Spelling suggestions: "subject:"4he ion"" "subject:"4he tion""
111 |
Source, transfert et devenir des microplastiques (MPs) en mer Méditerranée Nord-Occidentale / Source, transfer and future of microplastics (mp) in the North-West Mediterranean SeaConstant, Mel 17 December 2018 (has links)
Les déchets plastiques et les produits issus de leurs fragmentations (microplastiques ou « MP », <5mm) représentent une menace globale et persistante pour l'ensemble des écosystèmes marins, du fait de leur facilité d'ingestion par une grande diversité d'espèces marines. La mer Méditerranée, de part sa nature semi-fermée et son littoral anthropisé, est très impactée par cette pollution. Cette thèse a pour objectif de mieux comprendre l'origine et le devenir des MP en mer, et ce, par la mise en place d'une stratégie d’échantillonnage le long du continuum terre-mer, i.e. des sources continentales aux récepteurs marins finaux. Cette approche holistique a été appliquée à l'échelle locale du golfe du Lion (Nord-Ouest de la Méditerranée) à l’ensemble des compartiments côtiers. Les MP ont été retrouvés dans toutes les matrices étudiées (eau, sédiment, dépôtatmosphérique et tissus biologiques) dans des quantités très variables à la fois dans les compartiments et entre les compartiments. Aucune sélection qualitative (forme, taille, polymère et couleur) majeure ne semble s'opérer lors du transfert des MP d'un compartiment à l'autre, et la majorité des MP sont des fibres. Quantitativement, la concentration des MP varie à des échelles temporelles et spatiales très courtes (<1 heure et <1 kilomètre). Si aucune relation claire entre les concentrations en MP et les forçages environnementaux (e.g. précipitation, débit des fleuves, vents, etc.) n'a été observée, les événements de précipitation semblent influencer grandement les quantités de MP transférées entre les compartiments. En extrapolant nos résultats aux bassins-versants du golfe du Lion, 30 ± 20 tonnes de MP se déposeraient via l'atmosphère sur les zones urbainescôtières et 7 ± 10 tonnes de MP seraient transportées par les fleuves vers la Méditerranée, chaque année. L'extrapolation des quantités de MP dans les compartiments marins, semble indiquer que la surface de la mer et les plages ne sont que des compartiments transitoires (< 1 tonne), tandis que les sédiments et la colonne d'eau sont potentiellement plus impactés (jusqu'à 350 tonnes pour les sédiments). De nouvelles données sont nécessaires pour la colonne d'eau et les sédiments pourconfirmer cette hypothèse, mais les résultats laissent penser qu'ils pourraient avoir un rôle majeur dans le stockage des MP. / Anthropogenic litter, particularly plastic litter and their fragments (microplastics or “MPs”; < 5 mm) represent a highly pervasive and persistent global threat to marine ecosystems, as they can be ingested by a wide range of marine species. As a landlocked sea with a high population density, the Mediterranean Sea is highly exposed to marine litter pollution. This thesis aims tounderstand the origin and the future of marine MPs thanks to a holistic approach from terrestrial sources to marine sinks. This strategy was applied at the regional scale of the Gulf of Lion (Northwestern Mediterranean Sea) on all coastal compartments. MPs were observed in every studied matrices (water, sediment, atmospheric fallout) with a high variability within and betweenthe different compartments. No significant qualitative trend seems to occur during the transfer of MPs between compartments and fibers were the most abundant shape found in samples. MP concentrations changed at a short spatial and temporal scale (< 1 hour and < 1 kilometer), overlaying other variabilities (i.e. seasonal or between sites). If no obvious relationship betweenexternal forcing (e.g. precipitations, river flow rates, winds) and MP concentrations was observed, rainfall events seemed to have an important impact on the amount of MPs transferred into the sea. Extrapolating our results to the whole Gulf of Lion watersheds, 30 ± 20 tons of MPs would settle on urban areas and 7 ± 10 tons would be supplied by rivers into the Mediterranean Sea every year. The extrapolation of MP quantities within marine environments seems to indicate that the sea surface and beaches are only transitory compartments (<1 ton) whereas sea floor and water column couldbe more impacted (up to 350 tons for marine sediment). New data on water column and marine sediments are needed to confirm this hypothesis, but those results suggest that both latter compartments could be major sinks for marine MPs.
|
112 |
Modelling the effect of human-caused mortality on a lion sub-population using spreadsheetsHerrmann, Eric 03 1900 (has links)
Thesis (MScFor)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Free-ranging lions (Panthera leo) in the Kgalagadi Transfrontier Park (KTP) have been
subject to persecution by farmers following livestock depredation in adjacent grazing areas. In
recent years at least one adult female was killed annually from a sub-population of five
boundary prides that have home ranges adjoining these livestock grazing areas. While no
long-term records of human-caused mortality are available, the impact of current rates of
human-caused mortality is uncertain. Female-based, age-structured models were thus used to
estimate the long-term viability of the KTP lion sub-population subjected to human-caused
mortality under deterministic and stochastic environmental conditions. Population parameters
incorporated in the models included age-class specific natural mortality, female fecundity and
birth sex ratio. In so doing sustainable threshold rates of persecution were established, so that
effective conservation measures can be taken, if required, to ensure the continued survival of
boundary prides in the park.
Sensitivity analyses of natural survival rates indicated that adult female survivorship is the
most important population parameter with respect to maintaining population viability,
compared to younger female age-classes, fecundity or birth sex ratio. Hence adults were also
the most sensitive age-class with respect to human-caused mortality, as adult survival
repeatedly acts upon individuals with the highest reproductive value. In the deterministic
model, with the most optimistic survival parameter values, fecundity and birth sex ratio
(female-biased) estimates, the sub-population is only able to sustain an annual persecution of
three adult females, before the sub-population exhibits a sustained decline. In the worst-case
scenario, where fecundity and sex ratio estimates are at their lower extremes, the maximum
sustainable age-class specific persecution rate is zero, for all age-classes. Whilst these
hypothetical scenarios are unrealistic, they do highlight the extreme thresholds of potentially
sustainable persecution rates. Under the most optimistic scenario using the stochastic model,
the highest achievable survival probability of the sub-population, when subjected to a
persecution rate of one adult annually, was 78%. Although increased fecundity and birth sex
ratio biased towards females may increase the survival probability, these parameters are
generally at their mean values in the long-term, and may thus not necessarily prevent a
sustained population decline. The models therefore suggest that the current persecution rate of
one adult annually (or 4% of the adult sub-population), appears unsustainable in the longterm.
To ensure the survival of existing boundary prides and to maintain a viable subpopulation,
adult lionesses should, as far as possible, be afforded protection from persecution. / AFRIKAANSE OPSOMMING: Vrylewende leeus (Panthera leo) in die Kgalagadi Oorgrenspark (KTP) is onderworpe aan
vervolging deur boere as gevolg van predasie op vee in aangrensende weidingsgebiede. In
onlangse jare is ten minste een volwasse wyfie uit ‘n subpopulasie van vyf troppe met
loopareas wat aan die weidingsgebiede grens, jaarliks uitgewis. Geen langtermyn rekords van
vrektes as gevolg van menslike oorsake is beskikbaar nie, en die impak van vrektes wat deur
mense veroorsaak word, is dus onseker. Wyfie-gebaseerde, ouderdomgestruktureerde
modelle is daarom gebruik om te voorspel wat die langtermyn lewensvatbaarheid is van die
KTP leeu subpopulasie wat onderworpe is aan vrektes deur menslike invloede onder
deterministiese en stogastiese omgewingsfaktore. Bevolkingsfaktore wat deur die modelle in
ag geneem is, sluit ouderdomsgroep-spesifieke natuurlike vrektes, aanwas van wyfies en
geboorte geslagsverhouding in. Sodoende is volhoubare uitwissingstempos bepaal sodat,
indien nodig, effektiewe bewaringsmeganismes toegepas kan word om die voortbestaan van
troppe in die grensgebiede van die park te verseker.
Sensitiwiteitsanalises van natuurlike oorlewingstempos het aangetoon dat volwasse wyfies se
oorlewing die belangrikste bevolkingsfaktor is om die bevolking se lewensvatbaarheid te
volhou vergeleke met jonger wyfie ouderdomsgroepe, aanwas of geslagsverhouding by
geboorte. Daarom was volwassenes ook die sensitiefste vir vrektes as gevolg van menslike
invloede, omdat die oorlewing van volwassenes herhaaldelik inwerk op individue met die
hoogste reproduktiewe waarde. In die deterministiese model met die mees optimistiese
oorlewing, aanwas en geboorte verhouding (wyfie-gebasseerde) beramings, is die subpopulasie
slegs in staat om ‘n jaarlikse uitwissing van drie volwasse wyfies te onderhou,
voordat die sub-populasie ‘n volgehoue afname toon. In die uiterste geval waar aanwas en
geslags verhouding skattings op die laagste is, is die maksimum volhoubare ouderdomsklasspesifieke
beramings nul vir alle ouderdomsklasse. Terwyl hierdie hipotetiese senario’s
onrealisties is, onderstreep dit die uiterste vlakke van potensiële volhoubare
uitwissingstempos. Onder die mees optimistiese senario – ‘n uitwissingstempo van een
volwassene jaarliks – met die gebruik van die stogastiese model, was die hoogste haalbare
oorlewingswaarskynlikheid van die sub-populasie 78%. Alhoewel ‘n toename in aanwas en
geboorte geslagsverhouding (met oorhelling na wyfies), ‘n toename in
oorlewingswaarskynlikheid tot gevolg kan hê, is hierdie faktore oor die algemeen gemiddeld
oor die langtermyn en sal dit nie noodwendig ‘n volgehoue afname in die populasie verhoed
nie. Die modelle dui daarop dat die huidige uitwissingstempo van een volwassene (of 4% van die volwasse sub-populasie) op ‘n jaarlikse grondslag onvolhoubaar is oor die langtermyn.
Om die oorlewing van bestaande troppe in die grensgebiede, asook ‘n lewensvatbare subpopulasie,
te verseker, moet volwasse leeuwyfies so ver as moontlik teen vervolging beskerm word.
|
113 |
Quantification des flux sédimentaires et de la subsidence du bassin Provençal / Quantification of sediment fluxes and subsidence on the Gulf of lion marginLeroux, Estelle 14 May 2012 (has links)
Le Golfe du Lion et le Bassin Provençal sont l’objet de recherche intensive à toute échelle de temps et d’espace. Cependant, les budgets sédimentaires et les mouvements verticaux depuis la formation de la marge étaient restés inconnus ou sources de controverses. Ce travail se propose d’aborder leur quantification à partir de l’interprétation de nombreux profils sismiques, d’après les concepts de stratigraphie sismique et séquentielle [Vail et al., 1977], complétée par des données de forages et de sismique réfraction, et validée par des modélisations stratigraphiques avec Dionisos [Granjeon and Joseph, 1999]. L’établissement d’une continuité stratigraphique entre le domaine de plate-forme et le bassin profond offre une vision complète du remplissage sédimentaire de la marge. Les repères stratigraphiques du Plio-Pléistocène (2.6 Ma, 1.6 Ma, 0.9 Ma et 0.45 Ma) ont en effet été corrélés jusqu’au pied de pente. Les jalons messiniens, établis lors des travaux précédents [Bache, 2008] ont également été étendus et précisés localement. La mise en évidence d’une nouvelle unité, interprétée comme les résidus de l’abrasion lors de la transgression mettant fin à la célèbre crise, permet d’apporter des arguments pour l’établissement d’un nouveau scénario de l’évènement [Bache et al., 2012a](soumis). Des lois de conversion en profondeurs (métriques) des différentes unités chronostratigraphiques ont ensuite été établies en 3D à partir de l’ensemble des données de forage et de réfraction (ESP) et appliquées pour chacune de nos unités. Les profondeurs de l’ensemble des jalons plio-pléistocènes et messiniens ont ainsi pu être cartographiées, ainsi que les épaisseurs de chacune des unités définies depuis le substratum jusqu’à l’actuel (1 au Miocène, 6 au Messinien, 5 au Plio-Pléistocène). Les épaisseurs et volumes sédimentaires déposés ont alors pu être quantifiés sur chaque intervalle stratigraphique. Les séries sédimentaires ont été par la suite décompactées et les volumes "vrais" de dépôts et flux sédimentaires recalculés. / The Gulf of Lions and the Provençal basin have been studied intensively at variable timescale. However, sedimentary budgets and vertical movements of the margin remained largely unknown. This work aims to quantify them using a large grid of seismic data and their interpretations with seismic and sequential stratigraphy concepts [Vail et al., 1977], correlations with existing drillings, refraction data and validation by numerical stratigraphic modeling with Dionisos [Granjeon and Joseph, 1999].A stratigraphic continuity of reflectors from the platform to the slope and to the deep basin has been established describing the architecture of the sedimentary filling of the entire margin. Plio-pleistocene stratigraphic markers (at 2.6 My, 1.6 My, 0.9 My and 0.45 My) have been correlated down to the foot of slope. The Messinian units underlined by previous studies [Bache, 2008] were also extended and/or detailed in specific areas. A new unit is described and interpreted as the residuals of the abrasion during the transgression which ended the famous messinian crisis. This allowed us to bring some new arguments for a new scenario of the event [Bache et al., 2012a](submitted). Drillings and refraction data led to 3D time-depths conversion laws for our chronostratigraphic units. We were therefore able to produce all the Plio-Pleistocene and Messinian maps in meters as well as the thickness maps of all units defined above the substratumuntil today (1 for the Miocene, 6 for the Messinian, 5 for the Plio-Pleistocene). The thicknesses and the sedimentary volumes were then quantified for every stratigraphic intervals. After decompaction, "true" volumes of deposits as well as sedimentary fluxes were therefore recalculated.
|
114 |
Reducing cost and CO2 emissions in the gasoline to electric vehicle fleet transitionGrund Stålvinge, Emil January 2023 (has links)
If you buy a new electric car today it will take on average about ten years for you to start saving money compared to just continue driving your old gasoline car. It will also take about 4 years until you start saving carbon dioxide emissions, both of this is because of new production costs and emissions. As the EU has banned producing new fossil fuel cars from 2035, it’s just a question of time before the power train in our cars will be electric. This rapid transition will lead to the older generation gasoline cars left by the road, with still usable chassis. This calls for a solution that uses this chassis but swaps out its power train for an electric one, reducing the initial cost and emission to drive electric. But is it that easy? In this mission, we take that technical question into our hands and convert a Swedish classic Volvo 340 from 1979 and give it an electric power train from 2022. We provide a detailed theory about the technology, a guide in choosing the right components, and the legal build requirements to pass the inspection. The conversion is done in an ordinary garage with standard tools and a welder. Using a small power-train with a maximum power of 30kW (40hp) and a battery size of 20kWh gave us a car with a maximum speed of 110km/h and a range of 150km. The project costed a total of 60 000 kronor, including the registration process. The technical legality and registration process went smoothly thanks to the Organisation SFRO (Sveriges fordonsbyggares riksorganisation) which takes care of the technical inspection and handles the paperwork. After one year and 10 000 km of driving and collecting data, we estimate that transitioning from gasoline to electric via a conversion compared to a new electric car reduces the economical investment return time from 10 to 2 years. And saves 8 tons of CO2. The battery used is secondhand. The second-hand market of electric car batteries, mostly from crashed or defective cars is growing and is estimated to be enough to convert the majority of old gasoline cars that are in good condition. The life length of second hand batteries in conversion is estimated to be equal to the rest of the chassis, due to the lower power requirements in conversion builds. We see that this idea has potential on a larger scale due to satisfying the criteria: Enough low complexity to do a conversion (if using common car models), lower cost and CO2 emissions then other options, supply for batteries exists, donor cars exist with chassis in good condition, market size is big enough and it’s legal to modify your car in Sweden and a few other countries. / Det är bara en tidsfråga innan drivlinan i våra bilar kommer att vara elektrisk, eftersom EU har lagt ett förbud mot att producera nya fossilbränslebilar från 2035. Men det är inte det enda trycket på förändring eftersom även bensinpriserna fortsätter att öka. En mycket hög efterfrågan förväntas på elbilar. Men för de flesta är det inte ett ekonomiskt alternativ att köpa en ny elbil, även om användandet är billigare tar det cirka 10 år innan du börjar se besparingar. Även produktionen av nya elbilar släpper ut koldioxid, motsvarande cirka 4 års körning av en bensinbil. Den snabba övergången kommer också att leda till att den äldre generationens bensinbilar skrotas, med fortfarande användbara chassi. Detta kallar på en lösning som använder dessa chassin men byter ut sin drivlinan till en elektrisk, vilket minskar den initiala kostnaden för att köra elbil samtidigt som man sparar in utsläppen från en ny produktion. Men är det verkligen så lätt? Vi tar vi frågan i våra händer och konverterar en svensk klassiker, en Volvo 340 från 1979 och ger den en drivlina från 2022. Vi ger en detaljerad teori om tekniken, en guide för att välja rätt komponenter och lagliga byggkrav för att klara besiktningen. Konverteringen görs i ett vanligt garage med standardverktyg och en svets. Ett år och tusen mil senare av körning och insamling av data uppskattar vi att en övergång från bensin till el via en konvertering jämfört med en ny elbil minskar den ekonomiska avkastningstiden för investeringen från 10 till 2 år. Och sparar 8 ton koldioxid. Batteriet som används är begagnat. Andrahandsmarknaden för elbilsbatterier, främst från kraschade eller defekta bilar, växer och beräknas räcka för att konvertera majoriteten av gamla bensinbilar som är i gott skick. Livslängden för begagnade batterier vid konvertering uppskattas vara lika med resten av chassit, på grund av de lägre effektkraven i konverteringsbyggen. Vi ser att denna lösning har potential i det större perspektivet, främst igenom utbudet och livslängd av batterier och chassin för konverteringar. Men också att kostnaden och kompexiteten är tillräkligt låg om de vanligaste modellerna används. Denna lösning är just nu bara tillgänglig i sverige och ett fåtal andra länder där det är lagigt att modifiera sina bilar.
|
115 |
O monstro leonino que surge do mar: um estudo de Daniel 7:1-4 à luz de sua relação intertextual coma Bíblia Hebraica e a literatura e iconografia do antigo oriente médio / The leonine monster that emerges from the sea: a study of Daniel 7:1-4 in the light of its intertextual relationship with the Hebrew Bible and the literature and iconography of the Ancient Near EastCavalcanti, Diogo de Araujo 06 May 2019 (has links)
Em O monstro leonino que surge do mar, estuda-se a simbologia contida em Dn 7:1 a 4. Nesse capítulo, narra-se uma visão onírica em que quatro feras monstruosas emergem de um mar agitado pelos quatro ventos do céu. A primeira a surgir é semelhante a um leão com asas de águia, as quais lhe são arrancadas, e o animal é posto em pé e recebe um coração humano. Impregnada de simbolismo, a visão é seguida de uma interpretação geral dentro do próprio capítulo, mas ainda assim oculta sentidos que convidam à investigação. Este estudo propõe uma close reading desse recorte, em uma abordagem literária e sincrônica, contemplando diversas perspectivas do debate acadêmico atual. A análise se concentra nos principais elementos simbólicos do texto, culminando na aparição da fera leonina. Trata-se de um mergulho na Bíblia Hebraica (BH), bem como na literatura e iconografia do Antigo Oriente Médio (AOM), e no próprio livro de Daniel, com vistas a iluminar o objeto de estudo. Os resultados dessa investigação identificam a relação umbilical entre a visão de Dn 7 e as narrativas dos cap. 1 a 6, em torno da temática da soberania divina. A composição da cena dos quatro ventos e o grande mar (Dn 7:1, 2) aparenta ser polissêmica e alusiva ao preâmbulo de Gn 1:2 ao mesmo tempo em que mantém evidentes conexões com sentidos encontrados nos Profetas. As feras grandes, monstruosas (Dn 7:3), têm evidentes paralelos na BH, como nações destruidoras, em especial, na tradição profética. A fera semelhante a leão com asas de águia se liga à visão de Dn 2 em que o primeiro dos quatro metais da estátua representa Babilônia. Seu hibridismo comunica a combinação de capacidades, com paralelos conceituais nos mischwesen ou seres híbridos do AOM. Sua natureza política e voracidade imperial o conectam ao motivo leonino utilizado largamente na literatura e iconografia do AOM, que servia para reforçar a ideologia real. Nos Profetas, Babilônia é simbolizada pelo leão e pela águia. Por ter asas e emergir do mar em uma limitada alusão aos mitos de combate antigos, com reflexos na BH , termina por denunciar sua natureza antidivina e cosmológica. Essa fera leonina passa por processos incapacitantes da perda de mobilidade e ferocidade, inversamente ao ocorrido com o rei Nabucodonosor em Dn 4, o que prenuncia sua derrocada e ressalta a soberania de YHWH. / The leonine monster that emerges from the sea is a research on the symbology present in Dan 7:1-4. This chapter depicts a dream-vision in which four monstrous beasts come out from a \"great sea\" stirred up by \"the four winds of heaven.\" The first beast to appear is similar to a lion with eagle\'s wings, which are suddenly plucked off, and the animal is lifted up from the ground, stands as a human being, and receives a human heart. This deeply symbolic vision has a general interpretation within Dan 7 itself, but it still conceals meanings that call for an investigation. The present study does a close reading of this selected biblical text, in a literary and synchronic approach, taking into account multiple perspectives in the current scholarly debate. The analysis focuses on the main symbolic elements of the text, culminating with the appearing of the leonine beast. It delves into the Hebrew Bible, as well as the literature and iconography of the Ancient Near East, in connection with the book of Daniel itself, to cast light on the subject under investigation. The results of this research uncover the umbilical relationship between the vision of Dan 7 and the narratives of chapters 1 to 6, around the theme of divine sovereignty. The arrangement of the four winds and the great sea scene (Dan 7:1, 2) seems to be polysemic and allusive to the preamble of Gen 1:2 while maintaining strong connections with the meanings found in the Prophets. The large, monstrous beasts (Dan 7:3) have clear parallels in the Hebrew Bible, especially in the prophetic tradition, as destructive nations. The lion-like beast with eagle\'s wings (Dan 7:4) must be seen in association with the vision of Dan 2 where the first of the four metals of the statue represents Babylon. Its hybridism communicates the combination of abilities, finding conceptual parallels in the mischwesen or hybrid beings of the Ancient Near East. The lion\'s political nature and imperial voracity bridge the biblical use of the leonine motif with the widespread use of this imagery in the literature and iconography of the Ancient Near East, which served to reinforce royal ideology. In the Prophets, Babylon is symbolized by both the lion and the eagle. By having wings and emerging from the sea--a limited allusion to ancient combat myths with reflections in the Hebrew Bible--it denounces the anti-divine and cosmological overtones of such a beast. This leonine monster undergoes incapacitating processes of mobility and ferocity losses, in a reverse process to what happened to king Nebuchadnezzar in Dan 4, which foreshadows the ultimate demise of Babylon plus the other kingdoms and highlights YHWH\'s sovereignty.
|
116 |
O mico-leão-dourado ( Leontopithecus rosalia) como dispersor de sementes na Reserva Biológica União/IBAMA, Rio das Ostras, RJ. / "The golden lion tamarin (Leontopithecus rosalia) as a seed dispersal in the Uniao Biological Reserve, Rio das Ostras, RJ"Lapenta, Marina Janzantti 29 May 2002 (has links)
O papel do mico-leão-dourado ( Leontopithecus rosalia) como dispersor de sementes na Reserva Biológica União foi avaliado pelo acompanhamento mensal de dois grupos de micos, de dezembro de 1998 a dezembro de 2000, num total de 871,9h de observações no campo. No período de estudo os micos se alimentaram dos frutos de 57 espécies de árvores de pelo menos 17 famílias, ingerindo sementes de 39 espécies,das quais 23 foram colocadas para germinar em laboratório e/ou no campo. Leontopithecus rosalia pode ser considerado como agente dispersor legítimo para as espécies estadas, porque as sementes de todas as espécies germinaram, mesmo que em baixas porcentagens, após a ingestão. Também foi avaliada a velocidade de germinação das sementes. Estes primatas não apresentam um efeito consistente na germinação final de sementes, pois beneficiam algumas espécies, enquanto prejudicam a porcentagem e/ou velocidade da germinação de outras. Para as espécies de frutos mais consumidas foram anotados o tamanho e formato das sementes engolidas, o número de árvores visitadas, além dos hábitats de ocorrência das árvores e dos locais onde as fezes foram depositadas. O tempo de retenção das sementes no trato digestório e a distância de dispersão foram medidos, bem como foram procuradas sementes predadas e digeridas nas fezes. O tempo médio de passagem para as sementes das espécies ingeridas foi de 1,1 + 0,3h e a distância média de dispersão de 107,8 + 70,6m, sendo que de modo geral as sementes dispersadas por mamíferos não são depositadas próximo às árvores parentais. O hábitat de deposição das fezes foi adequado para a germinação das sementes para 88,9% das espécies testadas, estando de acordo com o ambiente das árvores visitadas pelos micos-leões. O mico-leãodourado é um dos primatas mais ameaçados de extinção do mundo, e estudos sobre seu comportamento e ecologia irão contribuir para a preservação da espécie, de seu hábitat, e da Reserva Biológica União, uma das últimas áreas de Mata Atlântica de Baixada Costeira do Estado do Rio de Janeiro. / The role of the golden lion tamarins (Leontopithecus rosalia) as a seed disperser was studied in União Biological Reserve. Two groups of golden lion tamarins were studied during 24 months from December 1988 to December 2000, on a total of 871.9h. During the study period the tamarins fed on fruits of 57 species of trees at least from 17 families. Seeds from 39 species were ingested, and of them, 23 were put to germinate in lab and/or in the field. Leontopithecus rosalia can be considered as a legitimate seed disperser for the tested species, because seeds of all species germinated after ingestion, even in low ercentages. It was still considered the seed germination velocity. These primates do not have a consistent effect on seed germination, since benefit the germination percentage and/or velocity of some species and decrease of others. It was noted the size and shape of swallowed seeds from most frequently eaten species, the total number of visited trees, the habitat where these trees occur and where the faeces were deposited. The retention time of the seeds in the gut and the dispersion distance was noted, and damage and digested seeds were searched in the faeces. The mean time of gut passage from seeds of ingested species was 1.1+0.3h and the mean distance of dispersion was 107.8 + 70.6m, and the seeds dispersed by mammals were not usually defecated near the parental trees. The habitats of faecal deposition and of visited trees were the same in 88.9% of tested species, being possibly appropriated for seed germination and establishment. The golden-liontamarin is one of the most threatened primates in the world, and studies on their behaviour and ecology will contribute to preserve the species the habitat, and the União Biological Reserve, one of the last areas of lowland Atlantic Forest of southeast Brazil.
|
117 |
Frugivoria, Dispersão Primária e Secundária de Sementes Consumidas por Micos-Leões-Dourados (Leontopithecus rosalia) na Reserva Biológica União, RJ. / Frugivory, Primary and Secondary Dispersal of seeds eaten by Golden Lion Tamarins (Leontopithecus rosalia) in the União Biological Reserve, RJ.Lapenta, Marina Janzantti 02 February 2007 (has links)
Os animais frugívoros podem influenciar padrões de distribuição espacial de plantas jovens e adultas, mas parte do recrutamento de uma população vegetal é perdida pela predação de sementes, sendo esta a principal força ecológica e evolutiva que afeta as comunidades vegetais. A maioria das sementes dispersadas por primatas na floresta é morta por predadores de sementes ou movida por dispersores secundários, alterando a sombra de sementes original. Pouco se sabe sobre as interações complexas entre a dispersão e predação de sementes, visto que poucos trabalhos foram realizados sobre a relação entre a dispersão de sementes por frugívoros, e a distribuição das plântulas das espécies consumidas. Para que Planos de Conservação possam ser desenvolvidos, as relações entre a fauna de frugívoros e a vegetação, e a estrutura das Florestas Tropicais devem ser bem entendidas. Na Reserva Biológica União dois grupos de micos-leões-dourados foram acompanhados mensalmente durante três dias cada um, de abril de 2003 a março de 2004 do momento em que deixaram o local de dormida, até o fim de suas atividades no final do dia. Outros grupos foram acompanhados esporadicamente entre agosto de 2004 e janeiro de 2005. Todas as árvores visitadas foram marcadas e amostras dos frutos foram coletadas para identificação e experimentos de germinação. As sementes retiradas dos frutos foram colocadas para germinar em comparação com sementes provenientes das fezes dos micos, ou sementes cuspidas por estes. As sementes foram acompanhadas na mata, quanto à germinação, desaparecimento ou dispersão secundária, predação, mortalidade, sobrevivência e estabelecimento de plântulas. Além disso, foi feito o acompanhamento fenológico de 791 árvores de espécies consumidas pelos micos-leões, de julho de 2003 a junho de 2004. Durante o período de estudo os grupos se alimentaram de 88 espécies de frutos de pelo menos 18 famílias, engolindo as sementes de 43 espécies e cuspindo as sementes de 45 espécies. Cento e sete experimentos foram realizados com 1711 sementes de 38 espécies de frutos (28 espécies de sementes engolidas e dez espécies de sementes cuspidas). No período de estudo mais de 50% das sementes (> 3 mm) dos experimentos desapareceram e cerca de 15% morreram antes de germinar. Vinte e duas espécies tiveram sementes germinando na mata e desenvolveram plântulas, mas no final do estudo apenas 15 dessas espécies ainda apresentavam plântulas sobreviventes. Para melhor se estabelecer se os predadores ou dispersores secundários das sementes depositadas pelos micos-leões-dourados são vertebrados ou invertebrados foram montados experimentos com gaiolas de exclusão de sementes. Outros aspectos quantitativos e qualitativos da dispersão de sementes foram analisados, incluindo a caracterização das deposições, tempo de passagem das sementes pelo trato digestório dos micos, distância e habitat de dispersão e outros. O mico-leão-dourado (Leontopithecus rosalia) é uma espécie frugívora e endêmica da Mata Atlântica, e o presente estudo é o primeiro a acompanhar a sobrevivência e crescimento de plântulas provenientes das fezes desse primata, detalhando a sua importância como dispersor de sementes. Estudos sobre o destino das sementes defecadas são fundamentais para a conservação do mico-leão e do seu habitat, a Mata Atlântica de baixada costeira do estado do Rio de Janeiro, um dos ecossistemas mais ameaçados do planeta. / The frugivores may influence spatial patterns of adults and juvenile plants, and a great portion of the potential recruitment of plant populations is lost to seed predators. The majority of seeds dispersed by primates on forest is killed by seed predators or moved by secondary dispersers. Little is known about the complex interaction between seed dispersal and post-dispersal seed-predation, and few researches were done on the relation between seed dispersal by animals and seedling distribution of exploited plant species. The golden-lion-tamarin (Leontopithecus rosalia) is a frugivorous endemic species of Atlantic Forest. This research will be the first to consider the survivor and establishment of seedlings from golden-lion-tamarins feces, studying the importance of this primate as seed disperser, ensuring the preservation of the Atlantic Forest, one of the most threatened ecosystems in the world. Two groups of golden lion tamarins were monthly studied in the União Biological Reserve three days each one, from April 2003 to March 2004 since left sleeping site until finished their activities at the end of the day. Other groups were sporadically monitored from August 2004 to January 2005. All visited trees were marked and samples of fruits were collected for identification and germination experiments. Seeds from fruits and from tamarins feces or spitted out were put to germinate. The seeds were studies to verify the germination, disappearance or secondary dispersion, predation, mortality and survival and establishment of the seedlings. Beside that, 791 trees from eaten species were studied from July 2003 to June 2004 to collect phenological data. During study period the groups ate 88 fruit species from at least 16 families, ingesting seeds of 43 species and spitting seeds from 45 species. A Hundred and seven experiments were conducted with 1711 seeds of 38 fruit species (28 species of ingested species and 10 species of spitted seeds). During study period more than 50% of seeds (> 3 mm) disappeared from experiments, and about 15% died before germinating. Twenty two species had seeds germinating on forest and until seedling stage, but at the end of the study only 15 of these species still had seedling surviving. To determine if the seed predators or secondary dispersers of seeds deposited by tamarins are vertebrate or invertebrate, experiments with seed exclosure cage were established. Others qualitatively and quantitatively aspects of seed dispersal were considered, including feces deposition, time of gut passage, distance and habitat of seed deposition and others. The golden lion tamarin (Leontopithecus rosalia) is a frugivore and endemic species of Atlantic Forest and this study is the first to attend the survival and establishment of seedlings from tamarins feces, and the tamarins importance as a seed disperser. Studies on seed fate are important to the conservation of golden lion tamarins and his habitat, the lowland Atlantic Forest of the state of Rio de Janeiro, one of the most endangered ecosystems in the world.
|
118 |
Rôle des nourriceries lagunaires dans le maintien d’une espèce de poisson à forte valeur commerciale, la daurade royale (L. 1758, Sparus aurata) / Nursery function of coastal lagoons in the maintenance of a commercially important fish population, the gilthead sea bream(L. 1758, Sparus aurata)Tournois, Jennifer 12 December 2013 (has links)
De nombreuses espèces de poissons marins côtiers à forte valeur économique ont un cycle de vie complexe impliquant des migrations saisonnières entre l'environnement marin et les habitats côtiers. Une meilleure compréhension de leur cycle de vie, en particulier l'identification de leurs nourriceries clés, est vitale pour la gestion durable des stocks de poissons exploités. Cette étude évalue la fonction de nourricerie des lagunes côtières du Golfe du Lion (Méditerranée NO) pour la daurade royale, Sparus aurata, une espèce d'intérêt commercial, dont les juvéniles colonisent ces habitats chaque année pendant leur premier été de vie. La qualité en tant que nourriceries de quatre lagunes aux conditions environnementales contrastées a été estimée par des mesures de la condition (indices de Fulton et TAG:ST) et du taux de croissance (par otolithométrie) des juvéniles. Les résultats montrent une condition et une croissance des juvéniles plus importantes dans les deux lagunes les plus dessalées et peu profondes (Bages-Sigean et Mauguio) que dans les deux lagunes profondes aux salinités proches de celle de la mer (Salses-Leucate et Thau). Les différences spatiales, stables dans le temps, de signatures élémentaires des otolithes ont permis de valider ces dernières comme tag naturel pour discriminer les habitats des juvéniles de daurade royale. Ainsi, l'identification a posteriori des nourriceries colonisées au stade juvénile chez des adultes pêchés le long de la côte du Golfe du Lion a pu être réalisée. Les estimations de la contribution relative des habitats des juvéniles au stock d'adultes (selon la contribution absolue ou la contribution par unité de surface) révèlent l'importance globale des lagunes pour le maintien des populations. Les lagunes les plus dessalées ont été identifiées comme les meilleures nourriceries de la zone d'étude. Le rôle important de la lagune de Thau pour le maintien des stocks de poissons a également été mis en évidence. Les résultats dans leur ensemble montrent une certaine convergence entre les estimations d'exports potentiel et réel des habitats des juvéniles. Les conclusions de cette étude sont primordiales pour la gestion et la protection des habitats clés des juvéniles ainsi que les ressources exploitées qui en dépendent. / Many coastal marine species of major socio-economic importance exhibited complex life histories include seasonal migrations between offshore marine environments and inshore coastal habitats. An adequate scientific understanding of their life cycle and, in particular the identification of the most significant juvenile nursery grounds are urgently needed for the sustainable management of fish stocks. This present study investigated the nursery function of coastal lagoons in the Gulf of Lions (NW Mediterranean) for a valuable fish species, the gilthead sea bream Sparus aurata, whose juveniles colonize these habitats each year for feeding and growing over their critical first summer of life. Habitat quality of four contrasted lagoons was measured with body condition (Fulton and muscle TAG/ST indices) and otolith growth rate of juveniles. Results showed better condition and higher growth rates in juveniles inhabiting the two shallow and brackish lagoons (Bages-Sigean, Mauguio) compared to the two deeper and more saline lagoons (Salses-Leucate and Thau). Otolith elemental signatures were temporally validated as natural tags to discriminate among juvenile habitats, allowing the retrospective identification of juvenile origin of S. aurata adults captured along the Gulf of Lions coastline. The estimations of relative contributions of juvenile habitats to adult stocks revealed the overall significance of lagoons for the maintenance of population. While, brackish lagoons were identified as the major contributors and best nursery habitats in the area, the importance of Thau lagoon to sustain fish stocks was also highlighted. Combined results of this research revealed some agreement between potential and effective export estimates from juvenile habitats. Information derived from this study is highly valuable for the sustainable management and protection of juvenile habitats, and the fishery resources that depend on them.
|
119 |
Frugivoria, Dispersão Primária e Secundária de Sementes Consumidas por Micos-Leões-Dourados (Leontopithecus rosalia) na Reserva Biológica União, RJ. / Frugivory, Primary and Secondary Dispersal of seeds eaten by Golden Lion Tamarins (Leontopithecus rosalia) in the União Biological Reserve, RJ.Marina Janzantti Lapenta 02 February 2007 (has links)
Os animais frugívoros podem influenciar padrões de distribuição espacial de plantas jovens e adultas, mas parte do recrutamento de uma população vegetal é perdida pela predação de sementes, sendo esta a principal força ecológica e evolutiva que afeta as comunidades vegetais. A maioria das sementes dispersadas por primatas na floresta é morta por predadores de sementes ou movida por dispersores secundários, alterando a sombra de sementes original. Pouco se sabe sobre as interações complexas entre a dispersão e predação de sementes, visto que poucos trabalhos foram realizados sobre a relação entre a dispersão de sementes por frugívoros, e a distribuição das plântulas das espécies consumidas. Para que Planos de Conservação possam ser desenvolvidos, as relações entre a fauna de frugívoros e a vegetação, e a estrutura das Florestas Tropicais devem ser bem entendidas. Na Reserva Biológica União dois grupos de micos-leões-dourados foram acompanhados mensalmente durante três dias cada um, de abril de 2003 a março de 2004 do momento em que deixaram o local de dormida, até o fim de suas atividades no final do dia. Outros grupos foram acompanhados esporadicamente entre agosto de 2004 e janeiro de 2005. Todas as árvores visitadas foram marcadas e amostras dos frutos foram coletadas para identificação e experimentos de germinação. As sementes retiradas dos frutos foram colocadas para germinar em comparação com sementes provenientes das fezes dos micos, ou sementes cuspidas por estes. As sementes foram acompanhadas na mata, quanto à germinação, desaparecimento ou dispersão secundária, predação, mortalidade, sobrevivência e estabelecimento de plântulas. Além disso, foi feito o acompanhamento fenológico de 791 árvores de espécies consumidas pelos micos-leões, de julho de 2003 a junho de 2004. Durante o período de estudo os grupos se alimentaram de 88 espécies de frutos de pelo menos 18 famílias, engolindo as sementes de 43 espécies e cuspindo as sementes de 45 espécies. Cento e sete experimentos foram realizados com 1711 sementes de 38 espécies de frutos (28 espécies de sementes engolidas e dez espécies de sementes cuspidas). No período de estudo mais de 50% das sementes (> 3 mm) dos experimentos desapareceram e cerca de 15% morreram antes de germinar. Vinte e duas espécies tiveram sementes germinando na mata e desenvolveram plântulas, mas no final do estudo apenas 15 dessas espécies ainda apresentavam plântulas sobreviventes. Para melhor se estabelecer se os predadores ou dispersores secundários das sementes depositadas pelos micos-leões-dourados são vertebrados ou invertebrados foram montados experimentos com gaiolas de exclusão de sementes. Outros aspectos quantitativos e qualitativos da dispersão de sementes foram analisados, incluindo a caracterização das deposições, tempo de passagem das sementes pelo trato digestório dos micos, distância e habitat de dispersão e outros. O mico-leão-dourado (Leontopithecus rosalia) é uma espécie frugívora e endêmica da Mata Atlântica, e o presente estudo é o primeiro a acompanhar a sobrevivência e crescimento de plântulas provenientes das fezes desse primata, detalhando a sua importância como dispersor de sementes. Estudos sobre o destino das sementes defecadas são fundamentais para a conservação do mico-leão e do seu habitat, a Mata Atlântica de baixada costeira do estado do Rio de Janeiro, um dos ecossistemas mais ameaçados do planeta. / The frugivores may influence spatial patterns of adults and juvenile plants, and a great portion of the potential recruitment of plant populations is lost to seed predators. The majority of seeds dispersed by primates on forest is killed by seed predators or moved by secondary dispersers. Little is known about the complex interaction between seed dispersal and post-dispersal seed-predation, and few researches were done on the relation between seed dispersal by animals and seedling distribution of exploited plant species. The golden-lion-tamarin (Leontopithecus rosalia) is a frugivorous endemic species of Atlantic Forest. This research will be the first to consider the survivor and establishment of seedlings from golden-lion-tamarins feces, studying the importance of this primate as seed disperser, ensuring the preservation of the Atlantic Forest, one of the most threatened ecosystems in the world. Two groups of golden lion tamarins were monthly studied in the União Biological Reserve three days each one, from April 2003 to March 2004 since left sleeping site until finished their activities at the end of the day. Other groups were sporadically monitored from August 2004 to January 2005. All visited trees were marked and samples of fruits were collected for identification and germination experiments. Seeds from fruits and from tamarins feces or spitted out were put to germinate. The seeds were studies to verify the germination, disappearance or secondary dispersion, predation, mortality and survival and establishment of the seedlings. Beside that, 791 trees from eaten species were studied from July 2003 to June 2004 to collect phenological data. During study period the groups ate 88 fruit species from at least 16 families, ingesting seeds of 43 species and spitting seeds from 45 species. A Hundred and seven experiments were conducted with 1711 seeds of 38 fruit species (28 species of ingested species and 10 species of spitted seeds). During study period more than 50% of seeds (> 3 mm) disappeared from experiments, and about 15% died before germinating. Twenty two species had seeds germinating on forest and until seedling stage, but at the end of the study only 15 of these species still had seedling surviving. To determine if the seed predators or secondary dispersers of seeds deposited by tamarins are vertebrate or invertebrate, experiments with seed exclosure cage were established. Others qualitatively and quantitatively aspects of seed dispersal were considered, including feces deposition, time of gut passage, distance and habitat of seed deposition and others. The golden lion tamarin (Leontopithecus rosalia) is a frugivore and endemic species of Atlantic Forest and this study is the first to attend the survival and establishment of seedlings from tamarins feces, and the tamarins importance as a seed disperser. Studies on seed fate are important to the conservation of golden lion tamarins and his habitat, the lowland Atlantic Forest of the state of Rio de Janeiro, one of the most endangered ecosystems in the world.
|
120 |
Distribution et remobilisation du plutonium dans les sédiments du prodelta du RhôneLANSARD, Bruno 24 June 2004 (has links) (PDF)
Ce travail pluridisciplinaire a pour objectif d'étudier la distribution et la remobilisation du plutonium (Pu) dans les sédiments situés face à l'embouchure du Rhône. Les isotopes 238Pu et 239,240Pu introduis dans le Rhône sont principalement issus des rejets d'effluents faiblement radioactifs effectués par l'usine de retraitement de Marcoule, située à 120 km de l'embouchure du Rhône. Etant données sa très forte affinité pour la phase particulaire et sa longue période radioactive, le 238Pu présente un intérêt particulier en tant que traceur anthropique du devenir des apports solides du Rhône en Méditerranée. Au cours de ce travail, les 3 campagnes REMORA ont permis d'échantillonner spécifiquement les sédiments du prodelta du Rhône et du plateau continental du golfe du Lion. Des mesures d'émetteurs alpha ont permis d'obtenir une première cartographie détaillée des concentrations des isotopes du Pu dans les sédiments situés face au Rhône. L'étude couplée du 137Cs et des isotopes du Pu a permis d'estimer pour la première fois les inventaires en plutonium de la zone étudiée. En 2001, les stocks sédimentaires de Pu sont estimés à 92 ± 7 GBq en 238Pu et 522 ± 44 GBq en 239,240Pu, pour une aire d'environ 500 km2. Le prodelta du Rhône joue un rôle essentiel dans la séquestration du plutonium puisqu'il piège à lui seul environ 50 % de ces stocks sur une aire de 100 km2. La remobilisation du plutonium a été appréhendée par des expériences originales de remise en suspension en canal à courant linéaire. Pour les sédiments du golfe du Lion et un stress hydrodynamique donné, les flux potentiels de remobilisation atteignent au maximum 0,08 Bq.m-2.h-1 en 238Pu et 0,64 Bq.m-2.h-1 en 239,240Pu. En parallèle, des mesures ADCP de courant et de houle ont été réalisées au printemps 2002 pour étudier in situ la dynamique sédimentaire du prodelta du Rhône. Ces mesures mettent en évidence le rôle prépondérant des houles de Sud-est dans l'érosion des sédiments prodeltaïques et dans leur exportation en direction du Sud-Ouest. Un premier bilan sur le devenir du plutonium indique qu'au minimum 85 % du plutonium rejetés par l'usine de Marcoule, au cours des quarante dernières années, sont actuellement piégés dans les sédiments situés face à l'embouchure du Rhône. Le remobilisation du plutonium est un phénomène potentiellement important mais la dispersion des sédiments contaminés serait relativement limitée dans l'espace. Ces résultats suggèrent alors une faible exportation du matériel particulaire originaire du Rhône vers l'ensemble du plateau continental du golfe du Lion et vers le bassin Nord méditerranéen.
|
Page generated in 2.3676 seconds