To see the other types of publications on this topic, follow the link: Bryozoa.
Dissertations / Theses on the topic 'Bryozoa'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Bryozoa.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Tsyganov-Bodounov, Anton. "Molecular systematics of Bryozoa." Thesis, Swansea University, 2008. https://cronfa.swan.ac.uk/Record/cronfa43148.
Full text
2
Markham, J. B. "Studies on feeding in Bryozoa." Thesis, Swansea University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638002.
Full textAbstract:
Procedures to reduce errors in Coulter analyses - In counts of suspensions of algae and inert particles made with a negative external electrode (EE), neither total number of particles per unit volume of suspension nor mean cell or particle volume (MCV) ever changed. In contrast, a count made with a positive EE exhibited a substantial change in MCV. A review of published investigations of damage to red blood corpuscles caused by a count suggests that they are affected in a similar way. Function of the gizzard in Bryozoa - Five gizzard-bearers frequently displayed significantly greater ability to break diatom frustules, when compared with two other bryozoans. The species lacking a gizzard have good ability to separate valves of some diatoms frustules, even to the extent of equalling the percentage broken by the gizzard of Bowerbankia. However, bryozoans that possess a gizzard are small, too small to ingest a majority of the common diatoms. Selection of food by two marine bryozoans - The preferences of Electra pilosa and Flustrellidra hispida have been investigated. E. pilosa, offered mixtures of algae and pollen, did not distinguish between pollen and algal cells but preferentially selected foods of 15-40 um diameter. E. pilosa appears able to select particles with regard to size but not taste, and preferences are affected by total but not relative food concentration. E. pilosa and F. hispida have lophophores of greatly different size, but preferentially selected similar size categories from seston. These were those sizes most abundant in local seawater samples. Optimal design of the bryozoan lophophore - The lateral cilia of Flustrellidra hispida close the intertentacular gap over the proximal 30%, or less, of the length of the gap. A method was developed to study optimal design, and used to determine which characteristics of funnel morphology are optimized by natural selection.
3
Fisher, E. M. "Competition for food in the Bryozoa." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279719.
Full text
4
Vieira, Leandro Manzoni. "Sistemática e distribuição dos briozoários marinhos do litoral de Maceió, Alagoas." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-12122008-103654/.
Full textAbstract:
Os briozoários compreendem um Filo de invertebrados geralmente coloniais, com aproximadamente 5.500 espécies descritas no mundo e apenas 346 relatadas para o Brasil. O presente trabalho trata do conhecimento sobre a diversidade de briozoários marinhos de águas rasas do Município de Maceió, Estado de Alagoas, incentivado pela carência de estudos na costa Nordeste do Brasil. Com os objetivos redescrever os táxons encontrados em Maceió e estudar suas variações morfológicas e distribuição espacial de acordo com o substrato ocupado pelas colônias, espécimes de briozoários foram coletados em 9 pontos no litoral de Maceió, em diferentes épocas do ano, durante períodos de marés baixas de sizígia. As colônias foram retiradas de diferentes substratos: seixos, rochas, algas, hidróides, ascídias, corais, poríferos, conchas, tubos de poliquetas, cracas e e construções antropogênicas. A identificação dos espécimes foi baseada em literatura específica e na comparação com materiais provenientes de outras regiões do Atlântico. Os espécimes foram estudados morfológica e morfometricamente quanto a caracteres macro e microscópicos, utilizando microscopia óptica e microscopia eletrônica de varredura. Foram encontradas 65 espécies, classificadas em 44 gênero e 36 famílias, com apenas dois táxons identificados no nível de família ou superior (uma espécie de Schizoporellidae e uma espécie de Lepraliomorpha). Duas espécies tiveram classificação incerta (Bowerbankia ?maxima e Bowerbankia aff. gracilis), e outras 20 espécies (32,5%) foram classificadas até o nível de gênero: Jellyella(1), Biflustra (1), Nellia (1), Bugula (2), Beania (1), Scrupocellaria (2), Puellina (1), Hippothoa (1), Trypostega (1), Reptadeonella (1), Celleporaria (1), Parasmittina (1), Hippoporina (1), Stylopoma (2), Cosciniopsis, (1),
5
Tischler, Mark. "Secondary metabolites from selected British Columbian marine organisms." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26650.
Full textAbstract:
The two purine alkaloids, phidolopin (36) and desmethylphidolopin (37), originally isolated from Phidolopora pacifica, were synthesized in order to produce sufficient quantities of the natural products for extended biological and pharmacological screening and to confirm the previous structural assignment of 37 which was based on spectral data.
Various combinations of phidolopin (36), desmethylphidolopin (37), 4-hydroxymethyl-2-nitrophenol (38) and 4-methoxymethyl-2-nitrophenol (39) were isolated from four different species of bryozoans, Diaperoecia californica, Heteropora alaskensis, Tricellaria ternata and Hippodiplosia insculpta. A dietary origin is suggested for these metabolites. The red sponge, Anthoarcuata graceae yielded six novel steroids including the ∆⁴-3,6-diketosteroids 116, 117, the A-nor steroids anthosterone A (118) and anthosterone B (119) as well as two diosphenol containing steroids, 120 and 121. The proposed structures were based on a combination of spectral analysis, chemical interconversions, synthesis, and single crystal X-ray diffraction analysis.Science, Faculty of
Chemistry, Department of
Graduate
6
Boonzaaier, Melissa Kay. "Diversity and Zoogeography of South African Bryozoa." University of the Western Cape, 2017. http://hdl.handle.net/11394/6308.
Full textAbstract:
Philosophiae Doctor - PhD (Biodiversity and Conservation Biology)The taxonomic history of South African bryozoans is fragmented and outdated, with the majority of published works in the 20th Century. Sampling gaps exist in deep-sea regions and parts of the coastline, while existing collections within museums remain undetermined due to scarcity of specialist taxonomists. This project forms part of a larger project aimed at updating marine invertebrate biodiversity in South Africa. Outcomes of this project include updating bryozoan biodiversity by identifying species from existing collections housed in natural history museums (e.g., Iziko South African Museum, Cape Town and Natural History Museum, London), and analysing current regional bryozoan biogeographical and depth-related species richness patterns. The biogeography and richness of bryozoan species around South Africa was investigated using published distribution records from the literature and museum catalogues as well as examining un-worked bryozoan material from Iziko South African Museum. A total of 368 species of bryozoans were recorded, including twelve new species (Favosipora epiphyta sp. nov., Chaperiopsis (Chaperiopsis) yinca sp. nov., Aspidostoma staghornea sp. nov., Micropora erecta sp. nov., Trypostega infantaensis sp. nov., Khulisa ukhololo sp. nov., Adeonella assegai sp. nov., Celleporaria umuzi sp. nov., Hippomonavella lingulatus sp. nov., Microporella lezinyosi sp. nov., Phidolopora cyclops sp. nov. and Reteporella ilala sp. nov.) and 70 unidentified species. Distribution data for 286 valid species were separated by depth zones (shallow waters, subphotic zone, shelf edge, bathyal zone and abyss) and four biogeographic regions are recognised a priori around South Africa, namely the west, south, southeast and east coasts. This study revealed that there is a clear biogeographic structure to regional bryozoan fauna of South Africa. Species richness and endemism appear lowest on the west coast (104 species) and highest on the south coast (174 species), while local peaks are observed in the Cape Peninsula/False Bay area, East London, Durban and St. Lucia, which coincide with distinct genetic lineages for some marine taxa (e.g. octocorals, chitons, echinoderms, fishes, seaweeds). Although, the faunal break in Durban does not represent a peak in species richness in this study, but rather very low bryozoan richness, highlighting the undersampled areas north of Durban. The northward-flowing Benguela Current and strong upwelling centres may influence the low diversity on the west coast. On the south coast, the high diversity may be attributed to the Agulhas Current that can carry larvae southwards and eastward-flowing counter currents produce great variability in bryozoan communities in this region. Within any biogeographic region, bryozoan diversity was higher in shallower (< 500 m) than deeper waters, which may be attributed to sampling effort and heterogeneity (e.g. variable substrate and wave action) in shallower waters. Keywords: Bryozoa, distribution patterns, gradients, species richness, South Africa
7
Bayer, Micha. "Genetic determinism, inducible morphology and phenotypic plasticity in the marine bryozoan Electra pilosa (L.)." Thesis, University of St Andrews, 1998. http://hdl.handle.net/10023/14623.
Full textAbstract:
The marine bryozoan Electra pilosa typically inhabits ephemeral substrata in the intertidal and shallow subtidal, and is probably the ecologically most successful bryozoan species in British waters. Modular organisms like E. pilosa frequently evolve pronounced phenotypic plasticity to cope with the ecological challenges resulting from passive larval dispersal into unpredictable habitats, and temporal variability of the environment colonized by the immobile adult stage. E. pilosa colonies on wave-exposed shores differ morphologically from those found on sheltered shores in possessing numerous long-spined zooids. The present study demonstrates that spine formation in E. pilosa is environmentally inducible by wave-related abrasion by macroalgae; additionally, the spines also have a fortuitous anti-predator effect in discouraging predation by the nudibranchs Adalaria proxima and Polycera quadrilineata. It is suggested that the inducible spines of E. pilosa constitute an adaptation for the protection of feeding polypides in high-energy environments, and that plasticity for the trait is of adaptive value in this organism which exploits a diverse range of habitats. Although a number of traits in this species clearly are subject to considerable phenotypic plasticity, other attributes apparently are highly deterministic, heritable and genotype-specific. Electra pilosa displays pronounced among-genotype variation in colony growth rate, and the present study shows that this variation is due to proximate factors which affect growth rate and covary with genotype. This study also presents the first evidence of senescence at the zooid level in E. pilosa: Zooids deteriorate systematically over time, as indicated by decreasing polypide life spans and increasing polypide regeneration times, but in contrast to this, whole-organism senescence does not appear to occur in this species.
8
Nascimento, Karine Bianca. "Investigação do padrão de distribuição do briozoário cosmopolita Zoobotryon verticillatum (Ctenostomata, Vesiculariidae), através de dados moleculares." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-24092015-103445/.
Full textAbstract:
Zoobotryon verticillatum (delle Chiaje, 1822) é um briozoário cosmopolita amplamente distribuído em regiões tropicais e temperadas em todos os oceanos. Por possuir meios de distribuição natural restritos, é possível supor que o táxon se trate de um complexo de espécies crípticas ou de uma espécie vastamente introduzida por ação antrópica. Para elucidar essa questão, foram realizadas análises populacionais e filogenéticas utilizando-se dois genes mitocôndrias, citocromo c oxidase subunidade 1 região 3\' (COI-3P) e subunidade ribossomal RNA 16S (16S). As análises filogenéticas suportaram o monofiletismo de Z. verticillatum e, juntamente com as análises populacionais, indicam que é uma única espécie distribuída mundialmente. A falta de uma estrutura geográfica evidente nas redes haplotípicas, a ausência majoritária de relacionamentos dicotômicos e clados altamente suportados (pp >= 5%) nas árvores filogenéticas, a falta de resultados significativos na maioria dos teste D e Fs realizados, a baixa diversidade genética em nível populacional e a falta de diferenciação genética entre a maioria das populações comparadas são compatíveis com um processo distribuição antrópico para Z. verticillatum. No entanto, com base nos resultados obtidos durante esta pesquisa, não é possível inferir um possível centro de dispersão ou local de origem para a espécie.Zoobotryon verticillatum (delle Chiaje, 1822) is a cosmopolitan bryozoan largely distributed in tropical and temperate waters of all oceans. With limited natural dispersal capabilities, it is reasonable to suppose that the taxon is a complex of cryptic species or a widespread species due to anthropogenic activity. In order to elucidate this question, analyses of two mitochondrial genes, cytochrome c oxidase subunit 1 (COI) and ribosomal RNA subunit (16S) were conducted. Phylogenetic data supported the monophyletism of Z. verticillatum and, together with the population analysis, indicated that it is one species with worldwide distribution. The absence of geographical structure in the haplotype networks, the majority absence of dichotomous relationships, and highly supported clades (pp >= 5%) in phylogenetic trees, the lack of significance in the D test and Fs statistics, the low genetic diversity at the population level and the lack of genetic differentiation between most of the population comparison are consistent with anthropogenic introduction process for Z. verticillatum. However, based on the results obtained during this study, it is not yet possible to infer the center of dispersion for the species.
9
Vieira, Leandro Manzoni. "Revisão taxonômica do gênero Scrupocellaria van Beneden (Bryozoa, Candidae)." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-01052013-152058/.
Full textAbstract:
O gênero Scrupocellaria senso lato (Família Candidae) compreende Ca. 92 espécies, 20 fósseis e 72 recentes. Muitas dessas espécies são morfologicamente semelhantes ou tratadas como tendo grande plasticidade morfológica, as quais consequentemente têm ampla distribuição mundial. Embora o gênero tenha uma longa história taxonômica e seus representantes sejam abundantes e comuns desde as regiões entremares até mais de 1,000 metros de profundidade, estudos taxonômicos do gênero são escassos. Os objetivos desse estudo são: (i) realizar o levantamento das espécies de Scrupocellaria, (ii) delimitar a variação morfológica intraespecífica das espécies, (iii) analisar a morfologia comparada de Scrupocellaria visando propor uma hipótese de relações filogenéticas entre as espécies do gênero. O estudo inclui colônias coletadas em vários pontos da costa brasileira, bem como espécimes depositados em coleções científicas nacionais e internacionais. Alguns espécimes foram selecionados para observação em Microscópio Eletrônico de Varredura. Entre os espécimes estudados foram incluídos 32 holótipos, sintipos de 22 espécies e 1 lectótipo. Várias estruturas morfológicas foram utilizadas pela primeira vez na distinção dos táxons, e.g. forma da superfície dos rizoides, tamanho dos vibraculários basais, tamanho e forma dos aviculários frontais e laterais. O lectótipo de Scrupocellaria reptans foi escolhido para redefinir a identidade dos espécimes descritos por Carolus Linnaeus, distintos de uma nova espécie descrita para o Mar do Norte pela forma do escudo, tamanho dos zooides e rizoides cilíndricos sem ganchos em sua superfície. Scrupocellaria jolloisii é relatada pela primeira vez no Atlântico e classificada no gênero Licornia, nome que é ressuscitado para incluir outras 9 espécies: Licornia annectens n. comb., Licornia cervicornis n. comb., Licornia cyclostoma n. comb., Licornia diadema n. comb., Licornia ferox n. comb., Licornia gaspari n. comb., Licornia longispinosa n. comb., Licornia macropora n. comb. e Licornia prolata n. comb. Um novo gênero, N.gen.1, é criado para acomodar Scrupocellaria bertholletii (Audouin, 1826). Outras 26 espécies, 19 das quais descritas como novas, são classificadas em N.gen.1, e uma chave dicotômica para as espécies do gênero é apresentada. Um estudo filogenético, baseado em 35 caracteres morfológicos de 84 espécies de Candidae, indica que o gênero Scrupocellaria compreende um táxon polifilético e que o gênero N.gen.1 é monofilético. Scrupocellaria \'sensu stricto\' é redefinido utilizando quatro características morfológicas: câmara vibracular com sulco do vibráculo curvo e obliquo, ectooécio com fenestra frontal, 2 vibraculários axiais e opérculo membranoso com margem distal distinta. Assim, Scrupocellaria \'sensu stricto\' inclui 10 espécies: Scrupocellaria aegeensis, Scrupocellaria delilii, Scrupocellaria harmeri, Scrupocellaria incurvata, Scrupocellaria inermis, Scrupocellaria intermedia, Scrupocellaria jullieni, Scrupocellaria minuta, Scrupocellaria scrupea, e Scrupocellaria scruposa. Cinco gêneros são criados para acomodar outras espécies classificadas anteriormente como Scrupocellaria, distintos pela forma do escudo e espinhos orais, forma do vibraculários e forma dos ovicelos. O presente estudo revelou uma diversidade ainda desconhecida para vários grupos de Candidae, e mostra a necessidade de mais estudos sobre a taxonomia e filogenia da família, para a melhor compreensão da distribuição, variação morfológica e relação filogenética entre os táxonsThe genus Scrupocellaria sensu lato (Family Candidae) comprises about 92 species, 20 fossil and 72 Recent. Many of the species are morphologically similar or have been treated taxonomically as having a high degree of morphological plasticity, with distributions of many of the species being reported to be \"worldwide\". Despite the long taxonomic history of Scrupocellaria and its occurrence in habitats ranging from intertidal to deep water, taxonomic studies of the genus are scarce. Therefore the purpose of this study was: (i) to carry out a species survey of Scrupocellaria, (ii) to delimit the intraspecific morphological variations of species, (iii) to analyze the comparative morphology of Scrupocellaria in order to propose a hypothesis of phylogenetic relationships between species of the genus. This study included both colonies collected in various localities on Brazilian coast and material of non-Brazilian species deposited at scientific collections around the world. All specimens were studied by light microscopy. Some specimens were also chosen for study with the scanning electron microscope. Specimens studied included holotypes of 32 species, syntypes of 22 species and 1 lectotype. Some morphological characters were used for the first time to distinguish taxa, e.g. rhizoidal surface, size of abfrontal vibracula, and shape of lateral and frontal avicularia. The lectotype of Scrupocellaria reptans was selected to redescribe and define the identity of the type species of Scrupocellaria from specimens described by Carolus Linnaeus, and to show its distinction from a newly described species from North Sea by means of the shape of scuta, size of zooids and, occurence of rhizoids with retroussé hooks. Scrupocellaria jolloisii is reported by first time in the Atlantic Ocean and placed in the genus Licornia, a name resurrected to acommodate 9 species formerly placed in Scrupocellaria: Licornia annectens n. comb., Licornia cervicornis n. comb., Licornia cyclostoma n. comb., Licornia diadema n. comb., Licornia ferox n. comb., Licornia gaspari n. comb., Licornia longispinosa n. comb., Licornia macropora n. comb. e Licornia prolata n. comb. A new genus, N.gen.1, is described to include Scrupocellaria bertholletii. Twenty-six species, 19 of them described as new, are assigned to N.gen.1, and a taxonomic key for species of that genus is presented. A phylogenetic study using 35 morphological characters of 84 Candidae species suggests that the genus Scrupocellaria is a polyphyletic taxa and the genus N.gen.1 is a monophyletic taxa. Scrupocellaria \'sensu stricto\' is redefined according to four morphological features: vibracular chamber with curved setal groove, ooecium with a single ectooecial fenestra, two axillary vibracula and a membranous operculum with a distinct distal rim. Thus Scrupocellaria \'sensu stricto\' includes 10 species: Scrupocellaria aegeensis, Scrupocellaria delilii, Scrupocellaria harmeri, Scrupocellaria incurvata, Scrupocellaria inermis, Scrupocellaria intermedia, Scrupocellaria jullieni, Scrupocellaria minuta, Scrupocellaria scrupea, and Scrupocellaria scruposa. Five genera are erected to include other species previously assigned to Scrupocellaria; they are distinct in the shape of scuta and oral spines, the shape of vibracular chamber and the surface of ovicells. The study revealed a high diversity in some groups of Candidae and the necessity of additional studies on taxonomy and phylogeny of the family to provide a better understanding of distributions, morphological variation, and phylogenetic relationships between the taxa
10
Sabri, Zakaria. "Révision systématique du genre Lichenopora Defrance, 1823 (Bryozoa, Cyclostomata)." Lyon 1, 1988. http://www.theses.fr/1988LYO11763.
Full textAbstract:
Ce travail porte sur la revision systematique du genre lichenopora defrance 1823. On discute la validite du genre disporella considere comme synonyme de lichenopora; deux groupes ont ete identifie: les lichenopores discoides et les lichenopores lamellaires. On precise la repartition stratigraphique de quatre especes, la repartition paleogeographique du genre lichenopora du cretace jusqu'a l'actuel ainsi que les tendances evolutives et les liens phyletiques existants entre certaines especes
11
Snell, Joanna Frances. "Palaeobiology of Bryozoa from the Much Wenlock limestone formation." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246486.
Full text
12
Sabri, Zakaria. "Révision systématique du genre Lichenopora, Defrance, 1823, Bryozoa, Cyclostomata." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37618334n.
Full text
13
Watts, Phillip Charles. "Population-genetic and biogeographic consequences of dispersal in cheilostome Bryozoa." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364350.
Full text
14
Paquette, Lance. "Phylogenetic analysis of the bryozoan Suborder Rhabdomesina." Diss., Connect to online resource - MSU authorized users, 2008.
Find full text
15
Gruhl, Alexander [Verfasser]. "Phylogenetic significance of mesodermal and neural structures in Bryozoa / Alexander Gruhl." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1023095785/34.
Full text
16
Carter, Michelle Clare. "The functional morphology of avicularia in cheilostome bryozoans : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy in Marine Biology /." ResearchArchive@Victoria e-Thesis, 2008. http://hdl.handle.net/10063/747.
Full text
17
Schmidt, Rolf. "Eocene bryozoa of the St Vincent Basin, South Australia - taxonomy, biogeography and palaeoenvironments /." Title page, abstract and contents only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phs3491.pdf.
Full textAbstract:
Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Geology and Geophysics, 2003?Includes Publication list by the author as appendix A. "July 2003." Includes bibliographical references (leaves 308-324).
18
Best, M. A. "Some aspects of the ecology and physiology of feeding in marine bryozoa." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354539.
Full text
19
Hatton-Ellis, Tristan Willmott. "The molecular ecology of Cristatella mucedo (Bryozoa: phylactolaemata) in space and time." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388021.
Full text
20
Fairall, Victor Roger. "A study of the colonial organisation of two species of arborescent cellularine Bryozoa." Thesis, Swansea University, 2004. https://cronfa.swan.ac.uk/Record/cronfa43194.
Full textAbstract:
The central aim of the study was to describe the spatial arrangement of the zooids within a colony of Scrupocellaria reptans, in sufficient detail to reveal previously undescribed characteristics. A rudimentary population study used monthly sampling to ascertain basic biological characteristics of the species. These included settlement period, colony size changes over time and longevity. Settlement period was June to August; colonies were annual, but suffered extensive partial mortality mid-winter. The inadvertent collection of Tricellaria inopinata, a species new to Britain, by a colleague, necessitated an investigation into its confused taxonomy, via the literature and historical and recent material. The species was differentiated from two similar species. A detailed study was made of the spatial arrangement of autozooids and polymorphic heterozooids within a colony of S. reptans. The arrangement of autozooids could reveal details of colony structure, whilst that of polymorphs, not easily ‘understood’, could suggest new lines of enquiry. The methodology involved ‘mapping’ the spatial arrangement of zooids within a colony, in respect of a number of parameters, in such a way that they could be investigated singly or in any condition. A similar study was made in respect of T. inopinata. Did any new characteristics of S. reptans occur more widely? Colonies of both species had a definite structure and form. The structure, which involved a small number of long sequences of short ‘internodes’, from each of which laterally limited ‘aggregations’ of short sequences, of generally longer ‘internodes’, developed, essentially the same in both species. The form was slightly different. Polymorphs occurred constantly, predictably or unpredictably. The spatial arrangement of the latter was very complex.
21
Ricciardi, Anthony. "Taxonomy, distribution and ecology of the freshwater sponges (Porifera:Spongillidae) and bryozoans (Ectoprocta) of eastern Canada." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61081.
Full textAbstract:
Specimens of freshwater bryozoans (Ectoprocta) and sponges (Porifera: Spongillidae), two of the most poorly known faunal groups in Canada, were obtained from various locations in Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland. A total of 14 species of bryozoans and 15 species of sponges were identified. In 31 cases, these species were recorded from a province for the first time. Species new to Canada include the bryozoans Lophopodella carteri, Plumatella orbisperma, and Pottsiella erecta, and the sponges Radiospongilla crateriformis, Spongilla aspinosa, and Trochospongilla horrida. The morphology, taxonomy, distribution, and ecology of each species are examined. Several taxonomic revisions are made. Eunapius mackayi and Plumatella orbisperma are redescribed. Spongilla heterosclerifera, considered an endangered species, is shown to be a species mixture. Taxonomic keys to Eastern Canadian species of freshwater bryozoans and sponges are presented. New limits of tolerance to pH, calcium and magnesium levels, and water temperature are established for several species.
22
Davidson, Seana Kelyn. "Biology of the bryostatins in the marine bryozoan Bugula neritina : symbiosis, cryptic speciation and chemical defense /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035405.
Full text
23
Southwood, David Ashley. "The taxonomy and palaeoecology of Bryozoa from the Upper Permian Zechstein Reef of N.E. Eng1and." Thesis, Durham University, 1985. http://etheses.dur.ac.uk/6816/.
Full textAbstract:
Eighteen species of Bryozoa are described from the Upper Permian zechstein reef - they are assigned to ten genera in the Orders Fenestrata, Trepostomat and cyclostomata. Emended diagnoses are given at various levels and superspecific taxonomic categories within the Fenestrata are discussed. The examination of type specimens and of a large suite of new material has allowed the limits of intraspecific morphological variability to be defined and has resulted in the synonymising of several species. Three new taxa are described, for which holotypes have been designated :- Ryhopora delicata gen. nov., sp. nov. Acanthocladia magna sp. nov. and Penniretepora waltherinodata subsp. nov. The genera Penniretepora and Kalvariella Are recorded for the first time from the Zechstein reef in N.E. England. Aspects of bryozoan palaeobiology And functional morphology have been inferred at zooid and colony level. A type of ovicell, new in the Fenestrata, is described and is compared with those of the Cheilostomata; the taxonomic significance of this chAracter is assessecl. Patterns of zooid-generated feeding currents are inferred and some correlation of intraspecifically varying zoarial morphology with environment is suggested. The characteristic distribution of Bryozoa in relation to Zechstein reef sub-environments is described. An analysis of species abundance and diversity demonstrates a marked faunal impoverishment in reef-flat communities; new evidence for contemporaneous reef lithification is assessed.
24
Sogot, Caroline Elizabeth. "Hard substrate communities across the K-Pg boundary." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648377.
Full text
25
Sanderson, William Guy. "Studies of influences on feeding in Antarctic and temperate Bryozoa : conducted in the British Isles." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386963.
Full text
26
Knowles, Tanya. "Fossil cheilostome Bryozoa of the mid-Pliocene North Atlantic and the interference of environmental regimes." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501324.
Full textAbstract:
The mid-Pliocene warm period (3.29-2.97 Ma) was a time broadly characterised by global warmth and high sea levels. It represents the last time in Earth history when the level of atmospheric CO2 was similar to today (~ 380 ppm) and as such, it may provide a model for future global warming. The Mean Annual Range of Temperature (MART) experienced by a bryozoan colony can be estimated utilising the inverse relationship between zooid size in cheilostome bryozoans and water temperature at the time of budding (O'Dea and Okamura, 2000a). In this study the technique is applied to Pliocene bryozoan material from the UK, US Coastal Plain, Florida and the Isthmus of Panama. Absolute temperatures have been reconstructed from stable isotopic analyses performed on bryozoans from a number of sites. This technique relies on the principle that the skeletal material is secreted in isotopic equilibrium with seawater. The lighter oxygen isotope, ¹⁶0, is preferentially incorporated into the skeleton during warmer temperatures therefore the ratio of ¹⁶0:¹⁸0 can act as a thermometer allowing temperature of the water at the time of skeleton formation to be inferred. Data from a range of latitudes provide information about shelf sea temperatures, and are found to be consistent with outputs from mid-Pliocene scenarios generated by numerical models of climate (General Circulation Models).
27
Swezey, Daniel Sergio. "Ocean Acidification on the California Coast| Responses of Marine Bryozoa to a High CO2 Future." Thesis, University of California, Davis, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10036209.
Full textAbstract:
As a result of human activities, the level of CO2 in the Earth’s atmosphere has increased by nearly 40% since the industrial revolution. The rate of green house gas emission is accelerating, with current trends exceeding those predicted by “worst case” global climate change scenarios. The chemistry of the ocean is fundamentally changing as a result of increasing atmospheric CO2, which dissolves in seawater, making it more acidic, a process referred to as ocean acidification (OA). A rapidly expanding body of science is now being generated to understand the impact of this global environmental change. To date, most studies evaluating OA effects have centered on simplified laboratory analyses that expose single populations to short-term treatments in order to quantify responses of individuals. These designs offer a limited assessment of the degree to which phenotypic plasticity and local adaptation might influence the response of populations to OA.
To address these questions, I carried out studies on members of Phylum Bryozoa, a species-rich clade of calcified colonial marine invertebrates distributed throughout the global ocean. Bryozoans were selected as a model system for this work because the clade exhibits a broad array of growth and calcification strategies, and because of the relative paucity of data regarding their expected response to future acidification. In addition, bryozoans can be subdivided into genetically identical replicate clones, which can then be assigned to separate treatments, allowing variation across treatments to be uniquely partitioned into the variance components of statistical models. In order to culture bryozoans for comparative experiments, I designed and constructed a new flow-through OA system at the Bodega Marine Laboratory, capable of finely manipulating both the temperature and carbonate chemistry of seawater, allowing for controlled laboratory experiments of long duration.
In Chapter 1, I performed a comparative 9-month laboratory experiment examining the effects of ocean acidification on the native Californian bryozoan Celleporella cornuta. C. cornuta was sampled from two regions of coastline that experience different oceanographic conditions associated with variation in the intensity of coastal upwelling. Under different CO2 treatments, the biology of this bryozoan was observed to be remarkably plastic. Colonies raised under high CO2 grew more quickly, invested less in reproduction, and produced skeletons that were lighter compared to genetically identical clones raised under current atmospheric values. Bryozoans held in high CO2 conditions reduced their investment in skeletal carbonate, changed the Mg/Ca ratio of skeletal walls and increased the expression of organic coverings that may serve a protective function. Differences between populations in growth, reproductive investment, and the frequency of organic covering production were consistent with adaptive responses to persistent variation in local oceanographic conditions.
In Chapter 2, I tested whether skeletal mineralogy can vary plastically in some invertebrates using the cosmopolitan bryozoan Membranipora tuberculata as a model. In a 6-month laboratory experiment, I cultured genetic clones of M. tuberculata under a factorial design with varying food availability, temperature, and dissolved CO2 concentrations. Elevated food availability increased growth in colonies while cold temperatures and high CO2 induced degeneration of colony zooids. However, colonies were able to maintain equivalent growth efficiencies under cold, high CO2 conditions, suggesting a compensatory tradeoff whereby colonies increase the degeneration of older zooids under adverse conditions, redirecting this energy to the maintenance of growth. Elevated food and cold temperatures also decreased Mg concentrations in skeletal material, and this skeletal material dissolved less readily under high CO2 conditions. This suggests that these factors interact synergistically to affect dissolution potential in this and other species.
Finally, in Chapter 3, I explore stable isotope values for δ 18O and δ13C in the calcium carbonate structures of the bryozoan Membranipora tuberculata. I tested whether this species accurately records both temperature and pH variability during periods of coastal upwelling by analyzing δ18O and δ 13C in colonies grown in the field and in controlled laboratory cultures. Field-grown colonies were out planted next to a Durafet® pH sensor, which provided a high-resolution record of the temperature and pH conditions these colonies experienced. δ13C was found to negatively co-vary with pH in both laboratory and field growth, and calculated field temperatures derived from laboratory δ18O temperature calibrations aligned with the records from the pH sensor. δ18 Oc values were more depleted under low pH in laboratory trials, which stands in contrast to patterns observed in other taxa. This may indicate that Membranipora utilizes bicarbonate ion (HCO 3-) in its calcification pathway, and could help explain why many bryozoan species appear to exhibit enhanced growth under high CO 2 conditions. (Abstract shortened by ProQuest.)
28
Eisenbarth, Sophie. "Isolierung, Strukturaufklärung und Untersuchungen zur Biosynthese von Sekundärmetaboliten aus Physarum polycephalum (Myxomycetes) und Pentapora fascialis (Bryozoa)." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-7626.
Full text
29
Dutra, Felipe de Souza. "Influência da heterogeneidade ambiental na aptidão e plasticidade fenotípica do briozoário marinho Schizoporella errata (Bryozoa, Cheilostomata)." reponame:Repositório Institucional da UFABC, 2015.
Find full textAbstract:
Orientador: Prof. Dr. Gustavo Muniz DiasDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Evolução e Diversidade, 2015.
Em ambientes heterogêneos, a evolução pode favorecer a plasticidade fenotípica como forma de aumentar a gama de condições nas quais os organismos podem sobreviver e reproduzir. Essa heterogeneidade pode ser o resultado da variação das condições naturais, mas atividades antrópicas também podem aumentar a heterogeneidade mesmo em pequenas escalas. Para saber como um organismo responde a essa heterogeneidade em pequena escala, investigamos a manifestação de diferentes fenótipos e as consequências da plasticidade fenotípica na aptidão do briozoário marinho Schizoporella errata frente a duas condições ambientais distintas ocasionadas por uma marina de recreação: no quebra-mar (maior hidrodinâmica) e no interior da marina (mais impactado). Realizamos dois experimentos: 1) no primeiro verificamos como as condições distintas dos dois locais influenciam os atributos relativos à aptidão de colônias de S. errata com duas idades (3 meses e 5 meses) e em dois momentos do ano. 2) No segundo, testamos se estes atributos são plásticos, através de um experimento de translocação recíproca utilizando clones de S. errata. Quando observamos diferenças no crescimento assexuado das colônias entre locais (períodos mais quentes), estas cresceram mais e apresentaram maior densidade de autozooides no quebra-mar. Já no interior da marina, as colônias investiram mais em reprodução sexuada. O investimento em defesa foi maior no segundo momento de experimentação, quando o percentual de colônias consumidas foi maior. As colônias apresentaram plasticidade em todos os atributos relativos à aptidão, com muita variação entre os genótipos. De modo geral, no quebra-mar os clones cresceram mais e tiveram maiores densidades de autozooides do que os do interior da marina corroborando o padrão descrito no primeiro experimento. Enquanto o investimento reprodutivo não variou entre os clones e locais de origem e destino, clones investiram mais em defesa no quebra-mar. As diferenças das condições ambientais entre os locais geraram efeitos variados na aptidão de S. errata, dependendo do momento do ano, da idade, do genótipo, mas principalmente da interação entre estes fatores. O hidrodinamismo no quebra-mar pode ter contribuído para o maior investimento em crescimento e densidade de autozooides, enquanto que no interior da marina o menor crescimento foi compensado pelo maior investimento reprodutivo, indicando uma possível demanda conflitante entre reprodução sexuada e assexuada. De forma geral, as alterações nas condições físicas e biológicas causadas pela construção da marina afetou a manifestação do fenótipo em S. errata, entretanto toda essa plasticidade diferiu entre indivíduos, indicando que dentro da população há uma grande variação na forma como o fenótipo é manifestado, o que explica porque Schizoporella errata é uma espécie invasora comum em muitos locais do mundo
In heterogeneous environments, evolution can promote phenotypic plasticity in order to increase the range of conditions in which the organisms can survive and reproduce. This heterogeneity can be caused by variation in the natural conditions, but human activities may also increase the heterogeneity even at small scales. To learn how the heterogeneity of environmental conditions affects the expression of different phenotypes and the consequences of phenotypic plasticity to the organisms fitness, we growth the marine bryozoan Schizoporella errata under two different environmental conditions caused by a recreational marina: on the breakwater, a more natural and hydrodynamic local and inside the marina, a more calm but disturbed place. We conducted two experiments: 1) on first we described how the different conditions of the two sites influence the attributes related to the fitness of S. errata with two different ages (3 months and 5 months) and two moments of the year. 2) On second we tested whether these attributes are induced by the environment, through reciprocal translocation of clones of S. errata. When the local affected clonal growth of colonies (warm periods), colonies reached larger size and zooid densities at the breakwater. However, inside the marina the colonies invested more in sexual reproduction. Investment in defense was higher in the second time trial, when the percentage of colonies consumed was higher. During the second experiment, the colonies showed plasticity in all studied traits, with large variation among genotypes. In general, clones in the breakwater grew more and had higher autozooids densities than those of the inside of marina, corroborating the pattern described in the first experiment. While the reproductive investment was not affected by the genotype, origin or destination, the clones invested more in defense in the breakwater. The differences of the environmental conditions between the sites, generated various effects on S. errata fitness, depending on the moment, age, genotype, but mainly on the interaction between these factors. The hydrodynamics on the breakwater may have contributed to the increased investment in growth and autozooids density, while inside the marina the lowest growth was offset by higher reproductive investment, indicating a possible trade-off between sexual and asexual reproduction. In general, changes in physical and biological conditions caused by marina construction affected the expression of phenotype in S. errata, however this plasticity differ between individuals, indicating that within the population there is great variation in how the phenotype is expressed, which explains why Schizoporella errata is a common invasive species in many parts of the world.
30
Bone, Elisa K. "Colonial integration and the maintenance of colony form in encrusting bryozoans /." Connect to thesis, 2006. http://eprints.unimelb.edu.au/archive/00003224.
Full text
31
CAVALCANTI, Thaynã Ewerlin Ribeiro. "Briozoofauna associada às esponjas em ambientes recifais (Pernambuco, Brasil)." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17960.
Full textAbstract:
Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-10-07T14:36:45Z
No. of bitstreams: 2
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
Dissertação_ThaynaCavalcanti_BiologiaAnimal_2016.pdf: 2263756 bytes, checksum: 798ca1c12e15256db092df9fe703fdaa (MD5)Made available in DSpace on 2016-10-07T14:36:45Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_ThaynaCavalcanti_BiologiaAnimal_2016.pdf: 2263756 bytes, checksum: 798ca1c12e15256db092df9fe703fdaa (MD5) Previous issue date: 2016-07-01
Briozoários são organismos sésseis e coloniais, que dependem de uma superfície firme para assentamento larval e crescimento da colônia. Entre os diferentes substratos disponíveis para briozoários, as esponjas podem oferecer uma superfície favorável, trazendo muitas vantagens como a presença de compostos químicos que inibem a predação. Este estudo verificou a presença de briozoários em seis espécies de esponjas, com finalidade de avaliar a abundância e riqueza desses briozoários em diferentes esponjas. Três espécimes das esponjas, Amphimedon compressa Duchassaing & Michelotti, 1864, Amphimedon viridis Duchassaing & Michelotti, 1864, Desmapsamma anchorata (Carter, 1882), Dysidea etheria de Laubenfels, 1936, Haliclona implexiformis (Hechtel, 1965) e Tedania ignis (Duchassaing & Michelotti, 1864) foram coletadas mensalmente entre setembro de 2014 e fevereiro de 2016, em Pontas de Pedra, Pernambuco, Brasil. Os briozoários encontrados foram identificados até o menor nível taxonômico possível e quantificados. Um total de 324 espécimes de esponjas foi analisado, no qual destas 88 apresentavam briozoários em sua superfície (27%). Onze espécies de briozoários pertencentes à Classe Gymnolaemata foram encontrados nas esponjas, sendo quatro pertencentes à Ordem Ctenostomata, Amathia distans Busk, 1886, Amathia verticillata (delle Chiaje, 1822), Amathia vidovici Heller,1867 e Nolella stipata Gosse, 1855, sete da Ordem Cheilostomata, Beania klugei Cook, 1968, Catenicella uberrima (Harmer, 1957), Caulibugula dendograpta (Waters, 1913), Licornia sp., Savignyella lafontii (Audoin, 1826), Synnotum aegyptiacum Canu & Bassler, 1928 e Thalamoporella floridana Osburn, 1940. Briozoários foram abundantes nas esponjas Te. ignis e De. anchorata e pouco frequentes em Ap. compressa e Ap. viridis. Desmapsamma anchorata e Te. ignis apresentaram a maior riqueza de espécies (nove espécies em cada esponja), seguida por Dy. etheria (sete espécies). Uma baixa riqueza de espécies foi observada em Ap. compressa, com apenas três espécies de briozoários, Ap. viridis com quatro espécies, e H. implexiformis com cinco espécies. Apenas o briozoário N. stipata foi encontrado em todas as espécies de esponjas, enquanto que At. distans e At. vidovici não foram encontradas apenas em Ap. compressa. Uma maior riqueza e abundancia de briozoários foram encontradas em De. anchorata e Te. ignis, que apresentam superfície lisa e aveludada, e lisa e vilosa, respectivamente. Por outro lado, superfície lisa também é característica das espécies Ap. compressa e Ap. viridis, que apresentaram a menor frequência e diversidade de briozoários. Adicionalmente, as esponjas De. anchorata e Dy. etheria que apresentam superfície lisa e conulosa, respectivamente, compartilharam grande parte das espécies encontradas. A presença de metabólitos secundários nas esponjas do gênero Amphimedon que apresentam toxicidade já descrita na literatura, pode ter influenciado na ocorrência dos briozoários. Enquanto que as esponjas Te. Ignis, De. anchorata e Dy. Etheria, que apresentaram uma grande abundância de briozoários, podem ter provido um microhabitat adequado para os briozoários da região. O padrão temporal de ocorrência dos briozoários nas esponjas durante os 18 meses de coleta foi aleatório. O presente trabalho permite identificar alguns padrões da ocorrência dos briozoários, relacionado a composição química das esponjas e sua posição no substrato.
Bryozoans comprise sessile, colonial organisms that require a hard surface for settlement and growth. Among different substrata for bryozoans, sponges may provide suitable substrata, with advantages such as presence of compounds against predators. This study analyses the bryozoan community on six sponges species throughout 18 months, to evaluate the presence of bryozoans on its surface. Three specimens of each sponges, Amphimedon compressa Duchassaing & Michelotti, 1864, Amphimedon viridis Duchassaing & Michelotti, 1864, Desmapsamma anchorata (Carter, 1882), Dysidea etheria de Laubenfels, 1936, Haliclona implexiformis (Hechtel, 1965) and Tedania ignis (Duchassaing & Michelotti, 1864), were taken monthly betweem September 2014 to February 2016, in Pontas de Pedra, Pernambuco State, Brazil. Bryozoans were identified to the lowest taxonomic level, and quantified. Total of 324 specimens of sponges were analysed, 88 from those were found bryozoans on its surface (27%). Eleven gymnolaemate bryozoans were found on sponges being four of the Order Ctenostomata, Amathia distans Busk, 1886, Amathia verticillata (delle Chiaje, 1822), Amathia vidovici Heller,1867 and Nolella stipata Gosse, 1855, and seven species Cheilostomata, Beania klugei Cook, 1968, Catenicella uberrima (Harmer, 1957), Caulibugula dendograpta (Waters, 1913), Licornia sp., Savignyella lafontii (Audoin, 1826), Synnotum aegyptiacum Canu & Bassler, 1928 and Thalamoporella floridana Osburn, 1940. Bryozoans were considered abundant on the sponges Te. ignis and De. anchorata, but few frequents on Ap. compressa and Ap. viridis. On De. anchorata and Te. ignis were found the highest bryozoan richness (9 species of bryozoan per sponge species), followed by Dy. etheria (7 bryozoan species). A low species richness was observed in Ap. compressa, Ap. viridis and H. implexiformis with respectively three, four and five species of bryozoans on their surface. Only N. stipata was found on the six sponge species, while At. distans and At. vidovici were not found only on Ap. compressa. Higher richness and abundance of bryozoans were found in De. anchorata and Te. ignis, with smooth and velvety surface, smooth and villous surface, respectively. Smooth surface is also characteristic of Ap. compressa and Ap. viridis, with the lowest frequency and diversity of bryozoans. Additionally, on sponges De. anchorata and Dy. etheria, with smooth and conulose surface respectively, were shared the majority of bryozoan species. We suggest the presence of secondary metabolites may have interfered the bryozoans on sponges of Amphimedon genus. Sponges Te. ignis, De. anchorata and Dy. etheria, have an abundance of bryozoans; thus, we suggest these sponges may allow a suitable substratum for the bryozoans. The temporal variation of bryozoans on sponges was random. In present work some patterns of occurrence of bryozoans are presented, with relation to the chemical composition and position of sponge.
32
Rapson, Trevor Douglas. "Bioactive 4-methoxypyrrolic natural products from two South African marine invertebrates." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1006766.
Full textAbstract:
This thesis presents an investigation of the 4-methoxypyrrolic constituents of two South African marine invertebrates, the nudibranch Tambja capensis and the bryozoan Bugula dentata. Three known compounds tambjamine A (7), tambjamine E (13) and the tetrapyrrole (15) were isolated during this investigation. All three compounds were shown to be active against oesophageal cancer in accordance with the general anticancer and immunosuppressive properties observed for 4-methoxypyrrolic natural products. Tambjamine A (7), tambjamine E (13) and the tetrapyrrole (15), together with tambjamine K (21) and L (22) (previously isolated in our laboratory) were used as standards to quantitatively assess the presence of these tambjamines in T. capensis and B. dentata collected from three different sites along the South African coast. This study confirmed that B. dentata is the source of the 4-methoxypyrrolic natural products sequestered by T. capensis and eliminated the closely related bryozoan B. neritina as a source of these metabolites. The paucity of tambjamine L (21) and K (22) obtained in previous investigations of the sequestered chemistry of T. capensis prompted an attempt at the development of synthetic methodology that could be used to synthesize tambjamines in sufficient yield for in depth bioactivity studies. In order to by pass the extensively reported problems associated with the synthesis of this group of compound 3-methoxy-2-formylpyrrole (47), readily accessible from 3-methoxypyridine N-oxide (48), was used as the starting material in a singlet oxygen induced 2,2’ bipyrrole coupling reaction. Although 47 proved unreactive in this coupling reaction, when the N-Boc protected analogue of 47 was used, and the reaction worked up in the dark, the novel methyl 4-aza-5-oxo-6,6-di-(2-pyrrolyl)-2(Z)-hexenoate (57) was obtained in low yield. The physical properties of tambjamine (E) (13) and the tetrapyrrole (15) were investigated to further the understanding of the proposed oxidative DNA cleavage mechanism and to determine the potential of the 4-methoxypyrrolic natural products as photodynamic therapy agents.
33
Scholz, Joachim, Kiyonori Nakajima, Teruaki Nishikawa, Jürgen Kaselowsky, and F. Shunsuke Mawatari. "First discovery of Bugula stolonifera Ryland, 1960 (Phylum Bryozoa) in Japanese waters, as an alien species to the Port of Nagoya." 名古屋大学博物館, 2003. http://hdl.handle.net/2237/7285.
Full text
34
Nytch, Christopher J. "Bad-Boy Bryozoan Biomarkers : Cheilostome Distribution Patterns Along a Bahamian Depth Gradient." Oberlin College Honors Theses / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1415358481.
Full text
35
Geraldine, Winzar. "Bryozoa of Antarctica : a first appraisal of the samples collected from 1929 to 1931 during the B.A.N.Z. Antarctic Research Expedition under the leadership of Sir Douglas Mawson /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09SB/09sbw795.pdf.
Full textAbstract:
Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1998.Location of stations off Antarctica stn. 30: Lat. 66 48's; Long. 71 24'E Stn. 41:Lat. 65 48's; Long. 53 16'E Stn. 107: Lat 66 45's; Long. 62 03'E. Bibliography leaves 163-164.
36
Aguiar, Bruno Sayão de. "Avaliação de identidade taxonômica de Amathia cf. crispa e Amathia cf. vidovici (Bryozoa: Ctenostomata) com ocorrência ao longo da costa brasileira, a partir de dados morfológicos e moleculares." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-19052015-092454/.
Full textAbstract:
Este trabalho visa esclarecer a identidade taxonômica de duas espécies de briozoários reportadas para o litoral brasileiro como Amathia cf. vidovici e Amathia cf. crispa, baseando-se em análises morfológicas e moleculares, utilizando os genes COI e 16S, que haviam se mostrado eficientes na diferenciação genética de outras espécies do gênero Amathia. Colônias foram amostradas em diversas localidades ao longo da costa brasileira, de Fortaleza, CE, a Palhoça, SC, tendo sido obtidas 107 amostras de A. cf. vidovici e 18 de A. cf. crispa. Uma espécie nova foi detectada para cada grupo avaliado: Amathia sp. nov.1 e Amathia sp. nov.2. Amathia sp. nov.1 é oriunda somente de localidades situadas em Cabo Frio, RJ e Vitória, ES, sendo distinta de A. cf. vidovici pelas medidas de maiores valores das seguintes características: 1) comprimento do agrupamento de zooides, 2) comprimento do internódio do estolão e 3) ângulo do agrupamento de zooides. Amathia sp. nov.2 foi encontrada exclusivamente na Ilha do Mel, PR revelando-se distinta de A. cf. crispa devido a medidas de menores valores das características: 1) ângulo da espiral, 2) número de pares de zooides, 3) comprimento do agrupamento de zooides e 4) comprimento do estolão. As análises moleculares corroboraram os resultados da morfologia, que conjuntamente revelaram também uma estrutura geográfica para A. vidovici. Esta foi encontrada em todo litoral do Brasil (CE, PB, PE, AL, BA, RJ, SP, PR, SC) sendo as colônias amostradas na ecorregião Nordeste, as que tiveram os menores valores mensurados das características analisadas quando comparadas com as das demais ecorregiões (maiores medidas). Amathia vidovici havia sido reportada anteriormente para localidades nos estados do Paraná, São Paulo e Alagoas, e Amathia crispa apenas para São PauloThis work aims to clarify the taxonomic identity of two species of bryozoans reported on the Brazilian coast as Amathia cf. vidovici and Amathia cf. crispa based on morphological and molecular analysis using the mitochondrial genes 16S rRNA and COI, which had proved useful in the genetic differentiation at the species level of other species of genus Amathia. Colonies were collected in different localities along the Brazilian coast, from Fortaleza, Ceará state, up to Palhoça, Santa Catarina state, including 107 samples of A. cf. vidovici and 18 of A. cf. crispa. A new species was detected for each evaluated group: Amathia sp. nov.1 e Amathia sp. nov.2. Amathia sp. nov.1 was found only on sites situated in Cabo Frio, state of Rio de Janeiro, and Vitória, state of Espírito Santo, being distinct of A. cf. vidovici by having: 1) longer clusters of zooids, 2) longer stolon internodes, and 3) spiral of zooid clusters describing a greater angle. Amathia sp. nov.2 was exclusively found in Ilha do Mel, state of Paraná; it is distinct from A. cf. crispa by the following: 1) spiral of zooid clusters describing a smaller angle, 2) fewer pairs of zooids per cluster, 3) shorter clusters of zooids, and 4) shorter stolon internodes. The molecular analyses corroborate the morphological results, both also revealing a geographical structure for A. vidovici. This specie was found throughout the coast of Brazil (CE, PB, PE, AL, BA, RJ, SP, PR, SC), the ones from the Northeast Ecoregion with the lower values of all measured characteristics when compared with those from other ecoregions. Amathia vidovici was reported previously to localities in the states of Paraná, São Paulo, and Alagoas, and Amathia crispa was reported only to São Paulo
37
Billing, Ian Michael. "British carboniferous Bryozoan biogeography." Thesis, Durham University, 1991. http://etheses.dur.ac.uk/6289/.
Full textAbstract:
The geographical and temporal distributions of the British Carboniferous Bryozoa have been determined, incorporating data from fieldwork (including localities in Scotland, North England, North Wales, South Wales, and Avon), museum collections, and literature searches. A total of 126 species has been recognised, though further work may reveal some synonymies within this list. The forty species collected during the fieldwork have been identified by reference to previous taxonomic work; most species can be assigned to established taxonomic descriptions, but two new species, Rhombopora bancrofti and Polypora hexagonaria, are proposed, and the descriptions of Rhombopora incrassata and Rhombopora similis are emended. The applicability of Student's t-test to the morphometric analysis of Carboniferous bryozoan species has been studied, and a computer program written to perforin this task, incorporating a database of species measurements. A new statistical method, the division t-test, is presented in this thesis; this method is useful in comparing the relative ratios of bryozoan colony parameters. Both the t-test and the division t-test were found to be of use in identifying bryozoan species. Analysis of the bryozoan faunas in nine regional areas of Britain has been made using the Simpson and Jaccard coefficients of similarity. The resulting coefficients are consistent with the limited distribution capability of many bryozoan taxa, and also match with the known palaeogeography and palaeocurrents of the Carboniferous of northwest Europe. Plots of species diversity against geographical distribution show a similar pattern to that produced by Tertiary non-planktotrophic larvae-bearing neogastropods. Further, additional plots of species diversity against species longevity produced a pattern consistent with normal background extinction events. A study of bryozoan morphology between different areas and different stages within the Carboniferous indicated that species showed no measurable temporal evolutionary or lateral geographical changes through the Lower Carboniferous. Rather, local environmental stresses are the major architects of bryozoan colony morphology.
38
Figuerola, Balañá Blanca. "Biodiversity and Chemical ecology in Antarctic bryozoans = Biodiversitat i ecologia química de briozous antàrtics." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/129165.
Full textAbstract:
The current thesis covers two important and poorly known aspects of Antarctic bryozoans: biodiversity and chemical ecology. The comparative analyses of diversity carried out here (Chapters 1 and 2) between Antarctica and the last separated fragments of Gondwana support the hypothesis of the sequential separation of Gondwana. We discuss that the high number of species from the Argentine Patagonian (AP) region shared with Antarctica found in our study question the real extent of Antarctic isolation for cheilostome bryozoans. The presence of shared common bryozoan species between these two regions may also be explained by the free migration of marine organisms in and out of the Polar Front, via the deep abyssal plains and the potential passive northwards transport of larvae (or perhaps even adults) to considerable distances, via the branch of the Antarctic Circumpolar Current (ACC) flowing northward along the continental shelf of Argentina, the Falkland/Malvinas Current. The role of the Scotia Arc and other dispersal pathways, like eddies of ACC, and human dispersal mechanisms, may increase the bryozoan connection found between the Antarctica and the AP region. Also, our studies (Chapters 1 and 2) are among the first characterizations of the bryozoan communities, mainly at the slope, from the AP region, and from the Southern Ocean (SO), specially the Weddell Sea. The bathymetric distribution from the AP region and the SO found in our studies fits well with the limits of the continental shelf, the slope and the deep sea. Interestingly, our research also shows an expansion in the known distribution of diverse bryozoan species from the AP region and the SO. Our results stress the importance of taxonomical studies in these scarcely explored regions, reporting a high number of new genera and species, and new records too. Among the new species found in our study, a bryozoan of the genus of Reteporella characterized by rare giant spherical avicularia is described in Chapter 3, leading us to discuss which are the potential roles of the avicularia. Since the studied bryozoan communities, below areas affected by local disturbances (iceberg scours and anchor ice), are mainly subject to biotic factors such as competence and predation, the evolution has favoured the development of chemical mechanisms in benthic organisms, which have also been investigated here (Chapters 4 and 5). Our studies are among the first reports on chemical ecology of Antarctic bryozoans. In order to study these chemical interactions, new adapted protocols were designed using sympatric and abundant predators. Our findings demonstrate the importance of diverse chemical ecology mechanisms against competence and predation in Antarctic bryozoans. Most bryozoan species tested here display cytotoxicity and/or repellent activity against the sea urchin Sterechinus neumayeri and the amphipod Cheirimedon femoratus, respectively (Chapter 4). In Chapter 5, our results demonstrate that bryozoans seem to be readily defended against at least one of the two abundant predators, Odontaster validus and C. femoratus. The intra- and interspecific variability in bioactivity suggest an adaptive response to diverse abiotic and biotic factors, presence of microorganisms and/or genetic variability. The general trend in our study indicates the presence of a combination of both chemical and physical defensive mechanisms in most bryozoan species, suggesting complementary traits. In general, these results lead to the conclusion that this phylum is very active with extended repellent activities.Aquesta tesi cobreix dos aspectes importants i poc coneguts dels briozous antàrtics: la biodiversitat i l'ecologia química. L'anàlisi comparatiu de diversitat realitzat aquí (Capítol 1 i 2) entre l'Antàrtida i altres zones geogràficament properes recolzen la hipòtesi de la separació seqüencial de Gondwana. Es discuteix que l'elevat nombre d'espècies de la regió de la Patagònia argentina (PA) compartides amb l'Antàrtida qüestiona el grau real d'aïllament de l'Antàrtida en briozous queilostòmats. Els nostres estudis (Capítols 1 i 2) són també una de les primeres caracteritzacions de les comunitats de briozous, principalment del talús, de la regió de la PA, i de l' Oceà Austral, especialment el Mar de Weddell. Els nostres resultats remarquen la importància dels estudis taxonòmics en aquestes regions escassament explorades, incloent un gran nombre de nous gèneres i espècies, i noves cites. Entre les noves espècies trobades en el nostre estudi, es descriu un briozou del gènere Reteporella caracteritzat per una rara aviculària esfèrica i gegant, portant-nos a reconsiderar quines són les possibles funcions de l'aviculària (Capítol 3). Com les comunitats estudiades de briozous, per sota de les zones afectades per pertorbacions locals (erosió per icebergs), estan subjectes principalment a factors biòtics com la competència i la depredació, l'evolució ha afavorit el desenvolupament de mecanismes químics de protecció (Capítols 4 i 5). Els nostres estudis són dels primers en ecologia química de briozous antàrtics. Els nostres resultats demostren la importància de diversos mecanismes d'ecologia química contra la competència i la depredació en briozous antàrtics. La majoria de les espècies de briozous mostraven activitat citotòxica i/o repel•lent contra l'eriçó de mar Sterechinus neumayeri i l'amfípode Cheirimedon femoratus, respectivament (Capítol 4). En el capítol 5, totes les espècies de briozous estudiats mostraven activitat de repel•lència alimentària contra almenys un dels dos depredadors abundants considerats, l'estrella de mar Odontaster validus i l'amfípode Cheirimedon femoratus. La tendència general en el nostre estudi indica la possessió d'una combinació de mecanismes físics i químics en la majoria de les espècies, fet que suggereix estratègies complementàries.
39
McGurk, Charles. "Culture of malacosporeans (Myxozoa) and development of control strategies for proliferative kidney disease." Thesis, University of Stirling, 2005. http://hdl.handle.net/1893/37.
Full textAbstract:
Proliferative kidney disease (PKD) poses a high financial burden upon the freshwater salmonid aquaculture industry of Europe and North America. The alternate hosts of the causative agent, Tetracapsuloides bryosalmonae (Myxozoa: Malacosporea), have been identified as freshwater bryozoans (Bryozoa: Phylactolaemata) within which spores capable of infecting salmonid fish develop. Currently, control of PKD relies upon complex management practices, with no licensed prophylaxis or treatment available. Assessment of the nutritional preferences of phylactolaemate bryozoans allowed development of an optimised laboratory culture system. Following laboratory maintenance, bryozoans collected from PKD-endemic sites were found to be infected with the malacosporean parasites T. bryosalmonae and Buddenbrockia plumatellae. Subsequent parasitic development was observed using light-, electron- and confocal-microscopy techniques. Methods of challenging rainbow trout with T. bryosalmonae spores were developed, with the minimum infective dose established. The presence of Thomsen-Friedenreich and Tn epitopes within the parasite was investigated, and experimental vaccine preparations based on either these specificities or T. bryosalmonae-infected bryozoans were efficacy tested in rainbow trout. In addition, salinomycin and amprolium were tested as prospective chemotherapeutants for PKD. Further insights into the development and subsequent release of malacosporean spores within their invertebrate hosts have been revealed. Long-term maintenance of T. bryosalmonae allowed controlled infection of rainbow trout previously vaccinated with experimental preparations. Findings of the project could potentially be utilised in future research into the development of control methods for PKD.
40
Hartikainen, Hanna-Leena. "Freshwater bryozoan abundence, eutrophication and salmonid fish disease." Thesis, University of Reading, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493801.
Full textAbstract:
This research investigates the links between nutrient enrichment, bryozoan abundance and the development of myxozoan parasites in bryozoans. It was found that bryozoan abundances are elevated in nutrient-rich rivers, demonstrating the potential bio-indicator value of bryozoans and predicting increased bryozoan abundances with increased planktonic productivity when space is not limiting. A comprehensive set of laboratory microcosm studies showed also that experimental nutrient enrichment increased growth rates and statoblast production in Fredericella sultana, corroborating the results from field surveys.
41
Ward, Mark Andrew. "The ecology of subtidal encrusting bryozoans from three temperate water communities off the South of the Isle of Man." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236435.
Full text
42
Robinson, Nicole. "INTERACTIONS BETWEEN THE NUDIBRANCH OKENIA ZOOBOTRYON AND ITS BRYOZOAN." Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3299.
Full textAbstract:
In the Indian River Lagoon, the nudibranch Okenia zoobotryon and its egg masses are found attached to the bryozoan Zoobotryon verticillatum throughout the year. Okenia zoobotryon is thought to live, feed, and reproduce exclusively on Z. verticillatum, which would make this a very specialized predator-prey interaction. The primary goal of my study was to document certain aspects of the ecological and chemical relationships between Z. verticillatum and O. zoobotryon. Specifically, I wanted to understand the cues used by the nudibranch to locate and remain on Z. verticillatum. Population surveys on Z. verticillatum, as well as other potential hosts, were performed. From these surveys, I found a small number of O. zoobotryon adults and egg masses on the red macroalga S. filamentosa mixed with Z. verticillatum (0.01 and 0.05 g/wet-weight, respectively), none on the bryozoan Amathia distans, and none on the red macroalga Gracilaria tikvahiae. To determine if prey identification was associated with an adult cue, I ran paired-choice trials. In these, the adults did not significantly prefer Z. verticillatum. Next, laboratory culture of larvae of O. zoobotryon was performed. During larval culture some aspects of this previously undocumented life-history were recorded; adults of this species developed from planktotrophic veliger larvae that hatched out of egg masses between 4 and 6 days, the time post-hatching to settlement was 7-8 days, and metamorphosis occurred approximately 24 hours after settlement. The final question addressed in this study was; "Does O. zoobotryon feed on and take up chemicals from Z. verticillatum?" To address this question, high-performance liquid chromatography was performed on extracts of Z. verticillatum and O. zoobotryon. Both organisms were compared and found to contain similar compounds, which suggest that the nudibranch is feeding on Z. verticillatum and taking up chemicals. Concentrations of compounds in Z. verticillatum varied between populations in the northern and southern regions of the Indian River Lagoon. There are, also, differences between the chemical composition of Z. verticillatum in the IRL (northern and southern) and the California species identified by Sato and Fenical (1983).M.S.
Department of Biology
Arts and Sciences
Biology
43
Hunter, Ewan. "Variation of growth and reproduction in a marine bryozoan." Thesis, Bangor University, 1991. https://research.bangor.ac.uk/portal/en/theses/variation-of-growth-and-reproduction-in-a-marine-bryozoan(01c416d6-a1a4-496d-8ffc-ade56209de43).html.
Full textAbstract:
This thesis investigates aspects of growth and reproduction in the marine bryozoan Celleporella hyalina (L. ). It was found that C. hyalina could live and grow in the laboratory on a range of algal diets. Chiorophyte algae proved unsuitable, but Rhodomonas baltica proved outstanding as a foodstuff. Astogeny of Rhodomonas fed colonies was the same as that reported for naturally occurring colonies, and resulted in the production of viable larvae. It was further noted that female zooids were occasionally produced in the basal layer. C. hyalina colonies were able to grow and attain sexual maturity in cell concentrations ranging from 10 to 300 cells µl1 Growth was greatest at around 100 cells µl, ' and was suppressed at low and extremely high cell concentrations. Food supply had a highly significant effect on growth parameters, but sexual parameters were largely unaffected. Cell ingestion rate increased as a function of cell concentration, whereas feeding episode length declined with increasing food supply. Feeding behaviour in C. hyalina is described. Highly significant genotype-environment interactions were found at all levels for both somatic and sexual parameters in 26 C. hyalina clones grown in four temperature/food supply combinations (macroenvironments). The number of autozooids per unit area was found to be strongly temperature dependent. The number of ovicells was consistently greater than the number of embryos produced. Male investment was favoured under conditions of low resource. Ranking of clonal performance varied considerably, both between macroenvironments, and according to the measure of fitness used. Significant levels of intraclonal variation occurred within replicates of a single genotype grown in four macroenvironments. Variance was more prominent in somatic rather than sexual parameters. The presence of one statistical outlyer suggested that somatic mutations may sometimes occur. C. hyalina colonies grown in isolation produced embryos sometimes as early as five weeks, but the number was low, and a high incidence of abortion was observed. When removed from isolation, the number of embryos increased significantly. There was no evidence of settlement from larvae produced in isolation.
44
Pagès, Escolà Marta. "New insights into the ecology and conservation of bryozoans: from global diversity patterns to the responses to anthropogenic stressors in the Mediterranean Sea = Noves aproximacions a l’ecologia i conservació dels briozous: des dels patrons globals de diversitat fins les respostes als impactes humans al Mar Mediterrani." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668538.
Full textAbstract:
Marine ecosystems are directly threatened by multiple and interactive human stressors at global and local scales. Hence, it is vital to study biodiversity and ecological patterns through a multi-disciplinary approach, from understanding global diversity patterns to evaluating the ecological responses of species to different impacts in order to protect marine ecosystems. In this thesis, we focused on bryozoans, an abundant group of sessile marine invertebrates distributed worldwide, but generally understudied. Accordingly, in this thesis we provide different approaches to understand discovery and macroecological patterns at global scales, and the response of species to different stressors at local scales, combining the use of open databases, the in situ monitoring of natural populations, experiments in aquaria and the development of restoration techniques.
At global scale, in Chapter I we unraveled discovery patterns of fossil and extant bryozoans and showed the highest number of fossil species described, highlighting that the current biodiversity represents only a small proportion of Earth’s past biodiversity. Beyond these differences, both groups showed an increase in the taxonomic effort during the past century. Despite this progress, future projections of discovery patterns of both groups showed a large proportion of species remaining to be discovered by the final of this century. In Chapter II, most of the global diversity patterns of marine sessile groups, including bryozoans, showed a non-unimodal latitudinal pattern with a dip in the number of species at the equator and a higher diversity in the Southern ocean. Moreover, this region will be less affected by global warming at the final of this century. In contrast, our analyses showed that the most sampled region for both marine sessile species and bryozoans was North Temperate Atlantic, highlighting the importance to quantify environmental drivers considering sampling effort biases. For this reason, we tested the effect of using the popular method of rarefaction (ES50) vs the incorporation of a frequency index of sampling effort as co-variate in quantitative models. Despite we obtained the same best predictors for both approaches (depth, nitrate, and SST), the models using the correction of sampling biases through frequency index showed better fitting, encouraging to incorporate this methodology in future studies.
Focusing on the Mediterranean Sea, in Chapter 3 we studied the responses of bryozoans to different stressors. First, we showed that two abundant and common bryozoans, Pentapora fascialis and Myriapora truncata, displayed different tolerances to warming through the combination of in situ monitoring and experiments in aquaria. Moreover, in Chapter 4 the in situ monitoring of Pentapora fascialis populations revealed its fast population dynamics, with high recruitment and growth rates, and a high capacity of recovery. Accordingly, we observed an increase in the density of its populations in the Medes Island Marine Reserve since the 1990s. However, we evidenced that diving can impact on the density, recruitment, survival, and size of the colonies, registering lower values in frequented localities. Our results highlight that the over frequentation of divers compromises the future viability of populations, highlighting the need to explore other active management strategies. For this reason, in Chapter 5, we tested and developed different restoration techniques for P. fascialis, focusing on the recruitment enhancement through the installation of recruitment surfaces and the transplantation of adult colonies. The successful results and the affordable and economic cost of tested techniques aim to encourage the managers of Marine Protected Areas to apply similar methodologies.
The results presented in this thesis show the importance to combine different approaches to understand the global and local ecological patterns of understudied but abundant groups, such as bryozoans. Our findings enlarge the current ecological knowledge of bryozoans at different scales, and highlight that more effort is needed to protect vulnerable populations.Els ecosistemes marins estan sotmesos a múltiples impactes a escales locals i globals i que a més interaccionen entre ells. Per aquesta raó, és important estudiar els patrons de biodiversitat i ecològics a través d’una aproximació multi-disciplinària, que pot anar des d’entendre els patrons de diversitat global fins a avaluar les respostes ecològiques de les espècies enfront diferents impactes, per així conservar i gestionar adequadament les comunitats marines. Fins aquest moment, la majoria d’estudis relacionat s’han centrat en grups carismàtics i populars, com ara les gorgònies, els coralls, les macroalgues o les fanerògames marines. En canvi, aquesta tesis es centra en l’estudi dels briozous, un grup abundant de invertebrats sèssils marins distribuïts per tot el món, però generalment poc estudiats. Per aquesta raó, el principal objectiu d’aquesta tesis és utilitzar diferents aproximacions per entendre els patrons de descobriment i macro-ecològics a escala global, i la resposta a diferents impactes a escala local, combinant el ús de bases de dades globals, el seguiment in situ de les poblacions, experiments en aquaris i el desenvolupament de tècniques de restauració. A més, la present tesis vol proporcionar un marc de treball per identificar, gestionar i conservar les poblacions vulnerables en el context de l’augment de les activitats humanes que afecten els ecosistemes marins. Els resultats presentats en aquesta tesis mostren la importància d’aplicar diferents aproximacions per entendre els patrons ecològics globals i locals de grups abundants però poc estudiats, com són els briozous. Els resultats obtinguts contribueixen a augmentar el coneixement dels patrons ecològics dels briozous a diferents escales, i mostren que cal més esforç per protegir les poblacions vulnerables. Així, mesures de gestió adaptativa i de restauració i són necessàries per promoure la conservació dels ecosistemes marins en un context de impactes creixents derivats de l’activitat humana tant a escales locals com globals.
45
Whitehead, John William. "Experimental ecology of epialgal bryozoans." Thesis, Bangor University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285518.
Full text
46
Hill, Samantha. "The ecology and conservation of the rare freshwater bryozoan, Lophopus crystallinus." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434311.
Full text
47
Price, Heather Leigh. "Investigation of larval sensory systems in the marine bryozoan, Bugula neritina." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1410.
Full textAbstract:
Bugula neritina is a sessile marine bryozoan with a pelagic larval stage. Larvae frequently settle on boat hulls, facilitating the introduction of B. neritina to bays and estuaries worldwide. Adrenergic agonists, such as the vertebrate hormone noradrenaline, inhibit larval settlement in a variety of marine invertebrate species, including B. neritina. Light also inhibits B. neritina larval settlement, yet the underlying mechanisms by which light and adrenergic compounds exert their effects on larvae are not well understood. Octopamine is considered the invertebrate analog of noradrenaline, and may be an endogenous hormone involved in larval settlement pathways. I observed the effects of the adrenergic agonist noradrenaline and the adrenergic antagonist phentolamine on larval settlement, and found that high concentrations of noradrenaline increased larval mortality, inhibited larval attachment, and increased larval swimming behavior. High concentrations of phentolamine also increased larval mortality, but increased larval attachment and decreased larval swimming behavior. I used fluorescent labeling and microscopy to localize sensory system components, and found that larvae possess adrenergic-like receptors, as well as tyrosine hydroxylase-like and octopamine-like immunoreactivity. I also exposed larvae to phentolamine in both dark and light conditions, and found that light significantly inhibited larval attachment, but phentolamine blocked those inhibitory effects. These results suggest that B. neritina larvae possess adrenergic-like receptors, which serve as the binding sites for noradrenaline and phentolamine. These are likely octopamine receptors, and octopamine may be one endogenous compound involved in controlling larval phototaxis and settlement behavior. Light may increase octopamine production, thereby stimulating cilial activity, extending swimming behavior, and preventing larvae from attaching to a substrate. This research sheds light on previously unknown sensory mechanisms in B. neritina larvae, and may aid in the development of new biofouling control strategies.
48
Waeschenbach, A. "Molecular evolutionary processes in ctenostome bryozoans." Thesis, Swansea University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639319.
Full textAbstract:
The phylogenetic relationships between species of the stoloniferan ctenostome bryozoan genus Bowerbankia were examined using DNA sequences for two mitochondrial genes, 12S rDNA and cytochrome c oxidase subunit I (COI). The resultant phylogeny based on COI sequences was shown to be confounded by nuclear mitochondrial sequences (Numts). Primers specific to mtDNA copies of COI were designed. 12S rDNA sequences with mutations in highly conserved regions, as determined by secondary structure folding, are also suspected to be Numts, however, 12S rDNA Numts and cytoplasmic mitochondrial sequences could not be separated by phyogenetic methods. Identical COI Numts were found in the carnosan Alcyonidium diaphanum and several Bowerbankia species, suggesting that transfer into the nucleus predates the divergence of the Stolonifera and Carnosa. One 12S rDNA haplotype common to Vesicularia spinosa, Amathia lendigera and bowerbankia spp. and two common to Bowerbankia spp. and Alcyonidium spp. were found. The occurrence of these identical haplotypes suggests that nuclear transfer of 12S rDNA might have occurred once within the Vesiculariidae and twice prior to the divergence of the Stolonifera and the Carnosa. Bryozoan sequences were obtained for the first time for the nuclear ribosomal multigene family 18S rDNA - ITS1 - 5.8S and species specific-primers for the ctenostome bryozoan Flustrellidra hispida were designed. Sequences from two populations, Millport (Scotland) and Mumbles (Wales) were obtained, with no significant genetic structure detected between the two populations nor within populations; however, ITS1 copies in the Mumbles population were slightly more homogenised than they were in the Millport population. Possible underlying processes leading to this difference are discussed. Furthermore, pseudogene copies could also be identified for 18S rDNA - ITS1 - 5.8S rDNA. In order to avoid amplification of contaminant DNA originating from cryptic organisms commonly present on the exterior and in the interior of bryozoans, such as ciliates, stramenopiles and fungi, a method using individually lysed larvae, previously used on Mytilus edulis (Sutherland et al 1998), was adapted for bryozoans.
49
Tompsett, Scott. "Taxonomy, morphometrics, and phylogeography of the cheilostome bryozoan genus Schizoporella in Europe." Thesis, Aberystwyth University, 2010. http://hdl.handle.net/2160/fe2d54b9-b4c2-4bf2-bcea-e98d897d81f9.
Full text
50
Manriquez, Patricio H. "Mate choice and reproductive investment in the cheilostome bryozoan Celleporella hyalina (L.)." Thesis, Bangor University, 1999. https://research.bangor.ac.uk/portal/en/theses/mate-choice-and-reproductive-investment-in-the-cheilostome-bryozoan-celleporella-hyalina-l(213eab65-9c53-4769-869d-8fe403021006).html.
Full textAbstract:
In the present research several aspects of the reproductive biology of the marine hermaphroditic bryozoan, Celleporell hyalin (Linnaeus, 1767) were investigated. First (see Chapter 2), aliquots, of different ages from a stock of allosperm suspension were used to fertilize a series of virgin ramets, so characterizing the decay in fertility of released sperm and any effects of sperm ageing on subsequent embryogenesis and larval metamorphosis. The effect of temperature on the above variables was also investigated. The fertile half-life of C. hvalina sperm was about 1-2 h, although significant decay in fertility occurred within a few minutes after release. Sperm ageing showed no deleterious effects on embryogenesis, larval viability, or metamorphosis. No clear effects of temperature on sperm ageing and fertilization success were found. Allosperm. storage was studied in colonies of C. hyalina. (L. ) under several experimental conditions (see Chapter 3). Recipient virgin colonies were exposed to sexually compatible allosperm suspension and the appearance of the last newly ovulated oocytes in the coelorn. was used to assess duration of sperm storage. The same experiments examined continuation of brooding cycle and brooding success throughout the period of allosperm storage. Similar obserVations were conducted on wild colonies of C. hyalina taken from the field and kept in reproductive isolation in the laboratory. Production of progeny in females zooids budded beyond the original colonial growing edge was taken as evidence of sperm movement. The results of the present study show that recipient colonies continue producing coelomic oocytes up to 5 weeks after exposure to allosperm suspension. Moreover, the progeny were produced not only by female zooids present at the moment of allosperm dosage but also by female zooids, budded later, beyond the limit of the original growing edge. Since oocytes were not present in control colonies exposed to selfsperm, the results of the present study indicate that recipient colonies store sexually compatible allosperm and transport them within the colony in order to produce viable progeny. The effect of water flow on both sperm release and fertilization success in colonies of C. hyalin (L. ) was studied (see Chapter 4). Maximum numbers of released sperm were found at low and zero water velocities. Moreover, protruded male lophophores were observed only under those conditions. Fertilization success was studied in virgin colonies of C. hyalina (L. ) exposed to compatible allosperm suspensions under different feeding activity and water flow conditions. Fertilization success was higher in colonies with more active feeding autozooids than in those with fewer feeding autozooids. High water flow conditions induced reduction in the proportion of protruded lophophores, and reduced the frequency of ovicells bearing progeny. Moreover, in all the experiments offspring were concentrated in areas of the colony bearing active feeding autozooids. The results of this study suggest that sperm release take place under similar conditions that enhance cross fertilization, with a possible role of feeding activity in bringing sperm to the proximity of receiver colonies. Sperm competition and female choice was investigated in virgin colonies of C. hyalin (L. ) exposed to sexually compatible allosperm cocktails (see Chapter 5). A microsatellite-based. genotyping system was used to determine paternity. Progeny were mainly the product of outcrossing. In a few cases, a small proportion of progeny was attributed to selffertilization. These results suggest that outcrossing is the main reproductive strategy in this species and that neither selective female choice nor sperm competition occur in C. hyalin . Cryptic incompatibility allowing a flexible mating strategy to produce out-crossed progeny Z) in the presence of allospenn and selfing when they were absent was not found. The effects of mating sequence and temporal interval between matings (2 or 48 h) on sperm precedence in double-mated individuals were studied (see Chapter 6). Paternity was determined by using a microsatellite-based genotyping system. Settled colonies produced after short mating showed evidence of sperm mixing and first-male precedence. However, last colonies produced after both short and long mating intervals showed evidence of first-male precedence. When analyses were conducted using all the sampled progeny, low incidence of paternity by the second sperm donor (P2) and absence of self fertilization were found. No effect of mating order on success of the second donor was found. Prevalence of outcrossing was also found. These results suggest that first-male precedence in C. hyalin may promote outcrossing under sperm limitation conditions, by acceptance of the first compatible allosperm to become available. The effects of exposure to sperm suspensions and stressors on sexual allocation in colonies were studied (see Chapter 7). In the first experiment the effect of a waterborne factor on receptor colonies was studied. Adult colonies were exposed to compatible allosperm suspensions that had been filtered through 0.45 Vrn pores potentially able to remove cellular sized particles. As a control, receptor colonies were exposed to non-filtered allosperin suspensions. Appearance and growth of oocytes occurred only in the coelorn. of the control colonies. The active factor is not a dissolved molecule, but a particle that can be removed from water by filtration through 0.45 [im pores. This result plus the absence of developing oocytes in the receptor colonies exposed to similar concentration of selfsperm, suggest the operation of self/honself recognition and an important and active role of allosperm in initiating colonial reproductive investment in C. hyalina. Prevention of colonial growth and others stressors were associated with production of basal male zooids. In other experiments, exposure to sperm suspensions of different degrees of genetic relatedness showed a virtual absence of production of progeny in those colonies exposed to closely related sperm (i. e. self and halfsibs). Finally, in experiments with sexually immature colonies, the onset of sexual reproduction was triggered by exposure to allosperm, resulting in the production of female zooids even before the appearance of male zooids. Contacts between colonies of different genetic relatedness were studied under laboratory conditions (see Chapter 8). Moreover, observations were made on colonies growing on their natural substrata. Five types of responses were observed, from total fusion to overgrowth. Maximum degree of fusion, or morphological fusion, was manifested as morphologic interconnection between the ad oining colonies (i. e. production of coalescent zooids). Fusion occurred in all contacts between colonies of the same genotype, between parental colonies and their progeny and, between full and half sib colonies. In most cases the production of coalescent zooids was found. Absence of fusion occurred in all contacts between unrelated colonies and between some of the half sibs. Observations on wild colonies growing in contact with each other failed to reveal any incidences of coalescence. Non-aggressive overgrowth was confined to dead areas of one colony overgrown by zooids of the other healthy colony, independent of the genetic relatedness of the pairs. Differences in the fusibility between isocontact and allocontact suggest that colony specificity exists in C. hyalin , as has been found in other sessile colonial marine organisms.