Productivity, trophic structure, and energy flow in the steady-state ecosystems of Silver Springs, Florida W.M. Kemp a,∗, W.R. Boynton b a Horn Point Laboratory, Center for Environmental Science, University of Maryland System, Box 775, Cambridge, MD 21613, USA b Chesapeake Biological Laboratory, Center for Environmental Science, University of Maryland System, 1 Williams Street, Solomons, MD 206...

This contribution examines various flow measures based on analysis of 41 quantified models of trophic interactions in aquatic ecosystems. System productivity/biomass ratio is shown to relate to ecosystem maturity and to the degree of cycling in the systems. Distinct patterns or clusters are observed for different types of resource systems with respect to average path lengths and residence times...

Ecologists have hypothesized that the exponent of species-area power functions (z value) should increase with trophic level. The main explanation for this pattern has been that specialist predators require prior colonization of a patch by their prey, resulting in a compounding of the effects of area up trophic levels. We propose two novel explanations, neither of which assumes trophic coupling ...

Data on nutrient concentrations and environmental parameters, recorded in the waters of the entire Venice lagoon (165 sites) in July 2003 and in two stations monthly sampled for two years (from April 1994 to March 1995 and from January to December 2005), are reported in order to compare the trophic conditions with the past situation. In summer 2003 the dissolved inorganic nitrogen varied betwee...

23 24 Understanding how marine ecosystems are structured and how they function is a 25 scientific challenge. Nowadays, to learn about ecosystem trophic dynamics ecologists use 26 two complementary methodological approximations, mass-balance ecosystem models and 27 isotopic tools. However, despite the wide applications of these methodologies, the 28 comparison and combination of both are still s...

Species experience landscapes differently depending on their needs and behaviors, and on their trophic level. We expect species at high trophic levels in a community to be more sensitive to habitat fragmentation than species at lower trophic levels. But this depends on attributes such as resource breadth, dispersiveness, reproductive rate, and longevity, which may not be related to trophic leve...

In a food web, nutrients flow via trophic links. For this reason, trophic interactions have a fundamental character due to the principle of mass conservation. To further comply with this principle, we consider a food web model that includes nutrient cycling. Non-trophic effects amongst species of the food web are modelled as interaction modifications, i.e., a functional change in the trophic in...

We consider trophic networks, a kind of networks used in ecology to represent feeding interactions (what-eats-what) in an ecosystem. We observe that trophic networks can be naturally modelled as Petri nets and this suggests the possibility of exploiting Petri nets for the analysis and simulation of trophic networks. Some preliminary steps in this directions and some ideas for future development...

in order to increase the knowledge of saurida tumbil biology and ecology, an investigation of food habits of this species was conducted from october 2010 to september 2011 in bushehr coastal waters, persian gulf. 485 fish stomach contents were studied. in this study the frequency of occurrence of prey, feeding intensity index, the index is empty stomachs, the mean trophic levels and the rate of...