Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2006. / Webster, Donald, Committee Chair ; Yen, Jeannette, Committee Member ; Roberts, Philip, Committee Member.

Thesis (M.Sc. (Zoology)) -- University of Limpopo , 2023 / Currently Copepoda consists of 14 600 species of which 2 275 species are members of the Siphonostomatoida. Siphonostomatoida consists of 40 families, with 17 families symbiotic on fish. Sphyriidae has 44 accepted species in eight reported genera, of which four genera infect teleosts and the remaining four infect elasmobranchs. Adult females undergo transformation through loss of locomotory appendages to suit their mesoparasitic lifestyle and develop outgrowths on the cephalothorax or neck for attachment to the host. To date, only 176 marine siphonostomatoid species have been reported from South African waters, with only nine sphyriid species. Sphyriids previously collected from marine bony fish off the east, south and west coasts of southern Africa and preserved in 70% ethanol were studied. Specimens were examined with stereo- and compound microscopes and identified using published literature. Selected specimens were stained in lactic acid with added lignin pink, appendages were dissected and illustrated with the aid of a drawing tube. Selected specimens were also studied through scanning electron microscopy. The examined specimens were identified as species of Sphyrion and Lophoura. Re descriptions were done for all valid Sphyrion species females (S. laevigatum, S. lumpi and S. quadricornis) and new descriptions for the males of S. laevigatum and S. quadricornis. Post-metamorphosis females of Sphyrion species can be differentiated by the shape of cephalothorax, length of the neck in relation to the length of the trunk and the length of posterior processes in relation to the trunk length, while males are mostly very similar. New information is provided regarding the appendages of S. laevigatum and S. quadricornis. The appendages of the three species bear close resemblance to one another. Additionally, an identification key for the post metamorphosis females of Sphyrion species is provided. Re-descriptions were done for five female Lophoura species (L. caparti, L. cornuta, L. cf edwardsi, L. tetraloba and Lophoura sp.) and a new description of the male of L. tetraloba. Differences between young and post-metamorphosis females of L. cf edwardsi and L. tetraloba were observed in the width of the holdfast organ processes and the length of porous peduncle and stalks of the posterior processes which appear to grow with age. The difference between the young and adult male of L. tetraloba lies in the lengths of the cephalothorax in relation to the trunk length and segmentation visible on the trunk of the young male but not adult male. The post-metamorphosis females of Lophoura species can be differentiated by the shape and number of processes on the holdfast organ, in combination with the cephalothorax length in relation to the neck length, neck length in relation to the trunk length, shape of the trunk, and the length and structure of the posterior processes. An identification key was drawn up for all species of the Lophoura post-metamorphosis females. An attempt was made to provide the COI barcodes for all the species of Sphyrion and five species of Lophoura. These would have confirmed the species identification of morphologically variable species e.g. S. laevigatum and S. lumpi and also provide an estimation of the interspecific divergence amongst the different species. Additionally, it would have assisted in distinguishing between L. tetraloba and L. cf edwardsi and provided an estimation of the amount of sequence divergence between the two genera. Unfortunately sequencing of apparently successfully amplified products was unsuccessful probably due to low DNA quality which possibly degraded due to collection methods used for the fish hosts and parasites and prolonged preservation of specimens. This study provides new host records i.e. Coelorinchus simorhynchus, Coelorinchus trunovi and Saurida undosquamis for Sphyrion quadricornis off South Africa which is also a new geographical record. Allocyttus verrucosus, Coelorinchus simorhynchus, Coelorinchus trunovi, Mesovagus antipodum and Ventrifossa nasuta are also new host records for S. lumpi. Additionally, Epigonus denticulatus and Bassanago albescens are new host records for Lophoura caparti and L. cornuta respectively off South Africa, which is a new geographical record for both species. Furthermore, Coelorinchus fasciatus and Lucigadus ori are new host records for Lophoura tetraloba and L. cf edwardsi off South Africa, which is also a new geographic record for both species. Thus, the results of the study improve the current knowledge of the marine siphonostomatoid biodiversity off South Africa as well as their distribution and infected hosts. / National Research Foundation (NRF)

No description available.

Neocalanus plumchrus is the most common copepod in the Northeast Pacific, and as such plays in important role in the ecosystems of that area. The bulk of N. plumchrus’ annual life cycle is spent in a dormant overwintering state, and little is known of its ecology, behaviour, or physiology during that period. The goal of this thesis is to describe the physiological changes that occur during the overwintering period, and explain how they interact with the physical environment to produce observed life history patterns. Lipid stores in N. plumchrus were primarily wax esters, and were in highest abundance in overwintering stage 5 copepodids. Consumption of wax ester stores began approximately two months prior to moulting in situ. Rates of lipid use in the in situ population and a number of laboratory incubations ranged from 0.3 - 1% d⁻¹ , with 22 - 60% of total wax ester reserves used prior to moulting, presumably to fuel gonadogenesis. Concurrent measurements of protein content and glutamate dehydrogenase activity (an enzyme involved in protein catabolism) did not show any significant protein use during overwintering. Incubation experiments suggest that N. plumchrus has some concept of the time of year (i.e. an endogenous clock), but the use of external cues cannot be ruled out. It is often assumed that the abundant lipids found in calanoid copepods play some role in buoyancy regulation. However, lipids are generally more compressible, and more thermally expansive than seawater, which means that neutral buoyancy will be inherently unstable. A simple model of mass density shows that (i) individuals will only be able to stay at depth if they are able to diagnose where they are neutrally buoyant, and (ii) the buoyancy properties of an individual are extremely sensitive to its chemical composition. In the Strait of Georgia, depth-specific measurements of abundance showed a shift towards deeper depth distributions over the course of the overwintering period. Model results suggest that lipid use could be responsible for those changes, though deep water renewal events that occur regularly in the Strait of Georgia in winter may also have been partially responsible. / Graduate

Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2017-05-23T14:19:21Z No. of bitstreams: 2 DISSERTAÇÃO BADPI_ LUIS - (VERSÃO DEFINITIVA).pdf: 1683978 bytes, checksum: 366084cb40f63be76253c54f267fc133 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-23T14:19:21Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO BADPI_ LUIS - (VERSÃO DEFINITIVA).pdf: 1683978 bytes, checksum: 366084cb40f63be76253c54f267fc133 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-10 / Instituto de Amparo a Ciência, Tecnologia e Inovação de Roraima - IACTI-RR / The study addresses to the copepods natural history of an urban lake in a protected municipal area in the lavrado of Roraima, whose lake has the characteristic of being the unique remnant of urban lakes in Boa Vista. The lake has a round format, measuring near 60 meters in diameter. The research was related to the population structure of the copepodes of the lake. The samples were taken in six visits during December 2014, the dry period of the region, covering three microhabitats: margin with vegetation of gramineans and cyperaceans, limnetical portion and margin with absent vegetation. Each visit corresponded to a sample in one microhabitat – in all 6 samples per microhabitat. These samples also encompassed three phases of the lake – full waters, empting and critical levels of the water. Four questions guided the study concerning the proportions of adults (male and female), copepodits (juveniles) and náuplius (larvae) inside and between the microhabitats. Each question had its respective hypothesis, considered the provisory answer to the question, which results allowed some inferences on the dynamics of the studied copepod population. The main results related to these four questions were: First – i) the proportion of adults and copepodits were greater than the náuplius in the thre microhabitats, ii) the proportion of náuplius, copepodits and adults were greater in the limnetical portion, iii) the proportion of adults was fewer in the margins with vegetation. Second – i) the sexual ratio was 1:1 among the three microhabitats, ii) inside the three microhabitats the proportion between males and females was also 1:1. Third – in the three microhabitats the proportion of females carrying eggs was slightly greater when the lake was full or empting, ii) female carrying eggs was equally distributed in the three microhabitats when the lake was full, iii) the proportion of females carrying eggs was greater in the center and in the margin without vegetation when the lake was in its critical water level. Fourth – i) among the three phases of the lake – full, emptying and critical levels of the water – the copepodits and males and females adults were more abundant than náuplius, ii) the proportion of náuplius was homogenous and more abundant in the high levels of water (full and emptying), less abundant in the critical levels of water, iii) the copepodits were more abundant when the lake was emptying, but homogenous in the extreme phases– full and critical levels, iv) adult males and females had its abundance reduced at the same proportion as the water was decreasing in a sequence of full water, empting and critical levels of water. / O estudo aborda a história natural dos copépodes presentes em um lago urbano situado em área municipal protegida no lavrado de Roraima que tem como característica ser o único remanescente dos lagos das áreas urbanas de Boa Vista. O lago tem formato arredondado, medindo aproximadamente 60 metros de diâmetro. A pesquisa foi relacionada à estrutura populacional dos copépodes do lago. As amostragens foram feitas em seis visitas durante dezembro de 2014 e Janeiro de 2015, época de estiagem na região, abrangendo três microhabitat do lago: margem com vegetação de gramíneas e ciperáceas, porção limnética e margem oposta sem vegetação. Cada visita correspondeu a uma amostragem em um microhabitat – ao todo foram 6 amostragens por microhábitat. Estas amostragens abrangeram também três fases do lago – cheia, período intermediário (entre cheia e seca) e seca (níveis críticos de água). Foram quatro perguntas norteadoras do estudo abrangendo as proporções de adultos (machos e fêmeas), copepoditos (os jovens) e náuplius (larvas) dentro e entre os microhabitat. Para cada pergunta foi formulada a respectiva hipótese, considerada resposta provisória à pergunta, cujos resultados permitiram algumas inferências sobre a dinâmica da população estudada dos copépodes. Os principais resultados relacionados a estas quatro perguntas foram: Primeira – i) as proporções de adultos e copepoditos foram maiores do que a dos náuplius nos três microhabitat, ii) as proporções de náuplius, copepoditos e adultos foram maiores na porção limnética, iii) a proporção de adultos foi menor na margem com vegetação. Segunda – i) a razão sexual foi 1:1 entre os três microhabitat, ii) dentro dos três microhábitats a proporção entre machos e fêmeas apresentaram distorção na razão sexual, sendo homogênea na margem sem vegetação e apresentando distorção sexual na zona limnética e margem com vegetação, sempre com fêmeas predominando. Terceira – i) nos três microhabitat a proporção de fêmeas com ovos foi ligeiramente maior quando o lago estava cheio, ii) fêmeas com ovos distribuíram-se igualmente nos três microhabitat quando o lago estava cheio e durante o seu período de redução espacial (intermediária entre a cheia e seca), iii) a proporção de fêmeas com ovos foi maior no centro quando o lago está com menos água, iv) as proporções de fêmeas com ovos foi maior no centro e na margem sem vegetação quando o lago está com nível crítico de água. Quarta – i) entre as três fases do lago – cheia, intermediária e seca, os copepoditos (jovens) e os adultos foram mais abundantes do que os náuplius, ii) as proporções de náuplius foram homogêneas nas fases altas de água (cheia e período intermediário) e menor nos níveis críticos de água, iii) os copepoditos foram mais abundantes na fase intermediária do lago e homogêneos nas fases extremas – cheia e seca, iv) os machos e fêmeas adultos tiveram abundância reduzida na mesma proporção que a redução de água do lago na sequência cheio, período intermediário e seco (nível crítico de água).

In the upper estuary of Yaquina Bay, Oregon, there is an annual population explosion of Acartia tonsa, (Dana) a calanoid copepod, during the months of July, August and September, followed by a rapid decline to virtual extinction in November. The restricted estuarine distribution affords an excellent opportunity to study the factors governing the population dynamics of A. tonsa without the disadvantage of potential mixing with other populations on different schedules of development. Field densities of A. tonsa during the 1972 summer were determined by twice weekly sampling with Clarke-Bumpus plankton samplers. In addition, explanation of the production of A. tonsa in the field was attempted by measuring the rates of egg production and development in the laboratory under temperature (21°C) and salinity (25‰) conditions comparable to those in the upper estuary. Daily egg production was found to be 30.5 eggs*day⁻¹*female⁻¹. The median rate of development from egg to adult required 11.5-11.6 days at 21°C in conditions of either laboratory cultured or wild food organisms. Mortality rates were substantial during the experiments as only 20-30% of the original populations survived to adulthood. The cause of mortality is not known but may relate to the molting process. In the field, six successive generations of A. tonsa were observed during the population explosion. The mean generation time ranged from 16 days in August to 19 days in October. A maximum density of 16,800 adults*m⁻³ in late August was followed by a crash to 2,100 adults*m⁻³ 10 days later. Predation and over exploitation of food resources are two possible causes of the crash. However temperature appears to be the major factor for the subsequent decline and disappearance of A. tonsa in the fall. This thesis presents the first results of ongoing research into the population dynamics of A. tonsa. / Graduation date: 1974

Thesis (Ph. D.)--Florida State University, 2003. / Advisor: Dr. David Thistle, Florida State University, College of Arts and Sciences, Dept. of Oceanography. Title and description from dissertation home page (viewed May 18, 2004). Includes bibliographical references.

No description available.

No description available.

Graduation date: 1986