OIMB Theses
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This collection contains some of the theses and dissertations produced by students in the University of Oregon OIMB Graduate Program. Paper copies of these and other dissertations and theses are available through the UO Libraries.
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Item access-status.open.access.listelement.badge MERCURY IN THE ENVIRONMENT(1971-09) Tsuneyoshi, KunioThe chances of us being exposed to mercury and its compounds are significant. During the past, farmers, miners, and manufacturers have used millions of pounds of mercury annually. Mercury containing agricultural chemicals are used widely because of their antifungal activity and mercury is used extensively in the manufacturing of many inorganic and organic chemicals, pulp, felt, and electrical appliances. The pollution resulting from these applications eventually finds its way into our food and water supply. The different forms of mercury which get into the environment can be converted to the more dangerous methylmercury by microorganisms. The ingestion of polluted freshwater and saltwater fish is probably the main route by which mercury enters the human body. In heavily polluted water the mercury level in fish can be very high.Item access-status.open.access.listelement.badge Review of factors contributing to the settlement and recruitment of barnacles(2007-03) Trainer, JamesBarnacles are popular study organisms for a variety of reasons. As adults, they are sessile, and they are often small and numerous, making them easy to manipulate in ecological experiments. A researcher can be sure that an adult barnacle that disappears between observations has died, and has not moved away. As larvae, they develop through a series of six naupliar instars in the plankton. Nauplii are easy to identify in plankton samples, and are easy to collect from the egg lamellae of adult barnacles and culture in the laboratory. Nauplii metamorphose into the non-feeding cyprid stage, at which point they attempt to contact and stick to hard substrata. Depending on condition of the substrate, cyprids metamorphose into juvenile barnacles or return to the water column. A juvenile barnacle feeds and grows at its site of metamorphosis until it dies.Item access-status.open.access.listelement.badge The High Nutrient Low Chlorophyll (HNLC) Phenomenon and the Iron Hypothesis(1996-04) Stenn, Erik StrickerWith rising CO2 levels in the atmosphere it becomes increasingly more important to understand the nature of the oceans as a sink for CO2 as well as the mechanisms that transport carbon from the atmosphere to the oceans. Regions of ocean in the subarctic Pacific, eastern equatorial Pacific and the southern Ocean have been recognized as being abnormally low in total biomass and yet they maintain high levels of available macronutrients. Due to the characteristic high nutrient low chlorophyll content of these regions, they have been dubbed HNLC. The 'biological pump' concept is a proposed mechanism serving as a carbon sink and was assumed to be limited by nitrogen. Early shipboard container experiments demonstrated that iron might be the limiting nutrient and not nitrogen. The data from the early experiments proved to be inconclusive due to imprecise methodology. In the late 1980' s there was renewed interest in HNLC areas championed by J.H. Martin. He maintained that HNLC regions exhibit Leibig limitation by iron, where, standing crops of phytoplankton are constrained by availability of iron: if iron were available, the standing crops of phytoplankton would increase and nitrate would be depleted despite grazing. Others argue that HNLC regions are a manifestation of active grazing in a steady state ecosystem. An intermediate camp claims that HNLC regions are a result of combined physical and biological processes that prevent the utilization of the surface macronutrients. The debate surrounding this issue prompted Martin and colleagues to perform the IronEx experiment: the in situ use of iron to enhance an HNLC patch in the Galapagos region of the Pacific. The ecosystem demonstrated an unequivocal response to iron; however, macronutrients were still relatively abundant after the experiment. Subsequent studies have revealed that iron impacts all cell size groups of phytoplankton and constrains new production in HNLC areas. What remains unclear is the effect of grazing within these ecosystems.Item access-status.open.access.listelement.badge The Ecology of the Dall Porpoise (Phocoenoides dalli) and Interaction With Japanese Fisheries in the North Pacific Ocean(1988-06) Stark, Kimberle AnnThe Dall porpoise (Phocoenoides dalli True) is a small, deep-bodied and easily identifiable cetacean found in the northern North Pacific Ocean and adjacent waters including the Gulf of Alaska, Bering Sea, Sea of Okhotsk, and the Sea of Japan.Item access-status.open.access.listelement.badge PACIFIC NORTHWEST COASTAL TEMPERATURES: INVESTIGATION OF INTERDECADAL CYCLES AND BIOLOGICAL IMPLICATIONS(1998-06) Shotwell, KaleiInvestigations regarding interdecadal climate cycles have surged in the past several years providing alternative perspectives into the forcings on climate change. The possible couplings between the various patterns of these physical processes (oceanic, atmospheric), terrestrial, and biosphere regimes are of substantial importance. This study seeks to explore the relationship between the ocean and the land-surface on a regional scale. It is hypothesized that Pacific Northwest coastal sea surface temperatures and surface-air temperatures are temporally identical, or merely offset by a time lag, with the same pattern and period. Correlation and regression analysis were completed for the chosen sites, and significant positive correlation (r: 0.843) was determined. The similar cycles of the marine and terrestrial environments have significant biological implications. The progress with and problems of biological climate patterns is discussed along with the importance of proxy indicators, and relevancy to fisheries and management.Item access-status.open.access.listelement.badge THE DIETS OF THE SHINER SURFPERCH (Cymatogaster aggregata Gibbons) AND THE STAGHORN SCULPIN (Leptocottus armatus Girard) IN THE UMPQUA RIVER ESTUARY, OREGON 1981-1982(1987-06) Seymour, John PatrickThis was the first diet study on the shiner surfperch and the staghorn sculpin in the Umpqua River Estuary, Oregon. Gammarid amphipods, teleosts, and ghost shrimp were the most important food items of the staghorn sculpin whereas barnacle cypris larvae, cancer crab megalops, and copepods were the main components of the shiner surfperch diet. Only large staghorn sculpins ate teleosts, whereas only the smaller ones ate isopods. This study supports literature reporting a change in sculpin diet with size. Staghorn sculpins ate larger prey if they were larger. Monophagous foraging by the shiner surfperch was found with cancer crab megalops and crab zoea. Adequate sample sizes for future studies were determined.Item access-status.open.access.listelement.badge SOME ASPECTS OF THE ECOLOGY AND BIOLOGY OF TWO CANCER SPECIES(1980-12) Selby, Richard S.As a commercially exploited species the Dungeness Crab, Cancer magister, has generated a fairly large, unconsolidated body of literature. Initial research undertaken in British Columbia, Washington, Oregon and California dealt with general biology and the fishery, with the goal of determining the adequacy of fishery regulations. At that time no danger of overfishing was thought to exist, although fishery effort was intensifying (Cleaver 1949). A number of authors also noted a coastwide cycling in abundance of crab landings. However, after the 1960-1961 season the central California fishery did not recover from low levels of abundance associated with a cyclic minimum. Concern for this fishery prompted a new wave of investigations of population dynamics, making use of recent ecological theory, computer analysis and modeling techniques. The possibility that the fishery could alter natural population cycles, resulting in drastically lowered population levels throughout the species' range, was suggested. The purpose of this paper is critically to review the ecology and exploitation of magister using the information gathered throughout the last 60 yearsItem access-status.open.access.listelement.badge A REVIEW OF MODELS ON THE SELECTION OF HERMAPHRODITISM AND THEIR APPLICATION TO A MARINE GASTROPOD: HERMISSENDA CRASSICORNIS(1989-12) Schmit, Valerie M.The current literature covering certain models for the selection of hermaphroditism was reviewed. The purpose of the review was to assess the models' ability to determine if there are constraints present that pressure a particular species to remain hermaphroditic. The models of Michael Ghiselin, E.L. Charnov, J.J. Bull, and J. Maynard Smith were examined in order to test their applicability to the nudibranch Hermissenda crassicornis. The ecology of H. crassicornis was reviewed in reference to the models so that their fit in relation to what is known about H. crassicornis could be evaluated.Item access-status.open.access.listelement.badge THE LARVAE DYNAMICS OF CANCER MAGISTER IN THE COOS BAY ESTUARY(2022-07-06) Rowell, DavidThe role of an estuary or bay in the life cycle of Cancer magister is not well understood. I believe Coos Bay, as well as other bays, is an important "nursery" ground for young crabs, its recruits are necessary for sustaining a commercial fishery. Tasto (1978) has shown that juveniles account for a larger percentage of an estuary's crab population than in nearshore waters. The juveniles in the S.F. Bay-complex exhibited a growth rate nearly twice that of ocean-reared crabs (Tasto et al 1981). It is postulated that this is due to reduced predation pressure and increased food supply within the estuary.Item access-status.open.access.listelement.badge THE BIOLOGY OF AN INTRODUCTION: RHITHROPANOPEUS HARRISII(1978-05) Pisciotto, Ronald JosephWhen I first arrived in the Hawaiian Islands on a teaching assignment in 1970 I naively expected to be greeted by a landscape clothed in the native flora. Instead, what I saw as I left the airport was a collage of introduced species which I took to be natives. It was not long before I realized the error (interestingly , one of the first courses I was to teach was entitled "Plants and Animals of Hawaii'', a little surprise for the man fresh off the boat.) Curiously, I had to travel 2,300 miles from my native California to be made aware of something that had so blatantly surrounded me all my life: that human habitations tend to assemble communities of exotic organisms. One look at any neighborhood garden with its many ornamentals should confirm this.Item access-status.open.access.listelement.badge A REVIEW OF INTRA- AND INTERSPECIFIC AGGRESSION AMONG SEA ANEMONES(1989-03) Petersen, Kristine K.This paper reviews the current knowledge of aggressive behavior in sea anemones (Anthozoa), considering the type of organs used in aggression and the lifestyles of the sea anemones involved. The mechanisms involved in the recognition of related anemones and the role of aggression in structuring populations are also addressed.Item access-status.open.access.listelement.badge Predicted response of eelgrass (Zostera marina L.) photosynthesis, growth, and survival to ocean acidification(2009-07-30) Morgan, ErinOver the past 250 years, the composition of Earth's atmosphere has changed as a result of anthropogenic emissions of greenhouse gases. For example, activities such as deforestation, agriculture, and the burning of fossil fuels have produced a 31% increase in the concentration of atmospheric carbon dioxide ([CO2]) since 1750 (IPCC 2001). Earth's atmosphere is linked to the oceans at the sea surface, such that alterations in atmospheric composition are reflected in the water. In particular, atmospheric CO2 exists in equilibrium with dissolved CO2 (CO2(aq)) in the oceans. As the atmospheric [CO2] increases, gas exchange with the oceans causes a concomitant increase in [CO2(aq)], with concentrations rising toward a new equilibrium value (Goudriaan 1993, Guinotte and Fabry 2008).Item access-status.open.access.listelement.badge EUTROPHICATION: CHANGES IN ESTUARINE PHYTOPLANKTON PRODUCTIVITY(1974) McLean, April G.Estuaries are individually unique ecosystems, each with specific environmental characteristics. There are, however, some generalizations that can be made describing estuaries overall. Caspers (1967) gives four features applicable to estuaries : 1) limited to rivermouths in tidal seas; 2) saline areas present, their extent dependent on the amount of freshwater runoff; 3) the upper limit of the estuary is defined by the upper limits of tidal influence into freshwater zones; 4) characterized by changeable salinities and instability of environmental factors. Brackish systems have been put into three categories by a number of workers (cf. Emery, et.al.(1957), Pritchard (1967)) breaking them into positive, inverse and neutral groups. Positive estuaries are river dominated, freshwater runoff exceeding evaporation rate. Inverse estuaries are characterized by rapid evaporation rate, surpassing runoff and precipitation. These are hypersaline the majority of the time. Neutral estuaries have a balance between evaporation and freshwater influx. These classifications, however, are oversimplifications. Pritchard (1967) defines an estuary as a "semi-enclosed coastal body of water which has a free connection with the open sea and within which seawater is measurably diluted with freshwater derived from land drainage." Pritchard's definition restricts the term "estuary" to signify only the so-called "positive estuary". Emery, et. al. (1957) use the term "normal estuary" to be equivalent to positive estuary.Item access-status.open.access.listelement.badge ENDOCRINE AND OTHER PHYSIOLOGICAL FACTORS ASSOCIATED WITH THE SPAWNING MIGRATION OF PACIFIC SALMON (ONCORHYNCHUS SPP.) AND THE STEELHEAD TROUT (SALMO GAIRDNERI)(1975-12) Mahony, Daniel LewisTwo genera of fishes in the family Salmonidae have stimulated considerable biological interest on the Pacific coast of North America. The anadromous life histories of both the Pacific salmons (Oncorhynchus spp.) and the migratory rainbow trout (Salmo gairdneri) have provided many research opportunities during the past several decades. Although the life histories of these two genera of fishes are quite similar, a basic difference is reflected in their post-spawning mortalities. While the universal post-spawning mortality of adult Pacific salmon restricts them to a single spawning, some of the anadromous trout may spawn repeatedly, but post-spawning mortality may amount to as much as 50%. The ability of the steelhead trout to survive under the same environmental stresses that result in the death of Pacific salmon represents -- a still somewhat Puzzling species difference of vertebrate physiological uniqueness. This paper will attempt to review current and past work on this question of survival vs. death in these anadromous fishes which comprise one of our most valuable local natural resources.Item access-status.open.access.listelement.badge THE MARINE PHYTOPLANKTON AND ITS NUTRIENTS: NITROGEN AND PHOSPHORUS(1971) Lo, Patrick S. F.Growth of phytoplankton can go on reasonably with only very small quantities of nutrients amounting to a: few milligrams of phosphorus as phosphate per cubic meter of sea water and usually a somewhat larger amount (about eight times by weight) of nitrate nitrogen. Their remarkable growth as compared with the growth of land plants at such great dilution is partly explained by t he microscopic size of the phytoplankton cells, which makes for better diffusion of nutrients a s well as a greater surface to volume ratio which promotes absorption (Raymont, 1963).Item access-status.open.access.listelement.badge AN ANALYSIS OF INCREASED TEMPERATURE AND ULTRAVIOLET RADIATION AS CAUSES OF CORAL BLEACHING(1994-01) Joslyn, Andrea LuisaSymbiosis, the cohabitation of two or more different organisms, is represented across species as well as phyla. A unique symbiosis has developed in the marine environment between the phylum Cnidaria and members of the Division Dinophyta ("zooxanthellae"). The relationship is one of mutualism, as both organisms benefit from the relationship. Although cnidarians, such as sea anemones, hard and soft corals, scyphozoans, and hydrocorals, comprise the majority of hosts that take part in this symbiosis, some nudibranchs and sponges also contain endosymbiotic dinoflagellates. Alternatively, some cnidarians may contain chlorophyte endosymbionts. The symbionts are usually held with vacuoles inside the host endoderm cells (Glider et al., 1980; Trench, 1987), but they have also been found within the epidermis and mesoglea of some cnidarians.Item access-status.open.access.listelement.badge THE EFFECT OF UV RADIATION ON CYANOBACTERIAL MAT COMMUNITY STRUCTURE(2000-06) Inman, Carrie EliseCyanobacteria are thought to have evolved during the early Precambrian, 2.5-3.8 billion years ago, when there were very high levels of UV radiation reaching the Earth's surface due to a lack of absorbing gases int he atmosphere. Oxygenic cyanobacteria were one of the few photosynthetic organisms that could survive under these harsh conditions. Cyanobacteria today have also been found to employ UV tolerant strategies to cope with the damaging effects of UV radiation. In this study three cyanobacterial mats were investigated to determine if UV had an effect on the mats in the field and subsequently on clonal isolates cultured from these mats in the lab. UV exclusion experiments, using UV blocking and UV transmitting filters, were carried out in the field over a two-month period. Protein and pigment analysis on the core samples collected from the field UV treatments showed no significant difference between the treatments. However, samples collected of new settlement cell material on ceramic tiles, did show a significant different between the two UV treatments. UV exclusion experiments run using two strains of clonal isolates of Lebtolyngbya sp. cultured from Mushroom Spring did show a highly significant detrimental effect of UV on growth measured by dry weights. In addition, the two strains, one cultured from the UV(-) field material and one cultured from the UV(+) material, were effected differently by UV radiation in the lab UV exclusion experiment. The isolate cultured from the UV(+) mat material was less effected by UV radiation, as measured by dry weight accumulation over time. This may imply the use of a unique UV tolerant strategy employed by this strain.Item access-status.open.access.listelement.badge 'Ligia'(1971-08) Heide, AllenAdaptation to land from a water environment is a common topic in many textbooks. Most of the organisms discussed, though, have already adapted themselves to solve the most vital problems of water retention and temperature control. Animals such as mammals, reptiles, and birds have all developed outer coverings that are permeable to water and allow these animals a great deal of independence from their water sources. Mammals and birds have physiological adaptations that allow them to regulate their body temperature, while reptiles have relied mostly on behavioral patterns to cope with this problem. In this paper I would like to discuss the Isopod Ligia that is considered terrestrial in habitat, but is yet to evolve a complete independence from the sea. Ligia belongs to the family Oniscoidae, which is the Family of Crustacea containing species living a completely terrestrial life. Within the Isopods there are species such as Carolana harfordi and Idothea wasnesenskii that live a marine existence and others such as Porcellio and Amadillidium that are completely terrestrial. Ligia represents an interesting point of study in that it appears to be an intermediate species in the transition from the sea to land. I would like to discuss some of the physiological and morphological characteristics of Ligia that place it in the intermediate position and its general habitat and behavioral patterns that may help to give a fuller understanding of this unique genus.Item access-status.open.access.listelement.badge HEMOGLOBIN TRANSFORMATION DURING METAMORPHOSIS IN ANURANS(1978-05) Haury, David L.Hemoglobin (Hb), one of the most abundant vertebrate proteins, distributes oxygen among body tissues following oxygenation at the respiratory interface between organism and environment. During the course of natural selection, the Hb molecules of a particular species take on biochemical and biophysical parameters which facilitate adaptation to a unique environmental regime. Extensive research has shown that during the life history of a particular organism there may be a progressive expression of Hb types as characteristic alterations in oxygen availability and oxygen demand occur. Such is the case among anurans; during the discrete postembryonic transition period known as metamorphosis , new molecular forms of Hb appear which persist in the adult frog.Item access-status.open.access.listelement.badge TERRITORIALITY AND AGGRESSIVE BEHAVIOR IN MALE PINNIPEDS(1988-06) Hartke, Monica KathleenThe three families of pinnipeds include the Phocidae, "true seals", the Otariidae, sea lions and fur seals, and the Odobenidae, or of polygyny similarities in walruses. It is remarkable that the evolution in pinnipeds has generated such marked their behavior, while simultaneously creating extreme differences in the social and reproductive organization between the different taxa. The evolutionary relationship of the three families is not yet fully understood, for the fossil evidence is not complete. As a result, many ethologists theorize about the evolution of polygyny in pinnipeds while attempting to understand the evolutionary background of behavior. Most ethologists share a phyletic method of inferring behavioral evolution which has been described by Hinde and Tinbergen (1958) as follows, ...(sic)"by comparing the behavior traits of species whose phylogenetic relations are established (usually on the basis of morphology), it is possible to make hypotheses about the probable origins o f that behavior, and thus about the course of evolution."