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Showing 1 to 20 of 50 for “"trophic position"”.
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Estimating Trophic Position of Lake Oahe Walleye Using Stable Isotope Analysis
… used stable isotope analysis to estimate walleye trophic position and then compared these values to trophic position estimates from diet content analysis for fish sampled from May 2001 to May 2002. Trophic position estimates generated by isotopes were not correlated to those estimated from diet …
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Biodiversity, distribution patterns and trophic position of meiobenthos associated with reduced environments at continental margins
… was characterised in terms of taxonomic composition, distribution patterns on different spatial scales, habitat preferences, vertical distribution within sediments, phylogeny, presence of symbionts, and nutritional sources.
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Mercury Concentrations in Fish from the Guadalupe River, Texas: Relationships with Body Length and Trophic Position
… the concentration of Hg in muscle tissue from 41 trophically diverse species (n = 1,772) in relation to body length and trophic position at five sites on the Guadalupe River in South Central Texas using a direct mercury analyzer and stable isotope analysis (δ13C, δ15N). The majority of fishes …
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Ecology of the marsh rice rat (Oryzomys palustris) in southern Illinois: wetland dynamics, metapopulations, and trophic position
… could change food webs and consequently the trophic diversity of the communities occupying these areas. My first objective was to assess the spatial and temporal variation in occupancy and turnover rates of a semi-aquatic small mammal at 2 hydrologically distinct wetland complexes over 3 …
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Spatial Variation in Basal Resources and Trophic Position of Selected Fishes of the North-Central Gulf of Mexico
… isotope value, estimate basal resource usage and trophic position of target species from Mississippi Sound, reef, and pelagic environments, and identify differences and similarities in spatial patterns of collection. Muscle tissue samples were collected from October 2014 through September 2015. …
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Stable carbon and nitrogen isotope ratios in the shallow-water cape hake, merluccius capensis (castelnau) as indicators of trophic position and diet on the west and south coasts of South Africa
13C/12C and 15N/14N were used to indicate the trophic levels of the shallow-water Cape hake, Merluccius capensis (Castelnau) at three sites on the west coast of South Africa, and five sites on the south coast. Gut content analyses show only the very recent diet of hake, therefore stable carbon and …
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Habitat, distribution, and diet of the Tennessee Bottlebrush Crayfish (Barbicambarus simmonsi)
… of the second part of my study were to determine trophic position and diet of B. simmonsi and B. cornutus using stable isotope analysis and gut content analysis, and determine if there was correlation between carapace length and trophic position for each species. Crayfish for the analysis were …
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Resident fish community impacts on stocked rainbow trout ecology in 15 eastern Washington lakes
… and lake habitat on energy source use and trophic position of stocked rainbow trout. Stable isotope analysis was used to accomplish this goal, with stable carbon isotope ratios indicating the source of carbon, pelagic or littoral, in each species' diet and stable nitrogen isotope ratios …
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Diet and trophic relationships of fishes from the nearshore of the Bay of Quinte and Kingston Basin, Lake Ontario
… spatial and seasonal variation in diet and trophic position of fishes within large lakes. Two areas of north-eastern Lake Ontario - the Bay of Quinte and the Kingston Basin – provide contrasts in temperature, nutrients and depth while supporting similar littoral fish communities and …
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TROPHIC ECOLOGY OF JUVENILE LEAN AND SISCOWET LAKE TROUT (SALVELINUS NAMAYCHUSH) FROM U.S. WATERS OF LAKE SUPERIOR
… were observed in waters from 40-60m. Trophic position (as measured by δ 15N) was similar for both ecotypes at small sizes (mm), but Siscowet exhibited a higher trophic position than Lean Lake Trout at larger sizes (>400mm) and older ages (>5 years). Base of production (as measured by δ …
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Examining the feeding ecology of two mesopelagic fishes (Lampanyctodes hectoris & Maurolicus walvisensis) off the west coast of South Africa using stable isotope and stomach content analyses
… species is unclear. This study examined the trophic ecology of the two principal mesopelagic fishes off the west coast of South Africa (lanternfish Lampanyctodes hectoris and lightfish Maurolicus walvisensis) sampled during the spring 2014 and autumn 2015 cruises, using stable isotope and …
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Investigating population structure and resource use diversity in Lake Huron Lake (Coregonus clupeaformis) and Round (Prosopium cylindraceum) Whitefish using compound specific stable isotopes analysis
… that reflect differences in prey, habitat, and trophic position within food webs making these isotopes valuable in differentiating ecological populations. Bulk stable isotope analysis (BSIA) has been used in previous research but interpretation is often confounded by various factors that …
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Determining the Trophic Role of Red Snapper (Lutjanus campechanus) in Mississippi State Waters Using Stomach Content and Stable Isotope Analysis
… goal of this study was to determine the diet composition, trophic position and ecological role of red snapper <em>(Lutjanus campechanus</em>) in Mississippi state waters utilizing stable isotopes (δ<sup>13</sup>C and δ<sup>15</sup>N) and stomach content analysis. Stable isotope analysis of fish …
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Spatial, temporal and within-species variation in the foraging ecology of a marine predator across a dynamic seascape
… among consumers add to the complexities of trophic structure and its processes across all biomes on Earth. In this dissertation, I investigated the foraging ecology and plasticity of an ice-adapted marine predator, the ringed seal (Pusa hispida), inhabiting the Arctic marine environment – a …
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Community composition, migration and trophic positions of micronekton in two biogeochemical provinces of the South West Indian Ocean
… province, copepods were chosen as baseline in trophic level estimations. Feeding regime and size were shown to influence the trophic position of micronekon. In the ISSG, carnivores (fishes and squids) and omnivores (crustaceans) had higher δ 15 N values and trophic positions than filter feeder …
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Elements and stable isotopes as tracers for sleeper shark biology and the Iceland marine food web
… Iceland was more clearly resolved concerning trophic links and carbon sources by combining mercury data with stable isotope and stomach content data. Mercury also indicated that 'Lycodes' potentially belonged to a different food web than the other fishes. Results from this research …
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Stable isotope ecology of South African kelp forests
… diverse ecological communities. The species composition of these communities has been shown to be spatially variable along the South African coast, controlled by abiotic processes and species interactions. Despite their importance in the southern Benguela Current Large Marine Ecosystem (BCLME), …
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Influence of riparian forest and agricultural land use on community structure and ecosystem function in headwater streams
… quality. Ordinations based on fish community composition revealed significant differences among all three land use groups due to differences in trophic structure. In addition, the fish assemblage matrix was significantly correlated to environmental patterns that clustered streams into each land …
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Stable Carbon and Nitrogen Isotopes of Shell Bound organic Matter, Implications for Modern and Ancient Food Web Dynamics
… than one stable isotope, and their isotopic compositions (δ15N and δ13C) vary in a foreseeable way and are specifically useful in studying global elemental cycles and energy flow through ecosystems. δ15N and δ13C of organic matter (OM) are diagnostic of an organism's diet and have been used as a …
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Plankton dynamics of the open Southern Ocean and surrounding the (Sub)Antarctic islands
… matter (SPM) and phytoplankton community composition, with diatoms exerting a particularly strong influence on the δ13C and δ15N of the SPM, which is subsequently transferred to the zooplankton. Secondly, I observed that the (Sub)Antarctic islands tend to increase the δ13C and δ 15N of …
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