南海北部HY4—901孔浮游有孔虫特征及意义

南海北部ＨＹ４－９０１孔沉积连续,粒度均匀,浮游有孔虫丰富,共鉴定１０属２６种,其中以暖水种占优势,凉水种也有相当含量,浮游有孔虫组合的研究表明,本区的溶解作用不强,不是影响ＣａＣＯ３分布的主要因素,全新世的气温变化,可以分为五期：１）迅速升温期;２）高温期;３）降温期;４）温暖期;５）温凉期。     

东太平洋CC南区有孔虫埋藏群特征及意义

通过对研究区４１个站位的表层沉积物样、１０个自返重力管（短柱）样和３个大型重力活塞样的研究,共鉴定有孔虫４８属８７种,其中浮游类６属１４种,钙质底栖类３２属６３种,胶结壳类９属１０种。表层沉积物中钙质有孔虫的分布表明,本区的ＣＣＤ界线大致为４９００ｍ。从柱状样有孔虫面貌看,其时代主要为早－中中新世,并可分为３个组合。大部分地区缺失中中新统－第四系。     

海南岛近岸沉积物中的有孔虫特征与分布

对位于海南岛近岸7-170 m水深、180个站位沉积物表层样的有孔虫分析表明,研究区浮游有孔虫类型较少、共发现浮游有孔虫19种,单个站位最多含有浮游有孔虫16种,而且浮游有孔虫含量(丰度)亦较低.底栖有孔虫则较为丰富,仅在较粗砂中底栖有孔虫丰度相对较低.常见近40多个底栖有孔虫属种,多数样品中以含有螺旋式与平旋式玻璃质底栖有孔虫为主,少数样品以胶结壳、列式玻璃质壳或大型底栖有孔虫为优势特征.本研究在详细阐述了底栖有孔虫主要特征属种的基础上进行了有孔虫分区,从而揭示其所包含的环境意义.     

东印度洋赤道南北两侧春季活体浮游有孔虫的组成与分布

2017年3月通过对在东印度洋海区6个站位53个垂直分层拖网浮游有孔虫样品进行的定量分析,探讨了该海区春季现代浮游有孔虫的组成、分布及其影响因素。东印度洋春季0～3 000m水层内共鉴定出17个浮游有孔虫属种,主要是Globigerinoides ruber,Globorotaloides hexagona,Globigerinoides sacculifer,Globigerinella aequilateralis,Neogloboquadrina dutertrei,Globorotalia menardii,Globiberinella calida,Pulleniatina obliquiloculata和Globorotalia theyeri等,它们是典型的热带亚热带暖水种浮游有孔虫群落。G.ruber,G.sacculifer最大丰度层在0～50m水层;G.conglomerata,G.hexagona最大丰度层均出现在50～100m;G.theyeris在100～1 000m间的水层均有活体出现,100～150m水层中该种浮游有孔虫丰度最高;G.scitula为深层水浮游有孔虫分子,主要出现于300～2 000m的深水水层。东印度洋春季浮游有孔虫群落的丰度在赤道中心区最低,由赤道向南北两侧扩展,其丰度逐渐递增的特点。浮游有孔虫丰度明显呈上层高,下层低的特点,在50～100m水层浮游有孔虫丰度最高,明显高于0～50m水层浮游的有孔虫丰度,这与印度洋50～100m水体中叶绿素最大值层相对应,表明浮游有孔虫受水体初级生产力影响明显。     

现代浮游有孔虫生态研究进展

古海洋环境是全球变化研究中的一个重要组成部分。作为表层古海洋环境信息主要载体的浮游有孔虫分布范围广泛,在海洋沉积物中大量保存,在该研究领域中具有不可替代的作用,是重建古环境的基础。对现代浮游有孔虫的生态特征进行研究,是正确理解浮游有孔虫群落及其壳体地球化学指标所蕴涵古海洋环境信息的前提。本文综述了国内外浮游有孔虫生态研究的一些主要方法及其进展,重点阐述了不同海域不同海洋环境条件下一些主要浮游有孔虫属种的区域分布、深度分布、季节性变化及其壳体同位素组成等特征。最后展望了我国南海现代浮游有孔虫生态的研究前景。     

珠江口盆地L2-X井中新统有孔虫生物地层及其沉积环境

珠江口盆地白云凹陷L2-X井中新世地层沉积连续,含丰富的有孔虫化石,是研究区较为典型的中新统钻井剖面之一.在L2-X井1490～2640 m井段内分析有孔虫岩屑样品127个,共鉴定有孔虫71属110种,其中浮游有孔虫12属37种,底栖有孔虫59属73种.根据浮游有孔虫标志种,在中新世地层中共识别出10个有孔虫化石带或联...     

晚更新世南海不同海区的浮游有孔虫群落特征差异及环境控制因素

本研究对晚更新世以来(～45万)南海西部浮游有孔虫进行定量统计分析,并与南海北部和南部该时期的浮游有孔虫组合进行比较.研究发现,南海浮游有孔虫组合在以Globigerinoides ruber和Globigerinoides sacculifer为代表的热带—亚热带组合面貌为特征的背景下,其不同海区的浮游有孔虫组合具有...     

海南岛东部近海新第三纪孢粉植物群

根据ＢＤ２３－１－１井与孢子花粉共生的海相浮游有孔虫和钙质超微化石,论述了中国海南岛东部近海新第三纪各个时期的孢粉植物群特征。建立了４个孢粉组合,它们是：１．Ｑｕｅｒｃｏｉｄｉｔｅｓ－Ｃｕｐｕｌｉｆｅｒｏｉｐｏｌｅｎｉｔｅｓ－Ｆｌｏｒｓｈｕｅｔｚｉａ－Ｄｉｃｏｌｐｏｐｏｌｉｓ组合（早中新世晚期）;２．Ｄｉｃｏｌｐｏｐｏｌｉｓ－Ｅｘｔｒａ－ｐｕｎｃｔａｔｏｓｐｏｒｉｔｅｓ－Ｔａｘｏｄｉａｃｅａｅｐｏｌｅｎｉｔｅｓ组合（中中新世早期）;３．Ａｂｉｅｔｉｎｅａｅｐｏｌｅｎｉｔｅｓ－Ｐｏｌｙｐｏｄｉ－ａｃｅａｅｓｐｏｒｉｔｅｓ－Ｌｉｑｕｉｄａｍｂａｒｐｏｌｅｎｉｔｅｓ组合（中中新世晚期至晚中新世）;４．Ａｂｉｅｔｉｎｅａｅｐｏｌｅｎｉｔｅｓ－Ｐｅｒｓｉｃａｒｉｏｉｐｏｌｉｓ组合（晚中新世晚期至早上新世）。孢粉植物群反映了海南岛东部近海新第三纪的气候基本上一直比较温暖湿润,并且逐渐降温的历程。     

低纬季风区现代浮游有孔虫主要属种的分布特征及其环境指示意义

提要本次工作利用2013年4月-2017年11月在低纬季风海区采集的浮游生物分层拖网样品为材料,共鉴定出活体浮游有孔虫27种,以热带-亚热带暖水种和较少的广适性冷水种为主。南海、西太平洋和东印度洋广泛分布的浮游有孔虫优势属种为Globigerinoides sacculifer,Globigerinoides ruber,Neogloboquadrina dutertrei,Pulleniatina obliquiloculata和Globorotalia menardii。优势属种中,表层种G. sacculifer和G. ruber丰度最高、占据全种60%以上,主要集中分布在0～50 m水层,受温度和生产力影响较大;次表层种N. dutertrei和P. obliquiloculata分别生活在0～100m、50～100 m水层,其分布与盐度和生产力密切相关。浮游有孔虫的分布受季风影响明显,冬、夏季风通过改变海水上层的温度、盐度以及温跃层、营养跃层的深度极大影响了浮游有孔虫在平面和垂向上的分布,同时也造成了浮游有孔虫分布的季节性差异。     

海南岛鹿回头珊瑚礁区全新世有孔虫

对海南岛鹿回头小东海和三亚湾珊瑚区底质中的样品进行分析研究,共获得有孔虫４０属９０种,其中包括３新种４未定种。小东海有孔虫壳一般较坚固。大有孔虫占绝对优热;三亚湾有孔虫壳体易破碎,大有孔虫相对贫乏。水动力状况及盐度差异是造成两地有孔虫不同的主要原因。磨蚀试验表明,有孔虫壳孔形态结构与环境有密切的关系。     

Paleoceanographic implications of smaller benthic and planktonic foraminifera from the Eocene Pazin Basin (Coastal Dinarides,Croatia)

Summary Smaller benthic and planktonic foraminifera from the clastic sediments of the Pazin Basin (Istria, Croatia) were studied in order to obtain more data about paleoceanographic conditions that existed in the Middle Eocene Dinaric foreland basin. The succession investigated corresponds to the Middle Eocene planktonic foraminiferal zones Globigerapsis kugleri/Morozovella aragonensis (P11), Morozovella lehneri (P12), and Globigerapsis beckmanni (P13). Benthic foraminiferal assemblages from the clastic succession are dominated by epifaunal trochospiral genera suggesting oligotrophic to mesotrophic conditions and moderately oxygenated bottom waters. Planktonic foraminiferal assemblages indicate mesotrophic to eutrophic conditions of the surface waters, with increased eutrophication in the upper part of the section. Water depth, based on the ratio between planktonic and epifaunal benthic foraminifera and on the recognized species of cosmopolitan benthic foraminifera, was estimated to have been between about 900 and 1200 m. The basin was elongated and open to marine currents on both sides allowing good circulation and ventilation of the bottom water.     

Basin-scale paleobiogeography and paleoecology: an example from Karpatian (Latest Burdigalian) benthic and planktonic foraminifera and calcareous nannofossils from the Central Paratethys

We present the paleobiogeography and ecology of benthic and planktonic foraminifera and calcareous nannoplankton during the Karpatian (Latest  Burdigalian) in the Austrian part of the Central Paratethys. Results are based on quantitative data of assemblages from the Molasse and Styrian Basins. Our data suggest that, although adjacent, the two basins underwent different paleoceanographic evolution during the Karpatian. Dysoxic bottom waters characterized the Molasse Basin, together with reducing environments, which produced the formation of pyritized levels. In the Styrian Basin, intense volcanic activity enriched surface waters in nutrient and produced strong primary productivity. Reduced planktonic foraminiferal abundance and dominance of agglutinated benthic forms in the Styrian Basin can be attributed to paleoceanographic conditions. The planktonic-depleted assemblages bias the paleodepth estimation by 100P(P + B) in the Styrian Basin and new tools for assessing paleodepth are needed. This study shows that paleobiogeography of foraminifera and calcareous nannoplankton is strictly related to local ecological conditions in enclosed basins and demonstrates that quantitative ecological studies are the best way to monitor the biogeographic evolution of enclosed basins.     

基于两级分段式算法的卷积神经网络的浮游有孔虫自动鉴定*

有孔虫个体微小、数量众多、地理分布广、演化迅速, 是记录海洋沉积环境的重要载体, 在海相生物地层划分和对比中具有十分重要的作用。因有孔虫属种众多, 传统的属种鉴定需要经验丰富的专业人员进行人工鉴定且耗时较长, 此外人工鉴定古生物面临人才匮乏和工作量大等问题。卷积神经网络在计算机视觉领域的应用可较好的解决上述问题。利用古生物专家对中新世浮游有孔虫化石标注为指导, 根据有孔虫化石不同方向的视角分类, 结合卷积神经网络算法, 开发了有孔虫化石图像识别系统。研究发现, 通过有孔虫化石腹视、缘视和背视角度分类, 采取两级分段式鉴定算法对中新世浮游有孔虫属一级进行识别, 属一级鉴定准确率达到82%左右。     

Molecular evidence for an independent origin of modern triserial planktonic foraminifera from benthic ancestors

Gallitellia vivans is the only Recent representative of the triserial planktonic foraminiferal family Guembelitriidae. The origin and evolution of this interesting albeit poorly known family are enigmatic. To elucidate the phylogenetic relationships between G. vivans and other planktonic foraminifera, we sequenced the small subunit ribosomal DNA (SSU rDNA) for comparison to our extensive database of planktonic and benthic species. Our analyses suggest that G. vivans represents a separate lineage of planktonic foraminifera, which branches close to the benthic rotaliids Stainforthia and Virgulinella. Both genera resemble Gallitellia in general morphological appearance, having elongate triserial tests at least in their early ontogenic stages. The divergence time of G. vivans is estimated at ca. 18 Ma (early Miocene), suggesting an origin independent from the Cretaceous and Paleogene triserial planktonic foraminifera. Our study thus indicates that modern triserial planktonic foraminifera are not related to the Cretaceous–Paleogene triserial species, and that the sporadic occurrences in the fossil record are not the result of poor preservation, but reflect multiple transitions from benthic to planktonic mode of life.     

Millennial-scale paleoenvironmental changes in the central Mediterranean during the last interglacial: Comparison with European and North Atlantic records

The environment of the central Mediterranean Sea is investigated on the basis of high-resolution planktonic foraminifera and calcareous nannofossil data (mean sampling resolutions of about 80 and 160 yr, respectively). MIS 5 is characterized by warm, oligotrophic and stratified waters, while coccolithophore communities developed a vertical zonation that, in today's oceans, is typical of the low-latitude gyres. The temperate-subtropical configuration of planktonic foraminifera and calcareous nannofossil assemblages is repeatedly transformed into a temperate-subpolar one during the suborbital cooling episodes C25-C18. A comparison with European pollen sequences and North Atlantic cores over the interval between about 128 and 110 kyr BP is carried out. Records from this broad geographical area show a series of environmental changes that occurred at comparable times. However, the first cooling episodes were more severe at high-latitude (approximately north of 50°N), where an anticipated end of interglacial conditions can be ascribed. Variations in the rate of the Atlantic meridional overturning circulation and the strength of atmospheric circulation in the Northern Hemisphere are discussed as likely climatic forcing mechanisms.     

中国海洋浮游端足类的物种多样性

中国海域已发现浮游端足类122种,呈现从北部往南部海区、从近海往外海区种数逐渐增加,且暖水性也逐渐增强的分布特征。渤海、黄海北部和西南部的浮游端足类同属暖温带分布,黄海东南部和东海西北部为暖温带分布和热带分布的过渡带,东海东部和东海西南部以及台湾海峡、南海均属热带分布,其中东海东部和南海中、南部热带大洋分布的特征显著。     

Distribution of some planktonic foraminifera species in deep-sea cores from the red sea and their relation to eustatic sea-level changes

Distribution patterns of planktonic foraminifera in four sediment cores from the Red Sea are studied. The most common species are Globigerinoides ruber, G. sacculifer, Globigerinella siphonifera and Orbulina universa. G. ruber and G. sacculifer show opposite trends of distribution in the sediment cores. Abundance of the foraminifera during the glacial periods suggests that the connection of the Red Sea to the Indian ocean was not completely interrupted and the salinity conditions were not extreme.However, higher salinities appear to have existed in the northern Red Sea, where most of the planktonic foraminifera that occur in the southern Red Sea are absent. It is inferred that the salinity in the southern Red Sea during the glacial period was less than 50%, whereas higher salinity might have existed in the north where the influence of the Indian Ocean was minimal.     

南海北部琼东南盆地BD-2井中新世有孔虫生物地层及沉积环境

南海北部琼东南盆地BD-2井中新世地层沉积连续,是琼东南盆地中新统较典型的钻井剖面之一。该井中新世地层中含丰富的有孔虫化石,共鉴定有孔虫62属98种,其中浮游有孔虫13属41种,底栖有孔虫49属57种。根据有孔虫标志种及螺旋浮游有孔虫旋向优势度的变化,对该井的有孔虫生物地层进行了详细划分,从早中新世至晚中新世共识别出11个有孔虫化石带或联合化石带。探讨了下中新统与中中新统,中中新统与上中新统界线的有孔虫划分标志。依据有孔虫丰度、分异度及组合特征,讨论了BD-2井从早中新世至晚中新世沉积环境演化特征。     

Neue mikropaläontologische Ergebnisse aus dem Paleozän des Haunsberg-Helvetikums (Salzburg, Österreich)

A revised stratigraphy based on planktonic foraminifera is presented for the Paleocene Oiching Beds of the Helvetic zone N Salzburg, Austria. Compared with the result of Gohrbandt (1963), the planktonic foraminiferal diversity is greater and a new interpretation of local tectonic is proposed. The planktonic foraminifera are described in brief.     

Molecular evidence for an independent origin of modern triserial planktonic foraminifera from benthic ancestors

Gallitellia vivans is the only Recent representative of the triserial planktonic foraminiferal family Guembelitriidae. The origin and evolution of this interesting albeit poorly known family are enigmatic. To elucidate the phylogenetic relationships between G. vivans and other planktonic foraminifera, we sequenced the small subunit ribosomal DNA (SSU rDNA) for comparison to our extensive database of planktonic and benthic species. Our analyses suggest that G. vivans represents a separate lineage of planktonic foraminifera, which branches close to the benthic rotaliids Stainforthia and Virgulinella. Both genera resemble Gallitellia in general morphological appearance, having elongate triserial tests at least in their early ontogenic stages. The divergence time of G. vivans is estimated at ca. 18 Ma (early Miocene), suggesting an origin independent from the Cretaceous and Paleogene triserial planktonic foraminifera. Our study thus indicates that modern triserial planktonic foraminifera are not related to the Cretaceous–Paleogene triserial species, and that the sporadic occurrences in the fossil record are not the result of poor preservation, but reflect multiple transitions from benthic to planktonic mode of life.