Дисертації з теми "Algal Grazers"
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Cervin, Gunnar. "Interactions between grazers and algal canopies, an experimental approach /." Göteborg (Ecologie marine) : Göteborg university, 2002. http://catalogue.bnf.fr/ark:/12148/cb39929291f.
Повний текст джерелаMadikiza, Liwalam Onwabile. "The role of grazers and basal sustrate cover in the control of intertidal algal distribution." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&.
Повний текст джерелаRosser, S. M. Jane Horner. "Phytoplankton ecology in the upper Swan River estuary, Western Australia: with special reference to nitrogen uptake and microheterotroph grazing." Thesis, Curtin University, 2004. http://hdl.handle.net/20.500.11937/1562.
Повний текст джерелаRosser, S. M. Jane Horner. "Phytoplankton ecology in the upper Swan River estuary, Western Australia: with special reference to nitrogen uptake and microheterotroph grazing." Curtin University of Technology, Department of Environmental Biology, 2004. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=16266.
Повний текст джерелаSpecific uptake rates (v), normalised to chlorophyll a, for NO;, NH4+ and urea were 0.2 ± 0.04 - 1831.1 ± 779.19, 0.5 ± 0.26 - 1731.6 ± 346.67 and 3.0 ± 0.60 - 2241.2 ± 252.56 ng N μg Chla-1 respectively. Urea concentration (14.8 - 117.7 μg urea-N 1-1) remained relatively constant over the 12 month study period. Measured ambient specific uptake rates for urea represent between 27.5% and 40.4% of total N uptake over the annual period February 1998 -January 1999. Seasonal nitrate uptake over the same period constituted only 11.3% (±10.77%, n=12) to 24.4% (± 13.02%, n=12) with the highest percentage during winter, when nitrate levels are elevated. It is suggested that urea provides a nutrient intermediary over the spring - summer period during transition from autotrophic to heterotrophic dominated communities. Grazing ,and nitrogen recycling are intricately connected by simultaneously providing top-down biomass control and bottom-up nutrient supply. Zooplankton (> 44 μm) grazing has been shown to reduce up to 40% of phytoplankton standing stock at times. Microheterotrophs (<300 pm) can reduce phytoplankton biomass production by up to 100% (potential production grazed, 11.1% day' - 99.6 % day-1) over an annual cycle. This correlated to mean seasonal day-time grazing loss of 80.47 ± 3.5 ngN μg Chla-1 in surface waters and 20.17 ± 9.7 ngN μg Chla-1 at depth (4.5m). Night time grazing for surface and bottom depths resulted in similar nitrogen loss rates (13.03 ± 4.84 ngN μg Chla-1).
Uptake rates for nitrate (r2 0.501) and urea (r2 0.512), doing with temperature (r2 0.605) were shown to have the greatest influence on phytoplankton distribution over depth and time. This research emphasises the need for more detailed investigations into the physiology of nutrient uptake and the effects of nutrient fluxes on phytoplankton biomass and distribution. Further research into the roles of organic nitrogen and pico and nanoplankton in this system is recommended.
Collins, Scott Andrew. "Bottom-Up Controls (Micronutrients and N and P Species) Better Predict Cyanobacterial Abundances in Harmful Algal Blooms Than Top-Down Controls (Grazers)." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8584.
Повний текст джерелаMarsham, Sara. "The application of a functional group approach to algal-grazer interactions." Thesis, University of Hull, 2007. http://hydra.hull.ac.uk/resources/hull:16058.
Повний текст джерелаMcKenny, Claire. "The Diversity of macroinvertebrate grazers in streams relationships with the productivity and composition of benthic algae /." Click here to access, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060308.131239.
Повний текст джерелаWhittington-Jones, Kevin John. "Ecological interactions on a rocky shore : the control of macroalgal distribution by intertidal grazers." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005350.
Повний текст джерелаMcKenny, Claire, and n/a. "The Diversity of Macroinvertebrate Grazers in Streams: Relationships With the Productivity and Composition of Benthic Algae." Griffith University. Australian School of Environmental Studies, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060308.131239.
Повний текст джерелаMcKenny, Claire. "The Diversity of Macroinvertebrate Grazers in Streams: Relationships With the Productivity and Composition of Benthic Algae." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/368092.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Full Text
Basic, Dunja. "Grazer control on benthic algae in the Berg River, Western Cape, South Africa." Bachelor's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/26088.
Повний текст джерелаSchneck, Fabiana. "Efeitos da rugosidade de substratos, distúrbios físicos e organismos pastejadores na estruturação de assembleias de algas bênticas e na biomassa perifítica em um riacho subtropical : uma abordagem experimental." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/49267.
Повний текст джерелаThe studies presented in this thesis aimed at understanding some aspects of the organization of benthic algal assemblages in streams. Specifically, the studies evaluated the effect of habitat heterogeneity on the scale of substrate roughness and its interaction with hydrological disturbances and grazing organisms. An experimental in situ approach was used, in which the treatments were constituted by smooth and rough (with crevices) substrates. The experiments were conducted in the Marco River, a fourth-order stream at the region of Campos de Cima da Serra, São José dos Ausentes, Rio Grande do Sul, Brazil. After a general introduction on the subjects of this thesis, the chapters with the studies are presented. The Chapter 1 describes a study to evaluate the effects of substrate roughness on species richness, density, composition and distribution patterns of benthic algal assemblages. Algal assemblages on rough substrates were richer than on smooth substrates, but this result differed among algal life forms. Similarly, results on species composition also differed among life forms, indicating that only some groups were benefited by the occurrence of refuges on rough substrates. It was also observed that differences in the composition of assemblages between rough and smooth substrates resulted from nestedness and turnover. The Chapter 2 describes a study in which was tested the hypothesis that rough substrates harbor more persistent assemblages than smooth substrates. The results confirmed this hypothesis and were attributed to the effect of roughness per se after the exclusion of some confounding factors, such as the physical stability of substrates and differences in species richness. It was concluded that the most plausible mechanism that could explain the higher persistence in rough substrates is the greater availability of refuges in relation to smooth substrates. The main aim of the study described in Chapter 3 was to evaluate the effect of substrate roughness on algal assemblages in the face of an experimental hydrological disturbance. Specifically, it was tested if the resistance and resilience of algae is higher on rough than on smooth substrates and if algal life forms differ in their response to disturbance. The results indicated that substrate roughness had no pronounced effects on benthic algal resistance and resilience. However, algal life forms differ in their resistance and resilience, and the observed pattern was mostly related to biological traits that confer abilities to support disturbances. The results of this study, in addition to the results obtained in Chapters 1 and 2, allowed us to suggest that the importance of habitat heterogeneity and refuges is mediated by the intensity of disturbances. The Chapter 4 describes a study that evaluated the independent and interacting effects of substrate roughness, grazing fish and mesohabitats (pools and riffles) on algal biomass, organic matter and total dry mass accrual. The effect of grazers was not mediated by mesohabitats, and their exclusion caused an increase in the three response variables, regardless of mesohabitat. On the other hand, mesohabitats and substrates interacted to determine the accrual of total dry mass, since rough substrates accumulated greater amounts of dry mass in pools than in riffles, while smooth substrates accumulated similar amounts in both mesohabitats. Algal biomass and organic matter showed greater accrual on rough than on smooth substrates, independently of mesohabitat. These results indicate that the loss of grazers may affect the accrual of algal biomass and organic matter, which are important food resources in streams. Finally, in the last section are presented the concluding remarks.
Liess, Antonia. "Nutrient Stoichiometry in Benthic Food Webs – Interactions Between Algae, Herbivores and Fish." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6933.
Повний текст джерелаMosisch, Thorsten. "The Effects of Biological and Physical Disturbance on Rainforest Stream Algal Communities." Thesis, Griffith University, 1995. http://hdl.handle.net/10072/366305.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Graduate School of Environmental Science and Engineering
Science, Environment, Engineering and Technology
Full Text
Kahlert, Maria. "Biomass and Nutrient Status of Benthic Algae in Lakes." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5097-0/.
Повний текст джерелаKim, Dohong. "Seasonality of marine algae and grazers of an Antarctic rocky intertidal, with emphasis on the role of the limpet Nacella concinna Strebel (Gastropoda: Patellidae) /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2001. http://www.gbv.de/dms/bs/toc/331661446.pdf.
Повний текст джерелаLiteraturverz. S. 94 - 108.
Wacker, Alexander, and Eric von Elert. "Polyunsaturated fatty acids : evidence for non-substitutable biochemical resources in Daphnia galeata." Universität Potsdam, 2001. http://opus.kobv.de/ubp/volltexte/2008/1758/.
Повний текст джерелаPerrier, Fanny. "Nanocontamination d'organismes aquatiques par des particules inorganiques : transfert trophique et impacts toxiques." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0959/document.
Повний текст джерелаDue to an increasing and massive use, engineered nanoparticles are raising as potentialemerging contaminants in the environment, including aquatic ecosystems. While trophictransfer appears to constitute a major exposure route for organisms, scientific literature hasdifficulties to respond to the questions raised to explore the range of the interactions existingbetween nanoparticles and living organisms at different scales from the trophic interactionsto the cellular impacts. This problem is partly due to experimental difficulties inherent tothis exposure type. For this work performed in controlled laboratory conditions, sphericalgold nanoparticles (10 nm, coated with PEG-amines, positively charged) were chosen tostudy the trophic transfer and toxic effects on aquatic organisms. Trophic chains concernedseveral trophic levels (up to three) with a variety of species considered : the basis of thetrophic web with natural biofilms or microalgae, intermediate levels with grazing fish orsuspensivorous bivalves, and up to top food chain organisms, with the European eel, a carnivorousfish.With relatively low doses for exposures, this work tends to represent environmentalconditions. Integrative methodological approaches from subcellular to tissue levels(RT-qPCR, RNA-sequencing, histology) were performed in order to assess toxic impacts.The results indicate a high retention capacity of nanoparticles by natural biofilms. Followinga 21-day exposure, gold quantifications reveal a transfer from biofilms to grazing fish, witha gold distribution in all organs. Moreover, this transfer is associated with an inflammatoryresponse according to the histological lesions observed in the liver, spleen and muscle ofexposed fish. A longer food chain, with three trophic levels involving microalgae - bivalves- European eels, is set up to give a better representation of the complexity of trophic interactionsin the aquatic environment. It shows a significant transfer to the predatory fish.Transcriptomic analyses, using the RNA-sequencing approach, for the liver and the brain ofexposed eels by nanoparticles’ enriched food, highlight a joint response for these two organsin the biological processes associated with the immune system and its regulation, includingNOD-like receptors involved in inflammasome.All the experimental results suggest long-term harmful effects that nanoparticles would generatein aquatic ecosystems, emphasizing the ability of these contaminants to be transferredthroughout trophic chains
Campbell, Jena Renee. "The role of protozoan grazers in harmful algal bloom dynamics : tools for community and grazing analyses." 2012. http://hdl.handle.net/2152/19574.
Повний текст джерелаtext
Abitha, R. "Algiculture - A Novel Algae Cultivation Technique for Sustinable Algal Biofuel Production and Capture of Green House Gases." Thesis, 2016. http://etd.iisc.ac.in/handle/2005/4070.
Повний текст джерелаCruz, Joana Maria dos Reis Franco. "Induction of anti-herbivore defences by direct amphipod consumption and water borne grazer cues in macroalgae." Master's thesis, 2007. http://hdl.handle.net/10400.1/266.
Повний текст джерелаSerrão, Ester
Herbivores have been repeatedly shown to induce defences in terrestrial plants, but few examples exist from marine macroalgae. In two bio-assayed laboratory experiments we tested the effects of (1) direct amphipod consumption, (2) water borne cues from nearby grazed conspecifics, and (3) water-borne cues from non grazing consumers on the induction of anti-herbivore defences in macroalgae of the southern coast of Portugal. Both the brown alga Fucus vesiculosus and the red alga Sphaerococcus coronopifolius displayed distinct defence regulation. They induced defences when consumers were present and reduced defences again when consumption ceased. A reduction in palatability was considered to be indicative of an alga’s defence mechanism. Defence regulation reacted to consumption stimuli in less than two weeks. For F. vesiculosus we found the defence activity in the lipophilic fraction of the alga’s chemistry. Both algal species induce defences after receiving water-borne signals from nearby grazed conspecifics as well as non-grazing amphipods. These results imply that species of red and brown algae can recognise a suite of cues indicating herbivore pressure, allowing them to adjust their defensive traits in finely tuned short-term responses. Inducible defences may be more common in macroalgae than suspected.
Marunnamkattil, Ramachandrannair Ratheesh. "Effects of nutrient limitation, competitors and grazers on the abundance and toxicity of laboratory cultures of P. parvum, a harmful alga." 2008. http://hdl.handle.net/10106/914.
Повний текст джерела