Cascading Effects on Microbial Food Web Structure in a Dense Macrophyte Bed

Abstract

Heterotrophic microorganisms play a major role in the carbon and energy flow and nutrient recycling of aquatic systems. Planktonic bacteria are regulated by the supply of organic and inorganic nutrients and by predation of bacterivorous organisms. Most studies on controlling mechanisms of bacterioplankton have focused on assessing the direct effects of these factors. However, more recent studies have revealed that microbial and classic food webs have an array of interdependencies and are linked in many different ways (Turner and Roff, 1993). Therefore, the structure of the whole planktonic community must be considered for a better understanding of population dynamics at the microbial level (Pace et al., 1990).