نتایج جستجو برای: food web

تعداد نتایج: 481898  

Journal: :Environmental Pollution 2021

Biomagnification of mercury (Hg) in the Scotia Sea food web Southern Ocean was examined using stable isotope ratios nitrogen (?15N) and carbon (?13C) as proxies for trophic level feeding habitat, respectively. Total Hg isotopes were measured samples particulate organic matter (POM), zooplankton, squid, myctophid fish, notothenioid fish seabird tissues collected two years (austral summers 2007/0...

2017
Michael J McCann Kenneth W Able Robert R Christian F Joel Fodrie Olaf P Jensen Jessica J Johnson Paola C López-Duarte Charles W Martin Jill A Olin Michael J Polito Brian J Roberts Shelby L Ziegler

Identifying key taxa in the response of ecosystems to perturbations relies on quantifying both their sensitivity to stressors and their importance in the overall web of interactions. If sensitive taxa occupy key network positions, then they may decrease the capacity of ecosystems to resist perturbations. Despite widespread concern for coastal marshes after the 2010 Deepwater Horizon oil spill i...

2013
Raid Kamel Naji

In this paper, the dynamics of a three species food web model consisting of producers, primary consumers and omnivory is studied analytically as well as numeri-cally. The existence of equilibrium points and local stability analysis for this model is carried out together with a bifurcation analysis. The occurrence of hopf bifurcation is also investigated. The persistence conditions of the food w...

2015
JENNY W. OAKLEY JAMES SIMONS GREGORY W. STUNZ

Understanding spatial dynamics and creating spatial boundaries of marine food webs is an important topic that resource managers are beginning to understand. Food web structure, mediated by spatial and habitat differences, was examined in a subtropical estuary using stomach content and stable isotope analyses. The goal of this studywas to characterize the trophic structure in subtidal oyster ree...

Journal: :The American naturalist 1998
G R Huxel K McCann

In nature, fluxes across habitats often bring both nutrient and energetic resources into areas of low productivity from areas of higher productivity. These inputs can alter consumption rates of consumer and predator species in the recipient food webs, thereby influencing food web stability. Starting from a well-studied tritrophic food chain model, we investigated the impact of allochthonous inp...

Background and Objectives: The COVID-19 pandemic and consequent lockdown has multifaceted effects on people’s life including fall in economy which may affect food choices. This study was designed to evaluate changes in dietary intakes of the Iranian households during COVID-19 lockdown and also to predict the consequent health impacts. Materials and Methods: This cross-sectional descriptive-ana...

Journal: :The Journal of animal ecology 2009
Per-Arne Amundsen Kevin D Lafferty Rune Knudsen Raul Primicerio Anders Klemetsen Armand M Kuris

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...

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