Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 773 for “"Trophic"”.
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The effect of copper stress on inter-trophic relationships in a model tri-trophic food chain.
… (Triticum aestivum) using pot experiments. A tri-trophic food chain soil → plant → herbivore → predator was established as plants were infested with grain aphids (Sitobion avenae) which were subsequently fed to predatory ladybirds (Adalia bipunctata). Multiple measurements were conducted which …
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Landsat Trophic State Assessment of Fellows Lake
… LANDSAT remote sensing techniques for monitoring trophic state at Fellows Lake is examined. Data is obtained for ten individual scene days (thrity sample sites) covering a two year period. Models are derived for trophic state prediction based on trophic state indexes computed for chlorophyll a …
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Trophic Dynamic Interactions in a Temperate Karst River
… DIC availability in larger watersheds? 2. Are trophic niche breadths narrower in more karstified reaches than in less karstified reaches due to longitudinal differences in Cladophora standing stocks? 3. Do differences in trophic-dynamic relationships between primary consumers and their food …
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Predicting Multi-trophic Consequences of an Emerging Disease
… indirect consequences for organisms in multiple trophic levels. Devastation due to alien insect herbivores poses the greatest threat to native insect larvae that specialize on the impacted host species. The loss of pollinators whose larvae feed on impacted species and provide services for native …
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TROPHIC DYNAMICS OF THE LAKE SUPERIOR FISH COMMUNITY
… introduction of several nonnative species. The trophic linkages and ecological requirements of the entire fish community, including predators and prey fishes, has not been assessed on a whole-lake scale in over a decade. Here, I investigated the trophic dynamics across multiple regions of the …
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An Ecosystem Model with Evolutionary Adaptive Trophic Structure
… deeper understanding of the factors determining trophic structure. The individual-based approach permits the inclusion of traits to model heritable attributes. Population-level models imple- ment a mean-�eld approximation that led to the competitive exclustion principle. The addition of a trait …
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Trophic Level Changes and Alewife Predation on Conesus Lake
… has gone through a series of changes within its trophic levels. Walleye have been declining in numbers since the early 1970's. The introduction of an obligate planktivore, the alewife, in the late 1970's resulted in a rapidly expanding planktivore population and poorer water quality. Attempts at …
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Productivity and Trophic Interactions in the Missouri River Impoundments
… Oahe are poorly understood. In addition to the trophic interactions of walleye and gizzard shad, similarities/differences between foraging patterns of walleye and sauger Sander canadenses, two similar species found throughout the Missouri River impoundments, were examined. Sauger is of …
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Mesenchymal stem cells as trophic mediators of neural differentiation
… behaviour of other cell types via the release of trophic factors and cytokines was examined, with particular emphasis on the nervous system. An in vitro conditioned media model was developed in order to investigate the influence(s) of MSC-derived soluble factors/cytokines on neural development and …
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Organic Matter Dynamics and Trophic Structure in Karst Groundwater
… should be important energy sources to higher trophic levels in the aquifer. The ecosystem expansion and contraction model, originally developed to describe surface streams, may be a good descriptor of spatial and temporal patterns of microbial films in karst aquifers. The process of leaf and …
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Trophic and Competitive Interactions among Egg Parasitoids of Stink Bugs
The intra- and inter-trophic interactions in ecosystems can be disrupted by invasive species, with lasting effects on population dynamics of native organisms. An invasive species may be attractive as a prey or host to native species, but if unsuitable for consumption or for development of the …
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The Trophic Ecology of Psammechinus miliaris in Scottish Sea Lochs
Understanding the trophic relationships between organisms is crucial to understanding ecosystem functioning and as such regular echinoids have been termed keystone through the action of their grazing. Much research has focused on this group’s action as herbivores, but as a group omnivory is common. …
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Predation Vulnerability and Trophic Interactions of Pallid Sturgeon Scaphirhynchus albus
… fish, such as the pallid sturgeon, understanding trophic interactions will assist in implementing a successful recovery plan. Predation can play an important role in the recruitment dynamics of fishes with intensity regulated by behavioral (i.e., prey selectivity) and/or environmental conditions. …
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Selenium uptake, trophic transfer, and toxicity in boreal lake ecosystems
… 23,495 L/kg dm in the 0.12 µg/L treatment, and trophic transfer factors (TTFs) for benthic macroinvertebrates ranged from 0.49 for Gammaridae to 2.3 for Chironomidae. Selenium accumulated in fathead minnow ovaries to concentrations near or above the current British Columbia Ministry of the …
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An Examination of Trophic State Indices For Some Missouri Reservoirs
A variety of possible trophic state indicators is critically examined for applicability to nine Missouri reservoirs. Data presented are representative of collections made during the summer of 1978. Relationships between several physical, chemical, and biological properties are considered and the …
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Trophic State Monitoring Of Lakes And Reservoirs Using Remote Sensing
… there is increasing concern that anthropogenic eutrophication threatens the usability of these natural resources. Therefore, this research investigates these complex hydrologic ecosystems and recommends a methodology for monitoring the trophic state of lakes and reservoirs using remote sensing …
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Trophic role of small cetaceans and seals in Irish waters
… for the Irish Sea, based on data from 2004. Five trophic levels were found, with bottlenose dolphins and grey and harbour seals occurring at the highest trophic level. A comparison with a previous model based on 1973 data suggests that while the overall Irish Sea ecosystem appears to be …
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Smart marine sensing systems for integrated multi-trophic aquaculture (IMTA)
… One solution is to use an Integrated Multi-Trophic Aquaculture (IMTA) approach, where a variety of different species are grown in the same site, taking advantage of by-products (such as waste and uneaten food) from one species as inputs (fertilizer, food, and energy) for the growth of other …
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Some aspects of trophic relations of gizzard shad, Dorosoma cepedianum
Foods, feeding, voidance, and bioenergetics of gizzard shad were investigated. Ten of the 17 most frequently occurring plankters in Smith Mountain Reservoir were utilized as food: the bulk of the diet consisted of Glenodinium, Dinobryon, and copepod nauplii. The feeding behavior of shad was …
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