Global ETD Search

11	Size, form and function in the early life histories of the gastropod genera Nucella and Littorina Moran, Amy Ladd January 1997 (has links) Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 152-172). Description: xiv, 172 leaves : ill. ; 29 cm. Gastropoda -- Life cycles Gastropoda -- Development Emarginate dogwinkle Littorina Snails -- Larvae
12	Copper bioaccumulation in blue mussels and periwinkles from marinas Sjökvist, Tomas January 2019 (has links) Copper (Cu) is a heavy metal that is essential for life but toxic at high concentrations. This toxic effect is used on boats to prevent biofouling on boat hulls by painting the hulls with antifouling paint that contain high levels of Cu. The Cu is slowly diffused out in the water and accumulated by animals higher up in the food chain. In order to test the effects of marinas on Cu bioaccumulation in invertebrates, I sampled molluscs at seven marinas and seven shore sites on the Swedish west coast. Two molluscs with different feeding behaviours, one grazer, the periwinkle (Littorina littorea) and one filter feeder, the blue mussel (Mytilus edulis) were used as study organisms. Both species were sampled at each location within 50 m from each other. Body Cu concentration of both species was measured with a Flame Atomic Absorption Spectrometer (FAAS). Cu concentration of periwinkle soft body tissue was generally higher than in mussel soft body tissue. In addition, periwinkle tissue Cu concentration reacted strongly positively to the presence of marinas, whereas mussel tissue Cu concentrations did not. This shows that contamination from marinas affects the grazing periwinkle but not the filter feeding blue mussel. Thus, for biomonitoring purposes, grazers may be more suited as indicator organisms. Littorina littorea Mytilus edulis antifouling paint invertebrates biomonitoring Annan geovetenskap och miljövetenskap
13	Trematode infection effects on survival and behaviour of Littorina sitkana Ayala-Diaz, Monica 25 April 2014 (has links) Several parasites that require two or more hosts to complete their life cycles are known to manipulate host behaviour, enhancing their transmission to the next host. The intertidal snail, Littorina sitkana, is host to a diverse assemblage of parasites dominated by trematodes. Trematodes often use snails as first intermediate host and vertebrates as definitive host. Trematode infections can affect host behaviours such as dispersal and foraging. I identified four sites in Barkley Sound that varied in trematode prevalence and species richness. I measured dispersal of snails at these sites and in the laboratory to assess effects of trematode infection on behaviour. I measured feeding rate under laboratory conditions. Trematode effects lowered snail grazing activity at three of the four sites studied, suggesting trematode infection lowers feeding rate of L. sitkana, potentially affecting algal composition of the intertidal zone. Infected male snails travelled longer distances in some sites but shorter distances in others. There was an almost significant effect of trematode infection on vertical displacement of L. sitkana in the field. I estimated survival rates on each site through intensive capture-mark-recapture experiments. There was differential survival among sites, but no negative correlation between survival estimates and trematode prevalence. / Graduate / 0718 / 0329 / 0472 / mayala@uvic.ca trematode Barkley Sound dispersal mark-recapture snail behaviour snail parasites survival foraging Littorina sitkana prevalence WinBUGS
14	Population ecology of the littoral fringe gastropod Littorina planaxis in Northern California Schmitt, Russell James 01 January 1974 (has links) (PDF) Life history patterns of individual organisms are the result of natural selection and should be correlated with particular physical and biological characteristics of habitats in which they live. The littoral fringe is known to be the most severe physical habitat in the intertidal zone, and it is expected that organisms in it should have population characteristics associated with selective response to physical adversity rather than biological interaction. Ecological studies of populations of Littorina planaxis were made in the Dillon Beach and Bodega Head areas. The study localities differed principally in extent of wave exposure rather than geographical location. Gastropoda California Bodega Bay Marine ecology Littorina Biology Life Sciences Marine Biology
15	Ocean acidification effects on marine organisms : a study of Littorina littorea and Balanus improvisus Domeij Hilliges, Isak, Stendahl, Cecilia January 2011 (has links) The world’s oceans are becoming more acid in a process called ocean acidification. The pH of the ocean have already decreased by 0.1 units from pre-industrial time until today. Scientists predict that by the year of 2100 the pH will decrease by as much as 0.4 units. This is a big potential problem to many marine species, because they have developed in such a stable environment that has not changed for millions of years. It is difficult to predict how they might be affected by such a decrease in pH during a relatively short time period. Several studies have been made on marine species exposed to decreased pH-levels, the results showed changes in their physiology but it is hard to predict how these changes will affect the organism in a long-term scale and if this might change ecosystem dynamics. Our study measured the activity of Littorina littorea and Balanus improvisus when exposed to lower pH, the results of our study showed an increase in activity for the lower pH (pH 6.0-7.5) when compared to the control (~pH8). The area of ocean acidification is a field that requires further studies to fully understand its effects on the marine ecosystems and the species within it. ocean accidification accidification pH sea marine organism marine littorina littorea balanus improvisus periwinkle barnacle CO2 acid ecosystem activity cirral movement calcium carbonate system buffering low pH havsförsurning försurning pH hav marina organismer marin littorina littorea balanus improvisus havstulpan strandsnäcka CO2 surt ekosystem aktivitet cirrala rörelser buffrande lågt pH

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