Increasingly, stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR) using δ(15)N, and carbon range (CR) using δ(13)C, which are us...

The aim of this study is to assess the eutrophication and trophic status based on different indices and also reference threshold values in the Iranian coastal waters of the southern Caspian Sea (ICWSCS). The water samples (three replicates) were collected along four transects (off the coast from Anzali, Tonekabon, Nowshahr and Amirabad) between spring 2013 and winter 2014. The results show mark...

Trophic structure of the pelagic ecosystems of the western and central pacific ocean

phytoplankton communities play a significant role in the oceanic biological pump by forming the base of the trophic structure. increase in nutrients loading affects spatial and temporal distribution of phytoplankton. this study examined the phytoplankton community structure and ecological indices in relation to nutrients dynamics in both estuarine and oceanic areas of ramisi-vanga systems alon...

It is well recognized that assemblage structure of stream macroinvertebrates changes with alterations in catchment or local land use. Our objective was to understand how the trophic ecology of benthic macroinvertebrate assemblages responds to land use changes in tropical streams. We used the isotope methodology to assess how energy flow and trophic relations among macroinvertebrates were affect...

The flow of energy and nutrients between trophic levels is affected by both the trophic structure of food webs and the diversity of species within trophic levels. However, the combined effects of trophic structure and diversity on trophic transfer remain largely unknown. Here we ask whether changes in consumer diversity have the same effect as changes in resource diversity on rates of resource ...

www.frontiersinecology.org W know that predators play a vital role in maintaining the structure and stability of communities and that their removal can have a variety of cascading, indirect effects (Terborgh et al. 2001; Duffy 2003; Figure 1). But how important is predator richness? Are the numbers of predator genotypes, species, and functional groups ecologically important properties of predat...

Trophic interactions play a critical role in the structure and function of ecosystems. Given the widespread loss of biodiversity due to anthropogenic activities, understanding how trophic interactions respond to natural gradients (e.g., abiotic conditions, species richness) through large-scale comparisons can provide a broader understanding of their importance in changing ecosystems and support...

Lakes are important habitats for biogeochemical cycling of carbon. The organization and structure of aquatic communities influences the biogeochemical interactions between lakes and the atmosphere. Understanding how trophic structure regulates ecosystem functions and influences greenhouse gas efflux from lakes is critical to understanding global carbon cycling and climate change. With a whole-l...