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1.
Isao Sarashina Yoshiki Kunitomo Minoru Iijima Satoshi Chiba Kazuyoshi Endo 《Organic Geochemistry》2008,39(12):1742
Organic molecules such as proteins can be preserved in certain fossils. The bulk properties of fossil proteins of both vertebrates and invertebrates have been studied for over half a century. Named proteins have so far been identified, however, only in vertebrate fossils, such as collagen from mammoth bones. Using immunological assays, we examined 1500 year old fossils of the extinct land snail Mandarina luhuana from the Bonin islands for the presence of dermatopontin, a molluscan shell matrix protein. First, we examined the shell microstructure and mineralogy of the fossil shells using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) in order to estimate the extent of diagenetic alteration. The results suggest that the original microstructure and mineralogy of the shells are preserved. Antiserum raised against the Type-1 dermatopontin fragment of the living land snail Euhadra brandtii showed significant immunological reactivity with the extracts from the fossil shells of M. luhuana. Immunological binding curves drawn for the shell extracts of extant M. aureola and the extinct M. luhuana confirmed the presence of dermatopontin in the fossil shells and provided an estimate that about 75–98% of the original dermatopontin was lost from the M. luhuana fossils. This is the first report of a named protein being identified in invertebrate fossils. 相似文献
2.
扬子海盆奥陶纪末介壳动物群的分布及其古地理意义 总被引：1，自引：0，他引：1
通过奥陶纪末扬子海盆介壳动物群生态组合的划分, 并结合介壳动物群产出的岩性特征的研究, 分析了当时海盆内部的沉积分异特点: 扬子海盆中部, 水体相对较深, 为浅海较深水盆地, 指示的生态域 > BA4- 5;到海盆东部水体逐渐变浅, 生态域以BA4- 5为主; 海盆西部水体变得更浅, 生态域以 < BA3为主.此外, 将海盆划分为中部浅海深水黑色硅质页岩盆地、东、西部浅海碎屑岩和浅海碳酸岩-碎屑岩沉积盆地.从南往北, 进一步对以上3个沉积区进行了水体深浅变化的探讨, 并且认为: 海盆中部, 由西南往东北方向, 水体逐渐变深, 沉积中心位于湖北、湘中及湘北部分地区(桃园—安化一带); 海盆西部和东部, 从南往北, 水体均由浅变深(在海盆西部, 黔北生态域 < BA3, 川中至川东 < BA3, 川北和陕南为BA4;在海盆东部, 浙江桐庐、常山一带 < BA3, 安徽泾县和南京等地≥BA4- 5).此外, 根据生物群和岩性的空间变化, 认为扬子海盆以北面临大洋或洋盆. 相似文献
3.
Paul Loubere 《Quaternary Research》1982,17(3):314-324
The paleoceanographic-climatic record represented by deep-sea microfossils reflects conditions for only certain times of the year. Also, the relative abundances of microfossil species in deep-sea sediments do not usually reflect only one paleoceanographic variable, such as temperature. Rather, species distributions represent the integration of many factors that control biological production in the oceans. This influences the information on past climates that can be extracted from fossil material. The seasonal limitation is due to the cyclic nature of biological production in the open ocean. Case studies of the sediment record in the Atlantic for two species of planktonic Foraminifera, left-coiling Neogloboquadrina pachyderma (Ehrenberg) and Globigerinoides ruber (d'Orbigny), illustrate seasonal bias in environmental data reported by the relative abundances of species in deep-sea sediments. In addition, the study of G. ruber illustrates the operation of two oceanographic parameters in controlling a species distribution. These examples demonstrate that the environmental signal in the sediments is the result of the interplay of the ecological tolerance of the plankton species with seasonally variable biological and physical properties of the upper ocean. 相似文献
4.
M. Nair J. Jacob P. A. Nisha G. D. Martin K. Srinivas P. Sheeba C. M. Laluraj T. Joseph K. K. Balachandran 《Environmental Earth Sciences》2010,61(1):27-35
Temporal and spatial changes in the sediment properties of a mangrove ecosystem (Cochin, southwest coast India) are presented.
The region was freshwater dominated during monsoon (June–September) and seawater dominated during other two seasons. The system
remained eutrophic due to the high inputs of organic matter (OM) during most part of the year. The organic-rich sediments
accumulated high amount of carbohydrates (22% of OM) and proteins (11% of OM) during non-monsoon months as compared to coastal
environments. Principal component analysis showed that the biochemical properties are uniformly influenced by seasonal and
spatial variations. Higher concentrations of sediment protein over carbohydrate indicate an efficient mineralization leading
to the non-availability of aged OM in the system. The dominance of these labile components is generally indicative of the
eutrophic condition of the system. 相似文献
5.
为能比较确切地了解《中国岩溶》的网络影响力和明确今后办刊的努力方向,以中国知网( CNKI)中心网站2005年1月1日— 2007年3月15日的日志记录资料为依据,运用CNKI所提供的期刊文献评价统计分析系统软件对《中国岩溶》的网络传播特征进行了统计分析。结果表明, 1982— 1998年,由于论文的时效性等原因, 《中国岩溶》被访问和下载量比较小, 1982— 1993年所出版的论文平均每篇受访、下载率不足0. 7和0. 4次, 1994— 1998年为20. 1和7. 1次,属《中国岩溶》论文被访问下载量基本无升幅和小额度升幅时段; 1999年以后,由于能够主动地根据国家社会经济发展需要,及时调整选题并加强生态环境、水资源开发、环境地质等研究领域的组稿力度,被访问下载量明显提高,平均每篇被访问、下载率分别达78. 9次和34. 8次,为《中国岩溶》论文被访问下载的高额度升幅时段。当前《中国岩溶》网络传播存在的主要问题是国外网络传播能力比较小等,亟待通过不断加强海外宣传及规范中英文摘要的编写等手段加以解决。 相似文献
6.
Salinities occupied by different life stages of bay anchovy (Anchoa mitchilli) were compared over annual cycles at 128 stations in 12 Florida estuaries. The comparison included eight stations in an oligotrophic,
groundwater-based estuary in which all life stages were rare or absent. At other stations, adults, eggs, and early larvae
occurred in intermediate to high salinities (10-30 psu) with no apparent central salinity tendency. The larva-juvenile transition
was marked by an upstream shift to lower salinities (0-15 psu), also with no central salinity tendency. Mean salinities of
the juvenile catch were strongly dependent on the salinities of the sampling effort. This dependence was strongest in estuaries
that had weak horizontal salinity gradients. Weak salinity gradients were either natural or resulted from estuarine dams.
After using nonlinear regression to account for the interaction between effort salinity and catch salinity, catch salinities
were found to be similar from year to year within estuaries, but widely different among estuaries, with interestuarine differences
ranging as high as 10–13 psu. Lower salinities were occupied by juveniles in estuaries that had long freshwater turnover times.
Inherent geomorphic and inflow-related effects on the distribution of prey resources, coupled with an ontogenetic diet shift,
are proposed as the explanation for both the habitat shift and the strong interestuarine variability in salinity at capture. 相似文献
7.
P. Lafuente L. E. Arlegui C. L. Liesa J. L. Simón 《International Journal of Earth Sciences》2011,100(7):1713-1732
The Concud fault is a 13.5 km long, NW–SE striking normal fault at the eastern Iberian Chain. Its recent (Late Pleistocene)
slip history is characterized from mapping and trench analysis and discussed in the context of the accretion/incision history
of the Alfambra River. The fault has been active since Late Pliocene times, with slip rates ranging from 0.07 to 0.33 mm/year
that are consistent with its present-day geomorphologic expression. The most likely empirical correlation suggests that the
associated paleoseisms have potential magnitudes close to 6.8, coseismic displacements of 2.0 m, and recurrence intervals
from 6.1 to 28.9 ka. At least six paleoseismic events have been identified between 113 and 32 ka. The first three events (U
to W) involved displacement along the major fault plane. The last three events (X to Z) encompassed downthrow and hanging-wall
synthetic bending prompting fissure opening. This change is accompanied by a decrease in slip rate (from 0.63 to 0.08–0.17 mm/year)
and has been attributed to activation of a synthetic blind fault at the hanging wall. The average coseismic displacement (1.9–2.0 m)
and recurrence period (6.7–7.9 ka) inferred from this paleoseismic succession are within the ranges predicted from empirical
correlation. Such paleoseismic activity contrasts with the moderate present-day seismicity of the area (maximum instrumental
Mb = 4.4), which can be explained by the long recurrence interval that characterizes intraplate regions. 相似文献
8.
During the late Pleistocene and early Holocene, Bison was widely dispersed across North America and occupied most regions not covered by ice sheets. A dietary study on Bison paleopopulations from Alaska, New Mexico, Florida, and Texas was performed using two methods that relate dental wear patterns to diet, mesowear analysis and microwear analysis. These data were compared to a mixed sample of extant Bison from the North American central plains, extant wood Bison from Alberta (Canada) and a variety of other modern ungulates. Mesowear relates macroscopic molar facet shape to levels of dietary abrasion. The mesowear signature observed on fossil Bison differs significantly from the hyper-abrasive grazing diet of extant Bison. Tooth microwear examines wear on the surface of enamel at a microscopic scale. The microwear signal of fossil samples resembles to modern Bison, but the fossil samples show a greater diversity of features, suggesting that fossil Bison populations regularly consumed food items that are texturally inconsistent with the short-grass diet typical of modern plains Bison. Mesowear and microwear signals of fossil Bison samples most closely resemble a variety of typical mixed feeding ungulates, all with diets that are substantially less abrasive than what is typical for modern plains Bison. Furthermore, statistical tests suggest significant differences between the microwear signatures of the fossil samples, thus revealing geographic variability in Pleistocene Bison diets. This study reveals that fossils are of value in developing an understanding of the dietary breadth and ecological versatility of species that, in recent times, are rare, endangered, and occupy only a small remnant of their former ranges. 相似文献
9.
L. A. Kodina 《Geochemistry International》2010,48(12):1157-1165
Partitioning of carbon isotopes between main polymers of biomass of higher plants was investigated by the example of the structural
polymers of wheat plant: lignin, hemicellulose, and cellulose representing the ligno-carbohydrate complex, starch and proteins
representing storage compounds, and the lipid fraction. Biopolymers account from 80% (grasses) to 95% (trees) of the biomass
of higher plants and are of geochemical interest as biological precursors for the terrigenous organic matter (OM) of sediments
and sedimentary rocks. The biomass of algae is also dominated (∼80%) by polymers: proteins, carbohydrates, and lipids. The
isotopic heterogeneity of the organs and parts of plants is controlled by carbon isotope composition (from −33.3 to −25.9‰)
in biopolymers and their distribution: among various parts of plants. The carbohydrates: starch and hemicellulose are isotopically
heaviest (−25.9 and −26.2‰), proteins are slightly poorer in 13C (up to −27.3‰), and lipids (−33.3‰) and lignin (−32.6‰) are isotopically light components of the biomass. The regularity
of carbon isotopes partitioning among the large complexes of the biomass of higher plants is reflected in the existence of
a common linear trend of δ13C values of biopolymers versus the ranges of thermodynamic β-factor values calculated by the method of isotopic bond numbers
for the whole set of monomers in the composition of each polymer studied. The carbohydrates of grain and straw (starch, xylan,
and cellulose) form a common C6–C5 pool of the isotopically heaviest polymers of the higher plant biomass (wheat). No significant
isotopic effects were observed at the transformation between C6–C5 monomers and their transport between plant organs during
grain ripening. 相似文献
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12.
2009-2013年,从青海湖裸鲤内脏器官中共分离获得6株发光细菌,编号依次为Q1、Q2、Q3、Q4、Q5、Q6.这6株发光细菌细胞壁革兰氏染色均为阴性,细胞为杆状,大小为(0.5~0.8)μm×(1.0~1.5)μm,具有单极生鞭毛,有运动性.氧化酶和接触酶均呈阳性反应,能发酵葡萄糖产酸;吲哚试验和V-P试验均为阳性反应,能分泌淀粉酶、明胶酶、DNA酶,能将硝酸盐还原为亚硝酸盐.最适生长温度为20~25℃,最适生长pH为8.5~9.0.16S rDNA基因序列分析结果表明,6株发光菌与其亲缘关系最近的属为Vibrio(弧菌属),该属内和此次实验的6株发光菌亲缘关系最近的种Vibrio anguillarum(鳗弧菌)的16S rDNA序列相似值为99.57%.Biolog GenⅢ鉴定结果显示,该实验的6株发光菌在有氧条件下,在提供的71种碳源中,只能利用其中的30种,其中,糖类12种,氨基酸类5种,羧酸类4种,聚合物类2种,其他类7种.结合6株发光菌的形态学特征、生理生化特性、Biolog Gen III鉴定结果和分子生物学特性,将菌株鉴定为Vibrio anguillarum.该菌所具有的发光特性为首次报道. 相似文献
13.
Hundreds of natural catastrophes occur worldwide every year—there were 780 loss events per year on average over the last 10 years. Since 1980, these disasters have claimed over two million lives and caused losses worth US$ 3,000 billion. The deadliest disasters were caused by earthquakes: the tsunami following the Sumatra quake (2004) and the Haiti earthquake (2010) claimed more than 220,000 lives each. The Great East Japan Earthquake of 11 March 2011 was the costliest natural disaster of all times, with total losses of US$ 210 billion. Hurricane Katrina, in 2005, was the second costliest disaster, with total losses of US$ 140 billion (in 2010 values). To ensure that high-quality natural disaster analyses can be performed, the data have to be collected, checked and managed with a high degree of expertise and professionality. Scientists, governmental and non-governmental organisations and the finance industry make use of global databases that contain losses attributable to natural catastrophes. At present, there are three global and multi-peril loss databases: NatCatSERVICE (Munich Re), Sigma (Swiss Re) and EM-Dat (Centre for Research on the Epidemiology of Disasters). They are supplemented by numerous databases focusing on national or regional issues, certain hazards and specific sectors. This paper outlines the criteria and definitions relating to how global and multi-peril databases are operated, and the efforts being made to ensure consistent and internationally recognised standards of data management. In addition, it presents the concept and methodology underlying the NatCatSERVICE database, and points out the many challenges associated with data acquisition and data management. 相似文献
14.
Prey importance and ontogenetic transitions in the diet of stocked and wild mulloway (Argyrosomus japonicus) were compared between a southeast Australian reverine estuary and a coastal lagoon. Stomach content analysis of fish captured
from these estuaries in 1997–1979, 1997–1998, and 2003–2005 revealed size-specific and estuary-specific diets. Mysid shrimp
were most common in diets of fish <250 mm total length (TL), and prawns were common in diets of fish measuring 301–450 mm.
Forage fish were most abundant in diets of mulloway >500 mm. Index of Relative Importance (IRI) of forage fish increased with
TL, while IRI of mysids decreased with TL. Prawn IRI was greatest for fish 150–600 mm TL. Comparisons between benthic resources
and dietary composition revealed that Georges River mulloway consumed prey categories in proportions similar to those in their
environment. No mysid shrimp were detected in the coastal lagoon or in the diet of mulloway captured there; growth was comparable
to the Georges River. Hatchery-reared fish fed<16 d after stocking, indicating normal behavioural adaptation after release.
Dietary information can be used to optimize stocking locations, times, and densities, as well as estimate potential effects
of mulloway on potential prey and wild conspecifics. 相似文献
15.
The effect of parental growth form on ramets introduced to new sites has broad implications for ecological restoration. We asked whether transplants ofSpartina foliosa need to come from tall parents in order to produce tall stands for nesting by the light-footed clapper rail, one of southern California’s many endangered, salt-marsh-dependent species. Tall and shortS. foliosa transplants, collected from local salt marshes, were grown in a common garden and in microcosms, with different results. In the common garden, which had hypersaline soil, offspring of tall versus short clones did not differ, but they did respond to soil variations among blocks. In blocks with less sandy soil, stems were taller and up to 5 times more numerous, and patch sizes were up to 3 times larger. After two years in low-salinity microcosms, transplants receiving nitrogen additions produced more stems and over twice the total stem length of controls, regardless of parental height form. A slight parental effect was seen in this benign environment; the maximum height of tall-form transplants was 15 cm taller than that of short-form transplants, but the effect did not persist through year 2. Results indicate that both height forms ofS. foliosa grew better (taller and more dense) with less environmental stress (lower salinity, more nutrients). We conclude that environmental differences are more important than parental height form in determiningS. foliosa growth. This means that, for restoration purposes,S. foliosa ramets can and should be collected from short clones, rather than from existing, prime nesting habitat. 相似文献
16.
R.J. Muir 《Geology Today》2015,31(6):232-236
Current desktop technology is largely mouse‐driven, but many analysts predict that in less than five years we will have a professional workforce that have only experienced learning in a touchscreen environment. Midland Valley have developed a digital mapping tool for smartphones called FieldMove Clino, which has been downloaded more than 20 000 times over the past year. The free version offers an effective way of introducing students to digital field mapping. However, many geoscience departments and teachers of field mapping have yet to make the switch from traditional paper‐based methods to digital technology. This article aims to answer some of the frequently asked questions about digital field mapping and outlines some of the advantages for improving field skills and geological thinking in students. 相似文献
17.
The composition of Hippidion diet, and possible changes that could relate to its extinction, were evaluated in the Argentinean-Chilean Central Andes, a Neotropical environment characterized by arid to semiarid conditions (Andean hot and cold deserts). Microhistological analyses were made on feces of Hippidion found at Los Morrillos (31°43′S–68°42′W, 3000 m a.s.l.) and Gruta del Indio (34°35′S, 68°22′W, 660 m a.s.l.). At Gruta del Indio the diet of Hippidion was based mainly on woody species. At Los Morrillos, it was based on herbaceous species.This flexibility in diet composition could be a relative adaptive advantage allowing a longer permanence of this species in comparison to others recorded in the region (such as Megatheriumand Mylodon). Nevertheless, this advantage was not enough to guarantee its survival during the Holocene. Extinction could have been affected by diverse agents, such as growing aridification of the area, increasing competition with other species (mainly Lama guanicoe), and human presence, along with a relatively low population density (as expected from the limited presence of Hippidion at the archaeological and palaeontological sites of South America. At Gruta del Indio significant changes in the diet of Hippidion corresponding to different intervals of the period 31,000–9000 14C BP are not evident. Given this evidence for similar diets for Hippidion throughout the late Quaternary, other factors need to be considered to explain the extinction of this horse. 相似文献
18.
Meso-scale atmospheric events promote phytoplankton blooms in the coastal Bay of Bengal 总被引：1，自引：0，他引：1
K MANEESHA V V S S SARMA N P C REDDY Y SADHURAM T V RAMANA MURTY V V SARMA M DILEEP KUMAR 《Journal of Earth System Science》2011,120(4):773-782
The Bay of Bengal is considered to be a low productive region compared to the Arabian Sea based on conventional seasonal observations.
Such seasonal observations are not representative of a calendar year since the conventional approach might miss episodic high
productive events associated with extreme atmospheric processes. We examined here the influence of extreme atmospheric events,
such as heavy rainfall and cyclone Sidr, on phytoplankton biomass in the western Bay of Bengal using both in situ time-series observations and satellite derived Chlorophyll a (Chl a) and sea surface temperature (SST). Supply of nutrients through the runoff driven by episodic heavy rainfall (234 mm) on
4–5 October 2007 caused an increase in Chl a concentration by four times than the previous in the coastal Bay was observed within two weeks. Similar increase in Chl a, by 3 to 10 times, was observed on the right side of the cyclone Sidr track in the central Bay of Bengal after the cyclone Sidr. These two episodic events caused phytoplankton blooms in the western Bay of Bengal which enhanced ~40% of fishery production
during October–December 2007 compared to that in the same period in 2006. 相似文献
19.
Horia Mitrofan Constantin Marin Dorel Zugr&#x;vescu Alin Tudorache Lucian Beu?iu Mihaela Radu 《地学学报》2008,20(2):87-94
The Na, K, Mg and Ca contents of certain deep‐origin groundwater discharges have been used by Giggenbach (1988) to define a series of ‘geoindicators’, which may provide hints on the up‐flow depth of origin, on the duration of the fluid ascent to the ground surface and on the associated CO2 flux. On occurrence of a Mw = 6.0 Vrancea earthquake, significant fluctuations of Giggenbach’s geoindicators have been recorded in a saline spring, some 50 km away from the epicentre. A pre‐seismic overall anomaly was monitored for 1 year and a half, the sharpest variations occurring about 3 months before the earthquake. Processes controlling the geoindicator fluctuations assumedly took place at 7–8 km depth, while the earthquake hypocenter depth was about 100 km. This could be an evidence for a mechanical coupling still existing between the seismogenic body in the lithosphere and the overlying crust. 相似文献
20.
M.A. Wilson R.P. Philp A.H. Gillam T.D. Gilbert K.R. Tate 《Geochimica et cosmochimica acta》1983,47(3):497-502
Four humic extracts isolated from terrestrial, mahne, plankton and freshwater sources have been investigated by pyrolysis-gas chromatography-mass spectrometry. The results show that substantial quantities of phenols (some not derived from lignin), pyrroles and nitrites (derived from proteins, nucleic acids or porphyrins) are decomposition products. Small amounts of furans (derived from carbohydrates) and unsaturated ketones (derived from polycarboxylic aliphatic acids) are also present. The results illustrate how parent material, transport factors and biological activity affect the composition of humic extracts. 相似文献