Distribution and Adaptations of Sea Ice Inhabiting Harpacticoida (Crustacea, Copepoda) of the Weddell Sea (Antarctica)

Abstract. Seven harpacticoid species were found to be associated with sea ice collected during 5 Antarctic cruises of the RV Polarstern. Their distribution within the fast ice and pack ice zones of the Weddell Sea is presented. Whereas some individuals probably become entrapped into the ice only accidentally, at least 4 species arc genuinely sympagic. These have evolved remarkable adaptations, as evidenced by field and laboratory studies of Dresclieriella glacialis , which is by far the most abundant. Such adaptations include: the ability to penetrate deep into ice; a comparatively high salinity tolerance allowing it to endure large salinity fluctuations associated with ice crystal formation and melting; good swimming ability, necessary both for horizontal dispersal and for a planktonic intermezzo after annual melting of the sea ice. D. glacialis is the first polar non-vertebrate mctazoan to be cultivated through its entire life cycle. Its life history suggests an r-stratcgy; this would be the first indication of such a trait in the polar environment. A new species of Drescheriella , on the other hand, exhibits resting stages (C IV-V) known to date only for Calanoidu but not reported for Harpacticoida.     

Analysis of Benthic Communities in the Cyclades Plateau (Aegean Sea) Using Ecological and Paleoecological Data Sets

Abstract. In the Cyclades plateau (Aegean Sea), a qualitative and quantitative analysis of macro-benthic fauna was carried out in 1986. Standard multivariate analysis techniques were applied to both ecological (living benthic fauna) and paleoecological data sets in order to distinguish distribution patterns.
Results showed that caution must prevail in drawing conclusions from a limited data set. The clearest classification was obtained using total living fauna, while the dead molluscan fauna gave a similar pattern; this indicates similar response to the environmental conditions of the area. In the analysis of the living molluscan fauna, the groups failed to show any clusters, probably as an effect of some impoverished sites.
In the two groups delineated, depth seems to be the major factor in the distribution of species.
The fact that two distinct data sets (subfossil assemblages and living communities), when treated separately, produce similar grouping indicates that the subfossil assemblages could be reliably used as a first approach for determination of the living communities' distribution patterns.     

鄱阳湖鱼类资源及渔业利用

1997年冬至2000年春,对我国最大淡水湖鄱阳湖的鱼类与渔业利用状况进行了调查.在1955年至2000年期间,鄱阳湖累计记录鱼类136种,隶属于25科78属;其中鲤科鱼类最多,有71种,占总种数的52.2%,其次是鲿科,12种,占8.8%本次调查期间共记录鱼类101种,新记录鱼类6种,即亮银鮈、洞庭小鳔鮈、光唇蛇鮈、短须鱊、方氏鳑鲏和粘皮鲻鰕虎鱼.还分析了该湖鱼类区系组成的变化、主要渔具的渔获物组成特征以及渔产量动态,提出了未来湖泊渔业可持续发展的建议.     

更新世代表性哺乳动物群的生物年代排序及与测年值的对比

哺乳动物随着环境的变化不断演化出与原来不同的特征, 因此可以根据化石标本的形态特征判断它们在系统演化中的位置, 并根据动物群中各个种类的演化程度判断不同动物群之间的生物年代顺序。本项研究在传统的绝灭率、共有属种、二元相似性系数等方法的基础上尝试拓展了二元共有度和排序梯度等共9种方法, 对选自中国境内有代表性的15个更新世哺乳动物群进行了生物年代排序。自老至新的动物群以其产地为名的生物年代合意顺序及推测的绝对年龄为: 泥河湾下沙沟(1.75~2.2 Ma)-繁昌人字洞(1.7~2.1 Ma)-巫山龙骨坡(1.5~1.9 Ma)-元谋人遗址(1.4~1.8 Ma)-建始龙骨洞(1.3~1.6 Ma)-柳城巨猿洞(1.15~1.5 Ma)-蓝田公王岭(1.1~1.3 Ma)-崇左三合大洞(0.6~1.2 Ma)-和县人遗址龙潭洞(490~800 ka)-周口店第一地点下部(460~770 ka)-周口店第一地点上部(230~450 ka)-海城小孤山(30~80 ka)-本溪山城子(约30 ka)-大连古龙山(27~30 ka)-周口店山顶洞(18~27 ka)。研究表明, 使用不同的方法对不同的动物群进行生物年代排序的结果在大尺度范围内是一致的, 但在小尺度范围内会出现一些差异, 这与排序标准和统计计算方法有关。一旦化石标本的分类鉴定结果和生物年代排序的方法确定下来, 动物群的生物年代序列就基本上是固定的, 不会随研究者的更换而改变, 因此可以用来检验绝对年龄的测年结果。由于组成各个动物群的种类可能会因鉴定人员的不同而有差别, 造成生物年代排序结果与测年结果差异较大。因此有必要组织同一团队的研究人员核对各个地点的化石种类鉴定结果, 并与测年工作配合进行。和县人遗址的龙潭洞动物群在本项研究的生物年代排序中早于周口店第一地点, 这个动物群的化石标本以及产出地层值得重新观察和测年。根据本项研究的实践, 这类数字化排序的方法还有细化的发展空间。

     

关岭生物群和卡尼期早期裂谷

讨论晚三叠世卡尼期早期关岭生物群的生存环境和死亡埋葬特点,认为该生物群分布于裂谷地区;生物群的群体死亡并被迅速埋葬的原因是地震;贵州龙生物群与关岭生物群是同期生物群;"S形带"是一构造断陷带,在卡尼期早期是裂谷。     

泥河湾地区晚上新世一个新的地层单位——稻地组

本文记述了河北泥河湾盆地的一个新的地层单位——稻地组。在四个实测剖面上对稻地组进行了分层描述,根据其岩性、化石特征、及其与上下地层接触关系,确定了该地层组的含义,并对其时代(晚上新世)作了讨论。     

A new record of Pleistocene hippopotamus from River Severn terrace deposits, Gloucester, UK—palaeoenvironmental setting and stratigraphical significance

A new Pleistocene vertebrate assemblage from fluvial deposits of the River Severn in Gloucester, England, has yielded the remains of hippopotamus (Hippopotamus amphibius), a new record for this terrace system, with additional material from probable bison (cf. Bison priscus) and elephant (Elephantidae sp.). The presence of these taxa indicates fully temperate climatic conditions and the occurrence of hippopotamus, a significant biostratigraphical indicator for the British Late Pleistocene, suggests an age for the assemblage within MIS 5e (the Last Interglacial). This would contradict the older MIS 7-6 age for the gravel body that is currently accepted on the basis of deposit mapping and imply a more complex mode of deposition than presently envisaged in the valley.     

Terrestrial Mio-Pliocene Boundary in the Linxia Basin, Gansu, China

The Lower Pliocene of the Linxia Basin in Gansu Province is one of only a few representative sections for the Early Pliocene sedimentary records in northern China, and even in East Asia. Recently, abundant mammalian fossils were found from the base of red clays of the Lower Pliocene Hewangjia Formation at Duikang in Guanghe County within this basin. Previously, the Pliocene mammals were sparsely found in China, and most were collected from fluvial and lacustrine deposits in the eastern Loess Plateau. Mammals from the widely distributed Pliocene Hipparion Red Clay are less in number. The known fossils from Duikang include 20 species and belong to the Shilidun Fauna. Their faunal components are similar to the Early Pliocene Gaozhuang Fauna from Yushe, Shanxi. On the other hand, some taxa from Duikang have not been found in the Gaozhuang Fauna, are slightly more primitive in evolutionary level, and appeared mainly in the Late Miocene. As a result, the age of the Duikang fossils may be slightly earlier than that of the Gaozhuang Fauna and closer to the lower boundary of the Pliocene. The Duikang fossiliferous bed is 0.8 m above the top of the Late Miocene Liushu Formation, and the first occurrence of the three-toed horse Hipparion pater can be regarded as a biostratigraphical marker of the Miocene/Pliocene boundary. In conclusion, Duikang is an ideal candidate locality to establish as the stratotype of the lower boundary of the Chinese terrestrial Pliocene.     

Temporal and spatial changes in marine benthic habitats in relation to the EU Water Framework Directive: The use of sediment profile imagery

In 2002 to 2006, sediment profile imagery (SPI) was used to study the environmental impact of eutrophication-induced irregular and seasonal hypoxia on marine benthic habitats in six regions in the Skagerrak and Kattegat (West Sweden). The benthic habitat quality (BHQ) was assessed by parameterisation of biogenic structures observed by the SPI technique, and benthic quality status was related to the EU Water Framework Directive (EU-WFD). The temporal changes were analysed by a 5-factor nested ANOVA and significant temporal differences were recorded within three of the regions. Two of these were affected by hypoxia in the deeper parts and one was probably affected by hypoxia below the halocline. The environmental quality status according to the EU-WFD was bad to high in two regions, moderate to good in three regions, and good to high, i.e., acceptable according to the EU-WFD, in only one region. As BHQ is highly correlated to benthic faunal data, measures have to be taken to improve the coastal water quality in five of the six studied areas.