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1.
F. Andrieux-Loyer X. Philippon G. Bally R. Kérouel A. Youenou J. Le Grand 《Biogeochemistry》2008,88(3):213-231
The macrotidal estuary of Penzé (Brittany, Western part of the Channel, France) has been subjected to recurrent annual toxic
blooms of Alexandrium minutum since 1988. This study aims to specify the phosphorus dynamics and bioavailability in sediments in order to improve our understanding
of Alexandrium occurrences. Sediment-P pools and diffusive phosphate fluxes were studied under similar hydrodynamic conditions, in the intermediate
estuary in May, June and July 2003 and along the salinity gradient from August 2004 to June 2005. The results highlight a
decrease in bioavailable phosphorus (iron and organic bound) from the inner part of the estuary seaward. The ratio of iron-bound
phosphorus to iron-oxyhydroxides is lower in the inner and intermediate estuaries (5–8) than in the outer site (15), suggesting
a saturation of sorption sites and greater phosphorus bioavailability in this area. Pools of bioavailable phosphorus in surficial
sediments are about eight times higher than the annual net-export of P (7 ton year−1). Phosphate releases from sediments are always lower than 5 μmol m−2 d−1 in March. The highest supplies occur in June and August in the intermediate area (up to 400 μmol m−2 d−1) where they represent up to 50% of river loadings. These results further suggest that phosphate pulses coincide with occurrences
of Alexandrium reported in June. 相似文献
2.
Cearreta Alejandro Alday María Conceição Freitas M. Andrade Cesar Cruces Anabela 《Hydrobiologia》2002,(1):21-27
Benthic foraminifera from eleven stations sampled seasonally were analyzed in order to examine the biological response to rapid and intense environmental changes taking place in the Santo André coastal lagoon. Foraminiferal assemblages show a very low species diversity and a high dominance of three euryhaline species throughout the year. Under closed-inlet conditions, foraminiferal assemblages exhibit low abundance of foraminiferal tests, whereas under open-inlet conditions absolute abundance greatly increases due to sea water entrance. Present-day dramatic environmental changes are thought to be responsible for deformed foraminiferal tests that are commonly found. Comparison of modern assemblages with those obtained from the Holocene sedimentary record indicates persistent restrictive environmental conditions after sandy barrier formation, circa 5000 years ago. 相似文献
3.
Laurent Loison 《Genetics》2013,195(2):295-302
This Perspectives is devoted to the ideas of the French zoologist Georges Teissier about the mechanisms of evolution and the relations between micro- and macroevolution. Working in an almost universally neo-Lamarckian context in France, Teissier was one of the very few Darwinians there at the time of the evolutionary synthesis. The general atmosphere of French zoology during the 1920s and the 1930s will first be recalled, to understand the specific conditions in which Teissier became a zoologist. After a brief overview of his joint work with Philippe L’Héritier on the experimental genetics of Drosophila, this article describes the ways Teissier, during the 1950s, conceptualized the mechanisms that could allow for macroevolutionary transitions.IT is usually acknowledged that France did not significantly participate in the elaboration of 20th century evolutionary theory, often designated The Modern Synthesis. In their classical book on the history of the synthesis, Ernst Mayr and William B. Provine devoted a whole—nonetheless small—chapter to this specific issue (Mayr and Provine 1998, pp. 309–328). Mayr clearly stated that “France is the only major scientific nation that did not contribute significantly to the evolutionary synthesis” (Mayr 1998, p. 309). In the absence of a French architect of the synthesis, Mayr and Provine asked Ernest Boesiger, a Swiss population geneticist and a former student of Georges Teissier, to tell the story of what had happened in French biology at the time of the evolutionary synthesis. Boesiger, who died in 1975, wrote a paper in 1974 that provided the firm basis of the chapter. In very strong terms, he depicted French biology as “a kind of living fossil in the rejection of modern evolutionary theories” (Boesiger 1998, p. 309). He insisted on the fact that, even in 1974, most French biologists and philosophers were still reluctant to accept Darwinism. As regards the period of the 1930s, Boesiger was able to think of only two exceptions: Georges Teissier and Philippe L’Héritier. He then referred to their joint research in population genetics, which was based on the new technique of the population cages with the species Drosophila melanogaster, and listed their contributions to this new discipline.If Teissier and L’Héritier’s works on Drosophila are nowadays more widely recognized than in 1974, due in particular to the efforts of Jean Gayon and Michel Veuille (Gayon and Veuille 2001), this recognition could have as an unintended consequence the reduction of both Teissier and L’Héritier to being simply the inventors of a useful technique, namely the population cages (see especially how Mayr presented their work in his other classical book, Mayr 1982, p. 574), or as the founders of a French school of population geneticists (Gayon and Veuille 2001). The aim of this article is to reevaluate the way Georges Teissier (1900–1972) conceived Darwinian natural selection not only as an important mechanism for evolution at the population level but more fundamentally as a general key for the unification of biology, exactly as Julian Huxley or Ernst Mayr did during the same period (1930–1970). However, starting in the early 1950s, Teissier went on to conceive a very specific understanding of the evolutionary synthesis.In this article, I will first describe the general atmosphere of evolutionary issues in French biology at the time when Teissier started working as a zoologist, to understand against what he developed his joint research program with L’Héritier and afterward his general conceptions about evolution. During the 1930s and the 1940s, only a very few scientists in France could be seen as Darwinians. In addition to Teissier and L’Héritier, one may also consider Marcel Prenant, Boris Ephrussi, and the mathematician Gustave Malécot. Building on Jean Gayon and Michel Veuille’s work, I will then give a quick overview of L’Héritier and Teissier’s most important achievements in the field of population genetics. In the third part, I will discuss the discovery made by Teissier and L’Héritier of a case of cytoplasmic inheritance in Drosophila. This unexpected finding led them into the field of non-Mendelian heredity. I will then develop in detail the way Teissier finally went on to conceive the relation between microevolution and macroevolution, in light of the general context of French biology and of the development of the field of cytoplasmic inheritance. 相似文献
4.
An archaeological study of the artiodactyls was carried out in the richest layers of the Caune de lArago Cave in France, namely levels L, J, G (upper) and F. The fauna of these levels is dominated by the reindeer, the Cervini (red deer and fallow deer), the musk ox and the argali, respectively. Selective hunting, among other factors, can be responsible for the relative abundance of some population categories, such as males or females, young or adults, but other factors can also be responsible. We used the eco-ethological information obtained by studying present-day wild herds to determine the structure (age and sex) of a theoretical population for a specified season. The season of hunting is estimated through the study of tooth eruption, and this season is shown to have a severe impact on the composition of the studied animal populations. By comparing the theoretical population obtained for the selected season with our results on fossil materials, we demonstrate that there is no selection by hunters on the site. 相似文献
5.
《L'Anthropologie》2022,126(4):103065
The Caune de l’Arago (Arago) and Sima de los Huesos (Sima) human bones from the European Middle Pleistocene are penecontemporaneous, although the Sima hominins are closely related to Neandertal, and Arago hominins present more archaic features. In previous and in press studies, the cross-sectional geometric properties (CSG) of lower limb bones of Arago and Sima have been studied separately without comparative analyses. Here, in order to bridge this gap, we use the same criteria for both samples to highlight evolutionary affinities and to compare their level and pattern of mobility. This study focuses on the femur, fibula and tibia from Arago and Sima with references to fossils from the sites of Trinil, Zhoukoudian and Lazaret, and ancient and recent Homo sapiens (including athletes and non-athletes). We analyze the cross-sectional areas, biomechanical bone “shape” indices (Ix/Iy, Imax/Imin) and pattern of cortical bone distribution. All lower limb bones from Arago have noticeably high to very high relative cortical areas and low to very low medullary areas. The overall femoral pattern in Arago, like Sima, is similar to that of Middle Pleistocene hominins (e.g., low femoral shape indices, Ix/Iy) and Neandertals (e.g., large cross-sectional size). However, the femoral midshaft in Sima presents prominent posteromedial cortical thickening, as a result of a spiral cortical reinforcement along the medial side of the diaphysis. This characteristic is specific to Neandertal and some Middle Pleistocene hominins. In contrast, the midshaft femoral pattern in Arago is close to that of some Homo erectus. We also note that the femoral cross-sectional size and relative cortical area in Arago differ drastically to the small size and low relative cortical area of Lazaret and Trinil hominins. The very high shape index at midshaft (i.e., high Imax/Imin) of the Arago tibia is observed in ancient H. sapiens and runners; the tibial posterior “pilaster” is found in Neandertals and ancient H. sapiens; and the flat or convex tibial faces are similar to Neandertals. Furthermore, the Arago fibulas show marked fibular posterolateral cortical reinforcement with low anteroposterior strengthening. These leg features (tibia, fibula) are also found in some Sima hominins (but not in all individuals). Consequently, this study confirms the presence of archaic features in Arago and the close evolutionary relationship between Sima and Neandertal. This proposition is mainly based on the femoral midshaft pattern influenced by the pelvofemoral complex, considered to be substantially genetically controlled. The leg functional analysis highlights a high level of mobility and travelling in uneven terrains or in mountainous areas in Arago, consistent with known environments and hunting practices. Previously, an analogous hypothesis was proposed put forward for Sima hominins. 相似文献
6.
《Geobios》2021
We describe three new hyaenodonts from the late Ypresian locality of Prémontré (Aisne, France; close to MP 10 reference level). The new species – Lesmesodon gunnelli nov. sp., Cynohyaenodon smithae nov. sp., and Eurotherium mapplethorpei nov. sp. – represent the oldest occurrences of these three European genera. Lesmesodon gunnelli nov. sp. is also reported from the locality of Cuis (Marne, France; Ypresian, ~MP 10). We further present the dentition of two specimens of Lesmesodon edingeri from Messel (Hessia, Germany; type locality of the genus) based on µCT scans. Cynohyaenodon smithae nov. sp. and Lesmesodon gunnelli nov. sp. support the presence of small (300–400 g) hyaenodonts in the late Ypresian of the Paris Basin. Estimates of dental indices indicate that these hyaenodonts had an insectivorous diet. The third species – referred to Eurotherium – may have weighed 4–5 kg and, based on dental indices, likely incorporated more vertebrate prey into its diet. We also performed a phylogenetic analysis in order to test the relationships of these new taxa. These newly discovered species imply that the Proviverra/Allopterodon, Cynohyaenodon, and Eurotherium clades appeared in Europe earlier than previously known (i.e., Lutetian, MP 11). They reinforce the hypothesis that the hyaenodonts radiated during the middle-late Ypresian (MP 8/9–10) in Europe and adapted at that time to diverse ecological niches that they still occupied in the Priabonian (MP 13–14). 相似文献
7.
Smocovitis VB 《Genetics》2011,187(2):357-366
This article explores the sociopolitical backdrop of genetics research during the politically turbulent decades of the mid-20th century that saw the persecution, displacement, and relocation of unpopular minorities in both the United States and Europe. It explores how geneticists in the United States accommodated these disruptions through formal and informal émigré networks and how the subsequent war affected their research programs and their lives. It does so by focusing on the career and life of geneticist Masuo Kodani, who, as a Japanese American, found himself conducting unexpected cytogenetics research in Manzanar, a "relocation center," or internment camp, located in the California desert, after the attack on Pearl Harbor. After the war, Kodani's subsequent career continued to be shaped by his experiences as a Japanese American and by the specific skills as a cytogeneticist that he demonstrated at a critical period in the history of 20th-century genetics. His many relocations in search of employment culminated in his work with the Atomic Bomb Casualty Commission on human chromosomes, for which he is best known. 相似文献
8.
This article presents new accelerator mass spectrometry (AMS) radiocarbon dates of cutmarked ungulate remains from one of the uppermost archaeological layers (f) at the Grotte de Saint-Marcel, Ardèche, France. This site is situated in a key location regarding population dispersal and potential interaction between Neanderthals and modern humans, as it lies at the crossroads of two main routes of passage. Attributing the upper sequence of this site to a precise chronological period within the Mousterian was difficult until now. Previous conventional 14C analyses done on bulk samples over twenty years ago were considered too young (23,000–30,000 BP). Our new AMS radiocarbon results give two statistically identical dates of 37,850 ± 550 BP and 37,850 ± 600 BP, thus confirming the Late Mousterian attribution of the upper levels of this site. A third date overlaps them at two standard deviations. These are among the very few chronometric dates available for the Mousterian (especially its late phases) in Mediterranean France. The Late Mousterian of this zone, a key region in recent debates about late Neanderthal behaviour, is discussed in light of these results. 相似文献
9.
10.
This paper summarizes and evaluates ecological long-term observations at the island of Helgoland (German Bight, North Sea). It is an introduction to a series of seven contributions to an issue of Helgoland Marine Research (vol. 58, no. 4) dealing with observations on the physico-chemical environment and the local biota (pelagic bacteria, phytoplankton, zooplankton, macroalgae, macrozoobenthos). More than 150 years of research at Helgoland (at the Biologische Anstalt Helgoland, BAH, since 1892), and particularly the Helgoland Roads time-series which started in 1962, has provided a multitude of data which represents a valuable basis for analysing past changes, evaluating the present status and predicting future changes in ecosystem parameters. Predicting the consequences of the recent rapid ecological change on regional and global scales requires increased efforts of focus on long-term ecological observations. Future efforts in this field will rely on the application of innovative advanced technology and on the concerted activities of a large number of institutions which only collectively can establish the large-scale patterns of temporal and spatial change in ecosystem functions. 相似文献
11.
Water contents of suspended matter, algal pigments, particulate organic carbon and particulate phosphorus were measured in the rivers Garonne (2 sites) and Ariège (1 site) throughout an annual cycle. The general trend of the parameters was similar at the three sites. Depending on the sites, the period of algal growth (chlorophyll a + phaeopigments > 25 µg l–1), lasted from two to six weeks in August–September. The algal peaks reached 50 to 90 µg 1–1 of total pigments. High contents of particulate organic carbon (> 2 mg 1–1) occurred at the end of summer (coinciding with algal growth), and during the November and May floods. In summer 50–75 % of the suspended matter was organic, in spring this was 10 times less. The high linear correlation between particulate organic carbon and pigment contents (r = 0.87; P = 0.0001) suggested an algal origin of at least part of the particulate carbon. Algal carbon was minor in the annual fluxes of particulate carbon (25 to 39% depending on the sites), but relatively high in comparison with other rivers. The mean particulate phosphorus content calculated over the year was 24 µg l–1 ; it varied from 15 µg l–1 during the high water period to 28 µg 1–1 during the low water period. Likewise the percentage of particulate phosphorus in the suspended matter varied from 0.17 to 0.40. A negative linear correlation existed between particulate phosphorus content and specific discharge (r = – 0.46; P = 0.0001).The very marked seasonal trend of the parameters and the interactions led us to differentiate two modes of the rivers' functioning: a hydrologic phase and a biological phase. The hydrologic phase (high water) was dominated by the processes of erosion and transfer over the whole catchment area and the flood plain, while the biological phase was characterized by a high primary production in the river bed. 相似文献
12.
Within the framework of an investigation into the carrying capacity of the Bay of Marennes-Oléron (France) for bivalve culture,
thein situ uptake of suspended particulate material by oysters (Crassostrea gigas) and mussels (Mytilus edulis) was determined in experiments with benthic ecosystem tunnels. Very high fluctuations in seston quantity and quality were
observed within and between tidal cycles. The percentage of organic carbon was inversely related to seston quantity at low
concentrations. Organic carbon was diluted by resuspension of material rich in inorganic matter. At high seston concentrations
a constant level of about 2% organic carbon was found. The C/N ratio was relatively constant throughout the seasons and fairly
low (6.5 to 8.4). Owing to the presence of bivalves large fluxes of suspended particulate material were observed in thein situ measurements. Selective retention of organic carbon or nitrogen could not be demonstrated. Clearance rates based on chlorophyll
uptake were within a normal range compared to other studies. A large contribution to the food of the bivalves seemed to be
formed by resuspended microphytobenthos. Judged by the low C/N ratio, the food was of good quality. Although its quantity
was variable by dilution, it may support largely the carrying capacity of the Bay of Marennes-Oléron for the cultivation of
bivalves.
Communication no. 687 of the Netherlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, the Netherlands. 相似文献
13.
The Iranian Mountain Viper, Montivipera albicornuta, is a venomous snake endemic to Iran. We compared the seasonal cycle of testicular activity of 74 male specimens during a one-year period in two cold mountain climate habitats: Tarom (in Zanjan Province) and Bostanabad (in Eastern Azerbaijan Province) in northwestern Iran. The maximum testicular volume was observed in both habitats during autumn. The diameter of seminiferous tubules reached a maximum length in winter and a minimum in summer. The number of spermatids increased in autumn. Spermiogenesis occurred in spring and the maximum number of spermatozoa was reached then. In M. albicornuta in Iran, the testes were more active in autumn and spring, and spermatogenesis started in autumn and continued until mating in spring. 相似文献
14.
We designate lectotypes and propose nomenclatural changes in Xylographus Mellié (Coleoptera, Ciidae) based on type specimens deposited in the Museum of Comparative Zoology (USA), Museum für Naturkunde Berlin (Germany), the Natural History Museum (UK), Muséum d’Histoire Naturelle de la Ville de Genève (Switzerland), Muséum National d’Histoire Naturelle (France), Naturhistoriska Riksmuseet (Sweden) and Naturhistorisches Museum Wien (Austria). We designate lectotypes for the following species: Cis fultoni Broun, 1886, Xylographus anthracinus Mellié, 1849, X. bicolor Pic, 1916, X. brasiliensis Pic, 1916, X. ceylonicus Ancey, 1876, X. contractus Mellié, 1849, X. corpulentus Mellié, 1849, X. dentatus Pic, 1922, X. gibbus Mellié, 1849, X. hypocritus Mellié, 1849, X. javanus Pic, 1937, X. lemoulti Pic, 1916, X. longicollis Pic, 1922, X. madagascariensis Mellié, 1849, X. nitidissimus Pic, 1916, X. perforatus Gerstaecker, 1871, X. porcus Gorham, 1886, X. punctatus Mellié, 1849, X. ritsemai Pic, 1921, X. rufescens Pic, 1921, X. rufipennis Pic, 1934, X. rufipes Pic, 1930, X. seychellensis Scott, 1926, X. subopacus Pic, 1929, X. subsinuatus Pic, 1916, X. suillus Gorham, 1886, X. testaceitarsis Pic, 1916 and X. tomicoides Reitter, 1902. We propose the following syn. n. (senior synonym listed first): X. anthracinus = X. testaceitarsis, X. brasiliensis = X. lucasi Lopes-Andrade & Zacaro, X. corpulentus = X. lemoulti and X. richardi Mellié, X. madagascariensis = X. eichelbaumi Reitter, X. rufipennis, X. seychellensis Scott and X. tarsalis Fåhraeus, X. nitidissimus = X. longicollis, X. subsinuatus = X. rufescens. We exclude three species from Xylographus: Cis renominatus, nom. n. (for X. dentatus Pic, 1922, not C. dentatus Mellié, 1849), Paratrichapus fultoni (Broun, 1886), comb. n. and P. javanus (Pic, 1937), comb. n. 相似文献
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17.
The Kellwasser Crisis represents one of the most severe extinction events in the Phanerozoic. The ?umbera section (Moravo-Silesian Basin, Moravian Karst) spans the Upper rhenana to Palmatolepis minuta minuta (or younger) conodont zones and corresponds to the upper part of a carbonate ramp with material derived from shallower areas. A rich association of calcareous algae, cyanobacteria, and microproblematica, comprising renalcids (Izhella), Girvanella, Rectangulina cf. tortuosa, Rothpletzella, “solenoporaceans”, “Keega”-like microfossils, udoteacean alga Paralitanaia, volvocean and radiospherid calcispheres, palaeoberesellids, Umbellina bella, and Wetheredella, is similar in diversity to associations known from China, Australia, Canada, and Belgium. The ?umbera section represents a unique locality where changes in shallow-water biota at the Frasnian-Famennian boundary are well calibrated by detailed conodont biostratigraphy. We track in detail the evolution of shallow-water biota and the features that are often discussed in the context of “anachronistic” facies, such as flourishing microbial structures, enhanced early marine cementation, and flat-pebble conglomerates. Some features which could be indicative of environmental stress such as flat-pebble conglomerates developed during the Frasnian part of the Kellwasser Crisis (Upper rhenana to linguiformis Zones), whereas a renalcid boom started at the Frasnian-Famennian boundary. 相似文献
18.
Vegetation changes and development of agriculture at „Kerfontaine“ (Sérent,Massif Armoricain,France)
Lionel Visset 《Vegetation History and Archaeobotany》1994,3(1):1-6
As part of a new research programme, studies of peat bogs in Brittany are being carried out to trace the changes that have occurred in the course of time, and to determine the different regional stages related to the human activities of land clearance and agriculture. In this context, a palynological study of the Kerfontaine peat bog was undertaken to consider changes in local and regional vegetation dating from after about 7800 B.P. Local vegetation history from Neolithic times until the Middle Ages involved a succession of twelve pollen zones clearly related to variations in water level resulting from natural or anthropogenic influences. The dominant vegetation was alder carr, bog-myrtle mire and birch woods. Heath vegetation, which appeared at the end of the Iron Age, developed during the Gallo-Roman period, finally invading the entire bog in the Middle Ages. Regional vegetation history was characterised, among other things, by the presence of beech woods which developed after 3000 B.P. and then declined during the Middle Ages in conjunction with an increase of cultivation between the 8th and 11th centuries A.D., an indication of great activity during the Carolingian period. Human activity reached its peak around 1800 A.D. at the time of the first pine plantations. 相似文献
19.
André Nel 《法国昆虫学会纪事》2013,49(1):23-29
A new deposit of Lower Cretaceous amber, found in Charente-Maritime (SW France) has yielded an important entomofauna with numerous arthropod associations characteristic of moist ground. We describe a new species of Dolichopodidae: ‘Microphorinae’(Diptera: Empidoidea), Microphorites deploegi n. sp. on the basis of seven male and female specimens of exceptional state of preservation. This genus was previously only known from Lebanese amber of the Lower Cretaceous. The present discovery supports a reconstruction of the palaeoenvironment as a sandy beach along the sea, under a warm climate. 相似文献
20.
《Geobios》2016,49(6):469-498
The “calcaires à Productus” of the Montagne Noire (Aude-Hérault, southern France) are carbonate lenses embedded within a thick Carboniferous siliciclastic complex. Foraminiferal assemblages in some of the larger carbonate lenses are typically representative of the late Viséan and Serpukhovian. Eleven new species of foraminifers are described: Hemidiscopsis variabilis, H. pilleae, Planohowchinia rara, P. redondensis, Spireitlina minima, Rectoendothyra japhetensis, Mikhailovella enormis, Cribrospira? perretae, Pojarkovella occidentalis, Parabiseriella vailhanensis, and Biseriella delicata. Eight foraminiferal biozones are defined; they are based on the first occurrence of some taxa, and could be used for other regions of southern France (e.g., Mouthoumet and the Pyrenees). These biozones are informally named as A to H. Due to the problems with classical biozonations and substages in northern England as well as Belgium and northern France, the biozones established herein are mostly compared with the Russian standard substages. Thus, biozones A and B are correlated with the Mikhailovian, corresponding to the latest Asbian and earliest Brigantian in western Europe; biozones C, D and E are correlated with the Venevian, equivalent to the upper part of the early Brigantian in western Europe. Therefore, biozones A–E form part of the late and latest Viséan. The stratigraphically younger biozones F, G and H contain foraminiferal assemblages correlated with the Tarusian, Steshevian and Protvian, respectively. 相似文献