A decomposition experiment using eucalyptus leaves was carried out in a Southeastern Brazilian mountain stream located at the transition between the Cerrado and the Atlantic Forest to test whether nutrient addition increases microbial and invertebrate colonisation and accelerates breakdown rates. The results show that none of the tested variables was significantly affected by nutrient addition,...

Many mutualistic microbial relationships are based on nutrient cross-feeding. Traditionally, cross-feeding is viewed as being unidirectional, from the producer to the recipient. This is likely true when a producer's waste, such as a fermentation product, has value only for a recipient. However, in some cases the cross-fed nutrient holds value for both the producer and the recipient. In such cas...

Organisms are composed of multiple chemical elements such as carbon, nitrogen, and phosphorus. The scarcity of any of these elements can severely restrict organismal and population growth. However, many trophic interaction models only consider carbon limitation via energy flow. In this paper, we construct an algal growth model with the explicit incorporation of light and nutrient availability t...

Our previous experiments have shown that a certain physical radiation restricts the quantity of cells (infusoria) in developing culture “from above”. Given report describes the series of experiments which enabled to determine the nature of this phenomenon. Occurred that this radiation belongs to UV spectral region with the wave range (200-290) nm. Defined has been influence of concentration of ...

A three-trophic-level model of plankton dynamics with instantaneous nutrient recycling is considered. The model consists of autotrophic phytoplankton, herbivorous zooplankton, carnivorous zooplankton and dissolved limiting nutrient. Conditions are derived such that one or more components of the populations tend to extinction. Persistence criteria for the model are also obtained. As well, the bi...

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...