نتایج جستجو برای: nutrient resource
تعداد نتایج: 278576 فیلتر نتایج به سال:
Rapid chemotactic response enables marine bacteria to exploit ephemeral microscale nutrient patches.
Because ocean water is typically resource-poor, bacteria may gain significant growth advantages if they can exploit the ephemeral nutrient patches originating from numerous, small sources. Although this interaction has been proposed to enhance biogeochemical transformation rates in the ocean, it remains questionable whether bacteria are able to efficiently use patches before physical mechanisms...
Aquatic microorganisms are typically identified as either oligotrophic or copiotrophic, representing trophic strategies adapted to low or high nutrient concentrations, respectively. Here, we sought to take steps towards identifying these and additional adaptations to nutrient availability with a quantitative analysis of microbial resource use in mixed communities. We incubated an estuarine micr...
In an effort to identify the causes and patterns of temporal change in periphytic communities, we examined biomass accumulation, taxonomic and functional composition, rate of species turnover, and pairwise species correlations in response to variability in current velocity and nutrient supply in artificial stream flumes. Divergent patterns in community growth and succession were observed betwee...
A number of studies show that predators can depress prey growth rates by inducing reductions in foraging activity, but the size of this non-lethal effect is quite variable. Here I investigate how prey density and resource productivity may alter the extent to which predators depress the growth rates of their prey. Theory predicts that when resources are overgrazed, an increase in predation risk ...
The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutr...
Although aquatic bacteria are assumed to be nutrient-rich, they out-compete other foodweb osmotrophs for nitrogen (N) and phosphorus (P) an apparent contradiction to resource ratio theory. This paradox could be resolved if aquatic bacteria were demonstrated to be nutrient-poor relative other portions of the planktonic food web. In a survey of >120 lakes in the upper Midwest of the USA, the nutr...
Annual variations in biogeochemical and physical processes can lead to nutrient variability and seasonal patterns in phytoplankton productivity and assemblage structure. In many coastal systems river inflow and water exchange with the ocean varies seasonally, and alternating periods can arise where the nutrient most limiting to phytoplankton growth switches. Transitions between these alternatin...
Resource-ratio theory is one of the major logical frameworks used in ecology to predict how competition for growth-limiting resources influences biological diversity and function within a biological community. This paper presents experimental and other evidence that resourceratio theory can also be applied to nutrient supplementation in hydrocarbon biodegradation. The theory makes two major pre...
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