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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Diversité globale des poissons coralliens : histoire évolutive et influence de l'environnement passé / Global diversity of coral reef fishes : evolutionnary history and influence of Paleo-environment

Gaboriau, Théo 09 March 2018 (has links)
L’étude de la diversité des espèces de poissons habitant les récifs coralliens fascine les chercheurs du monde entier depuis plus de 200ans. Comment ces organismes qui n’occupent que 1% de la surface des océans du globe ont-ils pu former un des groupes les plus riches des vertébrés existants ? La complexité de cette question ne réside pas seulement dans l’exceptionnelle diversité de formes, de couleurs et de comportements de ces espèces mais aussi dans l’inégale répartition de cette richesse. Des explorations du lagon de Mayotte, des côtes Cubaines ou de la grande barrière de corail donneront des perspectives très différentes de la diversité des poissons coralliens. Ces différences très importantes sont le résultat de processus ayant modelé, pendant des millions d’années, la répartition des espèces coralliennes, leur morphologie et leur comportement. Pendant ces millions d’années d’évolution, les poissons coralliens, ainsi que les espèces de coraux qui les abritent, ont été confrontés à des changements drastiques des conditions climatiques et à la dérive des continents. C’est l’influence de ces facteurs sur la répartition et la diversité des poissons coralliens, que j’ai étudié pendant ma thèse. Comprendre comment les espèces et les écosystèmes ont réagi aux changements environnementaux passés peut nous apporter des clés essentielles pour anticiper les changements à venir des écosystèmes que nous connaissons, sous l’influence des changements globaux. Les récifs coralliens étant sous une menace de plus en plus présente, je me suis particulièrement intéressé à l’influence de la disponibilité de l’habitat corallien sur les processus d’extinction, de dispersion et de spéciation (formation de nouvelles espèces par divergence génétique) des poissons coralliens.Afin de répondre à ces objectifs, plusieurs méthodes ont été employées. Dans un premier temps, une approche descriptive basée sur la répartition de la co-occurrence entre espèces sœurs et une comparaison entre une reconstruction globale de la dynamique des habitats coralliens allant du Crétacé (≈ -140 millions d’années) et les taux de diversification de plusieurs grands groupes de poissons récifaux, ont permis de montrer que les taux de diversification de plusieurs familles de poissons récifaux étaient dépendant de la fragmentation des habitats coralliens, et d’observer la concordance entre des évènements climatiques et tectoniques majeurs et l’évolution de la biodiversité des poissons coralliens.Après avoir identifié un lien entre fragmentation de l’habitat corallien et la diversification des poissons, une grande question demeure : Comment cette dynamique de l’habitat influence-t-elle dans l’espace et le temps la diversité des poissons récifaux ? Pour répondre à cette question, une approche unique permettant de modéliser la dispersion, la spéciation et l’extinction des espèces dans un espace formé de grilles d’habitat dynamique a été développée et appliquée à plusieurs clades d’organismes marins côtiers (coraux, palétuviers et poissons). Cette approche a permis de démontrer comment la dérive des continents a contraint la dynamique de l’habitat corallien et a façonné les gradients de diversité de plusieurs groupes d’organismes marins côtiers. Enfin, l’extension de cette approche aux récifs tempérés, a permis de montrer l’interaction entre l’influence de la dérive des continents et des processus écologiques sur la colonisation et le maintien d’espèces de poissons récifaux dans les milieux tempérés, expliquant en partie la formation du gradient latitudinal de diversité des poissons récifaux.Ces travaux ouvrent la voie vers l’utilisation d’une nouvelle génération de modèles spatialisés de diversification et la prise en compte de la dynamique des habitats passés dans l’étude des processus de diversification. / The exceptional diversity of fishes that inhabit coral reefs fascinates researched from all over the world since over 200years. How can those organisms, that only occupy 1% of the surface of the oceans, form one of the richest group of extant vertebrates? The complexity of this question does not only lie in the extraordinary diversity of morphologies, colors and behaviors, but also roots in the heterogeneous repartition of that richness. Explorations of Mayotte’s lagoon, Cuban coasts or the great barrier reef will show different perspectives of coral-reef fish’ diversity. Those pervasive differences are the result of processes that shaped, during millions of years the repartition of coral-reef species, their morphology and their behavior. During those millions of years of evolution, coral-reef fishes along with species that shelter them, faced massive climatic and tectonic changes. During my PhD, I studied the influence of those factors on the repartition and the diversity of coral-reef fishes. Understanding how species and ecosystems responded to important environmental changes can provide essential insights to anticipate future changes of ecosystem composition and functioning under global changes’ pressure. As coral-reefs are under more and more threatening pressures, I particularly focused on the influence of coral habitat availability on extinction, dispersion and speciation processes of coral-reef fishes.To achieve this goal, several methods have been employed. First, a descriptive approach based on sister-species co-occurrence patterns and the comparison between a global reconstruction of coral-reef habitat dynamics from the Cretaceous (≈ -140 million years) to present and the evolution of several speciose groups of coral-reef fishes permitted to identify a link between diversification rates of several groups of coral-reef fishes and coral habitat fragmentation and to observe the concordance between major earth-history events and biodiversity dynamics of coral-reef fishes.After the identification of a link between habitat fragmentation and coral-reef fishes’ diversification, an important question remains: What are the mechanisms underlying the influence of habitat dynamics on temporal and spatial variations of reef-fish biodiversity? To answer this question a unique approach allowing modeling of species dispersal, extinction and speciation in a gridded space varying in function of habitat dynamics, has been developed and applied to several groups of coastal marine organisms (corals, mangroves, fishes). This approach provided mechanistic insights about how plate movements drove coral reef habitat dynamics and shaped biodiversity gradients of several groups of coastal marine organisms. Finally, the extension of this approach to temperate reefs (rocky reefs), provided mechanistic insights about the interplay between the influence of tectonic events and ecological processes in the formation of present-day latitudinal gradient of biodiversity of reef-fishes.This thesis paves the way towards the use of a new generation of spatialized mechanistic models of macroevolution and the consideration of the influence of past-habitat dynamics in the study of diversification processes.
292

Snapping shrimp protect host anemones from predators

Unknown Date (has links)
The sea anemone Bartholomea annulata, is an ecologically important member of Caribbean coral reefs. This anemone serves as symbiotic host to crustacean associates, some of which may control parasite loads by "cleaning" reef fishes. Associates may gain protection from predation by dwelling with anemones. B. annulata was the most abundant anemone documented on three reefs, with 52% host to crustacean symbionts. Of those occupied by multi-species groups, 92% included Alpheus armatus shrimp. A. armatus is an important anemone associate providing protection to the anemone from predators such as Hermodice carunculata, in laboratory and field trials. H. carunculata can completely devour or severely damage prey anemones. Here I show that anemones hosting symbiotic alpheid shrimp are extremely less likely to sustain damage by predators than solitary anemones. The role of protector may be reciprocally provided by anemone and decapod associates. / by Amber McCammon. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
293

The chemistry of Briareum asbestinum

Unknown Date (has links)
Briareum asbestinum, a soft coral, is a rich source of diterpenoid natural products. The secondary metabolites of B. asbestinum fall into four classes : asbestinins, briarellins, briareolate esters, and briaranes. Briareolate esters have been shown to possess biological activity and were previously only reported from Tobago. Our group recently isolated briareolate esters from a specimen collected off the coast of Boca Raton, Florida. To determine whether location has an impact on the chemistry produced by the organism, a method to discern between chemotypes was sought. Several techniques including thin layer chromatography (TLC), high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and sclerite analysis were employed, with NMR being the most successful method. By utilizing both 1H and COSY NMR experiments, it is possible to differentiate between the chemotypes of B. asbestinum. Application of this method allowed analysis of chemical variability with respect to location. / by Melody D. Rondeau. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / System requirements: Adobe Reader. / Mode of access: World Wide Web.
294

Dinâmica interanual do epibentos do infralitoral rochoso da Ilha da Trindade / Interanual dinamics of the rocky subtidal epibenthic community from Trindade Island

Medeiros, Carolina Cristina 14 March 2019 (has links)
As comunidades bentônicas concentram a maior parcela da biodiversidade marinha e constituem um elemento essencial da estrutura dos ecossistemas marinhos como um todo. São vários os fatores que influenciam na dinâmica bentônica, como interações competitivas, reprodução, aporte de nutrientes, temperatura, entre outros. Esses fatores regem o funcionamento da comunidade e alterações desses padrões, como pesca e poluição, podem induzir mudanças de fase. Ainda assim, é possível que mudanças de fase façam parte da dinâmica natural, a partir de fenômenos que agem em escalas de tempo maiores. Por esse motivo, torna-se bastante difícil indicar quais fatores podem suscitar mudanças lentas que culminem em diferenças importantes na estrutura das comunidades. Portanto, se fazem necessários estudos de variações temporais de longo prazo para melhor entendimento desses padrões naturais e das mudanças nesses padrões, que podem afetar o funcionamento e a resiliência do ecossistema. Esse tipo de estudo ainda é escasso para ilhas oceânicas brasileiras, sendo mais frequentes estudos de caracterização e de curto prazo. Dada a importância desse tipo de pesquisa, o presente trabalho é o primeiro para a comunidade bentônica recifal de uma série de estudos de longo prazo na ilha da Trindade, e integra o \"Programa de Pesquisas Ecológicas de Longa Duração das Comunidades Recifais das ilhas Oceânicas Brasileiras\" (PELD-ILOC), com objetivo central de analisar a dinâmica espaço-temporal da comunidade bentônica da ilha da Trindade e descrever sua composição entre os anos de 2013 e 2017. Para tal, foram demarcados quatro sítios em torno da ilha, com três transecções de 20 metros de comprimento em cada um, amostrando uma transecção por profundidade com 10 fotoquadrados em cada transecção. A cobertura bentônica foi avaliada por meio do software CPCe, com identificação dos organismos até o menor nível taxonômico possível, sendo posteriormente agrupados em grupos morfofuncionais. No geral, a comunidade bentônica da ilha da Trindade no período analisado foi dominada por macroalgas (Caulerpa sp., Canistrocarpus cervicornis e Jania sp.), turf e algas calcárias crostosas (Peyssonnelia sp.) e apresenta diferença significativa entre sítios e anos, porém não apresenta diferenças significativas entre as profundidades analisadas. Apesar do dinamismo natural dessas comunidades, foi possível observar diminuição da abundância de organismos bioconstrutores em 2016, que pode ter ocorrido devido ao El-Niño registrado no mesmo período. O ano de 2017 foi o que menos se assemelhou com os demais, apresentando aumento na riqueza, maior diversidade, maior relação entre sítios, grande crescimento na abundância de algas calcárias crostosas e mudança de dominância dentro do grupo de macroalgas, com a substituição da macroalga Caulerpa sp. pela macroalga calcária articulada Jania sp.. Para explicar essas alterações, assim como suas consequências, é necessária a continuação do presente monitoramento, incluindo novas abordagens e metodologias, integrando análises de variáveis físico-químicas e padronização nos estudos para possíveis comparações, o que ajudaria a compreender melhor o comportamento da comunidade bentônica insular oceânica brasileira no geral e responder questões que só podem ser elucidadas a longo prazo. / Benthic communities host a major fraction of the marine biodiversity, being an essential component in the structure of marine ecosystems. There are several factors that influence the benthic dynamics, such as competitive interactions, reproduction, nutrient, temperature, etc. These factors control the functioning of the community and changes in these patterns can induce phase shifts. Nevertheless, it is possible that phase shifts are part of the natural dynamics, from phenomena that act on larger time scales. So, it is very difficult to indicate which factors can lead to slow changes that affect the structure of communities. Therefore, studies of long-term temporal variations are needed to better understand changes in those patterns that may affect the functioning and resilience of the ecosystem. This kind of study is still scarce for Brazilian oceanic islands, with more frequent characterization and short-term assessments. Hence, the present work is the first one for the benthic reef community of a series of long-term studies in the Trindade Island, and integrates the \"Long-term Ecological Research Program of the Reef Communities of the Brazilian Oceanic Islands\" (in Portuguese Programa de Pesquisas Ecológicas de Longa Duração das Comunidades Recifais das Ilhas Oceânicas Brasileiras - PELD-ILOC). The present study describes and does a spatio-temporal analysis of the reef benthic community of Trindade Island, assessing the substrate cover dynamics of four sites from 2013 to 2017. Each site was sampled at three depth ranges, with three transects and ten photoquadrats in each transect. Benthic coverage was analyzed using the CPCe software, with organisms identified to the lowest possible taxonomic level, and later grouped into morphofunctional groups. In general, the benthic community of Trindade Island during the analyzed period was dominated by macroalgae (Caulerpa sp., Canistrocarpus cervicornis and Jania sp.), turf and crustose coralline algae (Peyssonnelia sp.) The results showed significant changes among sites and years, however did not show significant changes among depths. Despite the natural dynamism of these communities, it was possible to observe a decrease in the abundance of bioconstructors in the 2016 expedition, which may have occurred because to El-Niño during the same period. The year 2017 was the most different when compared to others years, with an increase in species richness, but also greater diversity, greater similarity among sites, and a pronounced growth in the abundance of crustose coralline algae. In the same year a change in the dominant species was also observed, with the substitution of the macroalgae Caulerpa sp. by the articulated coralline algae Jania sp.. It is important to continue the present monitoring in order to determine the main causes and consequences of these structural changes, including new approaches and methodologies, integrating abiotic variables and standardization in the studies for possible future comparisons, which would help to better understand the behavior of the Brazilian insular benthic oceanic community in general and answer questions that can only be elucidated in the long term.
295

Flora de macrófitas marinhas do arquipélago de Abrolhos e do recife Sebastião Gomes (BA) / The marine macroflora of Abrolhos archipelago and Sebastião Gomes reef (Brazil)

Silva, Beatriz Nogueira Torrano da 07 June 2010 (has links)
Flora de macrófitas marinhas do Arquipélago de Abrolhos e do Recife Sebastião Gomes (BA). Apesar dos avanços crescentes ao conhecimento da flora de macrófitas marinhas (algas e gramas marinhas) da costa brasileira, desde os trabalhos seminais de A. B. Joly a partir da década de 1950, existem ainda regiões que não foram adequadamente amostradas. Este é o caso das formações recifais mais afastadas da costa. Do sul da Bahia ao norte do Espírito Santo, um grande alargamento da plataforma, conhecido como banco de Abrolhos, abriga a maior formação recifal do Atlântico Sul. Duas regiões dessa extensa área foram escolhidas como foco deste trabalho: i. o recife Sebastião Gomes, a 16 km da foz do rio Caravelas, emerso nas marés-baixas e sujeito a uma maior interferência de sedimentos terrígenos e impactos antrópicos de naturezas diversas e ii. o arquipélago de Abrolhos, a 70 km da costa, caracterizado por formações sedimentares soerguidas, rodeadas por sedimento carbonático de origem biogênica e águas com baixa turbidez e pouco afetadas pela ação do homem. Além destes dois ambientes incluímos em nossas amostragens algumas visitas a chapeirões gigantes típicos da região do bordo do parcel de Abrolhos. Complementarmente, sintetizamos o conhecimento taxonômico existente para esta região do litoral baiano. Não foram estudadas as formas calcárias não articuladas. Como resultado de nossa pesquisa identificamos 103 espécies de macrófitas no recife Sebastião Gomes, sendo 48% Rhodophyta, 26% Phaeophyceae, 25% Chlorophyta e 1% Magnoliophyta. Este resultado, somado aos dados da literatura totaliza 110 táxons para esta região. Nossos estudos adicionam 74 táxons para a flora deste recife, sendo 43 Rhodophyta, 13 Phaeophyceae, 18 Chlorophyta. Para o arquipélago de Abrolhos encontramos 149 espécies, sendo 59% Rhodophyta, 22% Phaeophyceae, 18% Chlorophyta e 1% Magnoliophyta. Somados aos dados da literatura chega-se a um total de 164 táxons para o arquipélago. Nossos estudos adicionaram 59 táxons à flora do arquipélago, sendo 33 Rhodophyta, 11 Phaeophyceae, 14 Chlorophyta e 1 Magnoliophyta. A flora marinha do arquipélago de Abrolhos se mostrou mais diversa do que a do recife Sebastião Gomes, possivelmente devido a uma maior diversidade de hábitats e, talvez, por ser uma área menos impactada e com menor turbidez. Em comparação com o conhecimento da flora marinha das principais formações oceânicas da costa brasileira observa-se, em ordem decrescente de riqueza específica: o arquipélago de Fernando de Noronha, o arquipélago de Abrolhos, o recife Sebastião Gomes, o atol das Rocas, a ilha de Trindade e os penedos de São Pedro e São Paulo. O trabalho descreve e ilustra os atributos mais importantes das espécies encontradas. / The Marine Macroflora of the Abrolhos Archipelago and Sebastião Gomes reef (Brazil). Despite the considerable endeavor and advances in the knowledge of the macrophyte flora (seaweeds and seagrasses) on the Brazilian coast since the seminal works of A. B. Joly in the 1950s, there are still areas that have not been adequately sampled. This is the case of the reef formations along the coast. On the southern coast of Bahia there is a pronounced enlargement of the continental shelf known as the Abrolhos bank, which comprises the largest reef formation in the southern Atlantic. We selected two regions within the Abrolhos bank to focus our surveys: i. the Sebastião Gomes reef, 16 km off the mouth of the Caravelas river, and ii. the Abrolhos archipelago, a group of five small islands, 70 km off the coast. Sebastião Gomes reef is subjected to a larger anthropic impact and turbid water due to terrigenous sediments; the Abrolhos archipelago is surrounded by calcareous biogenic sediments, bathed by clear water and protected from human activities. Besides those two nuclear sampling sites we also got samples from some giant chapeirões, a unique reef formation, on the border of the archipelago. The nonarticulated calcareous red algae were not included in our surveys. As a result of our surveys we identified 103 species on Sebastião Gomes reef (48% Rhodophyta, 26% Phaeophyceae, 25% Chlorophyta and 1% Magnoliophyta). This, added to what was already known for this reef totalizes 110 species. Of those, 74 species correspond to first citations for this reef, being 43 Rhodophyta, 13 Phaeophyceae and 18 Chlorophyta. For the archipelago we found 149 spp. (59% Rhodophyta, 22% Phaeophyceae, 18% Chlorophyta and 1% Magnoliophyta). If we include the species that were reported to the archipelago by others, the flora amounts to 164 spp.. Our studies reported, for the first time to the archipelago, 59 taxa: 33 Rhodophyta, 11 Phaeophyceae, 14 Chlorophyta and 1 Magnoliophyta. The higher species diversity at the archipelago may be due to a higher ecological diversity and lower turbidity, but, perhaps also, to a lower human impact, what remains to be investigated. In comparison with other offshore islands and reefs along the Brazilian coast we have the following situation, in a decreasing order of species richness: archipelago Fernando de Noronha, Abrolhos archipelago, Sebastião Gomes reef, Rocas atoll, Trindade island and São Pedro & São Paulo islands. The work describes and illustrates the more relevant aspects of each species studied.
296

Marketing de lugares: estudo de impactos do recife artificial multifuncional / Place marketing: impacts study of the multipurporse artificial reef

Ocke, Marco Antonio de Moraes 24 August 2015 (has links)
Marketing de lugares se caracteriza como uma ferramenta para a gestão das trocas que ocorrem no âmbito territorial possibilitando o fortalecimento da competitividade e da imagem de uma determinada localidade através da geração e entrega de valor a seus diferentes mercados e da atração de investimentos que assegurem seu desenvolvimento no longo prazo. Neste cenário, esta pesquisa apresenta como objeto de estudo o recife artificial multifuncional, estrutura implantada em ambiente marinho com a finalidade de promover a proteção costeira, aprimorar as condições de surfe e criar novos habitats marinhos. Sob a perspectiva de marketing, o potencial benefício deste programa de ação está ancorado no desenvolvimento do lugar e na entrega de valor aos seus públicos a partir da manutenção da infraestrutura local de forma sustentável, da oferta de lazer aos usuários, do aumento do número de visitantes e do incremento da rede de serviços. Neste contexto, o objetivo da tese é a investigação dos impactos resultantes da implantação do recife artificial multifuncional e da relação entre as bases conceituais do marketing de lugares com suas implicações práticas a fim de incentivar o avanço desta linha de pesquisa, principalmente no Brasil, onde o conhecimento da área se encontra em estágio embrionário. Para tanto, a pesquisa qualitativa exploratória aqui presente se divide em duas partes. A primeira apresenta a revisão teórica abordando o conceito de marketing de lugares e três grandes blocos do marketing para fundamentar o raciocínio: produto, segmentação e posicionamento. A segunda parte desenvolve o estudo de caso da cidade de Gold Coast na Austrália contando com coleta de dados por meio de análise documental e entrevista. Os resultados observados na pesquisa indicam que a implantação do recife artificial multifuncional trouxe uma significativa contribuição para o desenvolvimento de longo prazo da localidade analisada e que grande parte das implicações práticas do marketing de lugares observadas no caso encontra-se alinhada à teoria revisitada. O estudo permite ainda sugerir recomendações para localidades que planejam implantar o recife artificial multifuncional em seus programas de ação. / Place marketing is characterized as a tool for the management of exchanges that take place in the territorial scope thus strengthening competitiveness and image of a particular place by generating and delivering value to its different markets and attracting investments to ensure its development in the long term. In this scenario, this research presents as the object of study the multipurpose artificial reef, a structure implemented in the marine environment in order to promote coastal protection, improve surfing conditions and create new marine habitats. From a marketing perspective, the potential benefit of this action program is anchored in place development and value delivering to its stakeholders, through the maintenance of local infrastructure in a sustainable way, the leisure offer to users, increasing the number of visitors and the enhance in services network. In this sense, the objective of the thesis deals with the investigation of impacts resulting from the implementation of multipurpose artificial reef and the relationship between the conceptual bases of place marketing with its practical implications in order to encourage the advancement of this field of research, especially in Brazil, where knowledge of the area is in the embryonic stage. To that end, the exploratory qualitative research hereby is divided into two parts. The first presents a theoretical review addressing place marketing concept and three major marketing blocks to support the reasoning: product, targeting and positioning. The second part develops the case study of Gold Coast City in Australia relying on data collection through documents analysis and interview. The results from this research indicate that the implementation of the multipurpose artificial reef brought a significant contribution to the long term development of the place in analysis and much of the practical implications of place marketing observed in the case are in line with theory revisited. The study also allows suggesting recommendations for places planning to deploy multipurpose artificial reef in their action programs.
297

Isolation of briareolate esters from Briareum asbestinum

Unknown Date (has links)
by Rian J. Meginley. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader. / The gorgonian Briareum asbestinum is widely studied because it possesses highly oxygenated novel structures, many of which exhibit useful biological activities. Recently, two new briarane diterpenoids, briareolate esters J and K, together with two known briareolate esters have been isolated from a specimen of Briareum asbestinum collected off the coast of Boca Raton, Florida. The method used was a 96-well plate real-time cell electronic sensing (RT-CES) system to discover compounds that impact human embryonic stem cell growth. The compounds were isolated using reversed phase polystyrene divinylbenzene chromatographic support HP20ss followed by normal phased HPLC using a luna silica column. The structures of the compounds were established though the interpretation of spectroscopic data. Activity testing was conducted against hESCs (BG02) with briareolate ester J showing no inhibition activity and briareolate ester K showing mild activity with an EC50 value of 25 (So(BM. These results confirm that the exact confirmation and existence of the (E,Z)-dienone is related to the activity that was observed with the previously isolated briareolate esters L and M.
298

Determining temporal recording schemes for underwater acoustic monitoring studies

Lindseth, Adelaide Virginia 21 February 2019 (has links)
Soundscape Ecology, the physical combination of sounds at a particular time and place, is a rapidly growing field. As acoustic technology advances, several possible future uses of passive acoustic monitoring (PAM), such as biodiversity counts and monitoring of habitat health, are being explored. This thesis is divided into two chapters; each is a stand-alone paper. The first chapter provides a review of soundscape ecology, ambient sound, current recording methods and data analysis used in PAM studies, and identifies several major future recommendations for the field. One of these recommendations is to standardize recording methods and indices used during analysis in long-term studies. The second chapter analyzes a 55-minute continuous recording on a coral reef in Tunicate Cove, Belize in 1996 by Professor P. Lobel. This recording was then subsampled with several intermittent recording schedules to explore the amount of acoustic information lost as periods of active and inactive recording vary. The continuous recording consisted of a high frequency band (3-4 kHz), which may correspond to abiotic sounds, and a low frequency band (0.1-0.5 kHz), which generally corresponds to biotic sounds. Two recording schedules, 30 seconds every 4 minutes and 2 minutes every 10 minutes, were significantly correlated with the continuous recording. The statistical significance of the other five recording schedules varied among the three parameters tested in this study (average power (dB), average entropy, and aggregate entropy).
299

Impacts of anthropogenic noise on behaviour, development and fitness of fishes and invertebrates / Étude des bruits anthropiques sur le comportement, le développement et le fitness des poissons et des invertébrés

Nedelec, Sophie 17 August 2015 (has links)
Dans la première partie de ma thèse, je fournis un programme informatique qui permet aux utilisateurs de déterminer dans quelles circonstances ils doivent mesurer le mouvement des particules. J’explique comment ces mesures peuvent être effectuées et fournissent un programme pour analyser ce type de données. La partie principale de ma thèse comprend des expériences portant sur l'impact de l'exposition répétée au bruit du trafic, la source anthropique la plus courante de bruit dans l'environnement marin, sur les poissons et les invertébrés pendant leur développement. Je démontre qu’une variété de comportements a été touchée par le bruit. J’ai aussi trouvé que le bruit prévisible peut conduire à des impacts différents sur le développement par rapport au bruit imprévisible, mais que certaines espèces de poissons peuvent être en mesure de s'habituer au bruit du trafic, tandis que d'autres non. En outre, je trouve que le développement et la survie des limaces de mer peuvent être impactés négativement par le bruit des bateaux. Les poissons et les invertébrés constituent une source de nourriture vitale pour des millions de personnes et constituent des liens essentiels dans de nombreux réseaux trophiques. L'étude de leur comportement, de développement et de remise en forme peut nous donner un aperçu des impacts de la population et le niveau de bruit de la communauté qui sont pertinents pour la survie des espèces et l'évolution. Le développement de certaines des nouvelles idées et techniques abordées dans cette thèse nous permettra de faire progresser ce domaine vital de la recherche. / As the first part of my thesis, I provide a computer program which allows users to determine under what circumstances they should measure particle motion; I explain how these measurements can be made and provide a program for analysing this type of data. The main part of my thesis comprises experiments investigating the impact of repeated exposure to traffic noise, the most common anthropogenic source of noise in the marine environment, on fishes and invertebrates during development. In all three chapters involving experiments on fish in tanks and in the field, I found that a variety of behaviours were impacted by traffic noise playback. I also found that predictable noise can lead to different impacts on development compared to unpredictable noise, but that some species of fish may be able to habituate to traffic noise, while others suffer lower survival. Further, I found that the development and survival of seahares can be negatively impacted by traffic-noise playback. Fishes and invertebrates provide a vital food source to millions of people and form crucial links in many food webs; studying their behaviour, development and fitness can give us an insight into population and community level impacts of noise that are relevant to species survival and evolution. Developing some of the novel ideas and techniques discussed in this thesis will enable us to advance this vital area of research.
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Depositional and palaeoecological characteristics of incipient and submerged coral reefs on the inner-shelf of Australia's Great Barrier Reef

Johnson, James January 2017 (has links)
Understanding how coral reefs have developed in the past is crucial for placing contemporary ecological and environmental change within appropriate reef-building timescales (i.e. centennial to millennial). On Australia’s Great Barrier Reef (GBR), coral reefs situated within nearshore settings on the inner continental shelf are a particular priority. This is due to their close proximity to river point sources, and therefore susceptibility to reduced water quality as the result of extensive modification of adjacent river catchments following European settlement in the region (ca. 1850 CE). However, the extent of water quality decline and its impact on the coral reefs of the GBR’s inner-shelf remains contentious and is confounded by a paucity of long-term (> decadal) datasets. Central to the on-going debate is uncertainty related to the impact of increased sediment loads, relative to the natural movement and resuspension of terrigenous sediments, which have accumulated on the inner-shelf over the last ~6,000 years. The main aim of this thesis was to characterise and investigate the vertical development of turbid nearshore coral reefs on the central GBR. This aim was achieved through the recovery of 21 reef cores (3 - 5 m in length) from five proximal turbid nearshore reefs, currently distributed across the spectrum of reef ‘geomorphological development’ within the Paluma Shoals reef complex (PSRC). The recovered reef cores were used to establish detailed depositional and palaeoecological records for the investigation of the (1) internal development and vertical accretionary history of the PSRC; and (2) compositional variation in turbid nearshore coral and benthic foraminiferal assemblages during vertical reef accretion towards sea level. Established chronostratigraphic and palaeoecological records were further used to assess the impact of post-European settlement associated water quality change in a turbid nearshore reef setting on the central GBR. Radiocarbon dating (n = 96 dates) revealed reef initiation within the PSRC to have occurred between ~2,000 and 1,000 calibrated years before present, with subsequent reef development occurring under the persistent influence of fine-grained (< 0.063 mm) terrigenous sediments. The internal development of the PSRC was characterised by discrete reef facies comprised of a loose coral framework with an unconsolidated siliciclastic-carbonate sediment matrix. A total of 29 genera of Scleractinian coral and 86 genera of benthic foraminifera were identified from the palaeoecological inventory of the PSRC. Both coral and benthic foraminiferal assemblages were characterised by distinct assemblages of taxa pre-adapted to sediment stress (i.e. low light availability and high sedimentation). At the genus level, no discernable evidence of compositional change in either coral or benthic foraminiferal assemblages was found, relative to European settlement. Instead, variations in assemblage composition were driven by intrinsic changes in prevailing abiotic conditions under vertical reef accretion towards sea level (e.g. hydrodynamic energy, light availability, and sedimentation rate). These findings therefore highlight the importance for considering reef ‘geomorphological development’ when interpreting contemporary reef ecological status. Furthermore, this research emphasises the robust nature of turbid nearshore reefs and suggests that they may be more resilient to changes in water quality than those associated with environmental settings where local background sedimentary conditions are less extreme (e.g. towards the inner/mid-shelf boundary). To this end, this thesis presents new baseline records with which to assess contemporary ecological and environmental change within turbid nearshore settings on the central GBR.

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