, the Kelp gull Larus dominicanus, feeds on Nacella during spring low tides. The gulls deposit empty Nacella shells as regurgitates mainly on roosts on coastal rocks. The regurgitates were found to consist of 40% shell fragments by weight and 60% intact shells. Faeces of Kelp gulls contained much smaller fragments than the regurgitates. Some of the Nacella, particularly those too large to ingest, are handled in the intertidal. The middens are, therefore, inadequate to study size selection by Kelp gulls: the largest Nacella are underrepresented. Seventy-five per cent of the intact Nacella shells from the Larus middens showed one or more shell repairs. Such repairs may be due to unsuccessful attacks by gulls, but more probably they indicate damage caused by rolling ice blocks and stones in the intertidal and shallow subtidal. A number of living Nacella were found stranded on the beach, detached from the rocks. They showed damage along the shell margin and even one Nacella was collected without any shell left. The observed repair frequency of 75% in Nacella was much higher than in other (smaller) intertidal gastropods at Potter Peninsula (3–11%, av. 8%). Comparably high frequencies are observed for instance in tropical intertidal gastropods, where repair is due to heavy unsuccessful crab predation; however, shell-crushing crabs are absent on King George Island. This indicates that palaeontologists should be cautious in ascribing all shell repairs in fossil shells (particularly from tidal environments) to predators. Shell repair in the related Nacella deaurata, collected in a less exposed site at Port Stanley (Falkland Islands), occurred only in 13% of the specimens. Another conspicuous form of shell damage was due to grazing by Nacella on the boring algae living in other Nacella shells. Epigrowth of crustose calcareous algae inhibited such grazing, but in the absence of epigrowth deep hollows were scraped in the shells, the parallel scratches by the radula clearly visible, urging Nacella to repair its shell by producing more shelly material on the inside.     

Hyperspectral Model of Solar Radiation Transport in an Atmosphere with Cirrus Clouds

Izvestiya, Atmospheric and Oceanic Physics - The radiation transfer theory, based on different approximations of the Boltzmann kinetic equations, is the theoretical basis for Earth remote sensing...     

近百年来南极威德尔海北部水动力环境演变

南极威德尔海水动力环境的变化及其对全球变化的响应有着重要的意义,近百年来以全球变暖为特征的全球变化已经影响到该地。对南极威德尔海北部ANT28-D5-6短柱沉积物进行了²¹⁰Pb测年、粒度参数和冰筏碎屑物含量的测试分析。结果显示威德尔海北部在近百年时间内(1922—2011年)水动力环境发生了显著的转变。在1922—1972年间,威德尔海北部处在高能高速动荡的水动力环境,并携带沉积了大量的冰筏碎屑物,对应了全球温度变化相对较低的阶段。但在1930—1936年间和1946—1952年间发生了2次水动力减弱事件。1939年和1950年两次冰筏碎屑物含量的增加可能与太阳活动峰年引起的威德尔环流经向增强有关。1972—2011年威德尔海北部处在较为平静的弱能状态,对应了全球气温持续升温的阶段。1955—1972年威德尔海水动力环境处在从高能动荡的状态向低能静水状态快速过渡的阶段。     

Discovery of a recent,natural whale fall on the continental slope off Anvers Island,western Antarctic Peninsula

Whale falls provide a substantial, nutrient-rich resource for species in areas of the ocean that may otherwise be largely devoid of food. We report the discovery of a natural whale fall at 1430 m depth in the cold waters of the continental slope off the western Antarctic Peninsula. This is the highest-latitude whale fall reported to date. The section of the carcass we observed—the tail fluke—was more complete than any previously reported natural whale fall from the deep sea and in the early stages of decomposition. We estimate the entire cetacean to measure 5–8 m in length. The flesh remained almost intact on the carcass but the skin was missing from the entire section except for the end of the fluke, clearly exposing blubber and soft tissue. The absence of skin indicates rapid and Homogeneous loss. The dominant macrofauna present were crustaceans, including most prominently the lithodid crab Paralomis birsteini, and zoarcid fish typical of the ‘mobile-scavenger’ successional stage. The density of mobile macrofauna was greatest on the carcass and declined to background levels within 100 m, indicating that they were attracted to the whale fall. This whale fall offers an important opportunity to examine the decomposition of a carcass under deep-sea conditions at polar latitudes.     

南极半岛渐新世早期冰盖的证据

始新世-渐新世(E—O)过渡时期,地球气候从温暖变为寒冷,甚至进入冰期,渐新世早期(约33·5 Ma)的标志是海洋碳酸盐的氧同位素值有明显的快速正偏移(Miller等的Oi-1事件,1991),以及随着新生代南极冰盖的第1次大规模扩张而出现的南大洋冰携碎屑。这种偏移的规模以及相对大的幅度吸     

南极冰河下面的快速侵蚀、鼓丘形成和水文变化

极地冰盖的变化在未来几百年期间可能会极大地影响着全球海平面和地势低洼的海岸带地区,因此,人们投入了大量的人力、物力来进行冰川学研究,但是,我们尚缺乏将冰盖变化与未来海平面评价有机结合在一起的能力。对地球的冰盖演化进行预测需要正确的冰动力模式和对过去的冰川环境做出适当的解释,而这种模式和解释最需要的是要了解冰川地层的作用过程,但是,目前我们非常缺乏现代冰川之下和冰川底界的信息数据。     

基于光学遥感的海岛潮间带和湿地信息提取--以东沙岛(礁)为例

基于高分辨率遥感图像,采用相似三角形原理,结合海岛多年潮汐数据进行了海岛潮间带的确定;利用克里格（Kriging）插值方法,对水深图中海岛浅水区域的水深点数据进行单元网格化处理,在遥感图像的辅助下,进行了海岛湿地范围的界定。在此基础上,确定了东沙岛潮间带和湿地的范围,提取了各自的面积,并对结果进行了分析。     

Antarctic shallow water benthos in an area of recent rapid glacier retreat

The West Antarctic Peninsula is one of the fastest warming regions on Earth. Faster glacier retreat and related calving events lead to more frequent iceberg scouring, fresh water input and higher sediment loads, which in turn affect shallow water benthic marine assemblages in coastal regions. In addition, ice retreat creates new benthic substrates for colonization. We investigated three size classes of benthic biota (microbenthos, meiofauna and macrofauna) at three sites in Potter Cove (King George Island, West Antarctic Peninsula) situated at similar water depths but experiencing different disturbance regimes related to glacier retreat. Our results revealed the presence of a patchy distribution of highly divergent benthic assemblages within a relatively small area (about 1 km²). In areas with frequent ice scouring and higher sediment accumulation rates, an assemblage mainly dominated by macrobenthic scavengers (such as the polychaete Barrukia cristata), vagile organisms and younger individuals of sessile species (such as the bivalve Yoldia eightsi) was found. Macrofauna were low in abundance and very patchily distributed in recently ice‐free areas close to the glacier, whereas the pioneer nematode genus Microlaimus reached a higher relative abundance in these newly exposed sites. The most diverse and abundant macrofaunal assemblage was found in areas most remote from recent glacier influence. By contrast, the meiofauna showed relatively low densities in these areas. The three benthic size classes appeared to respond in different ways to disturbances likely related to ice retreat, suggesting that the capacity to adapt and colonize habitats is dependent on both body size and specific life traits. We predict that, under continued deglaciation, more diverse, but less patchy, benthic assemblages will become established in areas out of reach of glacier‐related disturbance.