Plus de 130 espèces de Vibrio, bactéries ubiquitaires des milieux marins et estuariens sont décrites, dont certaines sont des pathogènes d’organismes marins (poissons, coraux, coquillages, …). Douze espèces sont pathogènes pour l’homme, parmi lesquelles V. cholerae, V. parahaemolyticus et V. vulnificus. Les cas d’infections humaines sont essentiellement liés à la consommation de produits de la mer crus ou à l’exposition de plaies cutanées à l’eau de mer. En France, ce risque est faible mais pourrait s’accentuer en raison de la consommation croissante de produits de la mer, de l'augmentation de la part des individus immunodéprimés dans la population, de l'impact des activités anthropiques et du réchauffement climatique sur le milieu marin. Une meilleure compréhension de l'écologie de ces bactéries (distribution, abondance et diversité) est un pré-requis à la mise en place d’une surveillance environnementale de ce risque. L’étude menée au cours de ma thèse en zone Manche-Mer du Nord, dans le cadre du programme Vibrio Manche (2009-2012, partenariat EDFR&D/Ifremer/Institut Pasteur de Lille), avait pour objectif d'évaluer la diversité et la distribution spatio-temporelle côtière des vibrions, dont des espèces potentiellement pathogènes pour l’homme et les animaux, et leur relation avec les paramètres environnementaux biologiques (phytoplancton et zooplancton) et physico-chimiques. La stratégie de suivi a reposé sur le dénombrement et l’isolement de souches de Vibrio, à 22°C et 37°C sur milieu sélectif, à partir d’eau de mer et de sédiments superficiels collectés au cours de neuf campagnes d’échantillonnage et associés à la mesure de paramètres environnementaux. Le développement et la validation d’outils d’identification des souches environnementales par PCR en temps réel et le séquençage de marqueurs génétiques discriminants ont conduit à mettre en évidence une grande diversité d’espèces parmi les isolats à 22°C, celle-ci étant composée principalement de pathogènes d’organismes marins dont l’espèce V. splendidus. Les isolats à 37°C, marqués par la prédominance de deux espèces, V. alginolyticus et V. harveyi, et la rareté des pathogènes humains détectés dans les conditions d’analyses retenues pour cette étude. Au terme de l’étude, nous avons mis en évidence la présence de 20 et 17 espèces de vibrions respectivement à 22°C (deux campagnes) et 37°C (neuf campagnes) sur la zone étudiée, et l’influence probable de conditions environnementales contrastées sur la structure de ces populations. En termes d’abondance, les vibrions cultivables à 37°C ont montré une forte saisonnalité, et une relation significative à la température de l’eau et à l’abondance totale du zooplancton. La saisonnalité des vibrions cultivables à 22°C a été moindre, et leur abondance a pu être reliée de façon significative à la concentration en chlorophylle a totale et également à l’abondance totale en zooplancton. Ces éléments de connaissance et la stratégie d’identification développée pourront, à terme, contribuer au développement d’outils de surveillance microbiologique environnementale et ouvrent des perspectives pour mieux comprendre l’écologie des vibrions et les facteurs structurant non seulement leur abondance, mais aussi leur diversité. / One hundred and thirty species of vibrios, ubiquitous bacteria of marine and estuarine environments have been described, some of them being pathogenic for marine organisms. Twelve species are classified as human pathogens, Vibrio cholerae, V. parahaemolyticus and V. vulnificus being the most frequently reported in cases of infection. Human infections are linked mostly to raw seafood consumption or to the exposure of skin wounds to contaminated seawater. In France, the risk is low but it is expected to increase in the future due to the increase of raw seafood consumption, the part of immuno-compromised people, but also the impact of anthropic activities and global warming on the marine environment. A better understanding of the ecology of these bacteria (distribution pattern, abundance and diversity) is a prerequisite for the monitoring of the Vibrio-risk in the environment. The 2-year study carried out in the Eastern English Channel during my PhD was part of the Vibrio Manche program (2009-2012, funding EDF R&D/Ifremer/Institut Pasteur de Lille), which main objective was to characterize the spatio-temporal distribution of the vibrios, among which the potentially pathogenic species for human and animal, and their relations with the biotic(phytoplankton and zooplankton) and abiotic environmental parameters. The strategy consisted in the enumeration and isolation of Vibrio strains, at 22°C and37°C on a selective medium, from seawater and superficial sediments collected during nine sampling campaigns and associated with the recording of environmental parameters. The protocol developed in this study provides an appropriate and rapid screening tool to identify a large number of bacterial strains routinely isolated from the environment. This was based on real-time PCR assays and the sequencing of discriminant genetic markers. We highlighted the important diversity of species among the 22°C isolates, represented mainly by species pathogenic for marine organisms such as V. splendidus. Contrastingly, the 37°C isolates were mainly represented by two species, V. alginolyticus and V. harveyi, and the potentially pathogenic species for humans were rarely detected using this experimental approach. We detected 20 and 17 species of vibrios among the 22°C (two sampling campaigns) and 37°C(nine sampling campaigns) isolates, respectively, and highlighted the probable influence of contrasted environmental conditions on these populations structure. These two populations presented different seasonal dynamics, as the seawater temperature and the zooplankton abundance showed to be the main drivers for the 37°C population. The 22°C population seemed to be linked to the chlorophyll a concentration and zooplankton abundance. These data and the approach developed in this study could contribute to the development of tools for the monitoring of coastal environment and they give perspectives to better understand the ecology of the vibrios and the environmental factors driving their abundance and diversity.

Passive acoustic monitoring has been used to investigate many aspects of marine mammal ecology, although methods to estimate absolute abundance and density using acoustic data have only been developed in recent years. The instrument configuration in an acoustic survey determines which abundance estimation methods can be used. Sparsely distributed arrays of instruments are useful because wide geographic areas can be covered. However, instrument spacing in sparse arrays is such that the same vocalisation will not be detected on multiple instruments, excluding the use of some abundance estimation methods. The aim of this thesis was to explore cetacean abundance and density estimation using novel sparse array datasets, applying existing methods where possible, or developing new approaches. The wealth of data collected by sparse arrays was demonstrated by analysing a 10-year dataset collected by the U.S. Navy's Sound Surveillance System in the north-east Atlantic. Spatial and temporal patterns of blue (Balaenoptera musculus) and fin whale (Balaenoptera physalus) vocal activity were investigated using generalised additive models. Distance sampling-based methods were applied to fin whale calls recorded by an array of Ocean Bottom Seismometers in the north-east Atlantic. Estimated call density was 993 calls/1000 km².hr⁻¹ (CV: 0.39). Animal density could not be estimated because the call rate was unknown. Further development of the call localisation method is required so the current density estimate may be biased. Furthermore, analysing a single day of data resulted in a high variance estimate. Finally, a new simulation-based method developed to estimate density from single hydrophones was applied to blue whale calls recorded in the northern Indian Ocean. Estimated call density was 3 calls/1000 km².hr⁻¹ (CV: 0.17). Again, density of whales could not be estimated as the vocalisation rate was unknown. Lack of biological knowledge poses the greatest limitation to abundance and density estimation using acoustic data.

Master of Science / Department of Biology / Jack F. Cully, Jr. / Black-tailed prairie dogs (Cynomys ludovicianus) are a species of management and conservation concern. Prairie dogs have lost both habitat and occupied area due to plague, which is caused by the bacterium Yersinia pestis, pest control, and habitat conversion to agricultural land. Our goals were to estimate survival rates and dispersal rates, and to compare methods for estimating abundance of black-tailed prairie dogs for both management and conservation. We trapped black-tailed prairie dogs at four small National Parks from April 2009 through August 2011. Prairie dogs were trapped and marked for two trapping sessions per year in order to estimate seasonal rates of apparent survival. Apparent survival rates were estimated using the package RMark in R to construct models for program MARK. We found estimates to vary according to field site, sex, year, and season (summer or winter). Possible reasons for the differences in survivorship among sites could be presence of disease, quality of forage, predation, or frequency of dispersal. Visual counts were also conducted each trapping session beginning in April of 2010 to estimate abundance. Mark-recapture, mark-resight, and visual counts were compared to determine which method would be the most effective for estimating abundance of prairie dogs. We found mark-resight to produce the most precise estimates of abundance. While it costs more money to conduct a mark-resight estimate than visual counts because of repeated sessions, they produced significantly different results from one another 75% of the time, which was especially apparent on sites that had some form of visual barriers such as tall vegetation and uneven ground. However, if further information is needed in terms of sex ratios, age ratios, or the exact number of prairie dogs, then mark-recapture is the only method that can be used. Land managers need to address the level of accuracy needed, topography, and vegetation height before choosing which sampling method is best for the prairie dog towns in question. Finally, we looked at rates of intercolony and intracolony dispersal by placing 149 VHF collars and 6 GPS collars on prairie dogs at three colonies. Intracolony dispersal was also monitored through visual observation and trapping records over the three years of the study. We found 23 intracolony and eight intercolony dispersal events. Combined, these three studies offer insight not only into monitoring of prairie dog populations but also potential influence by plague both within and among colonies of prairie dogs.

L'estimation des abondances de population est essentielle pour comprendre les dynamiques de population, les interactions entre espèces et estimer les risques de transmission d'agents pathogènes dans les populations. Plusieurs méthodes d'échantillonnages, basées sur des hypothèses spécifiques permettent d'estimer ces abondances : les méthodes par comptages uniques, par « distance sampling », par échantillonnages successifs ou par capture marquage recapture. Nous nous sommes intéressés à l'abondance des tiques Ixodes ricinus, vecteurs de nombreux agents pathogènes. Cette abondance est classiquement estimée par le nombre de tiques capturées lors d'échantillonnages uniques réalisés sur différentes unités d'observation. Cependant, de nombreuses études remettent en cause cette hypothèse forte et suggèrent que le taux d'échantillonnage est variable selon les conditions d'échantillonnage (type de végétation,…) mais ne prennent pas en compte ce taux d'échantillonnage pour autant. A partir d'une méthode d'échantillonnage par « removal sampling » (RS), (i) nous avons montré que les conditions environnementales influençaient le taux d'échantillonnage et l'indicateur d'abondance usuel i.e. le nombre de tiques capturées lors d'un seul échantillonnage (ii) nous avons proposé une méthode pour détecter l'indicateur d'abondance, basés sur le nombre cumulé de capture, le moins soumis aux variations du taux ; (iii) par une approche Bayésienne hiérarchique, nous avons estimé simultanément l'abondance de tiques des unités d'observation et la valeur du taux d'échantillonnage en fonction du type de végétation et de l'heure d'échantillonnage. Nous avons montré que le taux d'échantillonnage sur des arbustes (entre 33,9 % et 47,4%) était significativement inférieur au taux d'échantillonnage sur des feuilles mortes (entre 53,6 % et 66,7%). De plus, nous avons montré que le modèle RS tend vers un modèle de Poisson iid lorsque la taille de la population N0 tend vers l'infini ce qui pose des problèmes d'indétermination pour estimer les paramètres N0 et τ, le taux d'échantillonnage. Nous avons également montré que (i) les estimateurs Bayésiens divergent lorsque les lois a priori sont des lois vagues ; (ii) les lois a priori β(a, b) avec a > 2 sur τ conduisaient à des estimateurs Bayésien convergents. Enfin, nous avons proposé des recommandations quant au choix des lois a priori pour τ afin d'obtenir de bonnes estimations pour N0 ou pour τ. Nous discutons de la pertinence des méthodes RS pour les tiques et des perspectives envisageables pour (i) estimer le risque acarologique représenté par la population de tiques potentiellement actives sur une unité d'observation, (ii) estimer un risque à l'échelle d'une parcelle, à savoir comment répartir l'effort d'échantillonnage entre le nombre d'unités d'observation et le nombre d'échantillonnages successifs par unités d'observation. / The estimation of animal abundance is essential to understand population dynamics, species interactions and disease patterns in populations and to estimate the risk of pathogens transmission. Several sampling methods such as single counts, distance sampling, removal sampling or capture mark recapture could be used to estimate abundance. In this study, we are investigated the abundance of Ixodes ricinus ticks, which are involved in the transmission of many pathogens. Tick abundance is commonly estimated by the number of nymphs captured during a single observation (a cloth dragged on a given surface). In this case, analyses of abundance patterns assumes that the probability of detecting a tick, hence the sampling rate, remains constant across the observations. In practice, however, this assumption is often not satisfied as the sampling rate may fluctuate between observation plots. The variation of sampling rate is never taken into account in estimations of tick abundance. Using a removal sampling design (RS), (i) we showed that the sampling rate and the usual abundance indicator (based on a single drag observation per spot) were both influenced by environmental conditions ; (ii) we proposed a method to determine the abundance indicator the least influenced by sampling rate variations ; (iii) using a hierarchical Bayesian model, we estimated simultaneously the abundance and the sampling rate according the type of vegetation, and the time of sampling. The sampling rate varied between 33,9 % and 47,4 % for shrubs and 53,6 % and 66,7 % for dead leaves. In addition, we show that the RS model tends to Poisson iid model when the population size N0 tends to infinite. This result conduct to infinite estimations for N0. We show that (i) Bayesian estimators were divergent for vague prior ; (ii) β(a, b) prior for a > 2 on τ conduct to convergent estimators. Then, we proposed recommendations for prior choice for τ parameter to give good estimations of N0 or τ. We discuss the relevance of RS for ticks and the possible perspectives to (i) estimate the acarologic risk associated to all potential active ticks for given spot, (ii) estimate the risk at the larger scale, i.e. how to distribute the sampling effort between number of spot and number of consecutive sampling by spot.

Den studerade enheten, Trafikledning Öst Stockholm, lider av en stor personalbrist som medfört att medarbetarna har problem med att hinna inhämta och ta till sig information samt att enhetens chefer behöver ägna mycket tid åt att lösa bemanningsfrågor. Det största problemet anses vara mängden mail som gör det svårt att sålla i informationen. Syftet med den här studien är att undersöka den interna kommunikationen på enheten med målet att ta fram en implementeringsplan för att förbättra den interna kommunikationen. Studien avser att besvara följande frågeställningar: (1) Vad är grundorsaken till kommunikationsproblemet? (2) Hur påverkar ledarskapet den interna kommunikationen? (3) Hur påverkas medarbetarna av den interna kommunikationen? (4) Hur kan den interna kommunikationen förbättras?   Det teoretiska ramverket bygger på teori om kommunikation och intern kommunikation och behandlar bland annat synsätt på kommunikation och vägar till en effektiv intern kommunikation.   Studien är en fallstudie och har sin utgångspunkt i ett kvalitativt angreppssätt. Insamling av data skedde dels genom en workshop med utvalda organisationsmedlemmar samt via enkäter som skickades ut till samtliga medarbetare och chefer på enheten.   Resultatet visar att organisationen präglas av ett transmissionssynsätt på kommunikation där kommunikation ses som överföring av information uppifrån och ner, från ledning till medarbetare och där medarbetaren utgör en passiv mottagare. Medarbetarna upplever att de tar emot för mycket information medan cheferna anser att de skickar iväg en lagom mängd. Tidsbristen tycks påverka båda parter där cheferna kämpar med att få ut informationen och medarbetarna med att hinna ta till sig av den.   Studiens slutsatser visar följande: (1) Transmissionssynsättet på kommunikation bedöms vara problemets grundorsak. (2) Ledningen har en avgörande roll för den interna kommunikationen och bör fokusera mer på att anpassa kommunikationen efter mottagaren. (3) Medarbetarna påverkas negativt av bristerna i den interna kommunikationen genom bland annat stress och minskad trivsel. (4) Ett förändrat synsätt på kommunikationen från överföring till delning av information tros kunna förbättra den interna kommunikationen tillsammans med förbättringsåtgärderna i den framtagna implementeringsplanen. / The studied unit at the Swedish Transport Administration, Trafikledning Öst Stockholm, suffers from a substantial personnel shortage, which meant that employees have problems with obtaining and absorbing information. Also the managers need to spend a lot of time solving staffing issues. The biggest problem is considered to be the large amount of mail that makes it difficult to screen the information. The purpose of this study is to investigate the internal communication at the unit with the aim of developing an implementation plan to improve the internal communication. The study intends to answer the following questions: (1) What is the root cause of the communication problem? (2) How does leadership affect the internal communication? (3) How are the employees affected by the internal communication? (4) How can the internal communication be improved?The theoretical framework is based on theory of communication and internal communication and for instance deals with approaches to communication and pathways to effective internal communication. The study is a case study based on a qualitative approach. Data collection was done partly through a workshop with selected organisational members and through surveys sent to all employees and managers at the unit.The result shows that the organisation is characterised by a transmission approach to communication where communication is seen as the transfer of information from top to bottom, from management to employees and where the employee is a passive recipient. The employees feel that they receive too much information while the managers believe that they send out a reasonable amount. The lack of time seems to affect both parties where the managers are struggling to get the information out and the employees are struggling with having time to comprehend the information received.The conclusions shows the following: (1) The transmission approach to communication is considered to be the root cause of the problem. (2) The management has a vital role in internal communication and should focus more on adapting communication to the recipient. (3) The employees are adversely affected by the deficiencies in internal communication through, among other things, stress and reduced well-being. (4) An altered approach to communication from transmission to sharing of information is believed to be able to improve the internal communication along with the improvements in the developed implementation plan.

No presente trabalho foram levantados dados sobre a fauna de imaturos de Trichoptera dentro e fora de unidades de conservação estaduais da região da Serra de Paranapiacaba, Estado de São Paulo, com o objetivo de testar os efeitos dos fatores ambientais e do estado de conservação ambiental sobre a composição faunística, abundância e riqueza das larvas. Também foi testada a relação entre a abundância e a distribuição dos diferentes gêneros de Trichoptera. As coletas foram feitas em riachos de 1a a 4 a ordem totalizando 33 pontos de coleta. 25 pedras de tamanho padronizado (18-20 cm de maior diâmetro) foram amostradas com auxílio de um puçá. Análises de ordenação e agrupamento não detectaram nenhuma estruturação da fauna de Trichoptera. Entre os fatores ambientais testados, os escores de integridade ambiental, características físico-químicas e localização do riacho (dentro e fora das unidades de conservação) não foram significativos para explicar a distribuição faunística, enquanto vazão e distância geográfica foram significativos, porém com baixo poder explicativo. Não houve diferença significativa entre a abundância e a riqueza (observada e padronizada) de riachos dentro e fora das unidades de conservação. A ausência de estruturação da fauna pode ter sido provocada pelos picos de chuva registrados antes e durante as coletas, o que poderia ter homogeneizado a fauna, e pelo diferentes graus de impacto antrópico encontrados nos riachos fora dos parques, os quais podem não ter sido fortes o suficiente para provocar diferenças de comunidades. Foi encontrada uma relação positiva entre a abundância relativa e a distribuição de gêneros, corroborando resultados de diversos estudos de macroecologia. / Data on the fauna of immature stages of Trichoptera were gathered for sites within and outside the range of conservation units in Serra de Paranapiacaba, State of São Paulo, aiming to test the effects of environmental variables and degree of environmental integrity on faunistic composition, abundance and richness of larvae. The relationship between abundance and occupancy of Trichoptera genera was also tested. Sampling was conducted in 1st-4th order streams, in a total of 33 stations. 25 stones with a standardized size (18-20cm along the longest axis) were sampled with a net (0,250mm mesh size). Ordination and cluster analysis failed to detect any faunal structure of Trichoptera. Among the environmental variables, the environmental integrity scores, physico-chemical factors and location (inside and outside of the conservation unit) were non significant in explaining the distribution, whereas discharge and geographic distance were significant, although with little explanatory power. No significant differences were found for abundance and richness (observed and standardized) between sites inside and outside of the conservation units. The absence of faunal structure may have resulted from peaks of rain recorded just before and during sampling days, which could have homogeneized the fauna, and due to differences in the degree of anthropic impacts found for sites outside of the conservation units, which may not have been severe enough to cause the differentiation of faunal assemblages. A positive relationship between relative abundance and distribution of genera was found, in accordance with various macroecology studies.

Utilizando-se materiais coletados durante qua-tro cruzeiros oceanográficos com o N/Oc .\"Prof. W. Besnard\", na região Sudeste do Brasil, compreendida entre Cabo Frio (RJ) e Florianópolis (SC), de janeiro de 1980 a março de 1982, foram realizados estudos quali quantitativos so-bre ocorrências de larvas de peixes, relacionando-as com fatores abióticos. Problemas concernentes aos processos de amostragem tambem foram verificadas. Realizaram-se dois tipos de arrastos: arrasto oblíquo com a rede Bongo usando-se malhagens de 0,333 mm (fina) e de 0,505 mm (regular), e arrasto horizontal de superfície com a rede de Neuston, de 0,333 mm de malhagem. Em cada estação oceanográfica, alem das amostras biologicas, efetuaram-se as medições de temperatura e coleta de água para determinação de salinidade. Um total de 35.090 larvas foram analisadas, incluíndo as coletas das redes fina e regular da Bongo e a rede de Neuston. Dentre estas, 61 grupos diferentes foram separados, chegando a níveis específicos em alguns casos.- Dois gêneros e quatro especies foram identificados pela primeira vez na região: Saurida spp, Hygophum spp, Trachinocephalus myops, Synodus foetens Bregmaceros can-tori e Maurolicus muelleri. As famílias predominantes foram Clupeidae, Engraulidae, Myctophidae e Gonostomatidae. De uma maneira geral, a região Sudeste apresentou grande riqueza em taxa, mas com o predomínio de poucos grupos, em termos de abundância. Análises da relação entre larvas de peixes e fatores abióticos revelaram a existência de padrões de ocorrência e distribuição próprios para cada espécie, dentro de uma determinada faixa de variaçao de temperatura e de salinidade. Estudos realizados durante uma estação fixa de 36 horas em Cabo Frio, mostraram uma situação típica da estrutura oceanográfica da região, notando-se mudanças de massas de água no local, devido ao fenômeno da ressurgiê-cia. Este fator, associado ao horário de coleta, deve ter exercido influência de maneira complexa sobre o componen-te biológico, induzindo mudanças na ocorrência de diferentes tipos de larvas. Dois transectos, um ao largo de Cabo Frio e ou-tro ao largo de paranaguá, foram analisados com o intuito de obter-se informações a respeito da ocorrência e distribuição de larvas de acordo com a distância da costa. Os dados hidrográficos comprovam a existincia de diferentes massas de água compondo a estrutura oceanográfica daregião, que por sua vez influenciam a ocorrência e distribuição de larvas. A família Gerreidae teve a maior abundância associada à massa costeira. Sardinella brasiliensis, Harenguia jaguna e Engraulis anchoita foram de distribuição tipicamente nerítica, assim como as famílias Sciaenidae, Bleniidae, Ophidiidae, Carangidae e Cynoglossidae. Por ou-tro lado, Myctophidae, Gonostomatidae, Paralepedidae e Scombridae ocorreram preferencialmente na região ocêanica, que sofre influência da Corrente do Brasil. Análise do material coletado com a rede de Neuston comprovam a importância deste tipo de amostragem su-perficial para os estudos relacionados com o ictioplâncton, uma vez que esta rede captura uma porcentagem da população que é subamostrada pela rede Bongo. Observou-se a tendência de estratificação na camada superficial, principalmete de formas jovens, como no caso de Sardinella brasiliensis. Um aspecto especialmente notável foi o caso das fa-mílias Mugilidae e Mullidae em que a captura se deu significativamente em maior número no arrasto de superfície do que no arrasto oblíquo. Comparando-se os materiais coletados com as re-des finas e regular da Bongo, pôde-se verificar dois pro-blemas relacionados com a seletividade: o entupimento da rede e o escape de larvas menores através da malhagem. Ecomparando-se os materiais coletados durante os períodos diurno e noturno, pôde-se verificar o outro problema importante de seletividade, que é a fuga da boca da rede de larvas maiores. As nossas amostragens parecem nao ter sido afetadas pelo problema de entupimento, como mostram as análises do volume de água filtrada. Já o escape de lar-vas menores foi constatado em vários grupos, tendo sido de terminado para três especies o tamanho a partir do qual este problema começa a se tornar evidente: 7,5 mm para Sardinella brasiliensis e 6,5 mm para Harengula jaguana e Engraulis anchoita. A fuga da boca da rede ocorreu em lar-vas maiores durante o dia, concluindo-se que este problema varia conforme a especie, o padrão de migração vertical e o desenvolvimento do sistema visual. / Four oceanographic cruises have heen carried out off the southeastern Brazilian coast from Cabo Frio (23ºS) to Florianópolis (27°S) during the period from January 1980 to March 1982 by the R/V\" Prof. W. Besnard ,\". Fish larvae taken during these cruises were analysed and influences of abiotic factors on their occurrence were discussed.Problems regarding the sampling process were also discussed. Two kinds of sampling gears were used: Bongo nets fitted with a 0.505 mm and 0.333 mm mesh nets for oblique tow and Neuston net with a 0.333 mesh net for surface horizontal tow. At each sampling station, hydrographic data were sampled in addition to biological data. Total of 35,090 larvae were analysed. Sixty one groups were classified and some dominant ones were identified to spec1es level. Larvae belonging to two genera and four species were identified for the first time in the region under observation, i. e. Saurida spp., Hygophum spp., Synodus foetens, Trachinocephalus myops, Bregmaceros cantori and Maurolicus muelleri. The most abundant families were clupeidae, Engraulidae, Myctophidae and Gonostomatidae. In general, the ichthyoplankton from the southeastern Brazilian coast showed a large variety of larvae, but just few groups were outstandingly abundant. Analysing the relations between occurrence of fish larvae and hydrographic parameters, we found specific distri-bution patterns for each species. At the fixed station off Cabo Frio (22°59\'S; 042º05\'7W), 36 hour observations have been done and biological and hydrographic data have been collected every two hours. A change in the local oceanographic structure during the survey period has been observed along with wind induced coastal upwelling. A change of the oceanographic conditions associated with sampling time, may have influenced the occurrence of fish larvae. In order to obtain information on the distribution patterns of fish larvae in relation to distance from the coast, the samples collected on two transects off Cabo Frio and paranaguá were analysed. The presence of four different water masses in this region was confirmed and the occurrence and distribution of larvae seems to have close relationship with those water masses. Larvae of the family Gerreidae were more abundant in the coas tal water mass and those of Sardinella braziliensis, Harengula jaguana and Engraulis anchoita showed typical neritic distribution. Larvae belonging to the families Sciaenidae, Blenniidae, Ophídiidae, Carangidae and Cynoglossidae also showed the same distribution pattern. On the other hand, larvae belonging to the families Myctophidae, Gonostomatidae, Paralepedidae and Scombridae occurred mainly in the oceanic region where the influence of the Brazil Current is eminent. The ichthyoplankton collected at surface layer with Neuston net showed quite different types and size composition of fish larvae, In comparison with those taken with Bongo nets. Clear tendency of stratification in size composition at the surface layer was observed on some species (e.g. S.braziliensis). Larvae belonging to the families Mugilidae and Mullidae seems to be more concentrated at the surface layer, since they were more frequently sampled with the Neuston neto Three problems related to selectivity of plankton net (clogging, extrusion and avoidance) can be studied compar1ng the materials collected with the Bongo ets fitted with different mesh size nets and sampled at different times of the day. As shown in Figs. 23 and 24, there is no evidence of clogging of the fine mesh net during this survey. On the other hand, the extrusion of smaller larvae was confirmed for many groups and it was observed at sizes smaller than 7.5 mm, 6.5 mm, and 6.5 mm, respectively for S.brasiliensis, H.jaguana and E. anchoita. The avoidance was more remarkeble during the day time for larger larvae, but this problem varies depending on spec1es, migration pattern, and development stage of the visual system of each larvae

A recuperação de funções e processos ecossistêmicos, entre outros atributos, é um dos indicadores mais importantes no processo de retorno de um ecossistema à sua trajetória histórica. A ciclagem de nutrientes é um atributo fundamental do ecossistema, e relaciona-se diretamente à regulação do funcionamento e do desenvolvimento dos ecossistemas e inclui, em um modelo geral, as entradas de nutrientes, as transferências internas entre plantas e solo e as saídas do sistema. A compreensão das mudanças nos processos biogeoquímicos durante a sucessão secundária em áreas em restauração ecológica ainda é incipiente, principalmente em áreas de florestas tropicais. Esse estudo tem por objetivo elucidar a dinâmica do nitrogênio ao longo do processo de restauração ecológica em áreas reflorestadas com espécies nativas da Mata Atlântica. A questão norteadora deste estudo é a seguinte: A restauração florestal com alta diversidade de espécies e predominância de espécies arbóreas nativas regionais restaura a dinâmica original do nitrogênio? Esse estudo visa investigar o funcionamento da ciclagem de nutrientes, com foco no nitrogênio, que é um elemento limitante à sucessão secundária, especialmente em florestas tropicais. Para tal, alguns indicadores da ciclagem do nitrogênio foram mensurados em uma cronosequência florestal formada por uma floresta natural preservada e florestas restauradas de diferentes idades (21 e 52 anos) reflorestadas com alta diversidade de espécies e predominância de nativas regionais. Os indicadores utilizados foram: 15N e teor de N da vegetação, serrapilheira e solo; razão N:P da vegetação e da serrapilheira; taxas líquidas de mineralização e nitrificação; teor de amônio, nitrato, N mineral e razão nitrato:amônio. As florestas foram amostradas entre agosto de 2008 e abril de 2009, nas seguintes estações: seca, transição entre seca e chuvosa, chuvosa, e transição entre chuvosa e seca. Foram encontrados padrões claros de mudanças na ciclagem do N ao longo da cronosequência estudada, incluindo diferenças nos valores de 15N foliar, teor de N, razão N:P, N mineral e taxas líquidas de mineralização e nitrificação, caracterizadas por um aumento de valores médios dessas variáveis ao longo da cronosequência. Os resultados encontrados sugerem que as florestas em processo de restauração, mesmo a de 52 anos, ainda não possuem uma ciclagem de N característica de uma floresta madura e, portanto, a recuperação da ciclagem de N ainda não foi completamente atingida. Entretanto, é possível afirmar que as florestas em processo de restauração estudadas estão seguindo uma trajetória de desenvolvimento caracterizada por uma ciclagem de N cada vez mais parecida com a de uma floresta natural madura, como a da floresta natural madura utilizada como referência. Através dos modelos de restauração utilizados para as florestas da cronosequência estudada, os processos da ciclagem do N são recuperados à medida que a floresta desenvolve-se, com uma clara tendência de mudança na economia de N para economia de P típica de florestas tropicais maduras. / The recuperation of ecosystem processes and functions, among other attributes, is one of the most important indicators in the process of return of an ecosystem to its historic trajectory. Nutrient cycling is a fundamental ecosystem attribute, and relates directly to regulation of functioning and development of ecosystems and includes, in a general model, nutrients entering, being transferred internally between plants and soil, end leaving the system. The comprehension of changes in biogeochemical processes during secondary succession in areas in ecological restoration is still incipient, mainly in tropical forests. This study aims to elucidate nitrogen dynamics along the process of ecological restoration in areas reforested with Atlantic Forest native species. The question driving this study is: Does ecological restoration with high diversity of species and predominance of regional native tree species restore nitrogen original dynamics? This research investigated nutrients cycling functioning, focusing on nitrogen, which is a limiting nutrient in secondary succession, particularly in tropical forests. In order to do so, some indicators of nutrient cycling were assessed in a forest chronosequence formed by a preserved natural forest and restored forests of different ages (21 and 52 years) reforested using high species diversity and predominance of regional native species. The indicators used were: 15N and N content in green foliage, litter and soil; N:P ratio of green foliage and litter; net mineralization and net nitrification rates; content of ammonium, nitrate, inorganic N, and nitrate:ammonium ratio. The forests were sampled between August 2008 and April 2009, in the following seasons: dry, dry-rainy transition, rainy, rainy-dry transition. Clear patterns of change in the N cycling along the studied chronosequence were found, including differences in green foliage 15N values, N content, N:P ratio, inorganic N and net mineralization and nitrification rates, characterized by an increase in the mean values of these variables along the chronosequence. The results found suggest that the forests in restoration process, even the 52 years old one, still do not present a N cycling characteristic of a mature forest and, therefore, the recuperation of the N cycling was not completely reached yet. However, it is possible to state that the forests in restoration process studied here are following a development trajectory characterized by a N cycling progressively more similar to what is common to a mature native forest, as the one used as the reference ecosystem in this study. Through the restoration models used for the forests studied, the N cycle processes are recovered as the forests develop, as they present a clear tendency of changing from N economy to P economy, typical to mature tropical forests.

O Níquel (Ni) é um micronutriente para as plantas, por ser componente estrutural das enzimas urease e hidrogenase, que desempenham função no metabolismo do nitrogênio (N) nas plantas leguminosas. A aplicação de Ni via tratamento de semente em soja pode potencializar o processo de fixação biológica de nitrogênio (FBN) com a finalidade de proporcionar maior produção de biomassa da parte aérea e de grãos. Objetivou-se com este trabalho avaliar o efeito da aplicação de doses de Ni, via tratamento de semente, no processo de FBN em plantas de soja, por meio da atividade de nitrogenase (ANase) e da abundância natural de 15N (? 15N?). Foi realizado um experimento em casa de vegetação, em condições controladas. O genótipo de soja BMX POTÊNCIA RR foi cultivado em solo arenoso e submetido à aplicação de 0; 45; 90; 135; 180; 360; e 540 mg kg-1 de Ni aplicado via tratamento de semente. As plantas de soja foram conduzidas até o estádio fenológico R7 (maturação dos grãos). Foram avaliadas a concentração de macro e micronutrientes nas folhas utilizadas para diagnose, determinou-se o teor de clorofila, a atividade enzimática da urease, bem como se quantificou a massa seca de nódulos, no estádio fenológico R1 (Início da floração: até 50% das plantas com flor). Foram ainda determinados: as produções de massa seca de parte aérea e de grãos, o índice de colheita, os acúmulos de Ni e de N na semente e a contribuição da fixação biológica de nitrogênio, por meio da técnica de abundância natural de 15N e indiretamente através da técnica da redução do acetileno (atividade da nitrogenase). Observou-se que as doses de Ni exerceram efeitos em todos os parâmetros avaliados. A aplicação de Ni na dose de 45 mg kg-1 aumentou a fixação biológica de N na ordem de 12% em relação ao tratamento controle (sem adição de Ni) e incrementou o acúmulo de Ni e de N no grão, com efeito na atividade da enzima urease. A aplicação de 45 e 90 mg kg-1 de níquel via semente resultou, respectivamente, no aumento de 67% e 77% da atividade da NAase em relação ao controle. Pela análise da abundância natural de 15N no grão (?15N?) observou-se que houve diferença na FBN entre os tratamentos e que a aplicação da dose de 45 mg kg-1, de Ni via semente, revelou que 99% do N acumulado no grão foi proveniente da FBN, enquanto que no tratamento sem adição de Ni via semente, a contribuição da FBN foi de apenas 77%. Nas condições do experimento, a aplicação de Ni na semente refletiu em maior produção de massa seca de parte aérea e na produção de grãos de soja / Nickel (Ni) is an essential micronutrient for plants due to its role on structural component of the enzymes urease and hydrogenase, which perform nitrogen (N) metabolism in legumes plants. Seed treatment with Ni in soybean might improve the symbiotic or biological nitrogen fixation (BNF) process, by increasing biomass production and grain yield. The objective of this study was to evaluate the effect of soybean seed treatment with Ni rates on the biological nitrogen fixation (BNF) process by evaluating the nitrogenase activity (NAase), the natural 15N abundance (? 15N ?) and urease activity in soybean plants, as well. The experiment was carried out in greenhouse with controlled conditions. The soybean cultivar used was BMX POTÊNCIA RR, which was grown in sandy soil, and submitted to application of 0, 45, 90,135, 180, 360 and 540 mg kg-1 of Ni on the seed treatment. Soybean plants were grown up to the R7 developmental stage (grain maturity). Macro and micronutrients concentration in the leaves used for diagnosis, as well as the chlorophyll content and urease activity have been determined on these tissues, and dry weight of nodules were evaluated in developmental stage R1 (flowering stage). The following measurements also were made: dry matter yield of plant top, dry matter yield of grains, the harvest index, uptake of Ni and N in the seed and the contribution of biological nitrogen fixation by 15N natural abundance and to indirectly way by the reduction of acetylene technique (nitrogenase activity), as well. It was observed that Ni rates influenced all parameters. Application of Ni rate of 45 mg kg-1 increased biological nitrogen fixation in the order of 12% as compared to the control. Ni rates of 45 and 90 mg kg-1 via seed treatment increased the NAase activity, respectively, in 67% and 77% compared to the control. Other benefits of Ni-soybean seeds treatment were the increased accumulation of Ni and N on the grain and its positive influence on the urease activity. By analyzing the natural abundance of 15N on the grain (?15N ?) it was observed that there were differences between treatments in the symbiotic nitrogen fixation. Around 99% of total N taken up in the seeds came from biological nitrogen fixation by supplying Ni-seed application rate of 45 mg kg-1, whereas in the control, the contribution of BNF was only 77%. In these experimental conditions, seed treatment with Ni reflected in higher dry matter production of plant top and grain yield

A humanidade como conhecemos hoje é totalmente dependente da agricultura de grande escala. Estamos chegando próximo ao esgotamento de novas áreas para ampliação ou substituição de áreas agrícolas. Isso torna premente uma avaliação da sustentabilidade dos agroecossistemas a fim de averiguar se eles estão aptos a continuar sua função de prover alimentos a uma população crescente. Este trabalho tem como foco os aspectos físicos e químicos do solo com visão restrita aos processos internos do sistema produtivo, sem uma avaliação da sustentabilidade de toda a cadeia produtiva. O objetivo do presente projeto foi estudar o efeito temporal da cultura da soja nos atributos físicos e químicos do solo, quando uma vegetação de Cerrado é substituída pela atividade agrícola. Utilizando para tanto uma cronoseqüência de 5 áreas agrícolas com tempo de cultivo de 4 anos (C4D3) 12 anos (C12D5) 13 anos (C13D12) 14 anos de cultivo de grãos e 8 anos de cultivo de pastagem (C14P8) e 23 anos (C23D12) tendo como linha de base para comparação uma área sob Cerrado (CE). Todas as áreas apresentaram relêvo plano e mesmo tipo de solo (LATOSSOLO VERMELHO-AMARELO distrófico de textura argilosa) sendo a distância máxima entre elas de 3,4 km e pertencente ao mesmo produtor localizado a 30 km ao sul da cidade de Sorriso MT (12º42`41``S 55º53`38``W). Em cada área foram coletadas amostras para análises física e química do solo em cinco perfis diferentes nas profundidades de 0 a 5, 5 a 10, 10 a 20, 20 a 30, 30 a 50, 50 a 75 e 75 a 100 cm. Foram analisados os teores de macronutrientes, com exceção do enxofre, e de micronutrientes, com exceção do cloro e molibdênio. Ademais foi determinada a textura, densidade e abundância natural do isótopo ?13C que permitiu o cálculo do carbono (C) proveniente de plantas C3 (CC3) e o C proveniente de plantas C4 (CC4). Com essas análises foram quantificados os estoques de C, CC3, CC4 e nitrogênio (N). O estoque total de C de 0 a 100 cm aumentou com o tempo de cultivo a uma taxa média de 0,80 Mg C ha-1 ano-1, sendo que na área que teve o maior acúmulo a taxa foi de 1,09 Mg C ha-1 ano-1. Grande parte desse aumento no estoque de C se deve ao acúmulo de CC4 que apresentou uma taxa de acúmulo médio de 0,77 Mg CC4 ha-1 ano-1 na camada de 0 a 50 cm. Quanto ao estoque de CC3 de 0 a 100 cm na média não houve alterações com o tempo de cultivo sendo os pontos extremos o C14P8 com variação no estoque a uma taxa de -0,41 Mg CC3 ha-1 ano-1 e o C23D12 com aumentou no estoque de 0,52 Mg CC3 ha-1 ano-1. Ocorreu substituição de CC3 oriundo do Cerrado por CC4 proveniente das culturas C4, mas também houve um acúmulo de CC3 proveniente das culturas C3 (no caso soja). A variação no estoque de N não se correlacionou com o tempo de cultivo. O cultivo do solo aumentou o pH e as concentrações de fósforo, potássio, magnésio, cálcio, boro, zinco e cobre e diminui a concentração de ferro, manganês e alumínio tóxico. No quesito balanço nutricional e de carbono o sistema agrícola adotado não só manteve as qualidades originais do solo como aumentou o teor de grande parte dos elementos essenciais ao crescimento das plantas mostrando ser sustentável dentro de uma visão restrita aos processos de balanço nutricional internos do sistema produtivo. / Humanity as we know today is totally dependent in the large scale agriculture. We are getting close to the point where it will no longer be possible to expand or substitute agriculture areas. Making an evaluation of the agriculture system sustainability very important, to verify if they are fit to maintain there function as a food provider for a growing population. This work focus on the soil physical and chemical aspect with a restricted vision on the internal farm process, without an evaluation of the entire production chain. The object off this work was to study the temporal effect of the soybean cultivation in the physical and chemical soil properties when a typical Cerrado vegetation is replaced by agriculture. Five agriculture areas with different cultivation time, i.e. 4 years (C4D3), 12 years (C12D5), 13 years (C13D12), 14 years of grain production and 8 years of pasture (C14P8) and 23 years (C23D12) where compared to a nearby Cerrado plot. All plots had the same soil type (LATOSSOLO VERMELHO-AMARELO distrófico de textura argilosa) and relief, being the maximum distance between plots 3.4 km. They all belong to the same farmer located approximately 30 km south of the city Sorriso in the Mato Grosso state (12º 42` 41`` S 55º 53` 38`` W). In each plot five soil sampling pits where made, soil sampling was done at the 0-5, 5-10, 10-20, 20-30, 30-50, 50-75 and 75-100cm depth. All major nutrients, with the exception off hydrogen, oxygen and sulfur and all minor nutrient, with the exception off chlorine and molybdenum where analyzed. Soil texture and 13C natural abundance, that permitted the calculation off the C3 plants carbon (CC3) and the C4 plants carbon (CC4), was also determined with this results the carbon (C), CC3, CC4 and nitrogen (N) stocks was calculated. The total C stock from 0 to 100cm increased with the cultivation time at a average rate of 0.8 Mg C ha-1 year-1, and on plot with the greatest accumulation (C23D12) the rate was 1.09 Mg C ha-1 year-1. A significant part off this accumulation was due to the CC4 contribution with an average rate off 0.77 Mg CC4 ha-1 year-1 in the 0 to 50cm profile. The CC3 stock in the 0 to 100cm profile did not correlate with the cultivation time, being the extreme points the C14P8 with a depletion off -0.41 Mg CC3 ha-1 year-1 and the C23D12 with a accumulation off 0.52 Mg CC3 ha-1 year-1. This shows that a replacement off the original Cerrado CC3 by the agriculture CC4 (maize) occurred, but that in some areas a accumulation off soybean CC3 also took place. The N stock variation did not correlate with the cultivation time, probably a different variable not measured in this study is driving this element. Soil cultivation increased the pH and phosphorus, potassium, magnesium, calcium, boron, zinc and copper soil concentration. Other elements such as iron , manganese and aluminum decreased with the soil cultivation. In the carbon and nutritional balance the agriculture system adopted maintained the soil original qualities and even increase the concentration off some elements. Showing that within the internal soil nutritional balance the system is sustainable.