江苏宜兴骆驼墩、西溪遗址全新世软体动物   总被引：1，自引：1，他引：0  

黄宝玉  朱祥根  蔡华伟  林留根  田名利 《海洋科学》2005,29(8):84-94

江苏宜兴骆驼墩、西溪遗址化石丰富,除软体动物外,还有植物、孢粉、昆虫、脊椎动物等。作者研究的软体动物化石,计有8属17种,其中有一新种：Corbicula yixingensis Huang et Caisp．nov．,隶属于双壳类（Bivalvia）的殊蚌科（Unionidae）、蚬科（Corbiculidae）及腹足类（Gastropoda）的田螺科（Viviparidae）。可分成3个组合类群,一是Unio—Cuneopsis类群,本类群属种个体数量虽然少,但地质历程长,从第三纪晚期中新世至第四纪全新世均有,代表古老的类群。如：Cuneopsis spocki Leroy最早发现于内蒙古锡林郭勒盟二连第三纪晚期中新世通古尔期：Unio tschiliensis Sherany曾发现于河北张家口岔道口更新世早期,上述二种均未见现生种。二是Arconaia-Lamprotula类群。这个类群从第四纪早期至现代河、湖、池塘、水库中均有分布。其中Arconaia—laneceolata（Lea）见于江苏沭阳钱集西南更新世早期。Lamprotula（Sinolamprotula）leai（Gray）见于河南三门峡更新世早期。三是Corbicula-Bellamya类群。该类群时代长,分布广,适应性强,属种个体数量极多,其中Corbicula largillierti Heude从第三纪晚期至现代均有。化石种曾发现于内蒙古乌兰察布盟四子王旗第三纪晚期;山西垣曲,陕西大荔更新世早期：但在江苏金坛、江阴、宜兴的全新世时大量发育、繁衍、繁盛。以致现代长江流域太湖、洞庭湖、鄱阳湖及其相通的河流中也有,为中国广泛分布的特有种,本种似乎起源于中国内蒙古,而后向西、向南迁移。Bellamya quadrata（Benson）见于广西桂林南郊全新世,也有现生种。  相似文献   

Demersal Continental Shelf and Upper Slope Cephalopod Assemblages from the Balearic Sea (North-Western Mediterranean). Biological Aspects of Some Deep-Sea Species   总被引：1，自引：0，他引：1  

A. Quetglas  A. Carbonell  P. Snchez 《Estuarine, Coastal and Shelf Science》2000,50(6):739

The analysis of 79 hauls performed by commercial bottom trawlers from 50 to 800 m depth in the Balearic Sea (north-western Mediterranean) from June 1995 to September 1996 yielded a total of 30 cephalopod species belonging to 12 families. Cluster analysis of these data gave as a result two main groups 50–200 m and 200–800 m each subdivided into two other groups (50–100 vs. 100–200 m and 200–600 vs. 600–800 m). These results suggested the existence of two assemblages that could be associated to the continental shelf (50–100 m) and the upper slope (600–800 m) separated by a wide transitional zone (100–600 m) representing a region of overlapping shelf and slope faunas (ecotone). The faunistic bathymetric gradient showed a continuous substitution of species with depth rather than discrete assemblages separated by distinct boundaries. The more coastal species such as Eledone moschata, Loligo vulgarisSepia officinalis and Octopus vulgaris were found on the continental shelf; on the transitional zone, apart from species characteristic of this zone (Illex coindetii, Sepietta oweniana, Rossia macrosoma, Scaeurgus unicirrhus and Pteroctopus tetracirrhus), we also observed species from both the continental shelf and slope. The upper slope was characterized by typical species of deeper waters, such asBathypolypus sponsalis , Histioteuthis reversa, H. bonnellii, Ancistroteuthis lichtensteinii andOnychoteuthis banksii . The octopod O. vulgaris was the dominant species on the continental shelf and upper transitional zone, being substituted by T. sagittatus on the lower transitional zone and upper slope. Mean biomass decreased abruptly from the continental shelf to the transitional zone and from there to the upper slope. Mean species richness and species diversity were higher in the transitional zone than in the continental shelf and upper slope. Finally, some biological aspects of the more abundant deep-sea cephalopod species are studied: Bathypolypus sponsalis, Octopus salutii,Pteroctopus tetracirrhus , Histioteuthis reversa and H. bonnellii.  相似文献   

Late-glacial and early-Holocene Coleoptera assemblages as indicators of local environment and climate at Kråkenes Lake, western Norway     

Geoffrey Lemdahl 《Journal of Paleolimnology》2000,23(1):57-66

Thirty-six Coleoptera (beetle) taxa and other insects were identified from the late-glacial and early-Holocene sediments at Kråkenes Lake. Compared with other Scandinavian late-glacial sites, this is a rather sparse record. The water beetles found in the Allerod are characteristic of a poorly vegetated clear-water lake. The terrestrial fauna is indicative of dwarf-shrub and moss vegetation. A marked decline in the number of species at the start of the Younger Dryas was rather rapid, probably over less than 80 calendar yrs. No obligate tundra species replaced the Allerod fauna. Most of the Younger Dryas is virtually devoid of beetles. The increase in numbers and diversity of both aquatic and terrestrial species at the Younger Dryas/Holocene transition is very rapid. After an initial pioneer stage, beetles associated with dwarf-shrub heath and willow scrub appeared, but no obligate tree or forest taxa were recorded.Mutual Climatic Range (MCR) temperature reconstructions suggest that the Allerod was colder and more continental than present. The near absence of beetles in the Younger Dryas probably reflects very cold conditions. A rapid temperature rise at the start of the Holocene resulted in a warmer and more continental climate than present.  相似文献   

上海东部地区全新世孢粉组合及古植被和古气候   总被引：13，自引：6，他引：7  

张玉兰 《古地理学报》2006,8(1):35-41

通过对上海东部地区南汇鹤鸣Hm孔、东海Dh1井、高桥G2孔3口钻井全新世地层的孢粉研究,划分出5个孢粉组合带和3个亚带,恢复了本地区古植被演替和古气候波动的5个阶段：第1阶段为针阔叶混交林-草地,反映气候温凉略湿（前北方期）;第2阶段为含常绿阔叶树的针阔叶混交林,反映气候温和略干（北方期）;第3阶段为以常绿栎类、栲属、杨梅等为主的常绿阔叶林,反映气候热暖潮湿（大西洋期）;第4阶段是以栎、松、禾本科为主的针阔叶混交林,反映气候温暖略干（亚北方期）;第5阶段是以落叶栎类、常绿栎类、松为主的落叶阔叶、常绿阔叶、针叶混交林-草地,反映气候温暖湿润（亚大西洋期）。这为本地区的地层年代划分和对比提供了可靠的证据,为全新世古植被、古气候及古环境的重建提供了重要的孢粉学资料。  相似文献   

囊谦盆地贡觉组含膏盐地层粘土矿物组合特征及气候环境意义          下载免费PDF全文

赵廷仪  袁秦  陈俊彬  安福元  吕爽  孙爱军  山发寿 《盐湖研究》2020,28(1):25-32

囊谦盆地晚始新世贡觉组厚层红色含膏盐粉砂质泥岩是研究青藏高原始新世古气候演化和含膏盐沉积环境的良好素材。采集囊谦盆地贡觉组约257 m含膏盐地层的碎屑沉积物,研究其粘土矿物成分和组合特征及气候与沉积环境变化。结果显示,粘土矿物主要以伊利石(52.1%)为主,其次为绿泥石(8.1%)和高岭石(3.5%)。根据岩性特征及粘土矿物组合变化,剖面自下而上可划分为3个阶段,分别指示了暖湿—低盐度、冷干—高盐度、较暖湿—低盐度的气候和沉积环境。贡觉组气候与沉积环境受到青藏高原地区干湿交替变化大背景的影响。  相似文献   

渤海湾沿岸贝壳堤对潮滩有孔虫海面变化指示意义的影响   总被引：1，自引：1，他引：0  

李建芬  商志文  姜兴钰  陈永胜  王福  田立柱  王宏 《地质通报》2016,35(10):1578-1583

通过对渤海湾沿岸有贝壳堤发育和无贝壳堤发育的2类现代开放潮滩有孔虫组合的对比,研究了该2类潮滩环境沉积物中有孔虫的海面指示意义。5个有孔虫组合带被MHWST(平均大潮高潮位)、MHW(平均高潮位)、MHWNT(平均大潮低潮位)和MSL(平均海面)分隔,分别对应潮滩的高盐沼、低盐沼、潮间带上部、潮间带中上部和潮间带中下部5个不同亚环境。不同亚环境沉积物因其所含的有孔虫群的独特性,均可作为高精度海面标志物,误差为各亚带高差的1/2。沿岸贝壳堤可对潮滩有孔虫的属种组成产生影响,影响程度从高潮位向低潮位逐渐降低。在MHWNT潮位之下,有孔虫组合不再受到沿岸贝壳堤的影响。  相似文献   

Copepod assemblages in a highly complex hydrographic region   总被引：2，自引：2，他引：2  

A.D. Berasategui  S. Menu Marque  M. Gmez-Erache  F.C. Ramírez  H.W. Mianzan  E.M. Acha 《Estuarine, Coastal and Shelf Science》2006,66(3-4):483-492

Community structure and diversity patterns of planktonic copepods were investigated for the Southwestern Atlantic Ocean between 34 and 41°S. Our objectives were (1) to define copepod assemblages, (2) to accurately identify their association to different water masses/hydrodynamic regimes, (3) to characterize the assemblages in terms of their community structure, and (4) to test if frontal boundaries between water masses separate copepod assemblages. Biogeographic patterns were investigated using multivariate analysis (cluster and ANOSIM analyses). Biodiversity patterns were examined using different univariate indexes (point species richness and taxonomic distinctness). Five regions of similar copepod assemblages were defined for our study area each one corresponding to different environments (freshwater, estuarine, continental shelf, Malvinas and Brazil current assemblages). These assemblages have major community structure differences. In spite of the complex oceanographic scenario of our study area, that can lead us to expect a pattern of copepod communities with diffuse boundaries, we found a strong spatial correspondence between these limits and the presence of permanent frontal structures.  相似文献   

Soft-bottom macrofauna and responses to organic enrichment in the subarctic wates of Tromsø, northern Norway     

Brge Holte  Eivind Oug 《Journal of Sea Research》1996,36(3-4)

The soft-bottom macrofauna (> 1 mm) of Tromsøysund and Sandnessund near Tromsø, northern Norway (69°40′N, 19°0′E) was sampled quantitatively in 1983, 1990 and 1992 in order to assess enrichment effects from discharges of municipal sewage and fish factory effluents. The studies comprised 30 stations between 7 and 40 m depth at varying distances from effluent outfalls. In total 395 species/taxa were recorded. The polychaetes were the most important group both with regard to the numbers of species (146) and specimens (80% of total), but bivalves and amphipods were also common. Most stations had species numbers between 40 and 100 and densities between 2000 and 8000 ind. per m². The species assemblages could be related to organic enrichment, depth and sampling year. Evidence suggests that the organic discharges did not seriously affect the waters surrounding Tromsø, but the generally high abundances, the prevalence of polychaetes and a numerical importance of ‘opportunistic’ species (Polydora, Chaetozone, Heteromastus) might suggest that the whole area was stimulated by the organic inputs. Sharply delimited strongly enriched zones characterized by dense populations of Capitella capitata were found on shallow sites close to large outfalls in Tromsøysund. These local and restricted effects of the discharges may be related to strong tidal currents and wave action that disperse effluent components. The faunal composition remained largely stable from 1983 to 1992 at 9 revisited stations, but the number of small bivalve and crustacean taxa increased and the abundance of the dominant polychaete Polydora socialis strongly decreased. The effluent discharges were supposed to have increased from 1983 to 1992, but the faunal changes did not provide evidence of an increased enrichment of the area during the period.  相似文献   

An East-West Comparison of the Transition Zone Coastal Pelagic Nekton of the North Pacific Ocean     

Richard D. Brodeur  Joseph P. Fisher  Yasuhiro Ueno  Kazuya Nagasawa  William G. Pearcy 《Journal of Oceanography》2003,59(4):415-434

During the 1980s and 1990s, scientific research cruises were conducted in both the eastern and western boundary regions of the North Pacific Ocean. The main purpose of these cruises was to examine the abundance and distribution patterns of juvenile salmon in coastal waters. These studies created one of the most extensive databases ever collected on the species composition of coastal Transition Zone epipelagic nekton in the North Pacific Ocean. Catch data from two purse seine and two surface trawl surveys (one each from off northern Japan and eastern Russia and off the West Coast of the U.S.) were examined using multivariate techniques to analyze the community structure of nektonic cephalopods, elasmobranchs, and teleosts in the coastal zone during the summer and autumn months. Juvenile salmonids are generally among the most common species caught, but in terms of overall abundance, other potential competitors with juvenile salmon, such as small squids and clupeoid fishes predominated the catches. Species diversity and dominance varied among areas and gear types. Distinct assemblages were found in each area, but the two regions had closely related species occupying similar ecological positions in each habitat. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Community structure of fishes in Cabo Pulmo Reef, Gulf of California     

Lorenzo Alvarez-Filip  Héctor Reyes-Bonilla  & Luis E. Calderon-Aguilera 《Marine Ecology》2006,27(3):253-262

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