Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecili...

Competition is a ubiquitous structuring force across systems, but different fields emphasize the role of different types of competition. In benthic marine environments, where some of the classic examples of competition were described, there is a strong emphasis on interference competition: marine invertebrates are assumed to compete fiercely for the limiting resource of space. Much of our under...

There is increasing interest in the potential impacts that fishing activities have on megafaunal benthic invertebrates occurring in continental shelf and slope ecosystems. We examined how the structure, size, and high-density aggregations of invertebrates provided structural relief for fishes in continental shelf and slope ecosystems off southern California. We made 112 dives in a submersible a...

Nematomorph parasites manipulate crickets to enter streams where the parasites reproduce. These manipulated crickets become a substantial food subsidy for stream fishes. We used a field experiment to investigate how this subsidy affects the stream community and ecosystem function. When crickets were available, predatory fish ate fewer benthic invertebrates. The resulting release of the benthic ...

The purpose of this experiment was to find an environmentally safe herbicide using a representative chemical Acacia Gum Arabic Solution (from the Acacia sengal tree) to serve as the environmentally safe chemical to use against a representative invasive plant species (Pueraria lobata(Kudzu)). Pueraria lobata seeds were placed into a petri dish and were grown on filter paper soaked with either a ...

Benthic macroinvertebrates constitute the link between organic matter input in streams and fishes. However, the possibility of influence of predators on the invertebrates is still a controversial issue. The possibility of alteration of the benthic community by the modification in predation in a stream in the South of Brazil was studied by means of an exclusion experiment under semi-natural cond...

1.1 This guide covers procedures for measuring the bioac,cumulation of sediment-associatid contaminants by infaunal .invertebrates. Marine, estuarine, and freshwater sediments are a major sink for chemicals that sorb preferentially to particles, 'such as organic compounds with high octanol-waterpartitioning coefficients (KO,) (for example, polychlorinated ,biphenyls (PCBs) and dichlorodiphenylt...

The benthic communities of the deep insular shelf at the Hind Bank marine conservation district (MCD), an important spawning aggregation site for groupers, were studied with the Seabed autonomous underwater vehicle (AUV) at depths between 32 and 54m. Four digital phototransects provided data on benthic species composition and abundance of the insular shelf off St. Thomas, US Virgin Islands. Wit...