Thesis (Ph. D.)--University of Hong Kong, 2003. / Includes bibliographical references (leaves 209-226) Also available in print.

Resumo: A introdução de espécies é um dos fatores que mais causa prejuízo a ecossistemas, ocasionando a perda de biodiversidade em ambientes terrestres e aquáticos, tanto marinhos quanto dulcícolas. Regiões portuárias são muito suscetíveis a este processo, e a Baía de Paranaguá é o exemplo mais próximo. Muitos organismos são frequentemente transportados entre áreas portuárias, incrustados nas embarcações ou suspensos em águas de lastro, e podem se estabelecer em locais nos quais não chegariam naturalmente. Um dos fatores determinantes para seu estabelecimento em estuários, onde frequentemente se localizam os portos, é sua tolerância fisiológica às variações ambientais típicas destes ambientes. O potencial de invasão de uma espécie pode ser parcialmente relacionado a esta tolerância fisiológica, e à de organismos nativos que sejam seus competidores diretos. Para analisar este fenômeno, no presente trabalho foram comparadas as cracas (crustáceos cirripédios) introduzida Amphibalanus reticulatus (Utinomi,1967) e nativa Fistulobalanus citerosum (Henry, 1974). Os animais foram coletados no Iate Clube de Paranaguá, que fica próximo ao Porto de Paranaguá. Substratos foram instalados e posteriormente recolhidos com os animais adultos. Estes foram levados para o Laboratório de Fisiologia Comparativa da Osmorregulação (LFCO), do Departamento de Fisiologia da UFPR, onde foram mantidos em condições semelhantes às do local de coleta. As espécies foram expostas a dua modalidades de experimentos em laboratório. Na primeira, o tempo foi fixado em 6h, e as variáveis foram temperatura (10, 20 e 30ºC) e salinidade (0, 20 e 40‰). Na segunda, a temperatura foi fixada em 20ºC e os parâmetros variáveis foram salinidade (0, 10, 20, 30, 40‰) e tempo (9, 12 e 48h). Após a exposição às condições xperimentais, foram coletados os fluidos internos dos animais para as dosagens da osmolalidade e dos íons cloreto, sódio, magnésio e potássio. Também foram retirados os tecidos moles para a determinação de teor hídrico. Foi detectada diferença entre as espécies, sendo que Fist lobalanus citerosum apresentou valores de concentração de fluido mais estáveis, suportando por mais tempo as condições experimentais, e conseguindo sustentar maiores gradientes em relação à água. Amp ibalanus reticulatus demonstrou ser mais sensível a alterações ambientais, principalmente quando exposto a aumento de salinidade (40‰). Os resultados indicaram que F. citerosum é uma espécie que tolera uma maior amplitude de variação ambiental (mais euri-halina e euri-térmica), portanto melhor equipada para resistir a extremos de salinidade e temperatura do que A. reticulatus. Embora A. reticulatus seja a espécie introduzida, e presumivelmente mais resistente a extremos ambientais, F. citerosum apresentou maior tolerância a estas situações. Contudo, estudos adicionais sobre a fisiologia e biologia destas espécies seriam necessários para elucidar quais os mecanismos que fornecem esta vantagem para F. citerosum.

The initial aim of this thesis was to study the transmembrane and intracellular distribution of Cl⁻ in single striated muscle fibers of the giant barnacle, Balanus nubilus. The study was expanded to include the transmembrane distribution of K⁺ and a consideration of the Donnan relation. Chloride sensitive Ag-AgCl microelectrodes were inserted into single fibers to measure the activity of Cl⁻ in the myoplasm. The myoplasmic Cl⁻ activity was just slightly higher than predicted from the Nernst equation, indicating that Cl⁻ is probably distributed passively across the membrane of the resting fiber. Comparison of the electrode results with analytic results suggested that less than half of the fiber Cl⁻ is free in the myoplasm. Most of this extra Cl⁻ was located in an extracellular space, determined, by ¹⁴C-sorbitol penetration and a Cl⁻ washout method, to occupy about 5% of the fiber volume. Electron micrographs indicate that this space is comprised of large clefts and smaller tubules which penetrate deeply into the fiber. In a second series of experiments, the kinetics of Cl⁻ exchange and the outflow of intracellular Cl⁻ into solutions with reduced Cl⁻ concentrations were studied. The results indicate that the intracellular Cl⁻ can be divided about equally between a rapidly exchanging fraction which is free in the myoplasm and a slowly exchanging fraction which is either bound or compartmentalized. Furthermore, the free myoplasmic Cl⁻ appears to be excluded from about 45% of the intracellular water. In the third series of experiments, the activities of K⁺ and Cl⁻ in the myoplasm of single fibers at differing states of equilibrium were measured by means of ion sensitive micro-electrodes. Fibers were equilibrated in Ringer solution which was modified in three ways: [K]₀ and [C1]₀ were varied but [K]₀ x [Cl]₀ and [K]₀ + [Na]₀ kept constant; [K]₀ was varied but [Cl]₀ and [K]₀ + [Na]₀ kept constant; [K]₀, [Cl]₀, and osmolarity were increased. The results provide rigorous proof for the widely held theory that, under most equilibrium conditions, K⁺ and Cl⁻ are distributed across the membrane of a muscle fiber according to the Donnan relation. The results also confirm the finding.that Cl⁻ is apparently excluded from 45% of the intracellular water and earlier findings from this laboratory that K⁺ is excluded from a smaller fraction of the intracellular water. Finally, two experiments are described which show that the intracellular distribution of K⁺ and Na⁺ is not the same in fibers from barnacles collected in two different locations. It is suggested that although the sum of the K⁺ plus Na⁺ that is bound or compartmentalized may be constant, the differences in the results could be due to an inverse variation in the amount of each cation that is bound or compartmentalized. The results of this study are in accord with recent findings in this and other laboratories which indicate that monovalent inorganic ions and water are distributed in a heterogeneous manner in the striated muscle fiber. The intracellular Cl⁻of the barnacle muscle that is not free in the myoplasm must be either bound to proteins or accumulated in the sarcoplasmic reticulum; at present there is not sufficient evidence to select one or the other (or both) of these possibilities. It is proposed that the free myoplasmic Cl⁻ is excluded from water that is ordered by the cell proteins and partially excluded from water that lies within the electrical field that surrounds the negatively charged proteins. / Medicine, Faculty of / Graduate

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

<p>Eutrophication is a current problem on coastal lines worldwide. Cirripedia like the northern acorn barnacle Semibalanus balanoides actively help to prevent high amounts of plankton in the coastal zones by filtering plankton out of the surrounding water. This investigation focuses on the movements of Semibalanus balanoides in comparison to increasing concentrations of plankton in the water (between 33mg and 110 mg particles per litre) which simulate eutrophication. The four factors feeding activity, pumping activity, isolation time and clogging of the feeding apparatus in relation to the plankton concentration of the water were examined. </p><p>The results show significant interaction between pumping movement and the plankton concentration. The feeding activity, the isolation time and the clogging compared to the plankton concentration get no statistical results. </p><p>Less feeding activity and an increase in pumping behaviour will not decrease the amount of plankton in the coastal waters which will increase the problems of eutrophication. The paper shows that more investigation on suspension feeders and their surroundings needs to be done to be able to understand the dangers fully.</p>

Eutrophication is a current problem on coastal lines worldwide. Cirripedia like the northern acorn barnacle Semibalanus balanoides actively help to prevent high amounts of plankton in the coastal zones by filtering plankton out of the surrounding water. This investigation focuses on the movements of Semibalanus balanoides in comparison to increasing concentrations of plankton in the water (between 33mg and 110 mg particles per litre) which simulate eutrophication. The four factors feeding activity, pumping activity, isolation time and clogging of the feeding apparatus in relation to the plankton concentration of the water were examined. The results show significant interaction between pumping movement and the plankton concentration. The feeding activity, the isolation time and the clogging compared to the plankton concentration get no statistical results. Less feeding activity and an increase in pumping behaviour will not decrease the amount of plankton in the coastal waters which will increase the problems of eutrophication. The paper shows that more investigation on suspension feeders and their surroundings needs to be done to be able to understand the dangers fully.

Thesis (Ph. D.)--University of Hong Kong, 1995. / Includes bibliographical references (leaves 267-316).

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

This thesis deals with systematic revision, evolutionary trends, palaeoecology and migration patterns of crustaceans (Cirripedia and Decapoda) from the Upper Cretaceous of the Bohemian Cretaceous Basin. Thesis is presented as a compilation of 9 papers that were published in scientific peer-reviewed journals and includes not only old museum material, but also numerous crustacean specimens which have been recovered in the last decade. Besides, short remarks on fossil crustaceans currently under study or in the process of being published (Paraclythia, Oncopareia, Acrothoracica) are also included in this thesis. In view of the fact that the fossil crustaceans from the BCB were most recently recorded in the turn of the 19th and the 20th centuries (and partially revised in the first half of the 20th century) and since the systematics and taxonomy have changed significantly, all papers presented here focus primarily on systematic revision and modern description. The essential part of the thesis thus deals with taphonomy and its bearing on the identification of fossil material. Thanks to a modern description, new species of Ctenocheles fritschi (axiidean shrimp), Archaeochionelasmus nekvasilovae (acorn barnacle), Myolepas reussi and Capitulum sklenari (pedunculate barnacles) were erected. C. fritschi is...