Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 161-172. Also available online.

vi, 133 leaves : ill. ; 22 cm Photocopy of the 1966 edition Thesis--Oregon Bibliography: leaves 99-103 University of Oregon theses, Dept. of Biology, Ph.D., 1966

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on Jan. 6, 2010. Major professor: Dean E. Wendt. "Presented to the faculty of the Biological Sciences Department, California Polytechnic State University." "In partial fulfillment of the requirements for the degree [of] Master of Science in Biological Sciences." "September 2009." Includes bibliographical references (p. 61-69).

No description available.

In the urchin Strongylocentrotus purpuratus, the expression of the Spec3 gene is associated with the growth of cilia, one of the first morphogenetic events during development. The product of this gene was characterized using an antiserum raised against a peptide corresponding to the predicted amino-terminal portion of the protein. This thesis describes the localization of the Spec3 protein at different stages during embryonic development. Immunocytochemistry indicated that the protein is associated with cilia and Golgi complexes of ectodermal cells. Agents that inhibit protein synthesis and Golgi secretion also altered its normal distribution. Fractionation of cilia and immunoblotting indicate that the protein is associated with the ciliary axoneme and that it behaves as a large aggregate.

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains iv, 64 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 61-64).

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on October 23, 2009. Major professor: Nikki L. Adams. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Biological Sciences." "June 2009." Includes bibliographical references (p. ). Also available on microfiche.

Au cours de ces deux dernières décennies, la culture du pétoncle (Argopecten purpuratus) s’est développée dans les baies côtières péruviennes. La disponibilité trophique liée au système d’upwelling est favorable à la production du pétoncle. Cependant, les côtes péruviennes sont également connues pour présenter une forte variabilité environnementale surtout en domaine océanique. Bien que les élevages du pétoncle soient vulnérables aux aléas de production (mortalité, croissance faible), la variabilité environnementale dans les baies côtières du Pérou et ses effets sur la croissance, la reproduction et survie de cette ressource socialement sensible ont été peu étudiées. La baie de Paracas au Pisco-Pérou est une zone traditionnelle de culture du pétoncle où des hauts et des bas productifs liés aux conditions environnementales ont été enregistrés au long de son histoire. Dans le but d’approfondir nos connaissances sur cette problématique, cette étude se pose sous trois approches : (1) l’observation in situ, (2) l’expérimentation en physiologie et (3) la modélisation du bilan énergétique de A. Purpuratus. Un suivi environnemental mené dans la baie de Paracas montre que la variabilité océanographique peut être importante, en particulier pendant l’été. Des variations de température de 8°C et des conditions oxiques allant de la sursaturation à l’anoxie (absence d’oxygène) dans le cours d’une journée ont été observées. L’enregistrement haute fréquence a permis de révéler une exposition chronique, sévère et prolongée de la baie de Paracas aux conditions hypoxiques. Les pétoncles cultivés sur le fond, où l’exposition à l’hypoxie était importante (47% du temps observé) ont montré une croissance et les conditions de reproduction plus faibles. Cependant, au cours de l’été, les événements hypoxiques prolongés et sévères ont touché les deux profondeurs de culture- les pétoncles cultivés en suspension comme sur le fond-, causant des pertes de poids de tissu somatique ainsi que l’arrêt de la reproduction. Durant les expériences en laboratoire, les pétoncles ont montré une importante capacité à réguler leur respiration face à la diminution de la saturation en oxygène jusqu’à 24%. De manière surprenante, nous avons trouvé que cette espèce est capable de maintenir une filtration, quoique diminuée, même à des saturations en oxygène basses (5%). Sur la base des réponses physiologiques du pétoncle face à l’hypoxie et le rendement énergétique moindre du métabolisme anaérobie par rapport au métabolisme aérobie, nous faisons l’hypothèse d’une diminution de l’ensemble du métabolisme à des saturations en oxygène en dessous de la capacité de régulation de l’espèce. Des simulations d’un modèle incluant cette restriction énergétique (sur les flux d’assimilation et de mobilisation de la réserve) en conditions d’hypoxie parviennent à reproduire avec succès les observations de terrain effectuées dans la baie de Paracas : une plus grande exposition à l’hypoxie a pour conséquence une croissance réduite et un arrêt de la reproduction. Alors que le pétoncle possède des adaptations physiologique /métaboliques pour faire face à des conditions limitantes en oxygène, la croissance et la reproduction peuvent être compromises, affectant ainsi la productivité des cultures de cette espèce (cela en fonction de la fréquence, durée et intensité de l’hypoxie). Les résultats des observations, des expériences et des simulations réalisées lors de cette étude fournissent des informations utiles pour mieux gérer la culture de pétoncle péruvien. Sur la base de ces travaux, des estimations de capacité de charge des baies, et des évaluations de zones et profondeurs favorables pour la culture de ces pétoncles pourront être réalisées. / During the past two decades, the scallop (Argopecten Purpuratus) culture developed in the Peruvian coastal bays. The trophic availability linked to the upwelling system supports the production scallop. However, the Peruvian coasts are also known to have a high environmental variability especially in oceanic domain. Although scallop farms are vulnerable to production hazards (mortality, low growth), environmental variability in coastal bays of Peru and its effects on growth, reproduction and survival of this socially sensitive resource have been poorly studied. Paracas Bay in Pisco Peru is a traditional farming area where scallop highs and lows in productivity related to environmental conditions were recorded throughout its history. In order increase our knowledge on this issue, this study arises from three approaches : (1) observation in situ, (2) experimental physiology and (3) modelling of the energy budget of A. Purpuratus. An environmental monitoring conducted in the Paracas Bay shows that the oceanographic variability can be important, especially during the summer. Temperature variations of 8°C and oxic conditions ranging from supersaturation to anoxia (absence of oxygen) in the course of a day were observed. The high frequency monitoring has revealed a chronic, severe and prolonged hypoxic condition in Paracas Bay. Scallops grown on the bottom, where exposure to hypoxia was important (47% of the observed time) showed lower growth and reproductions conditions. However, during the summer, prolonged and severe hypoxic events affected both deep culture – scallops grown in suspension and on bottom- causing weight somatic tissue losses and cessation of reproduction. During the laboratory experiments, scallops showed significant ability to regulate their oxygen uptake face to decreased oxygen saturation up to 24%. Surprisingly, we found that this species is able to maintain filtration, although diminished, even at low oxygen saturations (5%). Based on the physiological responses of the Peruvian scallops face to hypoxia and the energy performance aerobic end anaerobic metabolism ; it is hypothesized that there exist a restriction in the energy flow available for metabolism at oxygen saturations below the regulation capacity of the organism. Model simulations including this energy restriction (on assimilation and reserves mobilization fluxes) against hypoxia can reproduce successfully field observations of Paracas Bay : greater exposure to hypoxia results in a reduced growth and reproductive conditions. Although the scallop has physiological adaptations/metabolism to deal with limited oxygen conditions, growth and reproduction can be compromised, affecting culture productivity of this species (according to the frequency, duration and intensity hypoxia). The results of observations, experiments and simulations obtained during this study provide useful information to better manage of Peruvian scallop cultures (ex. Load capacity estimates in the bays, evaluations of adequate areas/depths for culture, etc.).

Field surveys of Strongylocentrotus purpuratus demonstrated that concentrations of natural sunscreens, mycosporine-like amino acids (MAAs), were higher in females than males for both gonadal and epidermal tissues, increased in ovaries as spawning season approached, and were influenced by the sea urchins’ microhabitat. Sea urchins occupying burrows, or “pits”, had lower concentrations of MAAs than those outside pits, suggesting a trade-off between physical and UV protection. Overall, UV irradiance did not influence MAA accumulation in gonadal tissues. However, males increased their allocation of MAAs to epidermal tissues in the microhabitat with the highest irradiance. Relative concentrations of individual MAAs were similar for epidermal tissues from both sexes and ovaries, providing broadband UVA/UVB absorbance, but testes contained principally one MAA, palythine. This is the first study to demonstrate that S. purpuratus and eight species of macroalgae in California have MAAs, and that the concentrations can be influenced by microhabitat.

Marine dissolved organic matter (DOM) comprises one of the largest carbon reservoirs on earth and has long been considered a potential energy source for marine invertebrates. The importance of DOM transport has been adequately demonstrated for unicellular organisms, where DOM can meet 100% of an organisms energy needs, but the effects of DOM uptake for marine metazoans are less well understood. In this study, three general areas involving the influence of DOM transport to marine invertebrates were explored. First, we assessed the effects of using seawater exposed to high intensity ultraviolet radiation (UVR) on the study organism; embryos of the purple sea urchin, Strongylocentrotus purpuratus. This was important because we used seawater treated in this way to create water types used in the experiments. Exposing seawater to high intensity UVR oxidizes (and functionally removes) DOM in the seawater. Second, the influence of the presence of DOM on the timing of embryonic development was examined for embryos of S. purpuratus. Specifically, the time of cell division and the time of hatching were determined for embryos in seawater with and without DOM. Finally, the ability of DOM to moderate the negative effect of UV-exposure on time of cell division was assessed. To make these comparisons experiments were performed using three water types: FSW (0.22 micron filtered seawater), DOM-depleted seawater (UV oxidized 0.22 micron filtered seawater), and DOM-enriched seawater (UV oxidized 0.22 micron filtered seawater enriched with labile DOM). In the first experiment, batches of embryos in the three water types were either exposed or not exposed to ultra-violet radiation and the time of first cell division was compared for embryos across the six treatments. In the second experiment, batches of embryos were placed in the same three water types and the time of first cell division and the time of hatching were quantified. From these experiments several results were generated. First, seawater exposed to high intensity UVR did not influence the timing of development of embryos of S. purpuratus. Embryos in water exposed to high intensity UVR (DOM-enriched and DOM-depleted seawater) hatched at similar times and completed first cell division at times similar to embryos in water not exposed to high intensity UVR (FSW). Next, we found that the influence of the presence of DOM on the development timing of S. purpuratus embryos depended on the event that was examined. The time of first cell division was not affected by the presence of DOM but the time of hatching was. Embryos in water with dissolved organic matter hatched on average 86 minutes later than embryos in water without DOM. Potentially, embryos in seawater without DOM speed up development to more quickly reach the point that they can feed on particulates. Lastly, the presence of DOM did not influence UVR-induced cleavage delay. The percent cleavage delay was not significantly different for embryos in seawater with (DOM-enriched) and without (DOM-depleted) DOM. In addition to the experiments, all studies in the literature that examine the realized effects of DOM transport were analyzed to ascertain when the manifestation of DOM uptake is most likely to occur. From these results, it appears that the effects of DOM transport are most likely to manifest after the life stage in which the majority of uptake occurred. If DOM transport has an affect within a life stage it is most likely to manifest as moderation of biomass loss or maintenance of endogenous reserves. With the addition of the experimental results from this study to the information already in the literature we begin to more fully grasp the importance of DOM transport to S. purpuratus. DOM influences the time of hatching, biomass, arm length, and stomach size of the species; results that highlight the importance of examining multiple affects of DOM transport for a single species. In conclusion, future research should look for multiple effects of the presence of DOM both within and across life stages (for a single species) to better understand the importance of DOM to marine invertebrates.