Aquatic Plants as a Factor That Changes Trophic Relations and the Structure of Zooplankton and Microperiphytone Communities

Resumo

The development of bacteria, phytoplankton, zooplankton, and microperiphytic organisms in artificial ecosystems, such as microcosms with aquatic plants, depressing algae (water soldier Stratiotes aloides L.), and plants not possessing a significant impact on them (arrowhead Sagittaria sagittifolia L.), was evaluated. It was shown that the zooplankton biomass did not decrease among water soldiers, despite the fact that the concentration of phytoplankton pigments was 2–3 times lower. The number of euplanktonic Cladocera has not declined, and the number of littoral and phytophilic Cladocera increased, but the number of Diaptomidae was lower. It is assumed that a large zooplankton biomass was produced by the use of bacteria and protozoa as an additional power supply to the algae. The share of zooplanktonic species consuming bacteria increased in microcosms with arrowhead. The number of predators increased and trophic relations between zooplankton and microperiphyton became closer in experimental systems with the plants of both species.