The δ(15)N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ...

Hatchery-reared fish are commonly stocked into freshwaters to enhance recreational angling. As these fishes are often of high trophic position and attain relatively large sizes, they potentially interact with functionally similar resident fishes and modify food-web structure. Hatchery-reared barbel Barbus barbus are frequently stocked to enhance riverine cyprinid fish communities in Europe; the...

Ecological restoration projects have traditionally focused on vegetation as both a means (seeding, planting, and substrate amendments) and ends (success based upon primary productivity and vegetation diversity). This vegetation-centric approach to ecological restoration stems from an historic emphasis on esthetics and cost but provides a limitedmeasure of total ecosystem functioning and overloo...

PURPOSE To characterize trophic factor secretion of cultured adult and fetal retinal pigment epithelial (RPE) cells and to assess the impact on porcine retinal survival in vitro. METHODS Conditioned media (CM) were collected from cultured adult and fetal RPE cells and analyzed for trophic factor composition and concentration by multiplex ELISA. Trophic factor receptor occupancy was calculated...

The Northern California Current (NCC) is a seasonally productive and open ecosystem. It is home to both a diverse endemic community and to seasonally transient species. Productivity and food web structure vary seasonally, interannually, and decadally due to variability in coastal upwelling, climate-scale physical processes, and the migratory species entering the system. The composition of the p...

Stable isotope analysis has been used extensively to establish trophic relationships in many ecosystems. Present study utilised stable isotope signatures of carbon and nitrogen to identify trophic structure of aquatic food web in river and rice field ecosystems in Perak, northern peninsular Malaysia. The mean δ13C values of all producers ranged from -35.29 ± 0.21 to -26.00 ± 0.050‰. The greates...

1. Parasites permeate trophic webs with their often complex life cycles, but few studies have included parasitism in food web analyses. Here we provide a highly resolved food web from the pelagic zone of a subarctic lake and explore how the incorporation of parasites alters the topology of the web. 2. Parasites used hosts at all trophic levels and increased both food-chain lengths and the total...

Although recent work has reemphasized the general importance of ontogeny in evolution, underlying developmental molecular mechanisms are largely undefined. What heritable ontogenetic mechanisms result in the evolution of new morphologies and functions? Such questions are particularly difficult in the nervous system, in which each of 10(11) neurons forms approximately equal to 10(4) specific int...

To examine trophic dynamics over different size classes, an isotopic study of sailfish Istiophorus platypterus life-history stages was carried out. Samples were collected from eastern Taiwan and the South China Sea during April 2009 and February 2012. A total of 263 samples (111-245 cm, lower jaw fork length, LLJFL ) were examined for changes in trophic structure in relation to LLJFL by using s...

Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecolog...