These impacts of fisheries have led, in the late 1990s, to a growing interest in "ecosystembased management" (see e.g. NRC, 1999). Moreover, though the full implications of such form of management continue to remain elusive, there is a growing understanding that ecosystembased management must consider and maintain the structuring role of large predators in marine food webs. The demonstration by...

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...

We tested whether standing autotrophic (unicellular algal) biomass is sensitive to variation in initial consumer (nondecomposer, heterotrophic protistan) diversity in experimental microbial microcosms. Our results showed a strong, negative relationship between autotrophic biomass and consumer species richness. Additional microcosm experiments showed that this relationship was due largely to the...

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...

Understanding the impact of climate change on zooplankton populations is of major importance, as they represent the basis for higher trophic levels in the marine food web. In this study we analyze the 36-year copepod abundance time series in the Gulf of Trieste, northern Adriatic, to investigate its interannual variability, with particular attention to species trends and phenology. Following th...