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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Browsing OIMB Theses by Content Type "Thesis / Dissertation"
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Item Open Access 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 Open Access 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 Open Access Colonial Ascidian Dispersal: What are the effects of adult population density and isolation on recruitment?(2007) Braudrick, NateInvasive species are thought to be one of the largest ecological threats to healthy ecosystems today. This paper is an attempt to show how anthropogenic transport of species with short dispersal distances is the most important factor in their colonization of new areas. In the Charleston, Oregon marina three study sites were set up to attempt to show the significance of isolation and adult population density on the recruitment of colonial ascidians, an encrusting member of the fouling community. Significant results were found supporting the hypothesis that greater adult population density results in increased recruitment. The second hypothesis of isolation decreasing the recruitment of colonial ascidians was not supported with significant results.Item Open Access A CRITICAL REVIEW OF HOMING AND FORAGING BEHAVIOR IN LIMPETS (MOLLUSCA; GASTROPODA} : A CENTURY OF OBSERVATIONS , EXPERIMENTS , AND CONTROVERSIES (1894 TO 2001)(2002-12) April, Jane WrightHoming limpets are characterized by their predictable stationary resting behavior in their home territory during periods of inactivity, followed by active feeding excursions ranging up to a few meters away from home . They almost always return to their previous resting spot (home scar) during a tidal cycle. Limpets are grazers that use their radula to scrape and feed upon microalgae, macroalgal settlers, bacteria, cyanobacteria, diatoms and other phytoplankton, and animal larva that settle inside their grazing grounds, called the feeding arena. Home scars lie within the feeding arena and vary according to species . Most limpets live on rock, some live on macroalgal fronds, and some even live on the shells of other gastropods. Some home scars are visible as a chiseled indentation in rock that fits the shape of the limpet's shell perfectly. This depression is caused by the repeated scraping of the returning limpet's shell at the home scar. Other homing limpets do not make a strict scar, rather, they home to a region rather than a spot. Certain homing limpets will join clusters of conspecifics, returning to roughly the same position within the cluster from day to day.Item Open Access Detritus, a Critical Essay(1977) Chirarochana, JarDetritus plays an important role in the marine ecosystem. It forms a significant fraction of the available food sources (Darnell, 1958, 1961 , 1967; Gant et. al, 1971; Heald 1971; Lenz, 1977; E. P . Odum and Dela Cruz, 1967; W. E. Odum, 1971; W. E. Odum and Heald, 1975; Riley, 1970; Seki, 1972·; Teal, 1962). Detritus is the chief link between primary and secondary productivity in salt marshes and mangroves. This is because only a small portion of the net production of the marsh grass or mangrove is grazed while it is alive. The major energy flow between autotrophic and heterotrophic levels is by way of the detritus food chain (Gant et al, 1971; Heald, 1971; E. P. Odum and Dela Cruz, 1967; W. E. Odum, 1971; W. E . Odum and neald, 1975; Teal, 1962)Item Open Access 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 Open Access 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 Open Access 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 Open Access 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 Open Access ESTUARINE MICROPHYTE PRODUCTIVITY(1977-05) Gibson, Steven CharlesAn estuary is an interface where mixing of river and sea water occurs, often within the confines of an embayment. The abrupt environmental changes between these two environments pose a multiplicity of stresses to the estuarine biota, placing a premium on the ability to adapt to a wide range of conditions. Few species have sufficient adaptability to meet these conditions and so estuarine species diversity is low (Odum, 1970). Additionally, estuaries are "young" ecosystems in that pioneer species are always present because constant flushing by fresh water and the tides precludes a successional sequence from going to climax. Such "young," low diversity ecosystems are characterized by large standing crops of short lived species (resulting in short nutrient recycling times), and high primary productivity. Table l provides some net primary productivity values for various estuaries and other ecosystems. Microphytic net production plus macrophytic net production is often very high in estuaries, albeit less than tropical rain forests and many agricultural crops.Item Open Access 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 Open Access Factors Affecting the Retention of Eukaryotic Phytoplankton within the Euphotic Zone(1979-06) Corbett, Andrea CathrynPhytoplanktonic species face a serious problem in balancing photosynthetic light requirements with nutrient needs. Optimal light intensities are found toward the surface, while nutrients are usually in greater concentrations below the epilimnion. Motile species, such as the flagellates or gas vacuolate blue-green algae, collect at depths which optimize these needs, or migrate vertically to take maximal advantage of each in turn. Phytoplankton, with few exceptions, are denser than their media and without various internal and environmental suspension factors, non-motile species sink irrevocably from the euphotic zone. The subject of phytoplanktonic suspension has been reviewed by Hutchinson (1967), who dealt with limnetic species, and Smayda (1970) , who considered the problem in marine organisms. Research published after these papers appeared has added new dimensions to our understanding of the problem, and has stimulated the writing of this critical review. Since many of the suspension factors recognized are employed by both marine and fresh water species, it is convenient and useful to combine them into one paper. The prokaryotic phytoplankton are not considered here for a current and detailed analysis of gas vacuoles, the floatation bodies of prokaryotes, has been prepared by Walsby (1978). Many factors , both physical and biological, are implicated in maintaining epilimnetic populations of nonmotile phytoplankton. The primary mechanism is wind-induced turbulence. Even fairly light winds create Langmuir spirals which circulate and retain motile and nonmotile cells in an even distribution throughout the upper waters. Non-motile cells are dependent upon turbulence, and normally bloom only when a substantial mixing of nutrients and cells occurs in the euphotic zone. Motile cells lose position al control in turbulence but may become dominant in calm, stratified conditions. The many mechanisms which reduce sinking rate s in still laboratory media become effective in nature only as turbulence decreases. These secondary retention factors include cell size , shape, density, colony formation, mucous secretion, age, selective ion accumulation, fat storage, light, nutrient availability , etc. Each of these mechanisms are discussed and where possible their values to different groups of phytoplankton are compared.Item Open Access A GEOGRAPHI C STUDY OF THE CITY OF COOS BAY AND ITS HINTERLAND(1950-06) Feichtinger, John RudolphThe city of Coos Bay is a sea port located on the upper reaches of Coos Bay, mid-way on the Pacific Coast of the State of Oregon. With a valuable virgin timber supply which stretches east of it across the Coast Range to the vicinity of Roseburg, and with a thriving, though small, dairy industry which focuses on the city, the people of the city have attempted to rival Portland and Astoria as sea ports. And, t0 live up to their self-imposed title of "the largest lumber port in the world". A certain civic pride, and pride in achievement, are commendable and accepted in our modern society, but it is also possible to strain the limits of propriety. There is a desirability in "bigness" where size lends itself more effectively to efficient operation. But, the writer does not believe that extensive development is to be overly-encouraged where it is primarily dependent upon a single crop or industry. A false sense of security through large size alone is as -much a psychological boobytrap as is an overly pessimistic attitude. Both, or either, can lead to a misplaced reliance on emotional rather than factual data.Item Open Access Grazing of Zooplankton in the Oceanic Environment(1971-08) de Kort, Franciscus M. Th.Grazing in the oceans, in general, refers to herbivores feeding on plant material. It is an important factor in determining primary production in the sea, and is difficult to estimate. Also, this energy transfer seems at least in part to be responsible for population changes which occur in the ocean. Since it is only in the coastal waters that other plant material besides the phytoplankton is abundant (seaweed) and that other zooplankton organisms besides the copepods are abundant (meroplankton: the planktonic larval stages of Mollusca, Echinodermata and worms), attention will be primarily focused on the relation between phytoplankton organisms and copepods. (Marshall and Orr, 1966b) Most experimental work has been done with cope pods, al though other plank tonic animals (Euphausids, Chaetognaths etc.) are abundant at certain places for part of the year. In order to understand the problems involved in studying the quantitative aspects of grazing, a general discussion of the patterns of feeding is necessary (Chapter I). The second chapter provides the theoretical background. (mathematical models) for a discussion of the methods used and measurements obtained in chapter three. The last chapter discusses grazing as it relates to the ecological problem of population control and evaluates the progress made in this area of research.Item Open Access HAUL-OUT AREA USEAGE BY HARBOR SEALS (PHOCA VITULINA) AT THE NORTH COVE OF CAPE ARAGO, OREGON(2001-04) Cohnstaedt, Lee WilliamHarbor seals were observed on 70 occasions from 7 April to 10 August, 2001, at the North Cove, Cape Arago, Oregon, to determine if the harbor seals used different haulout zones within the haul-out area during different life history stages. This study identified sex and age as the most important factors influencing the selection of haul-out zones. A haul-out pattern was observed on days when both low tides occurred during daylight hours: the number of animals hauled-out during a morning low tide was fewer than those during the afternoon low tide regardless of weather conditions.Item Open Access 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 Open Access 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 Open Access 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 Open Access '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 Open Access 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).