Global ETD Search
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Showing 1 to 20 of 20 for “"Limpets"”.
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Dispersal and connectivity of northeastern atlantic patellid limpets: a multidisciplinary approach
Dispersal and connectivity of patellid limpets (Patella spp.) in the eastern North Atlantic have been examined by addressing reproductive biology, larval development, population genetics and physical modelling of dispersal. The reproductive cycles of four limpet species were assessed on the …
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Studies on the natural history of the limpets of the family Acmaedae
… findings of two years of part-time work on the limpets of the family Acmaedae. The major portion of the work was done on the Monterey Peninsula between Point Pines, 36° 38' 30" N. latitude, 121° 56' 00" W. longitude, and Pescadero Point 30° 33' 40" N. latitude, 121° 56' 30" W. longitude. The …
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Vertical zonation of three species of California limpets (Acmaeidae) as a function of predation
<p>Various studies indicate the acmaeid limpet species Collisella digitalis, Collisella pelta and Notoacmea scutum inhabit different vertical zones in the rocky-intertidal region. At Sunset Bay, Oregon, Shotwell (1950) found that C. digitalis was situated in the upper intertidal C. pelta inhabited …
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Interactive effects of temperature and grazing by seagrass limpets (Siphonaria compressa and Fissurella mutabilis) on seagrass (Zostera capensis)
… abundance by 70% in certain areas. Two limpets, Siphonaria compressa and Fissurella mutabilis depend on Zostera capensis for their survival in Langebaan Lagoon, feeding on epiphytic diatoms, filamentous algae and bacteria growing on blades on seagrass. Siphonaria compressa occurs …
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Phylogeny and biogeography of Southern African limpets in the genus Siphonaria in the context of a global phylogeny
Abundant, diverse and ecologically important, the 'false-limpet' genus Siphonaria has a near world-wide distribution. However, arising from uniformity of shell shape among species and its plasticity within species, frequent synonymisations and changes of names have created uncertainty about the …
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The Response of a protandrous species to exploitation, and the implications for management: a case study with patellid limpets
… to female sequential) hermaphrodite. Patellid limpets are broadcast spawners which can have specific implications for the effect of exploitation on reproductive output, due to sperm limitation. The combined zygote production model was made of three component sub-models; a population fecundity …
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Population ecology, desiccation, and food resources with respect to angle of substrate for two limpets, Collisella (Acmaea) digitalis and Collisella (Acmaea) scabra
<p>Two common limpets, Collis~ (Acmaea) digitalis and Collisella (Acmaea) scabra have overlapping distributions in the upper int.ertidal .spray zone. Haven (1971) found that Q. digitalis is more abundant on vertical surfaces while Q. scabra dominates horizontal surfaces. He assumed this preference …
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The effectiveness of Table Mountain National Park Marine Protected Area in the conservation of rocky shore biodiversity
… greater densities of the commonly harvested limpets Cymbula granatina, C. oculus and Scutellastra argenvillei, most obviously on sandstone ledges where abundances were greatest. In contrast, densities of the rarely harvested limpets, S. cochlear, S. longicosta and S. granularis did not differ …
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Benthic-pelagic coupling : rocky intertidal communities and nearshore oceanographic conditions across multiple scales
… observed, with only specialized kelp-trapping limpets showing a smoothly decreasing trend with latitide. Abrupt changes in the abundance of several species were observed at about 32° or near 34.5° S. Correlations between functional groups were strongest in the low (exposed) and mid (sheltered) …
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A genetic and morphological analysis of species complexes within the genus Patella
Limpets of the genus Patella are very common intertidal molluscs that have a widespread world-wide distribution. Despite this, the systematics of the genus is still in a state of confusion. However, in comparison to other regions, the southern African representatives of Patella are fairly well …
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A comparison between macrofaunal communities on mixed shores and rocky and sandy shores in False Bay
… meridiana/is and inability of patellid limpets and various algae, to withstand sand inundation are largely responsible for these differences.
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Investigating Predation in the Fossil Record: Modern Analogs
… subject to intense predator-prey interactions. Limpets are important prey for some crab species, yet little is known about the role of durophagy in the evolution of the limpet shell. Feeding trials using three common species of Pacific Northwest limpets (Lottia digitalis, L. pelta and Tectura …
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An Analysis of Human Disturbance to Rocky Intertidal Communities of San Luis Obispo County
… muricata</em>, <em>Mastocarpus papillatus</em>, limpets, and chitons. To assess whether long-term exposure to foot traffic could impact the abundance of access-indicator taxa in MDO, the abundance of these taxa was sampled at Hazard Reef and compared to the abundance of the same taxa at two …
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Contributions to Variable Selection in Complexly Sampled Case-control Models, Epidemiology of 72-hour Emergency Department Readmission, and Out-of-site Migration Rate Estimation Using Pseudo-tagged Longitudinal Data
… 50%. We also found that 44.1% of the limpets emigrate/die within their first 6-month time interval.</p> <p>In the third project, I investigated the most significant predictors of a return to the Emergency Department within 72 hours, with a focus on adult patients with a respiratory …
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Early evidence for coastal exploitation in Ireland
… settlements, oxygen-isotope analysis of modem limpets was undertaken. Unfortunately, the results were negative proving that such analysis is not viable for the west of Ireland. Finally, references to coastal resource exploitation were garnered from the post-medieval literary record and are …
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Coastal resources and nutrition among Middle Stone Age hunter-gatherers in the Southwestern Cape
… Marine foods, including intertidal mussels and limpets, are rich in the two most important omega-3 fatty acids found in the human brain, namely eicosapentaenoic and docosahexaenoic acid. The inclusion of coastal resources, particularly sessile, abundant, predictable and easily collected marine …
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Use of cell wall-hydrolytic enzymes in studies of the reticuloendothelial-stimulatory properties of Propionibacterium acnes
… bacterial surface. The bacteriolytic enzyme from limpets was purified over 150-fold by preparative isoelectric focusing and named Patella vulgata lytic (PVL) enzyme. PVL enzyme activity in crude extracts could lyse many bacteria not lysed by lysozyme. The purified PVL enzyme had an isoelectric …
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Biological adhesion in wet environments: adaptations and mechanisms
… mechanisms to the powerful attachment of common limpets (Patella vulgata) to rocks in the intertidal zone. I demonstrate that suction is not the primary contributor to their attachment forces; rather, it is their adhesive pedal mucus that is responsible. This adhesive mucus comprises of a complex …
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Behavioural and isotope ecology of marine-foraging chacma baboons (Papio ursinus) on the Cape Peninsula, South Africa
… unknown factors (e.g. alkaloids in mussels and limpets) may also limit the troop's exploitation of marine foods. In conclusion, this thesis represents the first in-depth study of marine foraging, a behaviour which exemplifies baboons' remarkable behavioural and dietary flexibility. That said, …